The Original CZ Forum
GENERAL => Ammunition, questions, and handloading techniques => Topic started by: charlielikesczs on January 19, 2020, 06:40:47 PM
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https://imgur.com/ZhCld3K
(https://i.imgur.com/P4N108i.jpg?1)
First off no one was hurt. Other than a gun and my pride. I humbly and shamefully ask the experts, what did I do wrong? I assume a double charge. I have reloaded maybe 10k rounds total between 9mm/45acp/.38/.223. But I,by no means, consider myself an expert.
The load data for these was:
45ACP
5.2 gr(or 10.4?) of winchester 231
mixed range brass
Hornady 200 gr xtp
O.A.L- i dont remember the exact length but i did set them in sig 1911 chamber until the base of the cartridge was flush with the
barrel hood?
Dillon 550B progressive
My first two mags shot well. Then, on the 3 magazine, the first round cycled normally, then a big bang. Not sure where the casing that caused this went. I looked around briefly for it but quite frankly I was too busy counting fingers and checking my drawers to care much at the time.
I assume a double charge and that I lost concentration/focus while reloading this batch. I know I had been finding a few 45 casings with small primers slip through(which messes up the whole rythym). I am usually very diligent with looking into each casing before placing the bullet but as they say, "1 awe sh*t negates 1000 atta boys."
I know most of you folks are alot more experienced than me. But for those who are new to reloading something like this will shake you to your core and make one wonder about the value in reloading. I will probably have a significant flinch for some time when pulling the trigger and I may just have some reloading equipment up for sale. Probably not but I'm considering it.
So I'll ask again, what did i do wrong? What can be done to prevent this from happening in the future? Double charge for sure orwould anything else cause something like this?
Also concerning the pistol, Should I send it out to Sig for examination? The action appears to cycle smoothly/normally. Nothing is swollen/bulged/cracked that I can see other than the grip panels. But I do worry about the chamber integrity.
Be safe. Please do be extra cautious when reloading and wear those safety glasses without fail! Because you never know.
My hope is someone other than myself can learn something from this.
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Not offering any insight, just commenting to follow along and say that I like your attitude. Happy you're okay and still have all your OEM body parts!
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Wow. Thanks for posting this, it helps to share both the good and the bad.
I don't know how it happened, or what exactly happened . . I don't use a progressive, but isn't it harder to double charge when using them?
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What my untrained eye focused on was the two cartridges in the lower part of the picture. I'm wondering if the projectiles set back and caused over pressurization? Perhaps someone else could chime in on this.
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It's really easy to miss primers or dump powder twice using a professive if you get in a hurry or distracted or don't have a routine. However, with the powder I use for 9mm, it's always obvious when I double charge because the projectile essentially will not seat.
I haven't loaded with 231, so idk how much room there would be in the case for a bullet to seat with a double charge.
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What my untrained eye focused on was the two cartridges in the lower part of the picture. I'm wondering if the projectiles set back and caused over pressurization? Perhaps someone else could chime in on this.
The projectiles set back in the casings were the top two in the mag. I'm sure this happened as a result of the "big bang". They were not like that when i loaded the magazine
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First, the 550 is not a true progressive, it is a manual advance press. Second, you can triple charge a 45 case at 5.2 231, it will be right to the rim but it will fit. I am going with a double charge. One thing I learned early on with my 550 was if you have to stop just empty the press of all cases as it is easy to charge the case have a problem with priming and by the time you have that worked out it just natural to prime the case and keep on going. Glad you were not hurt, lucky the 45 is a low pressure round.
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2BFREE, Great advice on clearing the shellplate if there is a snag or an issue! Now I realize that the pennies i was trying to save are just not worth it. Can anyone recommend any powder that is not as "dense" as W231? Just asking because it would be nice to have some powder that would overflow the cartridge if another inadvertant double charge were to happen. I did not realize that you could fit 3 charges in one casing.
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I'm not suggesting anything, just asking, but would barrel/chamber damage be expected from a double charge? is it possible that it fired out-of-battery, causing the magazine and grips to blow out?
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I'm not suggesting anything, just asking, but would barrel/chamber damage be expected from a double charge? is it possible that it fired out-of-battery, causing the magazine and grips to blow out?
Great question. Not sure either. But this was my first go around with reloading hollow points. Up to this point, everything else I loaded and shot through this particular gun was round nose
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How did you determine the OAL for your loads?
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Not suggesting any specific powder but one of the deciding factors for which powder i am going to use is having a nearly full obvious visual with the powder I select. Example would be Unique for 9mm overflows with double charge. Probably not a "best" powder nowadays but works fine and i bought a lot way back when. Used in 32, 380, 9mm, 45, light 44mag.
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How did you determine the OAL for your loads?
I use the barrel/chamber plunk? test. Its difficult to explain. I basically drop a bullet and casing in the chamber(with the barrel removed) and set the OAL so that the casing is flush with the "barrel hood/lug?-the longest part of the barrel on top". For the first few, i start too long and when its flush, i set my seating die there
Forgive my ignorance, but this is the method i have been using. Like I said, I am no expert.
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How did you determine the OAL for your loads?
I use the barrel/chamber plunk? test. Its difficult to explain. I basically drop a bullet and casing in the chamber(with the barrel removed) and set the OAL so that the casing is flush with the "barrel hood/lug?-the longest part of the barrel on top". For the first few, i start too long and when its flush, i set my seating die there
Forgive my ignorance, but this is the method i have been using. Like I said, I am no expert.
That's the correct method, but you didn't mention any allowance for OAL deviation. Typically we subtract ~.010-.015" from the plunk test result to allow for rounds that might vary.
I think Rock-it3 might be on to something with his wondering if you had an OOB incident.
If you have any of these rounds left that weren't in the magazine when the incident occurred, I'd be checking the length.
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Thanks Painter. I was definately not subtracting .010-.015. I do have about 100 or so more rounds from that batch and I will definitely [check] the length on all of them
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How did you determine the OAL for your loads?
I use the barrel/chamber plunk? test. Its difficult to explain. I basically drop a bullet and casing in the chamber(with the barrel removed) and set the OAL so that the casing is flush with the "barrel hood/lug?-the longest part of the barrel on top". For the first few, i start too long and when its flush, i set my seating die there
Forgive my ignorance, but this is the method i have been using. Like I said, I am no expert.
Charlie,
Your OAL method is slightly flawed. You want the case to headspace on the mouth. Essentially you want the case to be free of the lands of the barrel rifling. If you are just looking at the barrel hood to verify if it is flush you may still be loading too long (read into the lands).
If you want to verify your max OAL with the plunk test you need to make sure the case will spin when in the chamber.
Process:
Take a sized and unflared case and seat a bullet too long. Incrementally seat it deeper and deeper (0.005 increments) until the cartridge when dropped into a loose barrel falls under it's own weight into the chamber and makes a plunk sound. Then verify it isn't into the lands by lightly pressing with your thumb on the case head and verify it will spin freely. Then invert the barrel and ensure it falls out under it's own weight. If it passes all these tests that is your maximum OAL. Then you would subtract 0.015-0.020 to determine your usable OAL for loading that bullet in that barrel.
Given your top two rounds set back considerably, I would check your bullet retention. Take a seated bullet or finished cartridge and measure the OAL. Then press the bullet end of the cartridge into your bench (or other hard surface) and verify it didn't set back any (remeasure the OAL). If it did, then you need to look at your sizing process/die. I push hard enough to dent my workbench (soft pine 2x6).
If your willing to seat and crimp with the same die, you can install a RCBS lockout die that will lock up your press when an under/over charge occurs. I run it on my Lock n load but I have 5 positions for dies... The RCBS die isn't sensitive enough to prevent minor shifts in powder charge but will let you know about doubles. You should still visually verify powder in the case before placing the bullet. More info here: https://ultimatereloader.com/2010/09/19/rcbs-lock-out-die-part-i-theory-of-operation/
Glad you still have all your digits!
Good Luck,
Toby
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Good catch, Toby.
OP...check your loads in the chamber for the ability to spin when fully inserted
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How did you determine the OAL for your loads?
I use the barrel/chamber plunk? test. Its difficult to explain. I basically drop a bullet and casing in the chamber(with the barrel removed) and set the OAL so that the casing is flush with the "barrel hood/lug?-the longest part of the barrel on top". For the first few, i start too long and when its flush, i set my seating die there.
Forgive my ignorance, but this is the method i have been using. Like I said, I am no expert.
First of all, very glad you're OK. I don't see one glaring issue here. I see several possible small errors that could have simply aligned and then erupted.
• First of all, can we please verify the caliber ? I don't see the caliber mentioned anywhere. 200gr is used in several 1911 cartridges. Everyone has assumed 45ACP ??
• Primarily, as per Tdogg's comments, your reloading process is not refined nearly enough. It needs to be re-thought to provide room for physical variations to exist, and needs to provide more safety checks. As per Tdogg, your method of finding your Max OAL is (to put it lightly) awful. OAL has nothing to do with the barrel hood, and everything to do with head spacing.
[We can help you improve your process, but obviously you need to learn more and move on from whatever source taught you this very poor method.]
• I don't see W231 as an issue. The lesson I probably would draw from that portion of the tale is that... You are not looking into the cartridge case before seating the bullet. And maybe this is because you simply cannot see in there. I highly suggest a lighting system from KMS Squared Click Here (http://kmssquared.com/ufo550.html)
• If you are needing to stop to fiddle with primer size in the middle of reloading, then your basic brass sorting process is not very refined. Large/Small primers is now a way of life with 45ACP. And because it is, you need to focus on it, or change to a caliber that doesn't have this complexity.
• Finally, allow me to introduce my own reconstructed scenario that might go a long way towards a total explanation. This is only how I see this unfortunate event unfolding, and may/ or may not have any relevance....
You usually load 200 or 230gr RN for this gun. You were trying Hornady XTP for the first time. Your very basic process does not allow for changes in OAL driven by the bullet, and so you use the same OAL you've always used. The SIG chamber is a tighter-design. Chamber clearances were already nil-to-none with the RN, now with the XTP they are non-existent. That is to say, the XTP bullets are jammed into the rifling which raises chamber pressure. One might even be long enough to allow a firing in OOB condition, as per Mr Painter.
And I think that's what happened. The new-to-you bullet starts a sequence of events that's simply waiting on one round to be just 0.010" longer than the rest to cause real havoc.
Have your gun checked by a local gunsmith, but I believe you'll find it's OK. At the most, you'll probably only need some new grips and maybe a magazine.
All the best. ;)
PS. The process we use for finding Max OAL is here.... https://czfirearms.us/index.php?topic=103620.0 And in that document, the first 3 figures give a lot of background information as to WHY these steps are necessary. Bottom line, we're not going to "give you a fish", but rather give you the knowledge to become a "fisherman". Big difference.
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Out of curiosity... What did the mag look like?
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The magazine looks fine. And it is .45 ACP. Thanks to all for taking the time to share some knowledge.
You all make excellent suggestions and I will definitely “refine” some things throughout the entire process.
Charlie
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O.A.L- i don't remember the exact length but i did set them in SIG 1911 chamber until the base of the cartridge was flush with the barrel hood?
Forgive me, but reading between the lines of your post.... Of all the positive steps you could take TODAY, this may be the biggest of any of them... It's more important than OAL, more important than powders, more important than bullet selection....
You MUST get a 59 cent school notebook and start taking notes on your loads. That's the biggest step you can take, as far as your personal safety. It is impossible for anyone to remember after 5 days, all the detailed dimensions involved in building a cartridge. If you don't know where you started, then how can you possibly re-trace your steps when corrections are called for ?
A reasonable system I can highly recommend is to get a basic school "lab notebook" or other type of 8.5 x11 fixed page binder. Hopefully one notebook for each caliber. Then, since each bullet is going to have its own discrete loading dimensions, allow one whole page per bullet.
(https://i.imgur.com/LW0ay9M.jpg)
Typical page from one of my reloading notebooks. Bullet name at top. Bullet physical dimensions.
The OAL to use with this bullet. Load information. The loads and results, some with chrono data.
So at the top of the page record all the bullet dimensions. Then find the Max OAL and record that. Then decide upon what OAL you'll use for reloading that one bullet. Write all that down. Under all that you can record load data, powders you've used, impressions, accuracy, velocities, dates, etc. In that way if you like ithe load, you can return to it. And if something goes wrong, then you have a basis for research.
This "tractability" is supposed to be part of every reloader's standard process.
Hope this helps.
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Just IMHO...
I've seen similar incidents where the grips break and the gas comes down through the magwell usually blowing the mag out. In these incidents they were either case head separations or firing out of battery. Too bad you don't have the fired case to inspect. Also, with either of those scenarios a standard powder charge would be sufficient to blow the grips off. Do not want to discourage review of your reloading process, which everyone should do now and then, but it may not have been a "double charge" after all.
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I agree with Unamower
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Thanks for sharing, glad it wasn't worse.
Missed index = double charge on the 550. That's why a lot of 550 owners will just pull all cases if they have to stop. Harder to do with the 650, but still possible. The other reasons sound more likely though.
A couple things that have helped me: I took the notebook idea and use excel spreadsheet. After working up a load with a new bullet/new COAL as wobbly described, write the coal on the outside of a non primed, non powder case with a sharpie and keep it as a reference bullet. For lighting, I used a 20 ga shell in the center hole, that holds a small led flashlight. When I REALLY want close inspection, hook the 12$ ebay boresnake up to my computer/monitor. When determining COAL, do it with a sample of 5 bullets and take the avg, as no bullet is perfect, they are all like snowflakes.
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Missed index = double charge on the 550. That's why a lot of 550 owners will just pull all cases if they have to stop.
I'm sorry. Don't mean to start another bunny trail topic, but I'm not exactly following this statement.
The 550 is a progressive. As such it usually has a cartridge case in each of 4 shell plate stations. If the operator misses the shell plate advance, then there are still 4 cartridge cases in the shell plate. And the state of each one of them indicates where the machine is in the loading cycle.
I don't want to ding anyone's safety procedures, but of all the 550 owners I know, none take this extreme measure.
;)
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If you miss the advance double charge, right, that's basically what I've heard is possible. Its been years since I've been around one, but the auto advance feature of the 650 helps, but doesn't eliminate it.
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For the record, I measured all the remaining bullets from the suspect batch and the longest OAL was 1.200" with most closer to 1.197. Not sure if that seems out of wack or not with anything you folks are ending up with on OAL.
I dont have the gun right now so i can't perform a proper plunk/push/spin test.(Its at the gunsmith getting looked at) but I will do this when I get the gun back if the barrel checks out good.
I've gone through all my remaining .45 brass. All with small pistol primer pockets are in the trash.
I started a logbook when I began reloading but I found a few loads that I really liked so I got complacent. Not anymore. I will do a paper log on EVERY bullet and a spreadsheet as a backup.
If my process gets interrupted for any reason, I will clear the shellplate. and finish the rounds one a a time. As well as buy a better LED light.
You gentlemen were spot on with the "new to me round" and my failure to allow .010-.015 for variation in bullet size.
I was 100% positive that this was my fault before I decided to put this out there. I was 0% sure of what exactly I did or was doing wrong. I posted this here because you folks are a treasure chest of experience/knowledge and I wanted to learn from my mistakes.
THANK YOU- to each and every one of you for taking your time and sharing your wisdom.
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Yup, excellent knowledge here!
FWIW trade the small primer brass. I do that. Only I want the small so I trade for them.
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For the record, I measured all the remaining bullets from the suspect batch and the longest OAL was 1.200" with most closer to 1.197". Not sure if that seems out of wack or not with anything you folks are ending up with on OAL.
The Max OAL comes from the way the bullet and case interface with the barrel. Any tester needs all 3 components to make the comparison.... which eliminates most of us who lack a SIG barrel.
I don't have the gun right now so i can't perform a proper plunk/push/spin test. It's at the gunsmith getting looked at, but I will do this when I get the gun back if the barrel checks out good.
I came here particularly to suggest this very action, so good thinking on your part. Even if the barrel is damaged, you'll still be able to do the static Max OAL testing. You simply won't be able to test fire it afterwards.
I've gone through all my remaining 45 brass. All with small pistol primer pockets are in the trash.
Lots of people prefer the SPP for use in 45ACP. I'd suggest you get them back, and post them on Brass Bucket where you can swap them 1:1 with someone in the opposite position. This is a FREE service (it's the CraigsList of brass) and is run by one of your fellow members here at the Orig CZ Forum. http://brassbucket.net/
I started a logbook when I began reloading, but I found a few loads that I really liked, so I got complacent. Not anymore. I will do a paper log on EVERY bullet and a spreadsheet as a backup.
You'll see. Very small differences between brands of bullets... even though they look identical at first glance, can make a huge difference.
If my process gets interrupted for any reason, I will clear the shellplate. and finish the rounds one a a time. As well as buy a better LED light.
1. Start keeping a reloading notebook again
2. With each new bullet start a new notebook page
3. Do the "push test" and working with the bullet and barrel, accurately determine your Max OAL
4. Then determine what your OAL will be for whenever you load that cartridge with that bullet (doesn't have to be Max OAL !!)
5. Pre-sort your brass
6. Schedule reloading time to be at an off-peak, low stress time
You gentlemen were spot on with the "new to me round" and my failure to allow .010-.015 for variation in bullet size.
I was 100% positive that this was my fault before I decided to put this out there. I was 0% sure of what exactly I did or was doing wrong. I posted this here because you folks are a treasure chest of experience/knowledge and I wanted to learn from my mistakes.
THANK YOU- to each and every one of you for taking your time and sharing your wisdom.
It's very encouraging to see that your quest for safety, continued education, and process improvement, out-weigh your pride. Not many guys would have posted those photos, and even more would said something like... "A friend has this problem...". ;D So you get all the credit on this one.
Speaking personally for myself, I only know what I know from falling flat on my face so dang often !
Anyway, in the interim we clean and sort brass, and find a couple of pieces we can use for the telescoping push test.
;)
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Brass Bucket is closed to new posters at this time, but I can add you as a user if you want to sell brass. Same goes for anyone here. I had it open to post without verification, but spam quickly changed that.
Since a lot of people shoot 9 and 45, more are opting for SPP 45 so they don't have to change components/setup. 1 for 1 trade is great deal. If I shot more 45 I'd sell all LPP and make the switch too.
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Wow. Thanks for posting this, it helps to share both the good and the bad.
I don't know how it happened, or what exactly happened . . I don't use a progressive, but isn't it harder to double charge when using them?
exactly the opposite. I had a double charge when I was running a batch of brass that was not resizing/decapping and I think I pushed the handle back up after clearing a stuck primer but before it reindexed. I had the exact results as the OP but I had CZC Aluminum grips so they did not split. I would not worry about the integrity of the chamber. THe overcharge blew out the grips and probably the bottom of the mag long before the pressure built high enough to damage the chamber.
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Wow. Thanks for posting this, it helps to share both the good and the bad.
I don't know how it happened, or what exactly happened . . I don't use a progressive, but isn't it harder to double charge when using them?
exactly the opposite. I had a double charge when I was running a batch of brass that was not resizing/decapping and I think I pushed the handle back up after clearing a stuck primer but before it reindexed. I had the exact results as the OP but I had CZC Aluminum grips so they did not split. I would not worry about the integrity of the chamber. THe overcharge blew out the grips and probably the bottom of the mag long before the pressure built high enough to damage the chamber.
Proper reloading steps/techniques need to be employed to avoid mistakes like this. We do it all the time and the OP is correct to be looking for advice on what he did wrong and how to remedy that. The OP is lucky the chamber held up but a good inspection is in order anyway. Anyone who has had this happen and come away uninjured and with a gun not destroyed should say a thankful prayer because often that is not the case.
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I keep my logbook, maybe differently than some.
I enter data/record for every batch I reload.
I may have several entries per page.
Caliber, date, bullet used (brand, weight, style/type), powder used (brand, charge weight), primer used (brand/type) and case (brand). For new loads I also measure/list the cartridge overall length. I use a Lee brand loader with the turret so I don't have to change dies or adjust them/lock them down every time I change dies. I use it like a single stage press.
I repeat all the above data for that batch on a small piece of paper/cardboard (I cut used/empty primer covers into four sections) and put it in the box or can or jug/container the loaded ammo goes into.
I come back from the range and write (different color pen) in the data section for that batch, anything I notice about shooting ammo from that batch.
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I have an excel worksheet detailing all important info on every single round and batch of ammo I reloaded. In the same token, I also have an excel worksheet for each gun I own with the date, rounds fired, ammo/reload info and other related data. I know exactly how may and what type of ammo were bleep through each of my guns.
Here’s an example of my reloading worksheet:
DATE BULLET BRAND BULLET WT. Bullet Type POWDER POWDER WT. (Gr) PRIMER OAL (inches) AMOUNT CASE OTH
Jan 21, 2020 PD 124 Gr JHP SP 4.0 WPP 1.120-1.126 288. S & B
Jan 23, 2020 PD 124 Gr JHP SP 4.0 WPP 1.120-1.126 300 S & B
Excel work sheet for my sig MPX I use in USPSA.
DATE Number of Rounds Expended Brand/Type/Load Info. OTH
Jan 18, 2020 180 Handload 4.03 Gr Sport Pistol, 124 Gr JHP PD SAPSA Match, 3rd out of 52 overall, 1st of 7 PCC shooters.
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I have a similar spreadsheet. One poster on here I believe led me to it. One thing I do different is add a unique ## to every batch. that is, many times I run a few batches during the corse of a day, so they would all have the same date, but each will have an , -01 ,-02 ect.. to distinguish it.
George16: what kind of measure/drop are you using to get down to the tenths of a grain? How much variance do you have with the powder drop? I'm happy with +/- .1 grain using the D650 and same components.
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@newageroman, I average 10 drops to get those readings. I’m using a 1050 and the drop variance is +/-.1 Gr according to Dillon.
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@newageroman, I average 10 drops to get those readings.
Averaging is an age-old, tried and true method of adjusting the PM. At its heart is an admission that no PM is perfect. Therefore, there IS always going to be some form of variation present, no matter how small. If we set the PM based on a single drop, that one particular drop could have been higher or lower based on those variations. With a sample group of 1, we'll simply never know.
The process goes like this: You should never use the first 10+ powder drops from any PM, no matter what your process is. Then, by averaging 10 subsequent drops we actually get the PM setting closer to what we really want.
For example, say you're seeking powder drops of 4.1gr. If we find the total weight of 10 drops, then it should weigh 41.0gr. Basically, you've simply increased your sample group to 10. If it comes out at 40.3gr, then we know the setting needs to be increased because the average drop we're getting is closer to 4.0gr rather than 4.1gr.
I’m using a 1050 and the drop variance is +/-.1 Gr according to Dillon.
SDB, 550, 650, 750, 1050 all use the same Dillon powder measure mechanism. So the tips and tricks suggested for any, then work for all.
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@wobbly, I dump the first 10-15 drops from the powder measure before getting the average on the next 10 drops. I have found out that at least the first few drops have a lot of variance compared to the subsequent drops.
Oh yeah, I forgot that all the Dillon powder measures are the same. Thanks for the correction ;D 8).
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@George !!
I tweaked my previous post to be clearer and be more in line with what you've written. All good points, if you know your measure and you know it doesn't settle down until the 12th or 14th drop... especially when you're using XYZ powder... do what you know works for you.
;)
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No worries Wobbly 8).
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Thanks, the reason I'm asking is that I the bold number, which seems more of a benchrest powder drop accuracy...
Jan 18, 2020 180 Handload 4.03 Gr Sport Pistol, 124 Gr JHP PD SAPSA Match, 3rd out of 52 overall, 1st of 7 PCC shooters.
Basically, should that 4.03 be 4.3? If you really are able to measure out your charges to the 1/100 of a grain on pistol powder, I want to know how!
Whenever I touch the dial I throw at least 3, usually 5 drops and throw it back in the measure, then do 10 drops and avg those.
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Thanks, the reason I'm asking is that I the bold number, which seems more of a benchrest powder drop accuracy.
Jan 18, 2020 180 Handload 4.03 Gr Sport Pistol, 124 Gr JHP PD SAPSA Match, 3rd out of 52 overall, 1st of 7 PCC shooters.
Basically, Should that 4.03 be 4.3? If you really are able to measure out your charges to the 1/100 of a grain on pistol powder, I want to know how!
Not attempting to answer for anybody else, but one way to get that is via the 10 drop average- if you get 40.3 gr. for ten drops you would have 4.03 per drop (on average).
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Not attempting to answer for anybody else, but one way to get that is via the 10 drop average- if you get 40.3 gr. for ten drops you would have 4.03 per drop (on average).
Don't apologize. That's a great answer !
No one loads to hundredths of a grain for pistol. So, we would then need to round off back to the nearest tenth of a grain.
• Just as Duke said, 40.3gr for 10 drops averages out to 4.03gr (avg) per drop.... which we then round off to 4.0gr. In the example we were trying to achieve 4.1gr (avg) on all drops, so we need to increase the drop ever so slightly and weigh 10 more drops.
• Now, if the total of 10 drops came out to be 40.7gr, that would be 4.07gr (avg) per drop, which rounds off to 4.1gr and no more adjustment would be needed.
Yes, it would be the low side of 4.1gr, but most people would be hard pressed to make an adjustment so fine as to only add 0.03gr over 10 drops !! (You can't make an adjustment that adds 0.03gr in one drop. How would you increase each of 10 drops by 1/10th of that... 0.003gr ?? :-\ )
Yes, your answer is an average, but each of the individuals is still closer to 4.1gr than you can ever get with a single sample. Is it perfect ? No way ! But because the PM has drop-to-drop variations there is NWIH it's ever going to be perfect, aka "dead nuts on".
The only way to get closer is to use larger and larger sample groups. But 10 drops is easy math to do in your head, and gets done fairly fast. In professional QC production sampling the companies I worked for typically used a sample group of 30.
Is that clearer ?
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Ahh, that makes sense. All the best!
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Thanks, the reason I'm asking is that I the bold number, which seems more of a benchrest powder drop accuracy.
Jan 18, 2020 180 Handload 4.03 Gr Sport Pistol, 124 Gr JHP PD SAPSA Match, 3rd out of 52 overall, 1st of 7 PCC shooters.
Basically, Should that 4.03 be 4.3? If you really are able to measure out your charges to the 1/100 of a grain on pistol powder, I want to know how!
Not attempting to answer for anybody else, but one way to get that is via the 10 drop average- if you get 40.3 gr. for ten drops you would have 4.03 per drop (on average).
No apologies needed.
Winner, winner, chicken dinner ;D ;D. That’s how I arrive at that; by averaging 10 drops in which I got 40.3 Gr after 10 drops.