124gr lead RN questions

[ThompsonCustom]

Other than having that program, how would I calculate pressure from my rounds?

If I knew that I wouldn't have the 150 dollar program. With a chrono you can take the listed OAL, velocity, and pressure from your reloading manual and that will tell you where it is at. But if OAL or velocity changes so does pressure.

[Wobbly]

Other than having that program, how would I calculate pressure from my rounds?

There's only one way to know the chamber pressure, and that's to tap a hole into your chamber and hook a pressure transducer up. Not very easy or appealing task on an auto pistol. The software will help make an educated guess, but the only way to know is the transducer route.

But the chrono saves you all that trouble and equipment. Within the allowable load range, velocity and chamber pressure correlate nicely. However, this approach is still only an educated guess. So when you find load data for a bullet highly similar to the ones you use, you can relate the speed/pressure numbers given in that load data.

 

[1SOW]

With a chrono you can take the listed OAL, velocity, and pressure from your reloading manual and that will tell you where it is at. But if OAL or velocity changes so does pressure.

I know we're straying the original question, but this leads to an esoteric question by a curious member.
If container with a given amount of gas pressure inside is made 'half' the size, I believe pressure "doubles".    50 percent reduction in volume  = 100% increase in pressure.
IF SO:
There can be calcuted a given amount of volume below the bullet base when at the reloading manual OAL---lets say 1.142" OAL.   
GIVEN:  A  .748" Case has .580" of available empty space.  If following published OAL seats the bullet .200" into the case, _the case now has .560" of available space
GIVEN:  The measured pressure is included in the load data.---lets say 30,000 PSI.

GIVEN:   the bullet is seated .010" deeper into the case (1.140" oal), can the NEW Lower case volume's  increased "Pressure" be "Estimated" by reducing the height of the "cylinder"/"empty case space" and doing the math?  30K psi @ .560 cyl. height.  vs.  ??K @ .550" cyl. height                 

My geometry and physics were a lot of years back which may be obvious if the "givens" aren't roughly true.   (for discussion disregard the 'tapered' 9mm case )
If this approximates the new pressure generated, it would warn of OAL changes that would likely cause overpressures for those that don't have"Quickload".

Just idle time thoughts.

[levellinebrad]

some good info here guys. Thanks for the hookup on probable pressure. I think I have pretty well decided to load either the 115gr or 124 gr bullet. I know some of you guys are loading 124 and want your input on powder. I am loading for uspsa minor PF. I will of course be trying the wsf as that worked so well behind the 115 plated. Being a noob to reloading, I am still trying to understand the mechanics and physics behind it. Such as: heavy bullet- use fast powder... light bullet - use slow powder. Gotta keep it simple for me. I was a Marine so not real good with complicated answers. I do better with Duh broke! Duh Fix!. Not really but you get my drift. I actually followed 1SOW's potential math formula for calculating pressure. Anyway, back to the original question. What powder behind a lead 124gr bullet? So far I have HS-6, WST, and win 231. Problem being that I do not know what you are loading for. I need light recoil. I need to make around 1030 FPS. I will sacrifice pin point accuracy for faster follow ups. Thanks again for all the good info. It may take awhile to sink in. But it will eventually

[painter]

I'd use the 231.

[levellinebrad]

I have several other votes from other forums for the 231 behind a lead bullet. I'll have to see if my local high priced gun shop has it in stock. I think I am going to try loading a 125gr flat point. I always liked the swc in 45 and I would think that the flat point would be similar. Thanks.

[jabbermurph]

I would find the most accurate load, then respring to have the sights come back properly.  A few tenths of a grain more isn't going to be a noticeable difference in recoil during a match. 
   Accuracy is important, bigger matches will have longer/tighter shots.  I had a load for BBIs that had a spread of around 5" @ 20 yds.  I upped it .2 and it dropped it to about 3" @ 25 yds. 

At the hillbilly classic I tagged 2 poppers from 35 yds.  Gave me great confidence in the load.  The recoil change was a wash compared to the accuracy. 

Plus, faster bullet=faster slide return=faster follow up shots

[Wobbly]

? The general rule is this: The heavier the bullet, then the slower the powder. That's why you don't see 231 listed in any manual for 147grn bullets. What you do see is slightly slower powders such as Unique. Trying to start a heavy bullet with fast powder is like hitting a bowling ball with a baseball bat. Now that doesn't mean that specialty reloaders never use it like this; in fact it's done all the time. But you have to "work up" your load to find what's best and be very careful becasue the load "window" gets VERY narrow. So 'faster' powders demand great technique, a solid proceedure, and maybe even more accurate equipment.

? Secondly, fast powders and lead can be an issue unto themselves. Faster powders are hotter burning powders. So for someone worried about leading, sticking a blow torch under a lead bullet can give varying results. What works for one guy with jacketed or plated bullets may fail miserably for another guy with lead. Follow? You'll just have to see what works for you.

? 231 is a very good, general use pistol powder. You can never go wrong with Win 231 (also sold under the name Hodgdon HP-38), especially as a beginning reloader. The main reason being that 231 is about the perfect burn rate (aka "powder speed") to get you to 130 PF and still burn cleanly. It's also 'cool' enough to work extremely well with lead. 231 is considered "moderately fast" powder and works well in almost every pistol cartridge. So if you're buying powder for the first time, don't worry about being stuck with something that you won't use up. It's also a very conservative power, able to do with 4.3 grns what others may take 6+ grns to do. It also meters extremely well, so your loads are consistently accurate. You could do worse. And that is not to say that it's the one and only, becasue there are tens of acceptable substitutes. Some cost more, some are harder to find, some need those 6 grns charges.


Hope this helps!   

[levellinebrad]

I just bought some 231 so I will give it a try. I will also try the wsf and the clays. I guess I had it bass akwards on the powder vs weight.  Chrono should be here on Thursday so maybe I can start collecting accurate info on my loads.

[Riptide439]

brad,
How many test rounds are you planning to make for each load you test?

[levellinebrad]

I only make 10 of each different load.

[Riptide439]

Good.
W231 is a great powder to start with and well rounded. Works in 9mm as well as .45acp.
Work up to see which load your pistol prefers with each bullet selection. 
Always fun to see which combo is best! 

[levellinebrad]

Just to update my issue with not really liking the 147gr lead................ I think I know what part of the problem may have been. When I came downstairs tonight to determine my oal for the 125gr LTC, I realized that I had never done this with the 147gr. I was using an oal of 1.148. After doing the plunk test, I determined that my max oal for the 147gr was 1.122. What an idiot I am. I will have to go back and test the 147's again at a later date. On to the 125's. Max oal for that in my gun is 1.010.

[ThompsonCustom]

Jamming into the rifling huh, we've all been there.

Thought I'd help example loads vs recoil the little that I can. Powder=recoil is what it comes down to and the reason there is less recoil with a heavier bullet is there is less gas produce because of the decreased powder. Here's an example: With the lee 102gr bullet I put 6.0gr of unique behind it to hit powder factor which is over twice the amount of powder require to hit it with my 168gr SWC load and there is a big noticeable difference between these two loads, now if your changing from 3gr to 3.5 I'm not sure you would notice anything so there is no reason you can't have a low recoil round and still have great accuracy.

[levellinebrad]

Thanks.