Author Topic: Oal for 9mm  (Read 14600 times)

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Offline ezbobdad

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Oal for 9mm
« on: April 14, 2013, 11:10:36 PM »
So I have a question. I've been reloading and having a problem with the bullet fully going into the chamber. I was given some remmington ammo and took some mesurments off them and my oal was somewhere around 1.05 or 1.06.

So then I stole a single bullet from my father in laws stash the last time I shot with him. A Winchester white box kind. Oal on it was 1.16. So I worked up a batch today to test at 1.155. And they worked amazing.

I try to push test them all before I shoot them but I prob don't know what  I'm doing so they all seem to fit. I shoot a 75b. Is this a normal oal or should I try something else. Let me know genius's.
Allen

CZ 75B 9 Luger

Offline 1SOW

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Re: Oal for 9mm
« Reply #1 on: April 14, 2013, 11:38:55 PM »
Well, you missed the gen"iouses", but the BULLET itself is the driver for OAL
Just because a Remington bullet will run in your gun doesn't mean all similar bullets will at that oal.  A Berry's, WIN, ZERO, MG bullet bullet of the same "TYPE" may need a completely different OAL to run safely in your gun.

SEE the sticky for Wobbly's PUSH TEST and follow the instructions.  JMO:  This should be in your personal notes as STEP #1 before reloading any new bullet..
« Last Edit: April 15, 2013, 12:42:27 AM by 1SOW »

Offline Wobbly

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Re: Oal for 9mm
« Reply #2 on: April 14, 2013, 11:45:44 PM »
The learned 1SOW is correct. Different bullet makers use different formulas for the curve of the ogive. Therefore, each and every bullet will adapt to your chamber with its own distinct OAL. That also applies within brands. Just because a 115gr Remington does such and such, doesn't mean that the 124gr Remington will be remotely similar.

So the rule is this: the Max OAL is always set by the bullet-to-barrel interface.

Here's an extreme example....



Both bullets shown are advertized as "9mm 124gr RN" by major US manufacturers. The one on the left has a Max OAL in a CZ chamber of 1.000", while the one on the right has a Max OAL of 1.200".

 ;)
« Last Edit: April 14, 2013, 11:50:37 PM by Wobbly »
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Offline harkamus

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Re: Oal for 9mm
« Reply #3 on: April 15, 2013, 12:01:55 AM »
So I have a question. I've been reloading and having a problem with the bullet fully going into the chamber. I was given some remmington ammo and took some mesurments off them and my oal was somewhere around 1.05 or 1.06.

So then I stole a single bullet from my father in laws stash the last time I shot with him. A Winchester white box kind. Oal on it was 1.16. So I worked up a batch today to test at 1.155. And they worked amazing.

I try to push test them all before I shoot them but I prob don't know what  I'm doing so they all seem to fit. I shoot a 75b. Is this a normal oal or should I try something else. Let me know genius's.

1.05 or 1.16...holy bleep. If I loaded my Montana Gold JHPs to 1.05 or 1.16 that could be catastrophic. My over all length is 1.085 using Montana Gold JHP for my Accu-shadow. At 1.099 the bullet is dangerously close to engaging the rifling lands. At 1.100, the bullet engages the lands and makes the cartridge overlength, because it doesn't spin freely anymore. This is for my gun specifically. My point for this illustrative purpose is to show the importance of measuring per each gun individually.

Reloading is great and all, but please learn all you can before doing so. It can be the difference between safety and skirting danger (or worse).
« Last Edit: April 15, 2013, 12:11:27 AM by harkamus »

Offline Wobbly

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Re: Oal for 9mm
« Reply #4 on: April 15, 2013, 12:07:01 AM »
1.05 or 1.16...holy bleep.


You are such a potty mouth.
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Offline harkamus

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Re: Oal for 9mm
« Reply #5 on: April 15, 2013, 12:16:36 AM »
1.05 or 1.16...holy bleep.


You are such a potty mouth.
Found this online and had to post. All in good fun of course.



----------
Back on topic though, OP should learn what to measure for and how to measure. One does not simply enter Mordor...er reload.

Offline jameslovesjammie

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Re: Oal for 9mm
« Reply #6 on: April 15, 2013, 02:15:53 AM »
Found this online and had to post. All in good fun of course.


Where's the "Like" or Thumbs up button on the forum?!?

Offline Riptide439

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Re: Oal for 9mm
« Reply #7 on: April 15, 2013, 06:01:43 AM »
 O0 O0 O0 O0
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Offline ezbobdad

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Oal for 9mm
« Reply #8 on: April 16, 2013, 09:29:37 AM »
So of I did the test right. My max oal is 1.185. Soooo the 1.160 or the 1.155 should be fine. Right?
Allen

CZ 75B 9 Luger

Offline FireMoose

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Re: Oal for 9mm
« Reply #9 on: April 16, 2013, 03:43:04 PM »
Yes. Sammi Max is 1.169"

Sent from my CZ85 Combat


Offline harkamus

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Re: Oal for 9mm
« Reply #10 on: April 16, 2013, 03:53:35 PM »
So of I did the test right. My max oal is 1.185. Soooo the 1.160 or the 1.155 should be fine. Right?

That's not an assumption you should ever make. Reloads will vary based on a number of factors including gun (varies from gun to gun even if comparing the same model of gun), bullet (the projectile only, not the case), and bullet type. So you take a measurement of your reload and that number is okay for that reload with that bullet (again, just the projectile, not cartridge which is bullet + gunpowder + case + primer). Now you go compare to factory loaded ammo, and they are mutually exclusive. Basically for factory ammo, if you drop the cartridge in your barrel and it headspaces correctly without the projectile snagging on the rifling, then that's okay. But note, this will not be optimal length for your gun because factory ammo has to work on a broad range of guns. This is why reloaded ammo can be more accurate than factory ammo. Just because your reloaded ammo measures out to be a certain length doesn't mean that automatically all factory ammo that is the same length or shorter will work. Different projectiles have different shapes - ogive.

Now let's back track a sec. You measured 1.185. What measurement is this? Is this overlength? Overlength is when you do the push test with a fired casing and the projectile inserted into the barrel, and you push until the cartridge headspaces. This is the length that is "over" the length of what your ammo should be because the ogive is engaging the rifling. This is not the measure you should make ANY of your reloads. You subtract from .15 - .20 inch as a rule of thumb because you need a tad of jump space before the actual projectile hits the rifling.

Do you see now why you can't make a generalization that because your measurement is good (not that we know from what you said WHICH measurement this actually is - overlength of max length), it's automatically good for factory ammo?
« Last Edit: April 16, 2013, 04:05:13 PM by harkamus »

Offline painter

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Re: Oal for 9mm
« Reply #11 on: April 16, 2013, 04:48:52 PM »
So of I did the test right. My max oal is 1.185. Soooo the 1.160 or the 1.155 should be fine. Right?
If you did the test right then 1.16 or 1.155 is only safe for that bullet style from that manufacturer.

That would allow for a .015-.020 setback assuming the push test round fouled the rifling at 1.185.
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Offline Wobbly

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Re: Oal for 9mm
« Reply #12 on: April 16, 2013, 09:22:30 PM »
So of I did the test right. My max oal is 1.185. Soooo the 1.160 or the 1.155 should be fine. Right?

Not enough information to answer the question.


The heavier the bullet, the longer the bullet. A certain proportion of the bullet has to be gripped in the case mouth. So with a 90gr bullet you might only have .005" engagement at 1.160". With a 147gr bullet you might be good.

All we can say is that you will clear the rifling, and you will clear the mag. Both major hurdles, but not the only hurdles.

 ;)
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Offline 1SOW

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Re: Oal for 9mm
« Reply #13 on: April 16, 2013, 09:48:22 PM »
Some like to load as long as possible in THAT pistol with THAT bullet, but others like yours truly prefers to have ample seating depthe to secure the bullet and allow a good pressure build upon blast-off.  Hope this doesn't confuse the issue. O0

Offline ezbobdad

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Oal for 9mm
« Reply #14 on: April 16, 2013, 10:03:43 PM »
Confuse the issue?  Hahahahahaha. You guys are way too smart. Don't let anyone tell you different.

So the 1.185 was the max length.
The bullet head is berry's 124gr. Round nose. 9mm. And I'm shooting a 75b. And the shorter bullets don't always go into the chamber from the mag. She likes the longer bullets much better. I hope this helps clarify some things. So I can make some better bullets. 

And thanks for all the help.
Allen

CZ 75B 9 Luger