9mm C.O.A.L Question

RL-Photo · Jul 28, 2014

I just got some Missouri Bullet Co. 125 gr SWC lead bullets for my 9mm and am a little nervous about the Min. C.O.A.L listed for this load in my Lee manual. In the manual it says 1.125" and I loaded a few test rounds in that range all within +/-.001" of 1.125" I am shooting them out of a P938 (subcompact) and they seemed a little snappy. I had no signs of high pressure. I recently became aware of removing your barrel and dropping the round in and flipping it over to see if it is too long and these seem to "stick" and have much more of the case showing than factory rounds I tested. Most of the factory rounds I measured were around 1.100" at most. Any opinions on shortening them up a bit? I am loading them over 3.6-3.8 gr of IMR SR-7626 (listed max is 4.1) These are solely for paper and steel.

Va boy · Jul 28, 2014

In my manual, I see SR7625. The 1.125" is the cartridge minimum overall length, meaning don't go shorter. You can go longer. The manual shows a cartridge overall length of 1.169". I would stay between the two for sure and back away from the minimum at least a few thousandths. This way theres less risk of seating too deep

Jherexx · Jul 28, 2014

Per your manual 1.125 is the minimum I would go, if it was me I would load a little longer probably 1.130. As far as your rounds sticking in your barrel, are you running your rounds through a taper crimp die as the final step? Lead bullets are normally sized a thousandth or two thicker than jacketed and benefit from being run through a separate crimp die in the final stage, specially if loaded for semi-autos and most specially through Sigs which are known for tight chambers.

But since you have already tested your loads and show no pressure signs, they are probably fine. As far as your loads feeling snappy, remember you are running them through a sub-compact and not a full size pistol.

Khaot1c · Jul 30, 2014

Good rule of thumb is to shoot for a taper crimp that is .003 less than twice the case wall thickness and the bullet diameter. Gonna try some math in public here...

Crimp = Bullet diameter + (case wall * 2) - .003

9mm bullets are usually .355 but as Jherexx mentioned lead is usually a tad thicker so we'll say .356. Case walls are usually around .011 so with these numbers your crimp should measure .377 at the case mouth.

Va boy · Jul 31, 2014

They said there would be no math

Mr. Katanga · Jul 31, 2014

That min oal is probably for a round nose bullet, you mentioned that they are semi wad cutters so im assuming they have a flat nose and they would have less length. Also when shooting lead they will feel snappier even with relatively low powder charges compared with jacketed bullets, lead will go faster but if the pressure is good I wouldn't worry about it.

Please read the new forum rules! REQUIRED!

Click Here: https://www.gulfcoastgunforum.com/threads/general-forum-rules-code-of-conduct.70770/

9mm C.O.A.L Question

The #1 community for Gun Owners of the Gulf Coast States

Member Benefits:

RL-Photo

Expert

Va boy

Marksman

Jherexx

Expert

Khaot1c

Marksman

Va boy

Marksman

Mr. Katanga

Expert

Latest posts

Members online

Forum statistics

Share this page