COL question

[harleygsb]

I am loading 9mm .356 115 gr coated bullets, some from Brazos and some from Acme. I am using Win231. The Hodgdon website says to use 1.10 OAL for lead round nose. But the bullets are different lengths, so both seated to 1.10 would leave less room in the case and the longer bullet would create more pressure? At least that is my understanding.

I am thinking of loading the shorter with 1.10 and the longer closer to 1.15 to accommodate the longer bullet, but I want to make sure I have the concept correct.

I have loaded the Brazos to 1.10 and shot several hundred and they worked fine in both my 9mm guns. I am trying out the Acme bullets, which are a bit longer than the Brazos.

[anonymouscuban]

Yes. The less space or volume in the case, the more pressure and velocity. So the longer bullet will have less case volume and thus, more pressure at the same OAL. However, I wouldn't worry about as long as you're staying within the max charge weight. And an OAL of 1.10 is more than long enough especially with 115gr bullet.

More importantly, the OAL you use must chamber properly. The plunk test should dictate the max OAL. Will an OAL of 1.15 with that bullet profile even plunk and chamber in your gun?



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[harleygsb]

Thanks very much for the information. The longer reloads (close to 1.15) pass the plunk test on both my 9mm guns.

[duc748bip]

i'm in the same situation.
Handbook data say 115GR RN COL at 1.10", but a factory round I have is 1.15"
?

[MongooseV8]

Remember, most load data lists the C.O.L. as the minimum overall length. You can go longer and probably should.

[anonymouscuban]

Remember, most load data lists the C.O.L. as the minimum overall length. You can go longer and probably should.

Hmm... maybe I'm wrong but not always. Only if stated is it minimum. Most of the manufacturers load data simply shows the COL used in their testing. Even some loading manuals are this way.



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