adjusting OAL [Archive] - Glock Talk


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07-29-2012, 18:47
Please tell me if this seems right: Two bullets same type (CMJ), same weight , same diameter, same caliber but different manufacturer. The tried and true measures .6355 long. I have a number of bullets from a different manufacturer that measure .596 long.
If I wanted to duplicate the tried and true load with the shorter bullet, I should adjust my COL so that the round chamber volume would be the same?

All the math sounds right.

Thanks Ed

07-29-2012, 20:16
It seems sensible. I bought some pulled HSTs to load. They're longer than XTPs, which is the bullet used in most of my load data. I just added the extra length of the bullet to the OAL, and that seemed to work fine. Granted that's the opposite of what you're wanting to do, but along the same lines. I probably wouldn't shorten them all the way down at once. Shorten them a little at a time to watch for problems.

07-30-2012, 08:57
Well, sort of. As you have just learned, bullets are NOT plug & play. THe OAL MUST fit your gun, so try a dummy round loaded as you indicate, that should give the same internal volume, then check for fit in your barrel. If it won't chamber, then you have to seat it deeper & may or may not need to adjust powder charge depending on how close to max you are.

Zombie Steve
07-30-2012, 09:12
Use the longest OAL that functions well in your gun, and whenever you change components, it's always wise to back off the powder charge and work your way up again. It may be working at different pressures, and the gun may like something different anyway...

It doesn't sound like it will be a big deal in this instance, but it's the safe thing to do...

07-30-2012, 13:04