9mm Load Faster in a Shorter Barrel?

[Fantom919]

Hello all,

I'm new to hand loading so please bear with me. I loaded several rounds this past weekend and chrono'd them both in my CZ Shadow and my dad's Beretta 92. I was expecting the velocity to be higher out of the Beretta due to the longer barrel length (4.7 vs 4.9) but found the opposite. For the Loads I tested, it seemed about 20 to 25 fps lower in the Beretta across the board.

Can someone help explain? I'm thinking barrel design maybe?

Here's some of the data on the loads I compared:

Remington 115g factory

MG 124 CMJ - 4.7gr unique

MG 124 CMJ - 4.2gr Titegroup

1.125 oal

Each round was measured as exact as my digital scale reads (.02 gr resolution). Testing conditions were 75 degrees and overcast using a Ced M2

Thanks for the help!

[Justsomeguy]

Firstly, .2" is not much difference in barrel length. Even barrels from the same manufacturer will vary in land height and groove depth and produce velocity differences as great, or really, as little as you are describing here. I have several pistols equipped with aftermarket barrels from different sources and can tell you that some barrels are faster than others. This is nothing new. It has been noted by many shooters and reloaders over at least half a century, or at least as long as chronographs that were affordable have been used by a lot of shooters.

Velocity differences of over twice what you listed are not uncommon for guns with the same length barrels from different manufacturers, so just know it happens and expect it.

[kneelingatlas]

CZ Shadow and my dad's Beretta 92. I was expecting the velocity to be higher out of the Beretta due to the longer barrel length (4.7 vs 4.9)

First off, did you actually measure the barrel in the Beretta? because unless your dad has an Aussie Shadow, you didn't measure his barrel

http://www.saami.org/glossary/display.cfm?letter=b

[Fantom919]

Hey all,

Thanks for the reply, I appreciate it.

As for barrel length, I'm a bit confused..My CZ Shadow has a 4.7 inch barrel and the beretta a 4.9..but honestly I didn't take out a ruler and measure. I was going off of factory specificiations.

Thanks!

[CB45]

I think your over thinking this. Different gun, different barrel specs.

Barrel length is only one of many factors that determines projectile velocity.

[kneelingatlas]

Hey all,

Thanks for the reply, I appreciate it.

As for barrel length, I'm a bit confused..My CZ Shadow has a 4.7 inch barrel and the beretta a 4.9..but honestly I didn't take out a ruler and measure. I was going off of factory specificiations.

Thanks!

Get out your ruler, CZ USA is off in their catalogs (different from CZ UB and reality); I don't know about Beretta.