How much more velocity will my longer barrel pistol have??

[NYH1]

I bought a Glock G34 9mm, the Tactical Practical long slide model with a 5.3 inch barrel. I noticed Federal and Speer use a 4 inch barrel to get their ballistics. Federal's HST 124 gr. and 124 gr. +P are 1150 and 1200 fps respectfully. Speer's Gold Dots 124 gr. and 124 gr. +P are 1150 and 1220 fps respectfully. How much more velocity will my longer 5.3 inch barrel have over a 4 inch barrel pistol? I'm just curious that's all.

Thanks, NYH1.

 

[Hk Dan]

My old chrono tests showed about 75 FPS. Not incredible.

 

[rcmodel]

You might be lucky to get what the advertised velocity is.

You likely wouldn't get it in a 4" barrel.

rc

 

[R.W.Dale]

I bought a Glock G34 9mm, the Tactical Practical long slide model with a 5.3 inch barrel. I noticed Federal and Speer use a 4 inch barrel to get their ballistics. Federal's HST 124 gr. and 124 gr. +P are 1150 and 1200 fps respectfully. Speer's Gold Dots 124 gr. and 124 gr. +P are 1150 and 1220 fps respectfully. How much more velocity will my longer 5.3 inch barrel have over a 4 inch barrel pistol? I'm just curious that's all.

Thanks, NYH1.

I just tested the speer loadings you did in a short 2" barrelled Taurus 905 9mm revolver.

My numbers are only about 80 fps slower than yours. Velocity gain over a 4" barrel would be negligible and well within the barrel to barrel variation that's always present

 

[jmr40]

Only way to know is to buy a chronograph and see what your gun does. I use my chronograph more with rifles than handguns and have seen ammo from the same box shoot 130 fps faster in one gun than another with equal barrel lengths. That is unusual, but 25-50 fps is very common.

My G-19 is chronographing the Speer +p loads at 1250 fps so I'm actually slightly faster than published ballistics.

It also depends on the chambering. The 357 and 44 mags I've chronographed from 4" or shorter barrels are shooting far slower than the published ballistics.

 

[PO2Hammer]

http://www.ballisticsbytheinch.com/9luger.html