SMP-842

[R_Bert]

I will ladder down to 21 grains from 22.7 grains and post my chrono results. As a general rule, how many fps should I expect to give up using my 10.5" barrel rather than a 16" barrel?

I'm surprised that I got 2490 fps with 22.7 grains and the post I quoted got basically the same results with 21 grains from a 16" barrel.

 

 

chart here -

 

http://www.ballisticsbytheinch.com/223rifle.html