My current build is a Retro style Colt 9mm carbine. Can anyone help point me in the direction to find some ballistic information on difference barrel lengths or if you have that information, that’s even better. I’m wondering what kind actual difference there would be between a 16” barrel vs an 11.5” barrel? I have thought about cutting down my 16” colt carbine barrel to 11.5” and adding a faux XM177 style flash hinder but I’d like to research the following……

1). What would be the difference in velocity?
2). How much accuracy would I actually loose.

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

Agree, no difference. My preban colt 16" is very accurate, before my stigmatism I shot open sights, 100yds and chewed x ring out. MY new build is 11in quality barrel from Rudy, (Mad-Machinist) it shoots just as accurately BTW I shoot a mix of cheaper ammo through them Blazer/rem/win amercan eagle, as well as good loads too. This week I will be testing 124 and 147gr subsonics and +P+ loads.

Using my 16" barrel I saw 1355 fps



90g Frangible
4.5g accurate #2
Tula Mag Primer
1.12 OAL

supposed to be 1150 fps from a 4" barrel, I have a 6.5 barrel but haven't had a chance to chrono the load with it

You shouldn't lose any accuracy if the cut is done right.  I hit steel easily with my 5.5" QC10 barrel at 100 yards.  Everything I've ever seen is that all things being equal, barrel length doesn't impact accuracy, just velocity.

John

Thanks for the Feedback and the link, very much appreciated.