Should I build 12" or 16" AR?

[LRRPF52]

I have or have owned multiple samples of both barrel lengths, 12” and 16”, and still have a 16” and 2x 12”.

There isn’t a huge velocity difference between them that will mean much on-target within those ranges.

Federal 120gr OTM does 2384fps from the 12” suppressed on average (15ft from the muzzle, actual mv is 2393fps).

The same load does 2484fps from my 17.6” Lilja Grendel barrel 15ft from the muzzle.

I really like the compact size of the 12” suppressed.

Here’s an image with some velocities and effective ranges for 123gr SST and ELD-M:



Here’s with 129gr ABLR: