Hello all, I’ve been considering putting a BCM 14.5" upper on my 6920 for awhile now and think I have finally decided to ‘pull the trigger’ on the idea, so to speak. Anyways what, if any, would be the drop-off in accuracy going from a 16" to a 14.5" upper? I’m assuming it would be negligable or no? Is there anything I’m missing as far as noticeable differences in ballistics going from the different lengths? Any input would be appreciated. Thanks…
I have two BCM 14.5" carbines and the accuracy is very acceptable. I believe you lose something like 100fps muzzle velocity by going for 16" to 14.5". However, if you’re really concerned about accuracy then get a Noveske. 
I would keep the 6920 intact unless I needed a SBR for vehicle duty or clearing rooms, then I would get an 11.5" SBR upper from BCM. I played the 14.5" upper game and I’m done with pinned muzzle devices, I don’t really notice the 1.2" difference in handling between my 16" middy and my pinned LMT.
Yeah that’s a good point. I’m trying to get on the force here in Springfield but it’s been a rather long process so far. I really like my 16", so I guess I’ll wait till I actually get a LE job before I change my upper. When I do, and I’m confident I will, you think the 11.5 would be better than the 14.5?
FYI if you become an LEO it doesn’t exempt you from NFA. You won’t legally be able to use a shorter than 16" barrelled upper on your 6920 lower without getting a tax stamp on a Form 1.
Really? I did not know that. Is that on the federal level, or does it vary from state to state? Is getting a tax stamp a difficult process?
Thanks for the link.
Illinois is a no-NFA state isn’t it?
I honestly don’t know. Never done the research as it hasn’t affected me until now.
Correct, SBR’s are illegal in Illinois…one reason I’ll never move back…
The only NFA item that isn’t illegal if I remember correctly is AOW.
What’s an AOW?
“Any Other Weapon,” not to be confused with “Other Title I Firearm” which includes things like Mossberg Shockwaves, Remington TAC-14s and over-26"-OAL AR pistols. AOW is usually things like zip-guns, “disguised firearms” and Serbu Super Shorties, just to name a few.
This thread is 8 years old.
Well he had to wait 8 years for his question to be answered. 
Didn’t realize this topic was 8 years old until I responded