I've sent my Form 1 off to build an SBR, and I am looking to put on a QD silencer mount such as the AAC SPR/M4 Mod 08 mount.  However, the mount looks so long that it would destroy the benefits of having an SBR.  How much length does the AAC SPR/M4 Mod 08 mount actually add to the barrel?

Thanks

Its listed on AACs website under each type. The MITER mount adds 1.75", the other 2 QD mounts add 1.875"

AAC

I appreciate it.  My Form 1 specifies a 12.5" barrel, so it looks like I would be good to go.

This.



I am actually going to put a 12.5 on one of my SBR uppers just so that I can put the SPR/M4 on it.



 

Here's mine  on a 18" barrel....extra length isnt a prob. at all, however it is still a nice chunk of metal and with that it weighs some.

I just mic'd one of my spare SPR/M4 Blackouts:

-OAL = 4.225"
-rear of mount to barrel thread shoulder = 1.905"
-thread depth = 0.600"
-length past end of barrel = slightly less than 1.75"
-weight = 125.8 grams [4.43 ounces]

On my 12.5" N4 with a DD lite 9.0, there is right at 3/4" gap between the back of the can and the front of the handguard.  The weapon OAL with the can mounted is almost exactly the same as my wife's 16" N4 with a Blackout, but without the can.

12.5's with reflex cans are a most excellent combination.  I also have a 12.5" 6.8 with a SCAR-H SD.

ETA - here are some pics: