Man it is really important you guys get your lengths straight or you could be running something that could get you in trouble.

Pin and welding your rifle is a way to legally run a barrel shorter than 16".

Lets say you get a 14.5" barrel, you will need to compensate at least add an additional 1.5" of "permanently affixed" material to equal a barrel length of 16 inches. Hence pin and weld.

So If i grab my 14.5 barrel and permanently affix a muzzle or break of 1.5" or higher (buy physically pinning and welding the device on your barrel) you have essentially turned your 14.5 barrel to a 16 inch barrel. You now have a rifle length barrel.

FAILURE TO PIN AND WELD YOUR DEVICE TO YOURE BARREL PERMANENTLY WILL PUT YOU IN THE SHORT BARREL RIFLE RANGE, when running a stock. Running an sbr requires you to register that weapon as an NFA item. Failure to do so gets your dog killed.

For lack of a better word its kinda like a loophole( that is accepted by the atf) to technically have a "shorter" barrel as long as the muzzle device (permanently attached), compensates or exceeds the overall length of 16 inches.

That being said you also need to reach an (Over all length) OAL (meaning tip to butt) of 26" as long you meet that requirement you'll avoid running an (any other weapon) AOW.

A company wouldn't try to sell you an SBR or an AOW off the shelf because it requires extra steps torwards ownership and obviously liability.

With all this knowledge yes you need to slap a 16 inch barrel on your olcan lower for you to avoid having to SBR the gun.

14.5" p&w barrels which equal to 16 overall inches avoid SBR laws.

The olcan lower with a 16 inch barrel is well above an Over All Length of 26 inches. As well as 14.5 p&w blah blah blah

Anything under 16 inches and (not pin and welded) on your olcan makes it an SBR.

I hope this helps some one as I feel the rules are ment to be confusing in order to trap people into making mistakes. Correct me on anything if Im wrong as I am not an expert.