Barrel extension to reach 16"

[Scott-ak]

Not sure that I can explain clearly so please bear with me. The whole AR pistol SBR stuff has made me think about building a new 16" PCC for competition. There are commercial barrels that use an aluminum extension to bring a short barrel to the 16" requirement. Imma cheap SOB and not into those high end race guns. I can easily make a 10" extension, pin and weld to an 6" barrel. My question is about the ID of the extension. Are there any concerns that too small a diameter will cause inconsistent POI? Say 50 thou over bullet diameter? Or should the extension have a larger ID? 100 thou, 200 thou over? Any experience here? Opinions?

 

[LVLAaron]

.... Why not just get a 16 inch barrel if you're not wanting an actual SBR?

 

[DDriller]

The extension on my TacSol .22 is large enough for a 1" diameter suppressor to fit in it.

 

[VA_XTC_Shooter]

.... Why not just get a 16 inch barrel if you're not wanting an actual SBR?

The idea is to have a 5" barrel in the PCC with a shroud to make 16" legal limit. Why 5", that way they can tune a single load to work in PCC and their pistol. Also, an aluminum shroud to make 16" length is lighter than a steel barrel.

 

[VA_XTC_Shooter]

Not sure that I can explain clearly so please bear with me. The whole AR pistol SBR stuff has made me think about building a new 16" PCC for competition. There are commercial barrels that use an aluminum extension to bring a short barrel to the 16" requirement. Imma cheap SOB and not into those high end race guns. I can easily make a 10" extension, pin and weld to an 6" barrel. My question is about the ID of the extension. Are there any concerns that too small a diameter will cause inconsistent POI? Say 50 thou over bullet diameter? Or should the extension have a larger ID? 100 thou, 200 thou over? Any experience here? Opinions?

A larger opening. You don't want 10+ inches of "tighter" tolerances in a rifle that is swinging and moving around. Look at the end of the Taacom extension, it is not small.

Barrel Extension for 15-22P | Taccom3g

We've now engineered a 22 barrel after our successful 9mm ULW barrel. This will give the competitor fast transition and reliability in 22 competition and/or steel challenge.

taccom3g.com

 

[Scott-ak]

ok larger ID, thanx.

Those taccom pics look like there is a pipe seam along the length. Makes me wonder if they are just fitting a threaded plug in the end.

 

[wwbrown]

Whatever means you choose to extend the barrel I would make sure at the very least it is welded to the original barrel. A barrel modification that you can remove with hand tools will probably not pass muster by the ATF and then that whole 10&10 might upset your life (10 years and $10,000). As an example to make a short barrel legal with a muzzle brake the brake has to be pinned and tig'ed to the original barrel.

Given the possible penalties involved I would believe no one on the web and make a call to the ATF and talk about what you are trying to do to check the legality. I talked about the above just to get you thinking about, do not place any validity on what I say about this issue as I will not be the person with cuffs and orange jumpsuit in hand to check out the extension.