Just picked up a ATI Milsport 9mm Pistol and then I bought the shockwave.  Surprisingly the buffer tube has a smaller diameter than the Shockwave.  Any one got some ideas to stabilize the arm brace on the tube?  Yeah I know, I can buy the KAK buffer tube but I want to keep what came on it because it actually flares about two thirds of the way down to the lower.  

Some type of plastic shim?  2 sided tape?  Velcro Strip?  I'm open to ideas.  Won't see a lot of hard use but will ride in a bag in the trunk often.  

Thanks.

My CMMG  MK9 also has a smaller diameter tube. I simply wrapped electric tape around the tube until the blade fit nice and snug, then gently tightened the bolt. You would never know the tape is under the blade unless you took it off. The only issue with this is, if you plan to adjust the length often.  I have shot about 500 rounds and it hasn't budged.

Electrical tape works just fine, wrap unit it fits snug then tighten the set screw.

Sounds easy enough.  Thanks for the replies.   I'll do that tomorrow.  It's a cool lil' set up and look forward to a range trip to test it out.

Lotsa folks used electrical tape on the SB15 and SBX braces too, depending on tube. It seems to be the defacto specification now.  

- OS

Gaffers tape. Will do everything that electrical tape will do in this application but not fall apart after contact with chemicals or a few years of time.