Question about PSA Dissipator w/ FN barrel

[machman72]

Can someone measure the barrel diameter where the FSB mounts on thier PSA Dissipator with the FN barrel?

I have purchased a PSA Dissy upper without the FN barrel and the barrel measures .735". The problem is that the FSB inside diameter is .750". I am wondering if the FN barrel is a true .750" in which case I will return this upper and exchange for the Dissy with the FN barrel.

FWIW, my RRA measures .740", so I am not at all saying that PSA isn't good stuff. I am actually VERY impressed with everything else about the PSA upper.

Thanks

[GTifosi]

I wouldn't expect the barrel to be in the .750 spec range except right at the point where the gas block mounts.
There is generally a shoulder cut just in front of that area, then from there out to the muzzle is skimmed to a smaller diameter to allow the gas block to slip over it easily.
Doubtful changing from whatever you have to an FN barrel would make any difference unless they have some special thing they do for thier mock dissipators.

A pinned standard sight tower gas block out front would likely be just fine. Set screw mabe not so much.

[machman72]

I wouldn't expect the barrel to be in the .750 spec range except right at the point where the gas block mounts.
There is generally a shoulder cut just in front of that area, then from there out to the muzzle is skimmed to a smaller diameter to allow the gas block to slip over it easily.
Doubtful changing from whatever you have to an FN barrel would make any difference unless they have some special thing they do for thier mock dissipators.

A pinned standard sight tower gas block out front would likely be just fine. Set screw mabe not so much.

I understand what you are saying. But I can see a gap between the ID of the FSB and the OD of the barrel. It is pinned on, but I am a little bit leary of the integrity due to the difference between the diminsions. It seems that I can more the top of the front sight due to this issue.

On another note, a friend of mine has a 16" Bushmaster with the barrel being .750" in the area forward of the HG.

[MistWolf]

Contact PSA. They were real good answering all my questions when I PM'ed them

[machman72]

Contact PSA. They were real good answering all my questions when I PM'ed them

Will do. Thanks.