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Rough bore on 9mm full size

2936 Views 10 Replies 6 Participants Last post by  FieroCDSP
Has anyone eyeballed the bore on the M&Ps and compared it to other pistols they own? It seems the bore on my 9mm is very "rough" compared to my other pistols. This can be felt when pushing a patch through the bore and easily seen with a bit of magnification. I looked at the bore through my "OptiVisor" head worn magnifier (used for tying flies and a lot of other things the older I get) and can see machining "chatter" marks the full length of the bore. The bores on my 1911s and other handguns I've owned have a mirror polish on them.

Also, the ramp and bore seem to have the same finish on them as the exterior of the barrel.

I think this roughness causes the bore to build up with more debris from my cast bullet handloads and makes the bore harder to get clean than any of my other guns. My 9mm is also not quite as accurate as I'd hoped and wonder if a smoother bore would make a difference.

I've read somewhere about using JB paste to smooth bores. Any experience with this? Will the bore smooth out after a few thousand rounds of cast lead bullets (my gut feeling is, no)? Is it possible this roughness would contribute to inaccuracy?

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My .45 had a rough bore also. The JB paste will work wonders. It did on mine and man will that stuff clean.
1 - 1 of 11 Posts
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