Cutting and threading a barrel question

[omegajb]

When a gunsmith cuts and rethreads a barrel do they need to remove the barrel from the upper receiver?

The reason I ask is I have an opportunity to purchase a Sig P90/550 with a 20"barrel but the muzzle device isn't removable.
Being a piston gun, it would be a shame to not be able run a suppressor on it.

So I'm thinking of having it cut to 16" and retreaded.
I don't think the barrel is easy to remove from the upper receiver if the process is to remove it during the process.



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[gaijin]

I’d imagine if a lathe is involved you would have to remove the barrel from upper receiver.

[omegajb]

I’d imagine if a lathe is involved you would have to remove the barrel from upper receiver.Yeah, that's what I was thinking would be the best way to evenly cut and thread.

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[Todd.K]

It’s possible to thread a barreled receiver with the right machine, but far more difficult than just a barrel. I know it’s just a fancy AK but you probably should find someone who knows if that gas port needs to be opened up as well,

Your assumption that piston is automatically better for suppressed use is incorrect. Most of gas that flows back is actually through the chamber. So the timing with additional gas from the suppressor and how/if the system vents additional gas is more important.

For example the 10” 416 is probably the worst semi I have ever shot suppressed. It has a non vented piston system.

[MegademiC]

The muzzle device isnt a problem, you can just hack that off and clean it up after. As for removing and reinstalling the barrel, it looks like a PITA, so id go to someine experienced and discuss with them.

Also, this should go in the "other semi-auto" forum, you may get better amswers.