Barrel threading depth for 1/2x28 can mount

[Yellowfin]

I'm getting my .30-06 threaded for a suppressor mount and got a question back from my gunsmith before he does it. He wants to know which mount I want to put on it. Well, here's the kicker: I don't know yet. Just buying or borrowing a mount ahead of time that may or not be right puts me out $100 or more unnecessarily since it'll at least take me 4-6 months to even have the can in my possession anyway. So we know because of the barrel profile I need it done 1/2x28, but he says he needs to know how far to thread the barrel back. Would it be sufficient to tell him to do it to work with an A2 flash hider because most can mounts in 1/2x28 have AR's in mind and that's what they've got?

[Stock 87]

Why not just wait until you have the can?
FWIW there is going to be a flat/shoulder that the can or mount tightens up on/against. It will be perpindicular to the bore to keep the can strait, plus take up any slop in the threads.

Do it correct the first time.

[Yellowfin]

The reason I'm doing it ahead of time is so that I can try stuff out first, and also so I'm doing something now instead of a dead wait with nothing to show while in the process.

[Stock 87]

I understand the excitement of wanting to move on the threading. I also understand doing things twice doesn't always turn out as nice as if it was done correctly the first time. Remember you can always take more metal off, putting it back on is much harder.

Waiting 6 months for a can. I bet you could endure another week for the threading.

[animalmother85]

OP,
Do you plan on using a crush washer or shims?

[Stock 87]

OP,
Do you plan on using a crush washer or shims?

Enlighten me.

Why are you asking about shims? cans don't need to be timed.

[Nate7667]

Are you sure you need 1/2x28 for your 30-06?
My only guess it because it is probably a sporter barrel and you do not have enough meat to thread 5/8x24?
Custom can?
Most .30cal cans are 5/8x24 or M14x1L or R

1x2/28 threads are more common on 22LR, 223/556, 9mm.

Standard AR type threading for 223/556 muzzle devices using 1/2x28TPI is normally ~.600" long.
Anything used for 22LR is ~.400" or require a spacer to run a can on a .600" thread.

Do NOT use a peel or crush washer to mount a suppressor.
Which i believe why animalmother85 is asking Yellowfin and knows this can be bad juju.

[bogey1]

My gemtech (.223) instructions say to use a crush washer. I use nothing. Works fine.

[Yellowfin]

Are you sure you need 1/2x28 for your 30-06?
My only guess it because it is probably a sporter barrel and you do not have enough meat to thread 5/8x24?

That's exactly the scenario, and I've seen a few .308 can mounts that are in 1/2x28 and a couple of adapters that step up from 1/2x28 to 5/8x24.

[Nate7667]

Gotcha

Well, you cant go wrong with threading it ~.400" long.
Do you have the adapter that will be using to go 1/2x28 to 5/8x24?
If not go short, .400", that way you know the adapter will bottom out on the shoulder of the barrel.

An example of what i mean is the S&W MP15/22 AR. All the ones that i have seen have a 1/2x28 barrel threaded ~.600" long. To mount a 22 can, you need to use a .200-.250" spacer. With out the spacer, the can will run out of thread and most cases bottom out with the muzzle crown touching the first baffle. This is not a good idea.

With the spacer, it allows the can to bottom out solid to the should/spacer instead of the crown.

Not exactly the situation you may end up with, but somewhat useful rambling anyway LOL