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Out of spec threads issue

Delasangre4231

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So I just went up and checked out my new silencer at the FFL and when we went to put the QD muzzle brake on we noticed it was really loose and sloppy on the threads. It did tighten up nice on the shoulder and was perfectly concentric with the bore. I gave it 30ft-lbs and we fired 10-15 rounds to check function. It didn't back off or anything.

We measured the threads and the tops of the threads measure .612 and the chart he had said 5/8x24 is supposed to be .625, so it's a bit small.

We are concerned that if it does come loose it will be sloppy enough to cause baffle strikes.

So my question is will rocksett and a little extra torque be enough to hold it or will there be issues? Will the extra gap be a problem for the rocksett? Should I use a different host or get a new barrel?
 

Kruel J

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You might list the specs of your host/barrel.
 

Kruel J

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Have you reached out to PTR?
 
OP
Delasangre4231

Delasangre4231

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I just found out today and I think they are closed on weekends, its my first thing to do on Monday
 

Used To Hunt

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I would suggest measuring the pitch dia. If it is in spec for a class 3 fit I wouldn't worry much since you plan on using rockset... then again most suppressors end up costing $1000 and a 1 year wait so getting the barrel rethreaded is the safest bet. Sorry to hear you got a lemon
 
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This is why a good can manufacture will want to shorten and thread PROPERLY both the host barrel and the can. Takes time. Costs money to do it correctly. Once the can is properly torqued on it should remain on the firearm in question. Our Elite Iron Cans thread on very tightly and slowly. No spinning on.

Elite Iron Suppressors.
 

Used To Hunt

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Class 3 has a range of 0.625 and 0.617 and my threads are 0.612
Damn, my heart goes out to you even more now that I see what kind of firearm is in question. Also I said the Pitch dia not the major dia. The pitch dia is a better way of determining the engagement of the thread flank. If it was good and the O.D. was bad it might give one the confidence to let it ride.
 
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Delasangre4231

Delasangre4231

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This is why a good can manufacture will want to shorten and thread PROPERLY both the host barrel and the can. Takes time. Costs money to do it correctly. Once the can is properly torqued on it should remain on the firearm in question. Our Elite Iron Cans thread on very tightly and slowly. No spinning on.

Elite Iron Suppressors.
The barrel is factory threaded by PTR, it wasn't cut down or re-threaded.

Damn, my heart goes out to you even more now that I see what kind of firearm is in question. Also I said the Pitch dia not the major dia. The pitch dia is a better way of determining the engagement of the thread flank. If it was good and the O.D. was bad it might give one the confidence to let it ride.
I don't know enough about threads how to measure pitch diameter. I'll try and find out.
 
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Delasangre4231

Delasangre4231

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If you haven't already solved your problems - we have all the equipment to measure your threads, gauges threads mics etc. If you come in on a Friday I'd be more than happy to help you. Ask for Mike. We're in Hillsboro.
Thanks, I got the gun back from PTR and the threads were tighter but still not what I'd like. But I went ahead and used rocksett and installed my muzzle brake. It is concentric with the bore, I tested with an alignment gauge and my silencer installed. And so far so good.
 

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