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AR15.COM
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9/28/2004 5:05:08 PM EDT
Anyone know what the thread size and pitch is for 9mm AR barrels? Thinking of buying an adapter for the MAC10 can and doing an AR15 upper.
9/28/2004 6:08:52 PM EDT
[#1]
Most Colt style 9mm barrles are 1/2 X 36 TPI.
9/28/2004 9:24:59 PM EDT
[#2]
5/8-24 will allow you to use an AR-10, Vortec, or Phantom designed for a .308.  You will have to open it up less than for the 1/2 thread flash supressors, maybe not at all.  You can use the 1/2-28 thread flash supressors if opened up to over .355 ID.  I already checked with some machinists.  The key decision maker is if you want to install a can.  Consult the can manufacturer for threading.
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