9mm muzzle brake drilling a hole question

[mtnman]

Ok so i have a spare muzzle brake for 223 and the threading is correct for my project. I hate to buy another when i have this one laying around. I need to drill the end for 9mm bullets, what size bit should i use to give enough room for 9mm?
thanks

[edgerly779]

3/8 " or .375 should give enough clearance if you use a lathe. .400 if you try it with a vise and drill.

[dwalker]

Your sure the threads are the same? Because the 9mm threads are different on purpose to keep you from threading a 223 brake on a 9mm barrel

[mtnman]

yes i am, its a gen 2 sub2k, it threads right on, what size bit is .400? and thanks

[L4D]

There are some 1/2x28 9mm AR barrels out there. I have one from adco firearms so I could use a flaming pig on it.

[ar15barrels]

yes i am, its a gen 2 sub2k, it threads right on, what size bit is .400? and thanks

A letter X drill bit Is 0.397" and would be your best bet if following the general rule of 1mm over bullet diameter.

I usually just go 0.030" over and would use a letter W which is 0.386".

[kcstott]

yes i am, its a gen 2 sub2k, it threads right on, what size bit is .400? and thanks

what you need is a drill chart

Drill chart

[Spyder]

I've got a 1/2x28 flash can that is for 9mm sitting around waiting for a project. They're out there.

[mtnman]

I've got a 1/2x28 flash can that is for 9mm sitting around waiting for a project. They're out there.

Well i ordered a tanker brake for my AR 9mm to get rid of the flash hider for featureless, seller sent me a 223 by mistake and told me to keep it and he sent the correct 9mm tanker brake, so i figured i'd use the free 223 tanker brake for my sub2k.

[mtnman]

Got it with a 25/64 bit, i just wish my gen 1 .40 sub2k had a threaded barrel as well. It was a bit worrying taking the first shot out back...
Thanks all