Drilling out an A2 flash suppressor for 9mm carbine?

[ARCHIVED THREAD] - Drilling out an A2 flash suppressor for 9mm carbine?

Posted: 1/22/2018 4:39:28 PM EDT

Any tips/words from the wise regarding drilling out a 1/2-28 A2 FS for 9mm carbine use? I got a few of these laying around and with the new scorpion barrel coming with 1/2-28 pitch, I thought perhaps I can use an old A2 for 9mm. (Yes of course buying one is an option but I'd have to wait until the order is large enough, otherwise shipping would just kill it

)

Posted: 1/22/2018 4:49:29 PM EDT

[#1]

Use cutting oil, slow RPM's hand feed. Secure the FH, or lock it in ViseGrips.

Should be an easy task. Drill from the threaded end.

Posted: 1/22/2018 4:52:15 PM EDT

[#2]

Done a few of them for friends and myself.

Posted: 1/22/2018 6:03:58 PM EDT

[#3]

Thank you! I found out my closest bit to 9mm is 3/8" which seemed a little too close (.374" vs. .355-.356 projectile). Need better bits set.

Posted: 1/22/2018 9:04:11 PM EDT

[#4]

Lots of places sell these for around $10. Just need look around for cheapest shipped. Or just order a drill bit off ebay or amazon once again whoever is cheapest shipped

Posted: 1/22/2018 11:33:27 PM EDT

[#5]

best to do it on a lathe... any way, be sure to check for any run out with a range rod that fits the bore and check for even spacing around the hole

Posted: 1/23/2018 4:01:24 AM EDT

[#6]

Honestly just buy one

It’s cheap enough to where you can.

Posted: 1/23/2018 5:21:50 PM EDT

[#7]

LOL...this is where I ran into 'flawed economy', trying to reuse something that sits in the parts bin, now buying drill bits

. Actually I really don't mind buy new ones but sometimes the tinkerer in me got the best side of my brain!

Posted: 1/23/2018 11:55:36 PM EDT

[#8]

Quote History

Quoted:
LOL...this is where I ran into 'flawed economy', trying to reuse something that sits in the parts bin, now buying drill bits

. Actually I really don't mind buy new ones but sometimes the tinkerer in me got the best side of my brain!

View Quote

I too am guilty of that. I spent nearly an hour the other night fixing a broken pin on my RCBS decapping die when I could have just bought a new one for $8. But.....I had the tools and parts to fix it and being a man....I had to try to fix it myself........Silly me....I ended up buying a new one anyway.

Posted: 1/30/2018 4:18:24 AM EDT

[#9]

I was contemplating doing this, but decided to purchase a dedicated 9mm muzzle device.

I could always use the extra flash hider for an excuse to build another gun.

Posted: 1/30/2018 6:08:51 AM EDT

[#10]

My Colt 635 upper has a different thread pitch. Are you sure your muzzle threads are correct to try and use a 5.56 muzzle device and boring it out?
Most .manufacturers use a different pitch to keep a mistake from happening.

Posted: 1/30/2018 12:27:38 PM EDT

[#11]

Chuck the flash hider in the head stock and put a 7/16" carbide endmill in a drill chuck in the tail stock. High speed, low feed. Easy peasy!

Posted: 1/30/2018 12:32:26 PM EDT

[#12]

Quote History

Quoted:
Chuck the flash hider in the head stock and put a 7/16" carbide endmill in a drill chuck in the tail stock. High speed, low feed. Easy peasy!

View Quote

Posted: 1/30/2018 3:11:54 PM EDT

[#13]

Quote History

Quoted:
My Colt 635 upper has a different thread pitch. Are you sure your muzzle threads are correct to try and use a 5.56 muzzle device and boring it out?
Most .manufacturers use a different pitch to keep a mistake from happening.

View Quote

I'm building the upper. The barrel I purchased is advertised as 1/2-28.

Posted: 1/30/2018 3:15:08 PM EDT

[#14]

Quote History

Quoted:
My Colt 635 upper has a different thread pitch. Are you sure your muzzle threads are correct to try and use a 5.56 muzzle device and boring it out?
Most .manufacturers use a different pitch to keep a mistake from happening.

View Quote

This was my first thought upon reading the OP.

Posted: 2/2/2018 3:35:59 PM EDT

[#15]

I would just buy one, they seem cheap enough

Posted: 2/3/2018 8:26:45 AM EDT

[#16]

Quote History

Quoted:
My Colt 635 upper has a different thread pitch. Are you sure your muzzle threads are correct to try and use a 5.56 muzzle device and boring it out?
Most .manufacturers use a different pitch to keep a mistake from happening.

View Quote

This is for my scorpion K conversion, barrel is 1/2-28. It is done and shot without issues. I used a fresh 25/64 drill bit and then dremeled out the A2 cone portion to be on the absolute safe side. The A2 can be seen in this post https://www.ar15.com/forums/Armory/Impressive-ammo-barrel-combo-for-my-Scorpion/48-485943/

[ARCHIVED THREAD] - Drilling out an A2 flash suppressor for 9mm carbine?

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