Has anyone done this for PDW and what mistakes did you make?
- Thread starter BenjaminMartin6.5
- Start date
For me, if you want to call it a mistake... was getting into the game, Waaay too early. When 1, maybe 2 company's were making dedicated lowers. Now the floodgates are wide Open... it's easy breezy now !
Thanks, there are some many options it’s easy to get in the weeds.
1-Decide what mags you want. If you have Glock mags, great get a dedicated lower. If not I run Colt mags and they're just fine. I use ASC mags with a Promag adapter. People knock them but mine works just fine. YMMV. I do like that the colt mags are convertible. You can use a bottom feed mag well adapter to convert your lower to 5.56 if you want.
2-Decide if you're going blowback or doing the CMMG radial delayed system. Never tried the latter heard good things though.
3-If you're going straight blowback you need a heavy buffer designed for an AR9. Midway sells an 8oz one and when It was only 25 bucks. I broke my bolt catch with a light buffer. It will work, it just makes the gun not shoot near as well as it should. If you don't do this stuff $1.50 or so in quarters in front of your buffer. I shot mine that way and it worked well too.
4-The bolt. Perhaps one of the most important parts for a blowback. There are bolts for the Colt style mags (dual feed) vs the single feed aftermarket stuff. Besides this there are ramped and non-ramped bolts. If you run a non-ramped bolt you have to have a notched hammer. Just buy the ramped bolt appropriate to the mags you want.
5-I've had good luck with the New Frontier Barrel I've got but I've heard 9mm feeding for an AR is really a mixed bag. It's a 16". I'm not going to say the accuracy doesn't seem the best but it's probably a the fool behind the gun and the caliber. Based on reviews I've seen of other 9mms I probably have higher expectations than I should.
ED:
6-This is an interesting thing for consideration. Depending on the powder different barrel lengths give somewhat different results. Not only that but reloading does too. As I've mentioned here before Blue Dot and Titegroup shoot the same velocity out of my 4" SD9VE but have 140FPS difference in my 9mm Carbine.
http://ballisticsbytheinch.com/9luger.html
7-There is a half door with shell deflector made for 9mm by Colt and CMMG. About 15 bucks, works really great. Also works for 22lr builds as well. (not a clue who they are but you get the idea.)
https://9mmar.com/cmmg-ejection-port-cover-kit-with-gas-deflector/
2-Decide if you're going blowback or doing the CMMG radial delayed system. Never tried the latter heard good things though.
3-If you're going straight blowback you need a heavy buffer designed for an AR9. Midway sells an 8oz one and when It was only 25 bucks. I broke my bolt catch with a light buffer. It will work, it just makes the gun not shoot near as well as it should. If you don't do this stuff $1.50 or so in quarters in front of your buffer. I shot mine that way and it worked well too.
4-The bolt. Perhaps one of the most important parts for a blowback. There are bolts for the Colt style mags (dual feed) vs the single feed aftermarket stuff. Besides this there are ramped and non-ramped bolts. If you run a non-ramped bolt you have to have a notched hammer. Just buy the ramped bolt appropriate to the mags you want.
5-I've had good luck with the New Frontier Barrel I've got but I've heard 9mm feeding for an AR is really a mixed bag. It's a 16". I'm not going to say the accuracy doesn't seem the best but it's probably a the fool behind the gun and the caliber. Based on reviews I've seen of other 9mms I probably have higher expectations than I should.
ED:
6-This is an interesting thing for consideration. Depending on the powder different barrel lengths give somewhat different results. Not only that but reloading does too. As I've mentioned here before Blue Dot and Titegroup shoot the same velocity out of my 4" SD9VE but have 140FPS difference in my 9mm Carbine.
http://ballisticsbytheinch.com/9luger.html
7-There is a half door with shell deflector made for 9mm by Colt and CMMG. About 15 bucks, works really great. Also works for 22lr builds as well. (not a clue who they are but you get the idea.)
https://9mmar.com/cmmg-ejection-port-cover-kit-with-gas-deflector/
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I built a 9mm upper around the CMMG RDB bolt.
I bought the bolt/barrel on sale for just over $300.
Mine has the 8 inch barrel.
I bought a larue 7 inch handguard for $70 and already had a milspec upper receiver.
Then I bought a 3 pack of CMMG pmag conversions that allow you to shoot 9mm through normal pmags for around $100.
I used it with a "pistol" lower I already had in inventory.
It's actually one of my favorite guns to date.
As a side bonus, it's so quiet (suppressed) using my 147 grain handloads that my wife really took a liking to it -
Now she's totally trained on the AR15 manual of arms, and comfortable with all my ARs
(It took her a while to warm up to centerfire rifles because of a "bubba" type scope eye experience when she was young.)
It's very comfortable to shoot without hearing protection with my rugged obsidian 9.
The only quieter centerfire I have is my henry model x shooting 38spl through the obsidian.
With a red dot and WML it makes a great nighttime pest exterminator that won't bother the neighbors.
Wouldn't be so bad on bad guys either, but I prefer 77 TMKs for that
Being able to use any milspec lower is a huge plus for the CMMG system with their endomag conversion.
I also shot it back to back with a buddy's PSA 9mm AR - we both agreed my CMMG build had a much softer recoil impulse and was drastically quieter at the ear suppressed.
I'd do every part of the build again exactly the same.
I bought the bolt/barrel on sale for just over $300.
Mine has the 8 inch barrel.
I bought a larue 7 inch handguard for $70 and already had a milspec upper receiver.
Then I bought a 3 pack of CMMG pmag conversions that allow you to shoot 9mm through normal pmags for around $100.
I used it with a "pistol" lower I already had in inventory.
It's actually one of my favorite guns to date.
As a side bonus, it's so quiet (suppressed) using my 147 grain handloads that my wife really took a liking to it -
Now she's totally trained on the AR15 manual of arms, and comfortable with all my ARs
(It took her a while to warm up to centerfire rifles because of a "bubba" type scope eye experience when she was young.)
It's very comfortable to shoot without hearing protection with my rugged obsidian 9.
The only quieter centerfire I have is my henry model x shooting 38spl through the obsidian.
With a red dot and WML it makes a great nighttime pest exterminator that won't bother the neighbors.
Wouldn't be so bad on bad guys either, but I prefer 77 TMKs for that
Being able to use any milspec lower is a huge plus for the CMMG system with their endomag conversion.
I also shot it back to back with a buddy's PSA 9mm AR - we both agreed my CMMG build had a much softer recoil impulse and was drastically quieter at the ear suppressed.
I'd do every part of the build again exactly the same.
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Thanks, that's great info because I have a couple of reg lowers and want to build a 9mm for wife and 300 for me.I built a 9mm upper around the CMMG RDB bolt.
I bought the bolt/barrel on sale for just over $300.
Mine has the 8 inch barrel.
I bought a larue 7 inch handguard for $70 and already had a milspec upper receiver.
Then I bought a 3 pack of CMMG pmag conversions that allow you to shoot 9mm through normal pmags for around $100.
I used it with a "pistol" lower I already had in inventory.
It's actually one of my favorite guns to date.
As a side bonus, it's so quiet (suppressed) using my 147 grain handloads that my wife really took a liking to it -
Now she's totally trained on the AR15 manual of arms, and comfortable with all my ARs
(It took her a while to warm up to centerfire rifles because of a "bubba" type scope eye experience when she was young.)
It's very comfortable to shoot without hearing protection with my rugged obsidian 9.
The only quieter centerfire I have is my henry model x shooting 38spl through the obsidian.
With a red dot and WML it makes a great nighttime pest exterminator that won't bother the neighbors.
Wouldn't be so bad on bad guys either, but I prefer 77 TMKs for that
Being able to use any milspec lower is a huge plus for the CMMG system with their endomag conversion.
I also shot it back to back with a buddy's PSA 9mm AR - we both agreed my CMMG build had a much softer recoil impulse and was drastically quieter at the ear suppressed.
I'd do every part of the build again exactly the same.
Full disclosure - i did skip one small detail -
In order to get the CMMG endo mag conversions to properly hold the bolt open on the last round, I had to clip two coils off the mag catch spring.
Wasn't a big deal for me because I was using an aero "enhanced" lower with the threaded mag catch pin.
I landed on a spring that works well everywhere (11.5 556 and 9mm). No factor IMO, but if you're super picky about having your rifle "battle-ready" etc, that might bother you.
Very nice!
