dedicated 9mm AR build, clarifications please

[mr fixit]

I want to build a dedicated 9mm to SBR and Suppress for fun and cheaper practice. I have been reading lots of things on the web. Unfortunately, a lot of the FAQ's or Sticky threads are many years old and I'm not sure if the information has changed. Would some of the knowledgeable folks make sure I am on the right track please?

First of all, I want to use Glock Mags. I'm looking at the New Frontier or Spartan dedicated lowers. To that I would like to add a 4-5" barrel and then a suppressor. I plan on shooting mostly 147gr RN for fun and HP for more serious use.

To that am I correct that I will need a 9mm bolt, modified for Glock Mags, as well as ramped to use standard hammers?

Am I correct that any standard 5.56 upper receiver will work with that, but that I might want to add a gas deflector/modified port door to block escaping gas from the ejection port?

I think standard carbine receiver tube will work with what ever stock I would like.

I believe that a 9mm buffer and spring are the correct set up.

And finally, after that the rail is whatever standard rail I want.


So, do I understand what I am needing to build? What, if anything have I gotten wrong?

[themonk]

Looks good. I would go with a bit of a heavier buffer is shooting suppressed. Spikes makes one as does heavy buffers. If you go New Frontier dont hesitate to give them a call as I have a buddy that did a build with one of their lowers and called with a few questions, he said they were very helpful.

What suppressor?

I did not a do a glock build as I wanted to use an existing SBR lower but I have to tell you the Knights URX 4 is beyond awesome for tucking part of your can under the rail. I am running a tirant9 with an H&K 3 lug adapter. Took me a few rails and different configs to get to where I am at now but I am in love with that rail.

[mr fixit]

Looks good. I would go with a bit of a heavier buffer is shooting suppressed. Spikes makes one as does heavy buffers. If you go New Frontier dont hesitate to give them a call as I have a buddy that did a build with one of their lowers and called with a few questions, he said they were very helpful.

What suppressor?

I did not a do a glock build as I wanted to use an existing SBR lower but I have to tell you the Knights URX 4 is beyond awesome for tucking part of your can under the rail. I am running a tirant9 with an H&K 3 lug adapter. Took me a few rails and different configs to get to where I am at now but I am in love with that rail.

Yeah, I figured I might have to play with the buffer/spring to get it running well with a can. The can will be a form 1, already got one form 1 can on my 16" .223 varmint upper.

[montesf1030]

Here is my AR 9 Pistol build ... It is with a New Frontier Lower ... I did added a heavy buffer and a heavy buffer spring as well... Mine is a 8 inch barrel with a Lantac Dragon muzzle break... No malfunctions and it shoots very sweeeet !!!


Ferdi
Las Vegas, NV USA
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[Nocalsocal]

The one thing i noticed in my build was it didn't like federal 9mm aluminum. The aluminium cases would be pushed back partially unseating the bullet. The feed angle would cause the soft aluminum case to drag along the feed ramp, and cause that side of case to be pushed down toward the rim. It caused squib load like behavior. I had a fired bullet stuck in the rifling just past the chamber. As well as numerous of out of battery behavior-like conditions. Scary.
It made me rethink my choice in building a 9mm ar.
But once I switched back to brass the problems went away. So no aluminum cases for me. Thats what I get for trying to go really cheap.
NFA glock lower
Faxon 8.3 in. Barrel upper
Spinta bcg
Spikes heavy buffer w/ a 308 spring

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[FaxonNathan]

The one thing i noticed in my build was it didn't like federal 9mm aluminum. The aluminium cases would be pushed back partially unseating the bullet. The feed angle would cause the soft aluminum case to drag along the feed ramp, and cause that side of case to be pushed down toward the rim. It caused squib load like behavior. I had a fired bullet stuck in the rifling just past the chamber. As well as numerous of out of battery behavior-like conditions. Scary.
It made me rethink my choice in building a 9mm ar.
But once I switched back to brass the problems went away. So no aluminum cases for me. Thats what I get for trying to go really cheap.
NFA glock lower
Faxon 8.3 in. Barrel upper
Spinta bcg
Spikes heavy buffer w/ a 308 spring

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Send photos, please!

[Nocalsocal]

Send photos, please!

I'm not an expert so what I explained above was the best I could come up with. The only problems I experienced was with that particular ammo. The silver case on the far left is either a Hornady or Speer case and it too shows some drag marks. However it fired normally from what I can recall. The Federal Aluminum was a different story.

9mm .jpg9mm.1..jpg

[FaxonNathan]

I'm not an expert so what I explained above was the best I could come up with. The only problems I experienced was with that particular ammo. The silver case on the far left is either a Hornady or Speer case and it too shows some drag marks. However it fired normally from what I can recall. The Federal Aluminum was a different story.

9mm .jpg9mm.1..jpg

Apologies, we meant of the complete build. Should clarify!

The presentation of the round into the chamber is critical. Glock magazines typically present the round lower at a higher angle of attack compared to the common colt systems. The drag is surprising in that extent.

Are you using OEM Glock magazines?

[Nocalsocal]

The OEM mags seemed to feed better than the ETS 31 rd magazine. No weird behavior with the oem. Most of the problems were associated with the ETS magazines. The partially fired bullet as well as the deformed case was with the ETS. And only with the aluminum.

The first photo is with ETS and then the OEM. Also most of the malfunctions happened when there was some carbon build up from past firings. Not so much with a cleaner chamber.
The first 500 rds went smooth. But when I switched to aluminum things went awry. Then I lost confidence in it. But I built it for a range/training gun so it still serves a purpose. But oh how badly I wanted it to be my HD gun!
Hope this helps.

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[jesuvuah]

I had a qc10 and now have a PSA. Both worked fine other then the lrbho not working on either

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