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With the introduction of USPSA PCC, I'm in the market to build a 9mm AR.
Do they use regular 5.56 AR free float rails?
I see there's a 9mm buffer, I'd it necessary over a carbine or H1?
Which is better, Colt SMG or Glock lowers? As far as reliability in feeding goes.
Can I use a standard stripped upper I have laying around?
Colt 6951 is the standard. With that said, lots of companies are making lowers that accept Glock mags. You will want to use an upper geared toward a 9mm. Some rails will work, but others will need a spacer between the upper receiver and barrel.Quote:
Originally Posted by Caeser25
You will want to us a 9mm buffer and spacer.
C4
Thanks. Will a BCM rail work?
To save you some trouble googling, the PSA 9mm glock lowers do not have last round hold open. They do supposedly have a separate lower with that feature, but I've never seen or used one. They also have a colt pattern lower as well. Their uppers are interchangeable afaik. Sorta regret the purchase, but at the same time its a blasting gun. I've only put a few magazines through the gun and haven't had any issues (doesn't really say much). Basically waiting on the stamp to move forward with it.
Yes.Quote:
Originally Posted by Caeser25
C4
The BCM Keymod worked on mine but I traded with a buddy for Samson rail because i wanted a larger diameter so my can will fit inside the rail.
As far as rails go, I know DD, Larue, MI FF rails work well, Most should work ok just match the length of rail to barrel length and you should be good to go, You dont need a heavy robust rail though pick out a lightweight such as the MI.
With buffers, the 9mm buffer is slightly longer then a 556 carbine buffer, they do make a spacer that goes in back of the recoil spring so you can use a 556 carbine buffer, but I'd stay away from that and just get a dedicated 9mm buffer.
I read about people having problems with the colt style lowers with feeding problems, but I like them, if you load your NEW magazines and let them sit for a week or two the springs settle, and they load easier and reliability is great, I happen to have great success with ASC mags. I bought one metalform brand mag and had problems with the follower, I will not buy any more of those, other people will say the are good. Stay away from the Mag inserts that adopt a regular AR lower to work with colt style mags. The dedicated Glock mag lowers are good to go, there are other options out there, seen one that uses Beretta mags.
As far as uppers, the gas tube hole is usualy not drilled for the 9mm, ejection port door and additional large deflector are used. Also you dont need the FA it just ads weight. With that said, it be best to just buy a dedicated upper receiver. Your going about it right, ask questions and shop around and see whats out there be spending your $. Good luck
Why an AR vs one of the SMG options?
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9mm ball is cheaper then .223 ball and when setup right the 9mm AR will have closer recoil to a .223 AR is one reason. Another is that you can tinker with a 9mm AR a lot more and cheaper then a Sig MPX, CZ Scorpion or MP-5 clone. I picked two 9mm AR lowers: one for a practice gun and the other mostly just for the gee whiz factor of a SBR 9mm AR although I'm thinking the gee whiz factor of two 9mm AR SBR's may be better now.
I have a PSA Glock lower with lrbho. I also had a qc10 with the same setup. Neither lowers work reliably for lrbho. But other than that they work great. I also have a Hahn mag block adaptor for colt mags and it also works great.
On my last 9mm upper build I went with a utg pro rail. I was just trying to make a cheap blaster upper. I have to say, for the money, it is actually not a bad rail.
So far I have only ever used the 9mm buffer from heavy buffers. It is a heafty peice, but I have no complaints with it.
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Same feel, I would imagine same manual of arms with LRBO. Biggest factor though was the Geiselle SD3G since that's what I have in my 5.56 AR, which from what I have read, hammer reset reliability is spotty at best.Quote:
Originally Posted by Wake27
Thanks for all of the replies.
What specific upper receiver features do you need to run 9mm?
My current favorite is my AR-9 pistol build ... 8inch barrel with a NFA complete lower ... Did upgraded the trigger to a POF drop in trigger ....using a Kak shockwave pistol brace ... love it http://uploads.tapatalk-cdn.com/2016...e8678bc9ce.jpg
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I see that relatively recently Colt added 9mm ar again to the line up. Used to have a colt sporter lightweight ( fixed handle a1 sights) that I enjoyed and was very reliable. How do these new models compare?
Not much different actually.......just the updated receiver.
heres my old school Colt sporter, with some Magpul furniture tossed on. Have a form 1 pending and will get the barrel chopped to 10.5 in...anyone know if the receiver extension is different on the 9mms? That magpul stock was a tight fit on there, to the point it doesnt adjust easily..
Attachment 43009
Personally I would avoid Glock lowers, they are not designed for a sub gun and take a beating, would atleast want upgraded spring but Colt pattern mags are great and getting cheaper. Get Metalform or Brownells, don't waste your time on C Products.
Having broken a couple bolt catches, do not skimp on buffer either. Get a heavy (8.5oz) buffer and good spring system. Ultimately I would suggest just getting a Colt, building can be finicky in terms of finding a fcg that works (apart from standard 9mm hammer) and bolt compatibility. I really want to try the JP bolt and recoil system to quiet down the twang when shooting suppressed, but at $400+ it's not worth the change over. If i was starting, i would look into it further.
It will be heavy, but you can save some money and weight going the DDLES or Qtr Circle lowers as well.
what is your preferred barrel length for your ar9?
i'm not sure either to go 10.5" or 14.5" (like my M4)
i don't like the glock version because
a) the bolt does not stay open when empty
b) i don't want to mess around with my bolt carrier to make it work
Just get the 6951.... They work and there are still(at least as of a few years ago,) a handful of federal agencies using them.
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Nothing wrong with using a quality magwell adapter in a standard AR lower either. I see a lot of people going for dedicated lowers but there simply not required.
The new Gear Head Works brace should be a nice addition for those with AR pistols
http://uploads.tapatalk-cdn.com/2017...5c43851b57.jpg
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SSD just posted a teaser from ADM - AR lower for Glock mags
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They should, unless there is some rail that requires some weird barrel nut that would make it otherwise incompatible.Quote:
Originally Posted by Caeser25
Two reasons for that:Quote:
Originally Posted by Caeser25
1) To run reliably
2) To not break hammer pins and bolt catches
To address #1, an H3 @ 5.5 oz will do the trick- the gun won't know if it's an inertial buffer or a solid one. Bonus that you can leave it in for 5.56 application. I have done this for thousands and thousands of rounds. It works 100%.
To address #2, always use SS or extended pins, and consider either a SlashQ elongated buffer, a Colt buffer spacer, or just doing away with the LRBHO via a different block.
I don't know of any Glock lowers that feed 100% AND actuate the LRBHO 100%.Quote:
Originally Posted by Caeser25
Sure, if you don't mind a bit more stuff coming back at you, esp when suppressed. The 9mm deflector is really more of a gas shield.Quote:
Originally Posted by Caeser25
In other words... not working great.Quote:
Originally Posted by jesuvuah
Inconsistency in LRBHO will drive you insane.
This is my solution.Quote:
Originally Posted by wahoo95
Once you let go of the idea of LRBHO, just pick a block in a format you like, that runs reliably, and drop it into an already SBR'd lower.
Think about the savings in money and time alone... plus the versatility of being able to drop the block, swap uppers, and go back to 5.56...
LRBHO is next to useless, don't let that hold you back from the Glock mag lower. Glock mags are more readily available, and the ETS mags are very inexpensive. I suggest a dedicated lower. The only blocks that work are the ones that are more expensive than a dedicated lower, unless you have a 5.56 lower that's already SBR'd, then a Hahn mag block would suffice. In that case, I'd still choose the dedicated lower and SBR it. Grabbing a complete carbine is infinitely easier than converting calibers back and forth.
Nordic Components showed a lower today that uses a push pin to swap magwells. Glock, M&P, etc. I think they said they would be making something like 12 magwells. Sounds like it comes as a complete rifle too.
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I just saw this, looks awesome. If they can get LRBHO to work with different mags they're going to have a really impressive product, especially if you go to SBR one.Quote:
Originally Posted by Wake27
Not if you want to train on your 9mm AR the same way you do on your 5.56 AR.Quote:
Originally Posted by RIGPIG
I ended up buying a Slash 9Q-T buffer for my Quarter Circle 10 Glock 9mm. Was not getting consistent bolt hold open on last round like I was with the shorter KAK 9mm non-adjustable buffer. Was pulling my hair out trying to get it figured out by lightening the overall weight and just happened to notice there was only about 1/8" between the bolt and bolt catch when manually locking the bolt back. Ended up having to mill 1/8" off the end of the buffer bumper to give the bolt catch time to lift. This gun will be a dedicated suppressed gun if I ever get my form 4 back...
I can tell you it has been 100% reliable in every aspect until I played with the Slash buffer. Now that I have figured that out I expect it to continue to be 100%. That may change once I get is suppressed, but we shall see.
I think I am having the same issue with a slash buffer. I might have to try shaving it downQuote:
Originally Posted by Jeepman1320
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I have a QC10 Glock 9mm lower as well and was having problems with LRBHO with a Slash 10Q buffer and Wolff XP spring before I realized that going monopod with the mag definitely activated the LRBHO with rounds still remaining [emoji15]
As this may be a possible serious gun I just took the whole LRBHO assembly out...
Otherwise it runs like a champ with Glock, Magpul, and ETS mags of all available sizes with various ball and Ranger 147 HP.
Dennis.
My point stands. If you train to shoot until bold hold open, you're doing it wrong. Train to reload with one in the chamber, it's much quicker than an open bolt reload.Quote:
Originally Posted by mkmckinley
Except that requires counting the number of rounds you fired and being in a low enough threat area that you can afford to reload with rounds still in the mag. Viable technique for competition though.
Good food for thought but I haven't found that to be a reliable method under high levels of stress. I'd prefer my 9mm have the same features as my 5.56. To each his own though.Quote:
Originally Posted by RIGPIG
This......Quote:
Originally Posted by mkmckinley
Counting rounds in a high stress real world application is not reliable. Unless you are performing tactical reloads during a lull in the action there is no reason not to shoot to bolt lock.
Regarding buffers, a 5 oz carbine length buffer will overtravel. That is, it's going back farther than it needs to since the 9mm is shorter than a 5.56 round. On a Colt pattern setup with LRHO this will put more stress on that latch when it slams in to battery. Broken latches used to be common til the dedicated length buffers came around.
If you don't want to spring for a new buffer there's spacers available (Spike's has a nice aluminum one and I think Brownell's has a cheap delrin spacer) or you can drop some quarters in your buffer. I started with a RRA 5 oz carbine length buffer and when I added 7 quarters in my buffer to eliminate the overtravel it smoothed it out quite a bit.
I run a Spike's ST-9X 8.5 oz dedicated length buffer, runs good with light range loads up to +P loads. For a steady diet of +P I'd probably go up to a Slash's 10 oz.
My RRA upper has a gas deflector on it, and just picked up a PSA pistol upper with no door or deflector. For right handed use I notice no difference in felt gasses between the two. For left handed shooting I'd assume that deflector would be worth it.