I’m considering acquiring an 9mm AR pistol with a 7-8" barrel to run suppressed.
It seems that few AR options run 100% reliably with JHP defensive loads.
Can someone school me on what to look for to make sure a build runs 100%?
Are you building or buying this one?
Open to building or buying.
However, I’m currently not set up w/tools to build an upper and therefore would prefer to buy a complete, barreled upper if one was available.
I finished up mine several years ago, so my memory is not fresh. I can’t recall specifics or give a recommendation on brands.
9mm barrels have a sort of funnel like throat at the chamber. This enhances feeding and allows the extractor to grip the rim. It is a balancing act for the manufacturers to size that to feed well but not leave the back of the casing unsupported.
I run a QC10 barrel. I have had no issues feeding various hollow points and run 147 gr flat nose as my regular training/shooting ammo with no issues as well. I have no case swelling with even halfway decent ammo but I have seen some minor swelling with really cheap stuff like aluminum or thin wall “brass”.
I can’t recall which manufacturers were on my short list and which I chose to avoid, sorry.
Having a few drinks as I type this so bare with me…
I have been using a PSA (gen 2) 8’ barrel and a Nordic 16’ barrel on a QC 10 lower (Colt/Uzi mags) and have at least 5k rnds through it and probably closer to 10k.
This is my competition gun and I built it before PCC became a thing in USPSA. I initially built it as a range toy but it is now in its 4th iteration.
I primarily use Precision Delta 124g JHP but in a pinch I have been using Berrys RN.
So far I have had less than a handful of malfunctions and those I have had were induced by the bolt and one case head separation.
The QC10 bolt has a roll pin that tends to work its way out and drag on the side of the upper but it takes at least 1k rnds for it to happen.
I am in the process of switching to Glock mags and just got in a JP bolt and have only range tested it.
Also, you do realize that a direct blow back carbine is dirty and suppressing it will make it dirtier.
I would like to know where are you getting your info that JHP don’t run well in a PCC?
I’ve got a couple. One with a no-name barrel, one with one with a X-Caliber barrel. I’ve got a lot of rounds on them. Neither have a problem feeding Ranger-T 147, Critical Duty 135, various flat-nose ball, or anything. I’ve had other reliability problems with new parts, but once they were sorted, they’ve run a long time.
Our SUBGUN 9mm barrels do a nice job eating up all kinds of ammo.
Pictured are 147 gr HSTs, along with the feed cone and chamber radius that makes it all work.
https://blackrivertactical.com/WP/BRT-8-5-SUBGUN-9mm-AR-Barrel-p278516615
I have zero issues with my 6” Stern setup AR-9. Run their Glock adapter, and with the 8” handguard, it works great with my Dead Air Odessa. Only fault I can say… if your bolt isn’t notched for a forward assist, source some slick-side uppers. I swapped mine with an Anderson AM-9, and it made quite a noticeable difference. Well, maybe two… thread the barrel 1/2x28”, not 1/2x36”. Running an adapter does stink. Maybe I’ll look at a new barrel in the future, but it isn’t that big of a deal once the adapter is torqued.
We are transitioning to Speer G2 from Winchester Ranger (both 147 grain), and did not have any issues with the Ranger in the gun. I’m sure the G2 will be fine, as well. Another good barrel maker is Rudy at Macon Armory. One of those shop owners that view his product as his “kids,” and wants people to be happy with it.
Difference how, please? Would a small port dedicated 9mm/rimfire upper be even better?
Thank you
Andy
Not sure how they feed JHP’s but there are a lot of advantages to the CMMG delayed blowback over straight blowback. In 9 mm I like the 9 ARC PMAG conversion that allows using standard AR lowers.
Less weight. Have you ever held a slick side AR? Decent amount of weight loss. Add in a light forend and pistol brace…
Ah. Yes, I have 5.56 and 9mm pistols with Anderson sport upper receivers.
Andy
AR9s tend to not be as reliable as 5.56 and .300 blackout ARs. If you are going to run suppressed, you might consider one of those. Especially since you would get a major boost in terminal performance.
But you have to decide what reliability means to you. For a handgun I want at least 500 malfunction free rounds with no cleaning or lube (after initial clean and lube) with my defense ammo before I consider it good enough to to carry. I haven’t been able to achieve that with my AR9.
Having said that, my experience with AR9 reliability has been mixed but I’ve also been trying to tune mine to run with ammo it wasn’t designed for. I have a Foxtrot Mike and they are built to run with standard pressure 115 grain or 124 grain cartridges. I’ve been trying to get mine to run reliably with 147 grain defense ammo and it has been a challenge. I’ve changed the recoil spring, buffer weight, magazine and polished the feed cone a few different times. l would say I’ve got it running where it will fail to feed about once every 50 to 100 rounds of SD 147s.
I’m currently trying the Hornady Critical Duty 135 grain because it has a smaller frontal section and seems like it might feed better. I the standard pressure variation it is closer to the performance enevelooe the FM9 was designed around too.
Stinks about your AR… but that is not my experience at all (and 100% suppressed with that).
I’ve seen most people happy with FM stuff, but I do see some issues from time to time. I personally went with Stern, and completely happy with it (minus the barrel thread pitch and non-functional forward assist). I trust that AR as I do with any other of my defensive firearms.
For reliability… there is a YouTube video with a Stern setup (upper, bolt, and magazine adapter) on a M16 lower, shooting over 6,000 rounds before a hard failure (the non-functional forward assist was the cause… why I opted to remove it completely).
I don’t keep that much with my gun (one 24 rounder, with three 33 rounders in a pouch; 123 rounds total… but I do have a Glock 19 with three spare magazines on my duty belt), so I feel fine with it.
Screwball,
I don’t put the blame on FM because I am trying to run bullet weights outside of what they recommend.
What defensive ammo are you running in your AR9?
Winchester Ranger 147 grain…
Thanks!