AR9 - Are any 100% reliable with JHPs?

[mizer67]

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%?

[Stickman]

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?

[mizer67]

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.

[utahjeepr]

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.

[fedupflyer]

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?

[1168]

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.

[Clint]

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/BR...rel-p278516615

[Screwball]

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.

[AndyLate]

~SNIP~
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.
~Snip~

Difference how, please? Would a small port dedicated 9mm/rimfire upper be even better?

Thank you
Andy

[mack7.62]

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.