So I’m a little confused on what is going on with my 14.5” URGI.  It’s fairly new with a low round count (Received Nov 2021) and I have had zero issues with it until now.  I’m now having failure to feed problems with steel (Tula) when before it was fine.

Prior working conditions:
Daniel Defense BCG
Super42 Spring & H2

Yesterday I popped in a Toolcraft BCG and it seemed to run through a few rounds before it started the failure to feed issues.  I tried popping the Daniel Defense BCG back in, failure to feed.  I tried swapping the brand new Super42 & H1 that came with the upper, failure to feed.

Running the steel SUPPRESSED worked fine.  Running brass UNSUPPRESSED worked fine.  So I’m here scratching my head trying to figure out what the hell is going on?

Also, I swapped lowers with a friend and it worked fine.  He had a H2 but it had a LAW folder if that makes any difference.

Tula is notoriously underpowered ammunition.

That is disgusting you are giving it to your URGI.

Please stop immediately.

It sucks that ammo is so expensive now that Tula is the only thing half way affordable. I haven't had any issues with Wolf Polyformance or Barnaul in my 14.5 URGI. I haven't shot very much of it, though. Just enough to verify it will run it reliably. Try using a carbine spring and a carbine or H1 buffer when not shooting suppressed.

Tula ammo sucks.

It still should work. Try a carbine buffer, an H2 might be too heavy for Tula.

My URGI has shamefully eaten some steel case from time to time without issue. I use an H1 with my super 42. I’m sure the extra back pressure from the can doesn’t hurt either

Try using a standard (non-H) carbine buffer. That's what I had to do to get my Super Duty to eat some steel case I had left over from 2020.

This ??

For underpowered ammo unsuppressed a GI spring and buffer set up should work well with the URGI.

-GACS

Today I shot the last five rounds of steel case that my 14.5" Super Duty wouldn't cycle until I put in a PSA std weight carbine buffer and spring. I saved it until today, because my magneetospeed sporter came in this week. I got some velocities from different loads I use for different things, for comparison and so I can have really good holds on long 2-gun stages.

Results (All from the same 14.5" SD rifle with a round count around 2k):

Frontier FR320 (75 gr): 2615, 2637, 2645
Frontier FR310 (68 gr): 2756, 2752, 2713, 2774, 2795
Norma Tac .223 (55 gr): 2892, 2897, 2914
IMI "M193": 3011, 2960, 2949, 2946, 2936
Red Army Standard .223 55 gr FMJ: 2693, 2701, 2716, 2727, 2722

So, basically, about 200 fps slower than non-garbage .223 or 300 fps slower than 5.56 with same bullet weight, and still ~50 fps slower than match 5.56 with a 13 gr heavier bullet in a load that is optimized for a much longer barrel.

Tula is garbage.

What about using the standard weight buffer but use it with the Geissele Super 42 spring? If that works you have the best of both worlds, it will run slow ammo (for emergencies perhaps) but still have the great spring for hotter ammo & suppressed etc.

The Super 42 spring does not fit on a mil spec buffer.

Good stuff. Thanks for sharing.

You are having short stroking. Tula Ammo is underpowered.

I second this