New RIA 1911 causing bullet setback

[BeerSleeper]

Short story: I have a new Rock Island Armory 1911 GI that is causing bullet setback, sometimes as much as (approximately) .020"-.030" in a single chambering. This has happened with both handloads and on brand new factory ammo (WWB)

Questions:
1) Is this normal, or should I be concerned?
2) If it should be addressed, is it serious enough to seek warranty service? (I am a mechanic by trade, and have a high degree of mechanical aptitude (+), but no practical gunsmithing experience (-). I know 1911's can take a little finessing to run well, and I'm prepared to attempt basic solutions cautiously myself, as long as they are low-risk, reversible operations (I'm cautious, and not getting in over my head, i.e. I'm not touching the ramp myself, I'm not ready for that yet.)


Long story (read this if you want the details): I got this new 1911 (my first one). I ran a box of WWB through it, without any apparent problems. I then loaded a small batch of 200gr plated, flat point, berry's bullets. The first three in a test batch of 20 fired fine. Then I pulled the trigger, and got nothing. I noticed the slide was not in battery. Tried chambering a few other rounds, and noticed the same phenomenon. At this point, I aborted testing, and returned to the bench.

At the bench, a barrel drop test revealed the bullets, which were seated to loadbook OAL, were engaging the rifling, and not fully entering the chamber. These were starting charge loads, so I felt I had the room to shorten the rounds until they passed the barrel drop test. At this point, it was after dark, and too late to shoot, so I decided to perform a manual feed test. I chambered the rounds, one at a time, by dropping the slide from slide lock ( to simulate chambering a round with the approximate amount of force as would occur during automatic reloading when shooting). Every round chambered, going fully into battery. I thought the issue was solved, until I picked up the rounds, put them back in the ammo box, and noticed they stood at different heights. Most of them were set back to one degree or another (didn't measure, and it's too late now, they've been pulled).

That was over a week ago. I mistakenly thought it was because of the flat point bullets I was loading not wanting to feed up the ramp. Today, I got home with a new box of 230gr rn bullets, loaded up a test batch, and tried again. When I got the same bullet setback issues, I decided to try chambering a factory round. On three successive chamberings, the round shortened by .015", .015", and .010" for a total of .040" OAL shrink in three chamberings.

I'm aware bullet setback can happen with multiple chamberings. That is why I chamber the first round gently under normal circumstances, and especially when rechambering my carry ammo. My concern here isn't that this might be happening over multiple chamberings, my concern is that this gun could potentially cause enough setback on the single, first chambering of a round to cause a dangerous condition.

I eagerly await all helpful responses. Thank you.

 

[jmstevens2]

Mine would not go back into battery occasionally, but did not push back the bullet or deform the case. As it broke in it went away. Not sure if the phosphate finish slowed the slide down, or what. I will watch for other thoughts however.
Mine is the GI version.

 

[BeerSleeper]

Loading in slow motion, it looks like the bullet is wanting to nose dive, and hitting the feed ramp head on.
I have a friend who is somewhat of a 1911 guru, I think when next I see him, I'm going to borrow a known good-feeding magazine, and see what happens.

 

[mjsdwash]

1911 all cause some setback, as do most auto's that don't have roll crimps. That said, my Ria came with an undercut chamber, and an improperly cut feedway. Mag and frame ramp had correct geometry to each other, but not to the horizontal surface of the frame, and the breach face. This caused significant setback like what your describing. It also caused many malfunctions, a blowoff letter from the manufacturer, and me buying a better 1911. If yours does not jam, its most likely the undercut chamber they've gotten a reputation for.

 

[BeerSleeper]

I've got a little over 200 rounds through it now. We found the extractor to be excessively tight. Loosening it a little bit improved things slightly, but not much.

230 gr rn feeds ok. It's nosediving hard onto the ramp, especially the first three or so rounds from the mag. They are getting setback, consistently, but they are feeding every time. I had a round spit out a primer last week, and found one other piece of brass that had a loose primer. That particular trip to shoot was a box of factory ammo, and all the rest of the brass from that session looked normal, so I'm attributing the blown primer, and the loose primer, to a pressure condition due to setback bullets.

TC bullets jam often. They dive on to the ramp and stop there, with some setback.

SWC jam almost every time, and with substantial setback.

I just got a new Chip McCormick mag, to see if changing the mag makes a difference. The feed lips on this mag release a bit sooner. Manually feeding, doesn't look different. Dropping the slide on a mag full of 230 rn feeds, but still diving hard on the ramp, and setting back the bullet.

mjsdwash: how to I determine if I have an undercut chamber, or improperly cut feedway?
The TC rounds I tried were handloads. I figured out I had to seat them deep. The bottom of the cone had to be flush with the case mouth, or the gun would not go into battery due to the bullet sitting on the rifling. Until I read your post, I was just thinking it was a really tight chamber, but now that sounds like something that could be a symptom of an undercut chamber.

 

[mjsdwash]

If a loaded max oal round, or if you dont have calipers, whatever you want to have work will drop into the removed barrel, and sit flush or below flush with the end of the barrel hood, and fall out pretty easy with some shaking, the chambers probably allright. if not, its probably not gonna work great. I also found with mine if you put the rounds in the magazine with the case bulge (if present) on the extractor side it fed due to an out of round as well as short chamber. Sorry i didnt get back sooner, just caught your reply. theres a page on ramp geometry ill look for, but long story short, use a carpenters protractor, and a square flat object like plexiglass laid across the frame rail right above the slidelock hole. Use that as your flat, and put the protractor against that. you may need to shorten the protractor like i did with a standard home depot $10 protractor to fit into the magwell. Look for any angle around 31 degrees. plus or minus 90, because your resting against the frame. Example. 61 degrees good, 121 degrees good. 31 degrees good. 30,60,120 and so on or lower bad. 33,63,123, bad. Most defects are more than a half degree off, and can be seen with a carpenter protractor. Hope this helps, and hope this makes sence.