Misfeed Issue

PSA Products AR-15
1

Greetings to all; newbie here!

About a year ago, my son bought a new AR-15, chambered in .300 Blackout. The lower and barreled upper were both PSA, IIRC. It wasn’t until just recently that he finally took it to the range, and discovered that it would fire only a few rounds at best before the bolt would fail to return to battery.

The culprit seems to be a very sharp/square edge on the mouth of the chamber, with zero bevel or lead-in. The bullet enters the chamber, but then the square chamber edge catches on the mouth of the case, and shaves off a heavy line of brass down the neck to the shoulder, where it catches and jams. It does this regardless of which ammo or magazines are used.

Because the upper was purchased a year ago and has been fired, I assume there’s no returning it. So, my question is this: would it be appropriate to remove the buffer tube so as to allow straight-shot access to the chamber mouth face, and use a countersink mounted in an extension to lightly break the offending square edge?

I’m a toolmaker machinist, so this is no problem for me. Or, does anyone have other suggestions? Any insight is very much appreciated!

1 Like
2

You certainly can return it for repair. PSA has a lifetime warranty. You also could polish the chamber or take off the sharp edges, but if you mess it up you will likely void the warranty.

4 Likes
3

Id send it in if it were me.:man_shrugging:t2:

2 Likes
4

If it were me, that little bur would have been filed off and the chamber polished……
For the rest of that guns life……every time I pulled the trigger…. I would have the satisfaction of knowing “I know my rifle”……”I take care of my rifle”…… “I have confidence in my rifle”

Some people are like that……others have someone else doing these things for them.

2 Likes
5

Welcome to the forum. You sound competent and confident enough to make this fix yourself. I was also a machinist in a past life and I know what I would do if it were me.
But to @GuitarGuy’s point if you don’t have an immediate need for the upper you may be better advised to send it in.

1 Like
6

I’m definitely one of those guys! I’m a serial tinkerer anyway, and have done modifications to several of my guns including complete action jobs on my revolvers. Hence, he asked for me to handle this for him.

I’ll see what he wants to do, but he’ll likely opt for a return so as to preserve the warranty. He doesn’t have any immediate, outstanding need for it until deer season rolls around (he mentioned he’d like to harvest a deer with it), but even then he has bolt guns in more powerful chamberings to choose from.

Thank a million, guys! I’ll check into that PSA return. :slightly_smiling_face:

2 Likes
7

Are you 110% sure of the problem?

I’m a 300 blk junkie, and in my experience if you’re getting off a few shots then having a problem it’s either your buffer or your mags.

2 Likes
8

It’s definitely catching on the chamber mouth, and shaving a strip of brass from the neck of every case. When it misfeeds, it hangs on the case shoulder 9 times out of 10, regardless of which brand of magazine you’re using. The other time is when it’ll actually hang on the mouth of the case. When I said the chamber mouth is square and sharp, I mean it’s a very sharp, perfect 90 degree corner with zero edge break at all. It obviously somehow missed the chamfering operation following chamber reaming.

Whether cycling during live fire or when chambering a round from the locked open bolt position using the bolt release, the same thing happens. Every several rounds, she’ll hang up.

At first, I thought maybe it was the P-mags he was using, but we tried a few other brands with the exact same result. That’s when I took a closer look and discovered the sharp edge. By contrast, every rifle chamber I’ve ever seen has a small but definite edge chamfer, including my own AR (in 5.56).

9

Great for him if he wants to use his 300 BO for deer. There may be more powerful cartridges……but it’s all about the bullet and the shot placement. For a couple of seasons I used a 7.62x39….which has very similar ballistics to the 300. Three deer & a big hog. All went down quickly with a single shot to each. (Two of them were brain shots) but if he does his job……that 300 is more than adequate for the job. Make sure you post some pictures on the Hunting Thread after deer season.

10

:+1: I’ll definitely throw up a pic or two if he bags one, which he always does.

It’s indeed all about shot placement with the correct bullet. I know several people who’ve harvested deer with .22 cal needle blowers, and they were all clean DRT kills because of accurate vitals shots using the proper bullet geometry. Several years back now, a buddy drilled the heart and both lungs of a huge whitetail buck with his .22-250 at close range, and the hydrostatic shock damage was absolutely devastating. The only other thing I’ve ever seen that crazy was done by a MUCH larger round; a .300 Weatherby Mag. that fractured the ribs like eggshells in about 6" circles around the entry and exit holes.

OTOH, we’ve probably nearly all seen or known of wounded deer that were lost when shot carelessly and impulsively with “traditional deer calibers.”

Reminds me of one such fiasco when a real Einstein I know shot a doe with a .270. It was right at the end of shooting hours and it was too dark for him to see, but he took the shot anyway and hit her in the thigh. A buddy and I tracked it for 900 yards through thickets and brush the next morning, and she had just died and was still warm (on a very cold day), so thankfully it wasn’t wasted and he was able to process it.

11

I love the ballistics on these medium 30 cal rifles. They get the job done cleanly. No excessive meat damage. No exit wound.

12

as guitar guy said, psa has a lifetime warranty against manufacturing defects. i too like to tinker, but if it were me, id send it back to psa to be repaired then when i received it back i’d test her out… if all is good, then i’d go ahead and polish or make any other changes i wanted to at that time, knowing i have a good full warrantied rifle, that has been tuned by me.

1 Like
13

I am not a metallurgist, so I’d be curious if machining a very hard piece of BCG would screw up the casehardening? It would definitely ruin any nitriding or surface coating.

BTW – love that name “Rusan the Terrible”!

14

Should not be an issue at the mouth of the chamber. My biggest concern is the correct angle and depth of the chamfer, and if indeed that is the entire problem.

Things Happen - I’m a fairly competent machinist myself, but hold within me a fair amount of reluctance toward cutting on a Warranteed item.

I would send it back, just let THEM replace the barrel or upper.

15

I’m sure he’ll contact PSA about returning the barreled upper for repair/exchange, so as not to void the warranty.

Nvpurk, my username “Rusan the Terrible” is a old nickname with a funny backstory, although it wasn’t very funny at the time.

I got the name way back in 1990 when my old bluegrass band played at a culture festival. The theme was 1800s Appalachian life, and there were arts and crafts booths, blacksmithing demos, various presentations on what life was like, lots of antiques, vintage tools, people dressed in period clothing, a horsemanship/dressage show, a moonshine still, tons of authentic food cooked on an open fire, and all kinds of other cool stuff. And, lots and lots and lots of beer.

We weren’t required to dress up, but since we booked the gig a couple months early and had time to get some duds, we thought it would be fun. I was wearing what they called a “Common Shirt,” some moccasin boots that cuffed down at the top, and my big Arkansas toothpick on my waist. A very drunk heckler apparently thought I looked more medieval than 1800s Appalachian, and started talking smack about my outfit and calling me Lancelot, then out of nowhere started repeatedly saying, “All hail the great and noble King Rusan, the mighty warrior!”

Then, he yelled something very vulgar about my wife (who was playing the dulcimer) between songs. I’d already had enough of his nonsense, and screamed into the mic, “Buddy, that’s my wife, and you’re DANGEROUSLY close to wearing this mandolin up your ■■■.” Everybody was staring right at him, and security was already on their way and hauled him off. The guys were laughing so hard they were almost in tears, and after the gig I was christened “Rusan the Terrible,” and have been called Rusan ever since.

9 Likes
16

I had an PSA upper that would not cycle properly. Changed out BCG and spring but it still would not cycle. Sent it back to PSA, they replaced the upper without any problem. No issues after that.

17

That is awesome! Thank you for sharing that :smiley:

18

thanks for sharing the story… that had me smiling. i needed a good l augh.

1 Like
19

I second this. If you feel confident you know what’s wrong and can fix it then that’s an option but I’d give PSA the option to make it right first. They have a lifetime warranty and stand behind it so why not use it.

1 Like