PCC colt mags Failure to feed

[jaggy13]

My PCC is a cold mag block RRA with bolt hold open and 3 RRA colt style 32 round mags.
I have had the following malfunction twice but am still in the first 1000 rounds so not sure if it will work itself out or not.

The malfunction is a failure to fire, but the round is in front of the extractor. So it's getting in the chamber ahead of the bolt.

I think it's happened with the same mag both times, but haven't been able to recreate it. My mags are numbered, but I was on the clock when the malfunction happened. So I didn't get a chance to confirm.

Do I need to undercut the extractor? Or is this a mag tuning issue? All three mags appear to be working correctly and all feel similar when loading. But when emptying, they have a tenancy to "Spit" rounds out. as I slip a round out, sometimes 2 or 3 more rounds will follow...

For the most part, everything seems to be running really well and i'm not short stroking, its locking open on last round hold open.

Thanks in advance for any advice!

[Southpaw]

Is this a complete off the shelf RRA or did you build it? So the rounds are fully chambering, just not snapping onto the extractor? If so, that doesn't sound like a mag issue since they're feeding fine. If headspace is off on the barrel and brass sits too deep in the chamber it might not reach the extractor, but if that were the issue I think you'd have a lot more problems than just 2 out of 1,000. Did you inspect the 2 rounds that had this issue and notice anything unusual about them?

[Nightops]

You've already identified that the mags can release rounds too easily.

Get some good Metalform mags (Palmetto State Armory has them on sale regularly)

This is the easiest, and most likely culprit. Troubleshoot further from there if necessary.

[MickB]

This can also happen if you happen to accidentally reload .380 cases or 9X18. Ask me how I know...

Mick

[StealthyBlagga]

This can also happen if you happen to accidentally reload .380 cases or 9X18. Ask me how I know...

Mick

^^^ THIS. Was a source of much hilarity and harsh Australian curse words

[Southpaw]

This can also happen if you happen to accidentally reload .380 cases or 9X18. Ask me how I know...

Mick

Yup, that's what I was thinking when I asked if he inspected those rounds

[jaggy13]

Thanks for the reply's. The RRA mags are metal form.

Also the round looked fine, no primer strike. And unfortunately.... Not 380 brass.

At this point, I'm thinking its mag break in. I'll keep ya posted as I get more rounds down range.

Thanks for the comments!

[StealthyBlagga]

If the rounds are getting all the way into the chamber and are still in front of the extractor, then I am not sure how this could be magazine related. As mentioned above, check (1) the case length of the ammo, and (2) the headspace in the chamber... there is likely some mismatch. Spitting rounds is not necessarily abnormal with a double-stack/double-feed magazine, especially when unloading or if dropped.

[jaggy13]

I just left the range and was finally able to recreate the issue then it got worse culminating in a seized bold in the almost rear position.

When I pulled it apart, the buffer retainer was pinched and wedged against the bolt.

I may have been getting some drag from the retainer causing the feed issue.

I'll keep an eye on it and see how it goes.

[GunCat]

If the rounds are getting all the way into the chamber and are still in front of the extractor, then I am not sure how this could be magazine related. As mentioned above, check (1) the case length of the ammo, and (2) the headspace in the chamber... there is likely some mismatch. Spitting rounds is not necessarily abnormal with a double-stack/double-feed magazine, especially when unloading or if dropped.

Does not sound like a magazine issue to me either.

With the bolt out of the gun can you manually press a round into the bolt face with reasonable pressure?

Sharp edge on the bolt face that slows the cartridge rim from feeding into the bolt face recess?

Extractor too far in (or blunt on the end) and not snapping over the cartridge when feeding?

Brass, steel or aluminum cased ammo?

[jaggy13]

I was able to replicate the issue again only on mag2. I'm going to shoot a match tonight and use just mag 1 and mag 3.

I'll try and be as systematic as possible and note any malfuntions. I shot 200 rounds both saturday and sunday with only malfuntions on the top half of mag 2. Round 13 or earlier.

I just cleaned the extractor and checked the tension. everything looks great and i can snap an empty case in easily and yet it holds it tightly.

I'm apprehensive to start cutting or bending it at this point.

[jaggy13]

I think I have this solved.

I turned out not to be a mag, but more specifically it was jamming from the left side feed.

I noticed bullets where damaged from loading and with the help of another shooter in PM's I was able to isolate the issue.

My ejector was never touching the bolt, but my feed ramp was.
I used my iPhone and the "Slowmo" setting to record a round being loaded into the chamber.

I noticed that the right side was feeding fine, but the left side was just a tad low.

I broke the rifle down at the take down pin and separated the halfs only about 10 degrees.

Then bottomed out the mag block and closed the rifle up. I dropped the bolt slowly, chasing it down and saw where the high spot was on the front corner of the ejection port side of the feed ramp. I just took the corner town a hair and then tested both sides again.

Now I'm not getting any marks on the bullet and they seem to be feeding straight into the center of the chamber.

Thanks for everyone's input. I hope this helps someone else down the line.