Anyone else have issues with PMC Bronze?

[JSTICFRALL]

I went shooting this weekend on a camping trip and took 300 rounds of PMC Bronze with me. This is the first time I've ever fed PMC through my rifle and I ended up getting a failure to feed every 10-20 rounds. I'm using PMags and shoot a BCM with BCM internals. It's the first time my rifle has malfunctioned on me however I usually feed Federal bulk pack ammo through it and haven't had a problem yet. Just want to know if I should chalk it up to my rifle not being a fan of PMC or if I should look for other possible issues.

[markm]

It's a fairly weak load. And doesn't work well in some rifle gas systems... including mine.

I wouldn't worry about your gun not running it well. Carbines tend to run it fine, but longer gas systems not so much.

[JSTICFRALL]

I didn't even consider gas system length as a factor but it makes sense if it's a weak load. I'm running a mid-length system so that would explain it if others have the same issue.

[Doc Safari]

I put over 120 rounds through my BCM carbine the first day I had the rifle and it ran fine.

I haven't had the chance to acquire more but I have no reason to believe it won't run a carbine unless it's a bad batch or something.

[Hmac]

PMC Bronze is about all I buy for the last couple of years in my AR15's, 9mm S&W M&P, and .40 cal P229. I've put about 5000 rounds through my rifles, carbine length 16" and 11.5 SBR, as well as my 16 inch Noveske mid-length. I've had a couple of double-feeds with one particular defective Pmag, but no other malfunctions in any of those firearms.

Bottom line, thousands of round of PMC in a variety of weapons with no issues for me.

Failure to feed is usually a magazine problem. Do you mean short-stroking? That could be caused by weak ammo - ammo that's too weak for some component of your buffer/BCG/gas system.Any problems with your bolt not locking back on the last round of a mag?

My Noveske Light Recce mid-length shoots the stuff with no problem at all. My other rifles have all been assembled with buffer weights that were selected based on their ability to reliably cycle PMC Bronze

[JSTICFRALL]

I don't think it was a mag problem because the malfunction happened with all 8 of my PMags which have be extremely reliable for the year and a half I've had them. I did in fact have an issue with the bolt not staying locked open on the last round once or twice. Essentially what I did to correct the malfunction was just rack the charging handle and it would cycle the next round into the chamber. I am running an "H" buffer in my rifle. Maybe that could be what's causing the issue with PMC in particular.

[Iraqgunz]

Other members have also reported that the PMC was weak in their set up as well. I guess we should ask what buffer/spring are you using?

[Iraqgunz]

Can you provide a more accurate description of your "rifle"?

[Hmac]

I don't think it was a mag problem because the malfunction happened with all 8 of my PMags which have be extremely reliable for the year and a half I've had them. I did in fact have an issue with the bolt not staying locked open on the last round once or twice. Essentially what I did to correct the malfunction was just rack the charging handle and it would cycle the next round into the chamber. I am running an "H" buffer in my rifle. Maybe that could be what's causing the issue with PMC in particular.

Sounds like you're saying that you're actually short-stroking rather than FTF. Bolt going back far enough to eject the spent shell but occasionally not far enough to strip another shell from the magazine and occasionally not far enough to lock the bolt back on an empty magazine. My Noveske with 16 inch mid-length and H buffer never misses a beat with PMC Bronze, so I'd consider looking at the gas key/gas tube/gas block etc. If that stuff is all OK, then I'd probably chalk it up to weak ammo.

My guess is that a carbine buffer or lighter buffer spring would allow you to cycle the PMC, but I'm not sure I'd go to those lengths just for one particular brand of ammo unless I had a lot of it and got it at an outstanding price. My attraction to PMC is that I can get it for less than $.30 a round shipped, and it works fine for me, so I'm reluctant to change. Your solution might be to just not use PMC anymore.

How does one determine when ammo is "weak"? Would we expect that PMC, if it is indeed "weak" would chronograph slower? Anyone have any chronograph data on PMC Bronze?

[P2000]

I don't think it was a mag problem because the malfunction happened with all 8 of my PMags which have be extremely reliable for the year and a half I've had them. I did in fact have an issue with the bolt not staying locked open on the last round once or twice. Essentially what I did to correct the malfunction was just rack the charging handle and it would cycle the next round into the chamber. I am running an "H" buffer in my rifle. Maybe that could be what's causing the issue with PMC in particular.

Assuming you have a normal spring, and not some extra power spring, I would try a car buffer.

[Dobie]

Runs great in my DD Middy with 30 round Pmags. Pretty accurate too. PMC is a good value and I pick it over some others for my Glocks also.

[5pins]

I chronograph it about a year ago but can’t find the data, I think it’s packed away.

However the velocity was two to three hundred fps under normal IIRC.

[JSTICFRALL]

Can you provide a more accurate description of your "rifle"?

With pleasure!

BCM 16" Middy Upper
BCM HP MP Bolt and BCG
Battlecomp 2.0
Regular carbine buffer spring
Carbine "H" buffer
Stripped S&W M&P15 lower
DPMS parts kit

And then all the other bits and goodies that have no effect on cycling performance (i.e. stock, grip, etc.)

[stinkyDrunk]

I was at the range with a friend where he chrono'd the PMC stuff and Wolf from the same rifle, PMC was about 100 fps slower. Which surprised both of us, we expected better.

[Iraqgunz]

So you have a midlength carbine with H buffer. So I stand by my earlier assertion that it is the ammo.


With pleasure!

BCM 16" Middy Upper
BCM HP MP Bolt and BCG
Battlecomp 2.0
Regular carbine buffer spring
Carbine "H" buffer
Stripped S&W M&P15 lower
DPMS parts kit

And then all the other bits and goodies that have no effect on cycling performance (i.e. stock, grip, etc.)

[bluto0251]

I have put over 1k of it through my LMT with no issues whatsoever. Standard LMT rifle, with H-buffer, and D&H magazines.

[YVK]

I've shot a good deal of it through my 14.5 BCM middy with H-buffer without a single problem.

[infidelprodigy]

Perhaps you just got a super weak lot in production. I've shot well into the tens of thousands of rounds over the last few years of PMC Bronze with no issues in everything from mid-length, carbine, and "intermediate" length with CAR, H, H2, and H3 (in LMT 10.5") with no problems at all. No popped primers or short-stroking.

[JSTICFRALL]

I think I'm going to chalk it up to being a bad batch of ammo. My rifle has always functioned flawlessly up till this past weekend.

[curmudgeon9]

I've run thousands of 55gr. PMC Brass thru my 16" and 14.5" carbines with no problems. Reading these reports here, I would agree with previous posts that the mid-length and rifle-length gas systems might not be compatible with this slightly weaker round.

[Iraqgunz]

That really doesn't make sense as it should be able to run a rifle more of nothing else.


I've run thousands of 55gr. PMC Brass thru my 16" and 14.5" carbines with no problems. Reading these reports here, I would agree with previous posts that the mid-length and rifle-length gas systems might not be compatible with this slightly weaker round.

[markm]

PMC short stroked a little in my musket. The powder's pressure curve seems to peak early and not have much umph left over to cycle longer gas systems.

A similar thing was happening with the WOLF M-193 ammo that was briefly on the scene. That stuff was pretty hot ammo, but didn't like longer gas systems. The pressure spiked hard and fast, but dropped off to where it wouldn't cycle well in many rifles.

[Hmac]

PMC short stroked a little in my musket. The powder's pressure curve seems to peak early and not have much umph left over to cycle longer gas systems.

I think that's really a great point - pressure curve vs muzzle velocity. People tend to assume that it's "weaker" ammo, assuming lower muzzle velocity. I haven't seen any chrono data, but I'm not sure that's necessarily true.

[JSTICFRALL]

Well I'm not really sure what was going this time, but I got out and shot some more of the PMC I got yesterday and didn't have a single malfunction. Is it possible that maybe there was just a bum round here and there throughout the case I got? :confused:

[bp7178]

A similar thing was happening with the WOLF M-193 ammo that was briefly on the scene. That stuff was pretty hot ammo, but didn't like longer gas systems. The pressure spiked hard and fast, but dropped off to where it wouldn't cycle well in many rifles.


I speculate, from my limited reading about gun powder for handloads, that this is related to the burn rate of the powder.

Almost as if the powder burns off too quickly, its gone before the gas port, and the pressure is on the way down, instead of building. Realitively speaking.

On the same note, I would surmise PMC Bronze works great if you have a 16" with a carbine gas system.

[Hmac]

On the same note, I would surmise PMC Bronze works great if you have a 16" with a carbine gas system.
Works great with my 16" carbine gas system. Also with my 11.5 carbine gas system and my 16 inch mid-length. Buffer plays a role, spring plays a role, and presumably the gas port diameter plays a role.

[markm]

I speculate, from my limited reading about gun powder for handloads, that this is related to the burn rate of the powder.

Almost as if the powder burns off too quickly, its gone before the gas port, and the pressure is on the way down, instead of building. Realitively speaking.

On the same note, I would surmise PMC Bronze works great if you have a 16" with a carbine gas system.

I agree on both points.

1. My theory on the WOLF M193 was indeed that the propellant was too fast. Possibly a deliberate attempt to get velocity with minimum powder charge per round? I'll tell you that the brass on that ammo would stamp the ejector cut into every piece of brass. ;)

2. The PMC bronze indeed seems to run great on almost everyone's Carbine gassed guns.

[P2000]

I have run about 600 rounds of PMC through my SR-15 without a single malf. It has a longer than midlength gas system, and a 16'' barrel. It does seem to run the bcg quite slow. During the very first mag or two of the rifle's life I could actually feel the bcg moving. Now that it has broken in a little, it seems to run more normally.

Here is a link to some chrono data (not mine).

http://beta.ar15.com/archive/topic.html?b=3&f=16&t=505425

[Doc Safari]

...The PMC bronze indeed seems to run great on almost everyone's Carbine gassed guns.

It may be a blessing in disguise. Since a lot of threads have pointed out that the carbine may be prone to early parts failure due to the gas pressure, we may have inadvertently stumbled onto a "light load" that is appropriate for carbine gas and doesn't overly stress the bolt and gas port.

[markm]

I've reloaded .223 ammo for years like that. I don't see any value in loading full throttle 5.56 for practice ammo... Costs a little more and runs your gun harder.

[JSTICFRALL]

Okay so now the plot thickens: After cleaning my rifle and lubricating everything, I decided to see if I could somehow replicate the malfunction I was experiencing. So I loaded up a magazine and then racked the charging handle over and over to eject the rounds from the magazine. It turns out the tip of each round keeps getting jammed in the feed ramp and won't seat into the chamber. I tried it with different magazines and even switched to different ammo to see if that made a difference, but it didn't. Any thoughts :confused:

[Iraqgunz]

I suggest that you contact Bravo Company and ask then to look at it. Let's also not start a bunch of seperate threads so we can keep this on track.


Okay so now the plot thickens: After cleaning my rifle and lubricating everything, I decided to see if I could somehow replicate the malfunction I was experiencing. So I loaded up a magazine and then racked the charging handle over and over to eject the rounds from the magazine. It turns out the tip of each round keeps getting jammed in the feed ramp and won't seat into the chamber. I tried it with different magazines and even switched to different ammo to see if that made a difference, but it didn't. Any thoughts :confused:

[JSTICFRALL]

Will do. Didn't mean to start multiple threads, just figured I'd create the new one for the appropriate forum since it doesn't seem to be an ammo issue anymore. I appreciate your feedback and help though!

[Hmac]

Okay so now the plot thickens: After cleaning my rifle and lubricating everything, I decided to see if I could somehow replicate the malfunction I was experiencing. So I loaded up a magazine and then racked the charging handle over and over to eject the rounds from the magazine. It turns out the tip of each round keeps getting jammed in the feed ramp and won't seat into the chamber. I tried it with different magazines and even switched to different ammo to see if that made a difference, but it didn't. Any thoughts :confused:

I'm not sure that hand-cycling a semi-automatic firearm ever accurately replicates its function. I've had that happen on my Noveske Light Recce too...a rifle that hasn't missed a beat in thousands of fired rounds. It's a way that I can actually create a double feed, something I otherwise have never seen on that rifle.

[markm]

I'm not sure that hand-cycling a semi-automatic firearm ever accurately replicates its function.

It doesn't. And it's a dangerous excercise in futility.

[JSTICFRALL]

I'm not sure that hand-cycling a semi-automatic firearm ever accurately replicates its function. I've had that happen on my Noveske Light Recce too...a rifle that hasn't missed a beat in thousands of fired rounds. It's a way that I can actually create a double feed, something I otherwise have never seen on that rifle.

Definitely some food for thought, however the same malfunction I was experiencing through hand cycling was the same one I was experiencing at the range a few weekends ago. The weird part was when I went shooting on Tuesday I didn't experience the malfunction at all and ran about 6 mags through my gun.

[mhanna91]

I used to run alot of it in my M&P15 carbine-length. It always ran fine, but one time at the gun shop I was buying a few boxes and I opened one up to look at the rounds and one of them had the bullet seated so far in that a quick tap on the table sent the bullet through the neck and into the case. There was no powder charge in the case either. I showed the man behind the counter and he promptly exchanged me for a new box. Every time I shoot PMC now I pay close attention when loading mags.

[arizona98tj]

I chronograph it about a year ago but can’t find the data, I think it’s packed away.

However the velocity was two to three hundred fps under normal IIRC.

Just checked my chrono spreadsheet. You are quire correct.

The PMC I checked was the 2nd slowest 55 gr FMJ round I've ever checked. The only thing slower, by 11 FPS, was Herter's brand from Cabelas. LOL!!!

Even Tula was around 100 ~ 150 FPS faster than PMC.

[Hmac]

I chronographed some PMC Bronze .223 the other day. Two 30-round magazines each out of my 16 inch N4 and my 11.5 inch BCM BFH rifles.

PMC Bronze published velocity 20 inch test barrel -- 3200 FPS

Out of my 16" barrel...mean velocity was 2881 FPS with SD of 41 FPS

Out of my 11.5" barrel...mean velocity was 2443 FPS with SD of 51 FPS.

I have nothing to compare to, velocity or standard deviation-wise, but the trajectory curves are something I've been curious about.

[JSTICFRALL]

Thanks for the updates, guys! I haven't shot any PMC through my rifle since I had the malfunction however I did replace the buffer spring and switched back to Federal bulk boxes from Walmart. Haven't had a single hiccup since then and have put at least 500-600 rounds through it. I might try some PMC again in the future but I know I've had no problems with Federal so I'll probably just stick with that for practicing.

[gunfighter48]

It works fine in my S&W 15 Sport AR. I've only used 400 rds so far but does fine in my new AR.