Grendel Ammunition Failures

SnowmanMo

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The 6.5Grendel is a fantastic cartridge for use in the AR-15 platform. I was introduced to it when it first came around in 2004. In those early days we were pretty limited in parts and ammunition availability. Recently the cartridge has begun to surge to the fore front again with more readily available parts and ammunition.
We recommend that our customers use high quality ammunition when they use one of our rifles. We test our rifles with a variety of ammunition so that we can see how it performs.

Recently we were tutoring a client that we had built a 6.5 with a 20in stainless steel barrel built on our billet upper and lower combination. We started our client off with Hornady 123gr Amax ammunition. As our client began to gain confidence with his abilities with his rifle he began to engage targets at will out to 500 yards. As his confidence grew so did his rate of fire. We were firing 3 shot strings and after 40 rounds we had exhausted his supply of Hornady so we switched over to PPU to see how it performed in his rifle.
First round out went right where the client wanted it. Round #2 and #3 did the same. We reloaded and shots #6 and #7 went down. On shot #8 we were engulfed in a cloud of black smoke. The rifle was jammed and the magazine was in pieces. We secured the rifle and packed up to take it to the shop for diagnosis. While we were policing p the brass we found that ALL of our Hornady brass was in good shape. We found that 2 of the PPU cases looked fine. 4 of them showed signs of slight over pressure with indentations in the head stamp from the bolt face. One of the cases exhibited signs of extreme over pressure having deep head stamp markings and the primer was blown out. It appeared that we had an ammunition problem but until we broke down the rifle we weren’t going to declare anything.

Cases #1 and #2


Cases #2, #3, #4, #5

At the shop we were able to extract the BCG and the stuck case. It had ruptured out the side of the case and the primer was missing.

Ruptured case

Examination of the rifle showed that it had weathered the failure quite well. We got the rifle ready for another trip to the range for further testing the next day.
The next day found us again out in 98 degree weather. We test fired the customers rifle with Hornady ammunition and had no failures after 40 rounds. We then switched to one of our test rifles and continued testing. Again no problems. NONE of the cases showed any signs of over pressure, no head stamp indentations, no lateral scoring, no belting around the case bottom, no loose primers.


Some of our Hornady cases from both rifles


We switched to some hand loads and were able to fire 10 hand loads, 5 from each rifle with no problem.


Some of our handload cases

We then switched to the PPU. Test A: Round #1 went off fine. #2 and #3 showed slight signs of over pressure with some shallow head stamp bolt face markings. Round #4 popped out the primer. Test over. Spotting the pattern we decided to allow the rifles to cool and repeated the test. Test B: we popped a primer on shot #3. Test C resulted in the same as test B


Test A brass


Test B brass


Test C brass


We went back to the shop and rechecked the headspacing on both rifles as well as shook them down to see if they had any other problems. No other problems were found.

Our conclusions are this: At high ambient temperatures, with a heat soaked chamber, the PPU ammunition experiences high chamber pressures that appear to be unsafe. We researched further and found that other manufacturers had warnings against the use of sub standard or surplus ammunition. JP Rifles initially issued a warning against PPU by name but has since edited their original warning to remove references to PPU and Wolf specifically. Their warnings now state that “ammunition manufacturers may not have adequate data or rifle samples in their test libraries to make accurate determinations of what constitutes a safe load in all rifles chambered for this cartridge.” http://www.jprifles.com/safety.php?document_id=55

One concern that we have is their choice to use a large rifle primer in a cartridge that is designed for use with a small rifle primer. We also noticed inconsistencies in their annealing process.

We are not here to steer you away from PPU or Wolf specifically but we felt that we should make our fellow PM members aware of our findings and share our pictures as they clearly speak for themselves. There will be those shooters out there that will claim to have no problems with this ammunition. We cannot possibly shoot every rifle, chamber, caliber or manufacturer in every climate condition and in every firing sequence so we cannot dispute that some people may find this ammunition to work for them. But as you can see in the AR-15 forum, Chris.K experienced some very inconsistent performance recently from PPU/Wolf Gold ammunition. We have fired PPU ammunition before without problems but we noticed that on those cases they were annealed properly and we were not shooting rapidly at high ambient temperatures.

Regardless of the results that another shooter may or may not be getting, if you see signs of over pressure STOP using that ammunition.

Good luck, and good hunting.
 
good to know. I've only used Hornady factory ammo and my handloads using Hornady brass so far and have seen zero signs of pressure problems.
 
Originally Posted By: Eugene CanterburySo did it destroy the bolt in the first test?

Nope. The bolt and carrier survived the encounter. Looks like the gas vented down the feed ramps and into the magazine and saved the BCG.
 
This is just another instance for all the conversations I have had at the range with guys that spend "x" thousand dollars on an AR and is shooting the cheapest ammo they could find on the shelf and not getting results they thought they would.....go figure!
 
Have you contacted PPU and sent them the range/cartridge results of your findings?
I use PPU ammo/brass, but all in bolt guns so no hot chamber/pressure issues in those.


 
Originally Posted By: 5spdHave you contacted PPU and sent them the range/cartridge results of your findings?
I use PPU ammo/brass, but all in bolt guns so no hot chamber/pressure issues in those.




I have sent them our findings and pictures twice now and still have no heard anything from them. It has been a few weeks so at this point I wouldn't expect any response from them.

I really think that it was a "perfect storm" of conditions. High ambient temps coupled with the wrong primer and hot chambers=Overpressure. The question is can we trust that the "perfect storm" will not happen again? It is not quite the same as having a hot handload where you could control one of the variables and back off your powder to keep the pressure in a safe range. I used to see powders that exhibited negative temperature reactions at the height of my competitive career. We knew which powders to use for winter and which to use for summer. I preferred to find a powder that worked in all temps.

We have found that the Hornady's do not have problems with the temperature of either the air nor the chamber. Of course apples to apples, Hornady's quality control is obviously better and you pay for that. Nor do we have problems with our hand loads which are running IMR 4064 nor with Accurate 2200 but again you get what you pay for.

I really hoped to get a response from them, maybe get a chance to send them the remaining cartridges but really the bottom line is if you see the signs of overpressure, stop using it.
 
very interesting, I just shot 80rnds of wolf gold through my BHW 20" 264lbc type 1. It actually was very accurate(about .5moa) and consistent also I just ordered another 200rnds(this time PPU as its a bit cheaper). I saved my brass to reload and will have to look it over better but I know I had no blown primers. This worries me a bit as I'm living in Tx and its pretty hot, also I was shooting quite a bit breaking in the new build. I will definitely be more careful with this ammo in regards to rapid fire and ambient temps.
 
Well, [beeep]. And here I thought the Wolf Gold / Prvi Partisan 6.5G offerings would be just the ticket to get me into a 6.5G upper than I could afford to practice a lot on.
 
Originally Posted By: Will_PowerWell, [beeep]. And here I thought the Wolf Gold / Prvi Partisan 6.5G offerings would be just the ticket to get me into a 6.5G upper than I could afford to practice a lot on.

The 6.5 is a very forgiving and easy cartridge to load for. Hornady factory ammo can usually be purchased for about $1/round
 
Originally Posted By: San Antonio FJ[beeep], Can you post a lot # so I can check it against mine?

Looks like the lot# is 1501. We have boxes 14, 23, 30 and 46 here that we tested.
 
Originally Posted By: SnowmanMoOriginally Posted By: Will_PowerWell, [beeep]. And here I thought the Wolf Gold / Prvi Partisan 6.5G offerings would be just the ticket to get me into a 6.5G upper than I could afford to practice a lot on.

The 6.5 is a very forgiving and easy cartridge to load for. Hornady factory ammo can usually be purchased for about $1/round

I suspect I don't have the patience for handloading, and thus have held off on investing the $3-400 to get started.

Maybe once I'm getting good accuracy from all my shooting positions I'll make the jump up, but for serviceable accuracy for 2/3rds of the price, it's hard to make an argument for upgrading at this point given my low skill level.
 
I went through the ppu ammo I have and found a couple boxes of 1501..should I contact ppu for replacement or just write it off as a loss?
 
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