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.
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.