Need some help from the AR guys: 6.5 Grendel misfeeds

[Double Naught Spy]

What I found on ASC mags and sometimes on other mags, the front edge of the mag is too high and the case mouth will catch. This results in a stoppage at that point or the bullet will sort of jump up from there and then sometimes misfeed. Not all ASC mags do this, but most of mine I had to grind the front edge of the mag to make them reliable.

 

[wesmonster]

Only ASC mag that my PSA AR likes is a 15 round straight, jammed with a 25 round curved.
Most of my mags are 17 & 10 round Elanders and 20 & 26 round CPD/Duramags, no feed issues in my AR or Ruger Predator.
Elanders were heavy gauge steel and strong springs but had a long break in period and had to be downloaded a few rounds at first. CPDs ran right, right out of the box.

I had similar issues with ASC vs COD mags in my 7.62x39 & 5.45x39 ARs. CPDs were always more reliable.

D&H 6.5g mags are good too with heavy steel bodies so they don't bulge but can be a tight fit in some lowers. Work in my PSA, Anderson & RRA lowers.

The post above reminded me that filing down that front lip on my old 7.62x39 ASC mags helped a lot. With 6,5g and that steep shoulder good mags are crucial.

 

[45/30-06OKIE]

Need a little help. Here's the situation. I have a 6.5 Grendel that I assembled from a PSA lower and a PSA upper bought at different times. The upper has an 18-inch barrel with a rifle-length gas tube. Here's the problem. I have a couple of 10-round ASC magazines. Whether I load them up with 10 rounds, 5 rounds, or even 2 rounds, the second to last round misfeeds. It jams and the shoulder gets crushed in two places, no doubt from the bolt lugs. Looks like this. The dents get ironed out on subsequent firing.

View attachment 1176826

Weird thing is that it only happens on the next to last round in the magazine. If I took the round pictured above and put it back into the mag on top of one other cartridge, it would jam again. If I put it in on top of two rounds, it would feed fine, and the round immediately following would jam. I'm guessing this is a magazine problem, but I'm not enough of an AR guy to know how to troubleshoot it. Any suggestions?

I do have a few Elander mags I haven't tried yet; I'll take them along next outing.

I had this issue with 7.62x39 ASC mags and I had to cycle through them a couple times and then they seemed to work better... I didn't have the gun very long so I can testify to longer term use.

 

[Rlafever]

build a dummy cartridge and put it on the bottom , then count your rounds , the Gren is a hunting cartridge any way so there probably wont be a lot of shooting ,
I have a LaRue tactical 6.5 Grendel and there are no problems that I'm aware of, but I haven't shot any handloads out of it , yet

 

[Laphroaig]

Try some different mags, but keep on shooting it to see if things improve. Back in the day people used to talk about a break-in period before an AR ran smoothly. I know that was the case with my late 90's Eagle Arms where I got some jams in the first 100 or so rounds before it ran smoothly. Recently though, even my PSA ran well from the get-go. Ditto for my BCA 6.5G. Machining must have gotten better or something.

I have a Duramag and a couple of AR Stoners for my BCA. No problems with either.

 

[45/30-06OKIE]

Try some different mags, but keep on shooting it to see if things improve. Back in the day people used to talk about a break-in period before an AR ran smoothly. I know that was the case with my late 90's Eagle Arms where I got some jams in the first 100 or so rounds before it ran smoothly. Recently though, even my PSA ran well from the get-go. Ditto for my BCA 6.5G. Machining must have gotten better or something.

I have a Duramag and a couple of AR Stoners for my BCA. No problems with either.

I'm pretty sure ASC makes the AR Stoner mags cause they have/had ASC stamped in the followers lol.

 

[Legionnaire]

Got to the range again this morning. @courtgreene, the Duramags worked perfectly. So I guess it was a magazine problem.

Now that I have magazines that work, I might try @Double Naught Spy's suggestion and grind down the ASC mags to see if I can get them working. Low priority, though.

I appreciate the assistance.

 

[Double Naught Spy]

Got to the range again this morning. @courtgreene, the Duramags worked perfectly. So I guess it was a magazine problem.

Now that I have magazines that work, I might try @Double Naught Spy's suggestion and grind down the ASC mags to see if I can get them working. Low priority, though.

I appreciate the assistance.

At worst, you can make them into range mags for plinking.

 

[12Bravo20]

I'm pretty sure ASC makes the AR Stoner mags cause they have/had ASC stamped in the followers lol.

Yes the AR Stoner mags are made by ASC.

I have only used the 15 round 6 ARC ASC magazines along with 10 round and 25 round 6.8 SPC ASC magazines and have not had any issues with them.

As suggested, make a dummy round and color it with a permanent marker to see where it might be rubbing or hitting on anything. That should tell you right away what the problem is.

 

[horsemen61]

Those aren't bolt lug marks, they're feed ramp marks.

Don't let these guys talk you into buying a bunch of different magazines. My properly built Grendel won't feed reliably either and I've tried four different brands of magazines.

It will never feed 100%, in my experience and you'll just have to live with that aspect of the cartridge in that platform.

After building mine, I figured it was probably designed to sell a bunch of different mags for someone.

So that’s your solution just “Give Up and say that’s the best it will do” my 6.5 Grendel PSA build runs like a scalded dog so are you saying mine is a fluke? Have you tried different ammo or anything else like a different buffer/buffer spring BCG? that last statement is utter nonsense at best and I’ll leave that right there

 

[12Bravo20]

I know plenty of people with 6.5 Grendel uppers that run reliably. And there are plenty of people that use ASC magazines without issues too.

 

[marksman13]

I have had zero feed issues with E-Lander mags in my 6.5 G. My buddy has had similar feed issues to yours with his ASC mags.

 

[Gtscotty]

So that’s your solution just “Give Up and say that’s the best it will do” my 6.5 Grendel PSA build runs like a scalded dog so are you saying mine is a fluke? Have you tried different ammo or anything else like a different buffer/buffer spring BCG? that last statement is utter nonsense at best and I’ll leave that right there

I guess my two ARCs and my Grendel are both flukes as well, lol. ASC and Duramags work fine, can't remember the last time I had feeding our extraction issue.

 

[Legionnaire]

Thanks, guys. My problem seems to be solved. For me, changing magazines did the trick. Guess I'm fortunate the solution was easy.

Mods, okay to close this one.

 

[Mal H]

Closed at the request of the OP.