PRI 6.8 mags for 6.5 Grendel / longer COL

[ChellieWiles]

I know that pmags can hold up to 6-7 Grendel rounds and function properly; any more than that and the mag bulges. I recently noticed that Midway was selling a new mag for the AR, Lancer Systems AWM, http://www.midwayusa.com/product/269...er-translucent
that's their 20 round but they carry a 5/10 round and 30's as well. Has anyone tried one of these out yet in the Grendel? I imagine they would probably hold more than the pmag seeing as they have a top section made from from steel with a polymer body.
Also, I think I remember a guy that fabricated a steel wrap to form around the pmag just below the mag well and he was about to get 14 rounds in a 20 round pmag. I definitely think there are some polymer Grendel mags on their way...just a very strong hunch.

[Drifter]

I recently noticed that Midway was selling a new mag for the AR, Lancer Systems AWM, http://www.midwayusa.com/product/269...er-translucent
that's their 20 round but they carry a 5/10 round and 30's as well. Has anyone tried one of these out yet in the Grendel? I imagine they would probably hold more than the pmag seeing as they have a top section made from from steel with a polymer body.

They didn't work well at all for me. The feed lips are not even close to being appropriate for the Grendel case. Just wasn't a feasible alternative in my view. YMMV.

[ChellieWiles]

Drifter,
Was there enough material around the feed lips to apply a modification that would be comparable to an already established Grendel Mag?

[Drifter]

I don't remember seeing any feasible way for the Lancer mag or it's components to be compatible with Grendel cartridges. (I also don't claim to be the most gifted at successfully doing projects such as this. Thus, it might be possible, but not by me.)

[BjornF16]

There's some info on this link regarding mag and follower mods for the 6mmAR (necked down Grendel), which might also work with the Grendel too:

http://www.6mmbr.com/gunweek068.html

I'll probably try the follower mod with my 15rd PRI 6.8 mags.

Awesome! Thanks Drifter...(I love this forum!)

[sneaky one]

Chellie---Wow, this reminds me of my '09 try's w/ a pmag 5.56--20 & 30 rnd.- for the 6.5 G app.---- I hit the same wall time after time, then found-almost success- then realized after talking to magpul-not gonna work., Then I made it almost work- again--- then 1 more tiny tweak ------ killed it. Also the coal. is stuck at 2.245. The lancer is a no go too. Anyone want the 2 mags? Pay the 5-6$ for shipping. They were close.... may magpul, or ? would be interested. The best poly mag. idea is-same as the Lancer= upper region to include the perfect lip angles, with an ultra strong alloy , that will withstand a 4' fall---on the lip. Maybe we will -hopefully see some mags. from D&H ind. soon----maybe pmag will finally find a way--to think ,,, looks like a surefire 60 rnd., yet-plastic lower, metal upper.......

[ricsmall]

you would think with the technology we have today that someone could make a working mag for the 6.5G. I know there are some, but they are hit and miss. It just blows my mind. I think one could alter the feed lip angles on a 20rd GI mag then open the rear between the feed lip edges to match a grendel mag, swap in a blue follower and it might work. But you could buy a grendel mag and modify as well i guess. I think from what ive read that the pri mags may be worth a try. They make a 6.5 brake now so maybe they will do mags before long. who knows...

[Drifter]

Wonder if RRA's LAR-47 could be retrofitted with a Grendel barrel (assuming Grendel ammo would run in AK mags)...

http://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_id=558

[Variable]

you would think with the technology we have today that someone could make a working mag for the 6.5G. I know there are some, but they are hit and miss. It just blows my mind. I think one could alter the feed lip angles on a 20rd GI mag then open the rear between the feed lip edges to match a grendel mag, swap in a blue follower and it might work. But you could buy a grendel mag and modify as well i guess. I think from what ive read that the pri mags may be worth a try. They make a 6.5 brake now so maybe they will do mags before long. who knows...

Dangit, typed out a lengthy reply and got busy at work and lost it. Grrrrr!

Anywhoo, the problem with all 5.56 mags is the vertical ribs in the magazine sidewalls. The two rearmost ribs control the way the cartridges stack in a diagonal double column, and the front rib indexes the rebated diameter in the front. If you look at a CProducts Grendel mag you'll see that the rear ribs have been mostly "ironed out" (reduced in depth). This allows the larger diameter of the Grendel case to stack properly on that axis in a double column. Case taper isn't much, but apparently is close enough to match up to the curve of the regular 5.56 magazine.

Any 5.56 magazine body will necessarily be a relatively poor feeder of Grendel cases because of the rib depth (or in the case of Pmag type magazines-- sidewall thickness). CProducts appears to have gotten the lateral internal magazine width correct for the Grendel's diameter. I think their past problems were primarily more of an overall dimensional QC problem than anything else. Their mag bodies are stainless spring steel, and do exhibit a degree of warpage from time to time. I have also observed what appear to be jig alingment issues during assembly (spot welding) sometimes. Their quality did improve a lot over time, but some duds seem to occasionally make it through. Part of that problem is probably because of their price point. If they rejected mags at a much higher rate, and detailed folks to inspect each mag closely the reliability rate would likely skyrocket, but the cost per unit would as well.... So that's the conundrum (in my eyes) with the mags to date. Hopefully someone will come along that has better "magfu" at some point-- who can somehow hold much better tolerances and overall QC while staying near CProducts price point. Until then we are at status quo...

[Variable]

Wonder if RRA's LAR-47 could be retrofitted with a Grendel barrel (assuming Grendel ammo would run in AK mags)...



http://www.rockriverarms.com/index.c...ategory_id=558

Nope. The 7.62x39 has much more case taper, and AK mags are manufactured with that curve in mind. If you feed them a large quantity of Grendel cartridges they will choke also.

You could use 6.5x39 cartridges (7.62x39 necked to 6.5 for fireforming) in them though. They'd feed the first time until they were fire formed to Grendel dimension.

[sneaky one]

Vari- last time at the range, I pre- loaded ak brass -for forming plinker loads.,, and AA, & Horn. brass-1x2 & 2x1---- all in my 17 rnd. mag. =-the unit I made from the old , non-functioning Grrr. cprod. 25 rnd'er., from 09', junky mag.( It's in my albums). All the rounds ran thru just fine, all the 4 times- same mag filled- over and.. = easy to fix the mags., it takes a small study to see the spots that need the tweak.... I use a tiny crescent wrench--- -no.. it's not a work tool. The tiny smooth jaw= non marring== the easy way to bend a springy--SS. steel idea. Have fun, it takes a feww trys. ((((( Funny , I had to replace a -leaky - terrlett this wknd. after a Really wht. alien looking guy sat upon it,,)))). tee, hee hee.

[Variable]

Vari- last time at the range, I pre- loaded ak brass -for forming plinker loads.,, and AA, & Horn. brass-1x2 & 2x1---- all in my 17 rnd. mag. =-the unit I made from the old , non-functioning Grrr. cprod. 25 rnd'er., from 09', junky mag.( It's in my albums). All the rounds ran thru just fine, all the 4 times- same mag filled- over and.. = easy to fix the mags., it takes a small study to see the spots that need the tweak.... I use a tiny crescent wrench--- -no.. it's not a work tool. The tiny smooth jaw= non marring== the easy way to bend a springy--SS. steel idea. Have fun, it takes a feww trys. ((((( Funny , I had to replace a -leaky - terrlett this wknd. after a Really wht. alien looking guy sat upon it,,)))). tee, hee hee.

Oh, I've tweaked my own mags, it just irked me when I had to do it.

Also--- When I refer to whether mags will work or not with a particular cartridge, I mean when loaded to full capacity. Like the 30 round AK mags pictured above. They won't stuff full of Grendel ammo and still function. You could get away with just loading some, but that doesn't really count in my book. Kinda like when guys say "Pmags work ok with Grendel ammo". At that point I know that they and I have far different expectations of a magazine and the confusion lies in what we define as "works". If a guy gets 7 rounds (or 5, or 6, or whatever...) of Grendel stuffed into a 30 round Pmag and then it feeds them in his rifle, that doesn't qualify as a Grendel magazine in my book. Why would I want to screw around with a 5.56 magazine that has less capacity than a CProducts Grendel mag, and usually requires being screwed with to get it to work? In that case a person would have been better off to have just started off with a CProducts mag and tweaked it instead.LOL

CProducts 17 round Grendel magazine: while they do have the crappiest rep of the batch (I had some that were so bowed out they had to be crushed with screw clamps to get them back near the right shape!), I also have some that work ok after tweaking. I would still never trust them for anything serious though.

Your 17rounders function ok loaded to full capacity with 6.5x39 loaded in them? That's kind of surprising, but I guess the difference in taper wasn't enough in a column as short as the 17 rounders. See if they'll stack in a 25 rounder. I'm guessing they wouldn't run very reliably that way.

You lost me on the white alien thing???LOL

[sneaky one]

Variable, Remember,, the first mag-started as a- 6.5 Grr., 25 rnd. -cprod. shiite burd mag from hell.,,,, ahhhh the good ole dayz of 08'---- then - after I cut off 1.5" of mag - and made internal pushes, and tweaks=ended up as a 17 rnd.=Not an AR- 15 - 7.62 mag.--It will now feed any ammo I put in it, in any order= AK brass-Grendel brass, loadings. Same blue follower, same spring- albeit shorter--it's all about the angles-lip tweaks to see the spot of the bullet tip hitting the feed ramp in the perfect center- of it .Sounds like a zen like fix, eh? Are you so -- White, like a toilet paper, or ? on the rim, or seat-el- unit there- maybe a white fly? Mothra? Hats off to you, you Good old star warz junky. BTW, this mag -I CREATED---- to replace my- (17 rnd. orig. cprod.- the one I,never really trusted it---Bill A said same as, that's why AA stopped selling it 2 yrs. ago.) Make sense?

[Variable]

Variable, Remember,, the first mag-started as a- 6.5 Grr., 25 rnd. -cprod. shiite burd mag from hell.,,,, ahhhh the good ole dayz of 08'---- then - after I cut off 1.5" of mag - and made internal pushes, and tweaks=ended up as a 17 rnd.=Not an AR- 15 - 7.62 mag.--It will now feed any ammo I put in it, in any order= AK brass-Grendel brass, loadings. Same blue follower, same spring- albeit shorter--it's all about the angles-lip tweaks to see the spot of the bullet tip hitting the feed ramp in the perfect center- of it .Sounds like a zen like fix, eh? Are you so -- White, like a toilet paper, or ? on the rim, or seat-el- unit there- maybe a white fly? Mothra? Hats off to you, you Good old star warz junky. BTW, this mag -I CREATED---- to replace my- (17 rnd. orig. cprod.- the one I,never really trusted it---Bill A said same as, that's why AA stopped selling it 2 yrs. ago.) Make sense?

Hee hee, ok. I think I got it this time. You meant the avatar I was using.LOL I'm a little slow sometimes. You gotta' remember I'm just a government employee.

[BjornF16]

PRI 6.8 mag range report

Went to the range today in order to test the PRI magazine (5 rounder; no mods). It functioned flawlessly for me. Locked open on the last round and fed all 4 loaded rounds. Went through 40 rounds of Hornady A-Max using the magazine. No malfunctions whatsoever.