My Geissele 6mm ARC / 6.5 Grendel Magazine Experience

[StoneHendge]

(Note: This may be a bit of a rant, but I'm seeking a sanity check before I direct my rant elsewhere. It is also 6.5 Grendel content since Geissele states that their ARC mags are 6.5 Grendel compatible).

I've been troubleshooting some feeding issues in my 6 ARC. I initially thought they might be related to worn bolt internals but I don't think they are. Rumours abound on the world wide web of feeding issues with 6ARC and, well, some of them seem justified. The platform was designed for 223/556. That's a long narrow cartridge. The Grendel/ARC case is fatter. A 6mm bullet is sleeker than a 6.5. I never had any issues with Grendel. I never had any issues with 243 LBC. I never had any issues with 6ARC through a few thousand rounds. Nonetheless, I think that my trusty old 20 round Duramag Grendel mags circa 2020 may have gotten a little "tired". And maybe Hornady outsmarted themselves a bit when they bumped the shoulder back 0.03".

The mag companies gave up the ruse that the followers on their "6ARC mags" were any different than 6.5 mags in anything but the follower color a while ago. All of their mags are 6.5 Grendel/6mm ARC mags now. Except for one company who has a follower and feel lip designed for 6mm ARC. A company that I have had great experience with and likes to toot their horn about how their products are designed for military use. So I bit the bullet and ordered a 6mm ARC magazine from Geissele. The cost? NINETY dollars! Troubleshooting takes time and money, so why not buy the best I thought to myself. This will be a mag I'll never thing twice about bringing to the firing line at a match. Even if the total cost was $112.42 with tax and $15 shipping. I'll also note that between the time I ordered it and received it, the price went up to ONE HUNDRED AND FIFTEEN DOLLARS!

So I load up 20 rounds to break it in and there is a very loud rattle inside. Like, a really loud rattle. A round about halfway down is just jiggling around like your private parts would be if you were going commando. I call up Geissele and they actually answer the phone pretty quickly. I explained the issue and after talking to me like I was a 12 year old trying to build an AR as a science project, I was told to send them a video with my concerns and that their "tech team" would review it.

So I did. And here is the video:

https://drive.google.com/file/d/1e53CP7WfKThhgCUE-VZ7UWoDzKvwH5m0/view?usp=drivesdk

This is the response I recieved:

Good Afternoon Stone,

Thank you for sending that video. We shook one empty and it was silent then we put in 6 rounds but when we loaded it up with 20 rounds the full weight of the rounds does cause the same rattle. We also loaded a 30 round 5.56 mag and that rattled as well so this is typical of a fully loaded mag.

If you have any other questions, please let me know.

Thank you,

Yikes! This is their "tech team"? The tech team at a company that claims to do rigorous R&D and testing for products sold to elite military units? So I spent $90 dollars for a "typical mag" so I could have a Geissele floorplate and the four stickers they included in the box? If I buy another SSA-E and its gritty and sloppy, should I not b disappointed because a typical AR trigger is sloppy and gritty? If I were to spend over $300 on another Geissele scope mount, should I expect that it won't hold zero because a typical AR mount may not hold zero?

I bit my tongue and didn't fire back that a typical 20 round Grendel/ARC mag costs $18 - not $90 or $115.

In the meantime, I've loaded:

- A $18 20 round Duramag Grended mag with ARC. No Rattle.
- A $20 20 round Duramag .308 mag with 6.5 Creedmoor. No rattle and my 2 have never failed me in a PRS match.
- A $14 20 round ASC 5.56 mag (blem even!). Very slight rattle when I shake it side to side - none rear to fore.
- A $12 20 round Magpul 5.56 mag. Same as the ASC but more muted - likely do to polymer vs steel.

I intend to send them videos of each in comparison to theirs and am frankly ready to share them with the world on YouTube, but first want to make sure that my frustration isn't off base here.

Rant over. Thoughts appreciated!

[VASCAR2]

I’ve had some mags rattle when loaded but once the mags wore in the rattle seems to be less obvious or goes away. I bought some new aluminum 5.56/223 mags years ago that rattled badly when loaded to 30. Down loading the mag one or two rounds and the mag quit rattling. I’ve experienced the rattle with new S&W 5904 mags and some fifteen roundGlock 40 caliber mags. I never noticed the rattle from my mags seated in my pistol during training. The mags on my duty belt had worn in or the sound was muffled enough that I never heard them.

Clearing a building that has been burglarized in the middle of the night makes you very aware of any noise. I never heard my mags rattle but I’m probably too cheap to buy a $90 let alone $115 dollar mag. I say run your Geissele mag like you stole it and see how it performs. I’ll be surprised if the rattle doesn’t subside or go away with use. zz0.p3h1fcrjdvszz

[VASCAR2]

I’ve had some mags rattle when loaded but once the mags wore in the rattle seems to be less obvious or goes away. I bought some new aluminum 5.56/223 mags years ago that rattled badly when loaded to 30. Down loading the mag one or two rounds and the mag quit rattling. I’ve experienced the rattle with new S&W 5904 mags and some fifteen roundGlock 40 caliber mags. I never noticed the rattle from my mags seated in my pistol during training. The mags on my duty belt had worn in or the sound was muffled enough that I never heard them.

Clearing a building that has been burglarized in the middle of the night makes you very aware of any noise. I never heard my mags rattle but I’m probably too cheap to buy a $90 let alone $115 dollar mag. I say run your Geissele mag like you stole it and see how it performs. I’ll be surprised if the rattle doesn’t subside or go away with use. zz0.p3h1fcrjdvszz

[VASCAR2]

Obviously I’m having issues posting to this forum. I tried posting this response and kept getting 409 error. I tried a few minutes later and when the response loads it prints it four times. I’m using an AT&T hotspot and an iPad but this forum is the only site I have these issues.

[LRRPF52]

The reason why Hornady moved the shoulder back .030” for 6mm ARC was because of Elander mags and their tight COL, combined with optimal ogive and shoulder-neck junction placement for certain long bullets. AA even reduced the COL of factory ammo for 6.5 Grendel due to the Elanders.

On the Geissele 6 ARC mags, it looks like they addressed the COL by welding the front wall over to the side to allow maximum COL.

If you could measure your max allowable space from front to back in the Geissele mags to the inside front wall, that would be great. (Raw max COL)

Geissele also adjusted the barrel extension feed ramp angles to get 6mm ARC to feed more optimally since it’s narrower than 6.5mm.

That reduction in shoulder location with ARC always seemed like a way to make the cartridge tend to tip forward more, but once the bullets start feeding up the ramps, the control points are the bolt against the base, walls against the feed lips, ogive riding the feed ramp until the meplat enters the chamber, with minimal contact with the feeding cone in the breech. That tricky point is when the shoulder hits the ramps and the base pops up into alignment with the bolt face. It’s why I de-edge, blend, and polish my feed ramps.

My boy and I spent Friday blasting through 3 different Grendels, the 12”, 18” LaRue Stealth 2.0, and my 17.6” Lilja build without issue using Amend2 Polymer, old CProducts straight mags, and ASC 25rd mags. No malfunctions of any kind. We also shot at least 3 different types of ammo, namely 123gr ELD-M Black, 110gr PPU FMJs, and 123gr A-MAX hand-loads in Lapua brass.

I actually loaded up the old straight CProducts mag to try to get it to fail, since it didn’t work with my original 16” in an MGI quick barrel change upper (no M4 ramps). I let my boy shoot that whole mag to see if it would malf in the 17.6” Grendel, and it ran without a hitch.

[StoneHendge]

If you could measure your max allowable space from front to back in the Geissele mags to the inside front wall, that would be great. (Raw max COL)

Geissele also adjusted the barrel extension feed ramp angles to get 6mm ARC to feed more optimally since it’s narrower than 6.5mm.

That reduction in shoulder location with ARC always seemed like a way to make the cartridge tend to tip forward more, but once the bullets start feeding up the ramps, the control points are the bolt against the base, walls against the feed lips, ogive riding the feed ramp until the meplat enters the chamber, with minimal contact with the feeding cone in the breech. That tricky point is when the shoulder hits the ramps and the base pops up into alignment with the bolt face. It’s why I de-edge, blend, and polish my feed ramps.

You had to ask! I got 2.30" on one side and 2.32" on the other. Each side measured several times in a vise. I even flipped it around to make sure my angle of approach didn't have an impact on the measurements.

I had to strip the 20 rounds I had loaded in the Geissele to take the measurements. After I go the first one out (no easy task), the next round that popped up presented itself quite poorly with the nose pointing a bit downward. I stripped one out of a fully loaded 20 round Duramag. Its hard to see, but note the difference. The Duramag presents the bullet pointing upward while the Geissele bullet is pointed much lower. It looks like the case mouth may also hit the front of the mag. In my experience, that round in the Geissele is going to get its metplat slammed into the bottom of the feed ramps and get stuck there and probably cost at least 20 seconds of clock time in a 90 second stage. That's if the case mouth doesn't get caught up on the front of the mag like they do on the six ASC Grendel mags I unfortunately purchased.



This is how the feed lips guide a round (assuming everything else is working):

[LR1955]

Hmmm. The first couple of tries at a Grendel mag had the same problems. Combination of weak sheet metal for the magazine body, poorly designed followers, poor overall magazine shape.

With anything over ten rounds, the cartridges would nose dive or simply hit the front of the mag and stop.

Pisser having to clear malfunctions due to poor design and quality. Maybe easier to take if the mag only cost fifteen dollars but over a hundred?

And yes, guys bent feed lips but as I recall, it worked for the first couple of rounds but got more and more problematic as more ammo was used from the magazine.

Am sure you will find a solution though. Probably a bullet with a different ogive and shorter OAL but my bet is that it will not be what you need to be competitive.

GG

[StoneHendge]

Well, I *think* I got the issue worked out and it's not mag related. Hopefully I can get some testing done later this week with live rounds, but I got the bolt to lock down about 20 times in a row chambering a dummy round out of the fully loaded 20 round Duramag that has been my primary match mag. I don't want to jinx myself so I'll keep it to myself for the time being, but this Geissele experience did help in that it reminded me that I shouldn't assume that something new from the factory is going to work properly.

In the meantime, I tried to leave a one star review on Geissele's website entitled "A $15 mag with a $100 logo on the floorplate" on Sunday. I had to be logged in to my Geissele account to write it. After I hit submit, it said "Thank you for your review. It has been submitted for moderation." 48 hours later it's still being "moderated". I wonder if I'll hear anything from them or if the review will ever be published. Geissele 20 round 6mm ARC Magazine – Black

Now it's back to my latest unnecessary project, reinventing the wheel with my latest keg of H4350 which has a 123 gr Scenar running 90 FPS slower than my last keg holding everything else constant (same brass, same bullet, same brick of primers, same 40.6 grain charge).......

[StoneHendge]

Finally had some decent weather to get out and do some more testing and I believe I found the culprit behind my feeding problem and it's a simple one. I'll note that I haven't used the Geissele mag since I wanted to keep it out of the equation.

I should mention that the rifle has about 15k rounds on it. It has a long discontinued Aero monolithic upper and an Aero lower. I have no idea what LPK I used but I'm guessing its one that came chock full of small Chinese parts. Including the mag catch which is visibly worn on the top ridge that holds the weight of the mag. So worn that it appears that the mag has either been sagging or tilting forward enough for the nose of the bullets to get rammed into the feedramps at a bad angle and requiring force that I didn't have remaining to lock the bolt down. I found an unused one in my spare parts collection and was able to get the rifle to chamber properly releasing the bolt catch on a fully loaded mag a number of times. It also properly chambered the next round that same number of times.

I don't think I want to keep another Made in China mag catch in there in the long run. Looking around at what's available in standard catches, most are made from machined 8620 steel. I'm guessing one that's Made in the USA should suffice, but Geissele (ugh) does sell one made from stainless steel that taughts its corrosion resistance. Corrosion isn't a problem in the desert. My google foo tells me that stainless will actually wear more than quality 8620 but perhaps the metallurgists in the horde could comment on that. I could also get a super slick titanium catch for $40 or so, but again, it seems like titanium would wear more too....

[grayfox]

On first blush I'd agree that SS will wear faster than 8620, which as I understand is a hardened steel, like tool steel I think..? SS not known for hardness, but for corrosion resistance.
Anyway, IMO you'd be better off using the 8620 and doing a PM/ changeout at some regular interval, what maybe every 2500 or 5000?
Even better is to measure/photo the original of this 8620 one, then every 1000 rounds or 3 months, take another pic and do an inspect... sort of like oil change intervals.
I'm guessing that the heavier mass of the cartridge/mags would mean it wears out faster than a 556 round would do.
But, a very interesting and informative discovery.

[LRRPF52]

Finally had some decent weather to get out and do some more testing and I believe I found the culprit behind my feeding problem and it's a simple one. I'll note that I haven't used the Geissele mag since I wanted to keep it out of the equation.

I should mention that the rifle has about 15k rounds on it. It has a long discontinued Aero monolithic upper and an Aero lower. I have no idea what LPK I used but I'm guessing its one that came chock full of small Chinese parts. Including the mag catch which is visibly worn on the top ridge that holds the weight of the mag. So worn that it appears that the mag has either been sagging or tilting forward enough for the nose of the bullets to get rammed into the feedramps at a bad angle and requiring force that I didn't have remaining to lock the bolt down. I found an unused one in my spare parts collection and was able to get the rifle to chamber properly releasing the bolt catch on a fully loaded mag a number of times. It also properly chambered the next round that same number of times.

I don't think I want to keep another Made in China mag catch in there in the long run. Looking around at what's available in standard catches, most are made from machined 8620 steel. I'm guessing one that's Made in the USA should suffice, but Geissele (ugh) does sell one made from stainless steel that taughts its corrosion resistance. Corrosion isn't a problem in the desert. My google foo tells me that stainless will actually wear more than quality 8620 but perhaps the metallurgists in the horde could comment on that. I could also get a super slick titanium catch for $40 or so, but again, it seems like titanium would wear more too....

Another great example showing that parts are not all created equally. The US Mil-Std technical data package covers these types of things in detail, based on extensive testing, measurements, failures, and improvements over the past 67 years.

Anodizing and correct steels with the specified treatments are all meant to work together.

I noticed that when I first started Cerakoting lower receivers, I would check fit with mag catches and they were fine, until I tried to drop loaded mags, which then bound up tightly and wouldn’t release without force. I would have to then sand off the coating inside the mag catch slot for proper function.

Can’t say I’ve seen or heard of this before. Good catch.

[SDW]

In the meantime, I tried to leave a one star review on Geissele's website entitled "A $15 mag with a $100 logo on the floorplate" on Sunday. I had to be logged in to my Geissele account to write it. After I hit submit, it said "Thank you for your review. It has been submitted for moderation." 48 hours later it's still being "moderated". I wonder if I'll hear anything from them or if the review will ever be published. Geissele 20 round 6mm ARC Magazine – Black

Talking about Geissele's prices, I found this circa 2020 thread on SH about the standard aluminum GI type 30-rnd 5.56 mags they first offered for sale at $22 when everyone else was selling the same mags for ~$8... just because Geissele'd painted the mags brown and used a branded floor plate:

https://www.snipershide.com/shooting/threads/geissele-you-so-crazy.7041462/

I guess due to a public outcry of sorts, Geissele actually caved, admitted they were asking too much money, and dropped the price... to $14.

[StoneHendge]

I guess due to a public outcry of sorts, Geissele actually caved, admitted they were asking too much money, and dropped the price... to $14.

I had heard that story from an RO at my local range. To be fair, Geissele does send you 4 stickers with every order. I can't say I've ever gotten a sticker from ASC or Duramag .

LRRP52, was the "good catch" pun intended?

Got out again today and ran 5 rounds out of a fully loaded mag again without a hitch four times. I was standing and shooting off of a bag and once, just for fun, jammed the magazine up against my 17 lb Wiebad heavy fill bag which pushes the magazine back and dips the nose of the round presented forward and released the bolt. And the bolt didn't lock down. So "i think" I replicated the problem that I had been having. We'll see at the next match in a little over 2 weeks.

[Zeneffect]

$100 for a single mag? not something i would spend on, but if i did my expectation would be flawless function every time all the time, the best customer support with paid to and from shipping.

Thanks for reminding us that you cant just buy reliability sometimes based on name brand reputation... shame i would have thought geissele would have sorted everything out before releasing the product because they usually do have some of the best products available. good luck on your match, hope the mag performs as expected.