Surefire ICAR and PMAG 25rd

[LRRPF52]

Magpul made a 6mm ARC PMAG for the LWRC and New Frontier Armory receiver sets.

It’s in conjunction with a new carbine from Surefire called the ICAR.

These appear to be Six8 PMAGs with the internal geometry, feed lips, and followers designed for 6mm ARC.

I suspect Grendel will drop in. It also works with 338 ARC.

You need a different receiver set than a standard AR-15, which will not fit.

[A5Blaster Number 2]

I will soon confirm if it will work with grendel. I still have the one I built long ago on lwrci six8 receivers.

[m796rider]

Neat that these are closer to the same length as standard 5.56 PMAGs; the 30rd Six8 mags are kinda long.

[HighDesertDrifter]

Thats spiffy sure wish it would work with standard receivers ah well.

[LRRPF52]

PSA just announced a 6mm Sabre that will also have the larger mag well and take the ICAR PMAGs.

[StoneHendge]

This is getting interesting. Feeding reliability in 6 Arc has become enough of an issue for me that I've been moving back to 223 for practical matches and will only go with 6 arc if its windy. The larger mag well should help solve the feeding issues by giving the cartridge a bit of momentum before it hits the feed ramps. I'm certainly going to spend some time doing research.

[LRRPF52]

This is getting interesting. Feeding reliability in 6 Arc has become enough of an issue for me that I've been moving back to 223 for practical matches and will only go with 6 arc if its windy. The larger mag well should help solve the feeding issues by giving the cartridge a bit of momentum before it hits the feed ramps. I'm certainly going to spend some time doing research.

Magpul did a ton of testing over years with the PMAG 25 ICAR, to include the NATO sand/dust/saltwater and high cycle repeats through climactic chambers, then high volume in weapons working with Surefire on the ICAR.

They already had the Six8 testing and product development from LWRCi to start from, and they specifically mention dust and debris clearance with high cycle counts being tested before they nailed-down the production molds.

Reliability was priority #1 with this whole program.

[StoneHendge]

Reliability was priority #1 with this whole program.

Hopefully the industry can get there with the rest of of the system and satisfy the DoD's requirements.

Call it an AR .445 or anything else, keep the reciprocating mass near an AR 15 while getting the pressure tolerance up a bit, even if not to 60k. The differences wouldn't be bigger than those between an AR15 and AR10, and perhaps keep compatibility with AR15 handguards. I'd sign up in a heartbeat.

[BluntForceTrauma]

Magpul rep at SHOT Show 2025 says these PMags have a 2.32" COAL.

[biodsl]

Feeding reliability in 6 Arc has become enough of an issue for me that I've been moving back to 223 for practical matches and will only go with 6 arc if its windy. The larger mag well should help solve the feeding issues by giving the cartridge a bit of momentum before it hits the feed ramps.

StoneHendge...I know you've shot thousands of rounds of .243LBC. Did you have feeding issue with it? What's the explanation for the 6ARC feeding issues? The slightly shorter case?

[StoneHendge]

StoneHendge...I know you've shot thousands of rounds of .243LBC. Did you have feeding issue with it? What's the explanation for the 6ARC feeding issues? The slightly shorter case?

I did have a few, I remember twice in matches when the cartridge didn't go fully into battery mid-stage. I attributed it to (and the likely final contributing factor was) pushing my rifle into a "fortune cookie" style bag draped over a prop and having the bottom of the mag pushed back - and hence the top of the mag in the well pushed forward and down. One of the times was able to clear it and work my way through the stage and clean it - the other time I ran out of time after clearing the misfeed and dropped a few points. There were also a few times here and there where the bolt wouldn't completely lock down loading off a full mag. It wasn't a big deal at my normal monthly gas gun match since we close the bolt as part of make ready and not on the clock. If the bolt doesn't close, you clear it and do it again until it works before you go on the clock. That does become a much bigger deal in a Quantified Performance match where you close the bolt on the clock after you get in position on the first prop and find the target (akin to gas gun division in PRS).

I shot 95s in the LBC since it was a 1:8 - primarily SMKs and Berger Classic Hunters (which I loaded around 2.20) Yes, I've had more problems with the 6 arc, but I'm guessing that has to do with using sleeker 105s and loading them long.

The system was designed around 223/556. The nose of the bullet in any .445 diameter case sits lower than the nose of a 223 since the top of the body of the case limits the height. Its sits so low that more often or not, a 90 gr Scenar will hit the flat face at the base of the ramps and stop right there. A shame since I have a load that is soft on the shoulder and insanely accurate using Varget- it would be great for matches out to 500.

The bigger bulkier bullet than has to travel up at a pretty awkward angle through the feed ramps. I have actually had misfeeds trying to load a dummy off of a full mag where the nose of a Berger 105 BT (the fat stubby one - not the Hybrid) and a Berger 109 Hybrid where the nose of the bullet gets lodged between two ramps and everything stops there.

If the bullet does clear the ramps, the shoulder then hits them. Then it needs to align and I wouldn't be surprised if the nose of the bullet was scraping the chamber as the cartridge rights itself going into the chamber. All of this is using up valuable inertia.

Then, with what inertia is left, the bolt needs to lock over the rim of the case. Except the base of the extractor is sitting in the same spot it does for 223 and using the same extractor spring, donut and insert while the lip of the extractor needs to rise almost 20% more than on a 223 case. A lot of my misfeeds have made it to that point and then everything has stopped without the extractor going over the case rim.

That's where I see the problems coming from. They also exist in a lesser form in 6.5G and are probably helped by the fatter bullets and smaller shoulder, but I don't think 6.5G has been put through the wringer a lot like 6 arc has in Quantitative Performance matches (or QP style matches). Everyone here always used to wonder why the US military never adopted 6.5G - maybe they ran into feeding problems in rigorous use too. I'm guessing its even worse with 22 ARC (which, if you hadn't noticed, we haven't been hearing a lot about recently).

So hopefully we finally do get a new system designed around the 445 case head family of cartridges. Hopefully Magpul figured the mags out and hopefully the players in the industry can figure out a receiver/bolt/carrier/barrel extension system that can meet the DoD's tortuous requirements. Maybe we'll have to go through some of the Armalite/DPMS type stuff we did with AR-10, but I'd long for the day where we have a "mid frame" with reciprocating mass close to a small frame.

[biodsl]

Thanks for all that SH. The fact that I understood and followed your explanation is a testament to what I've learned on this forum over the years. I'm pretty excited to see where this all leads.