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AT-X CHASSIS and magazines

CST

Sergeant
Full Member
Minuteman
Dec 31, 2002
353
6
Md
I just bought a ATX chassis and bought a PMAG AICS magazine. The mag is too loose and undersized and readily falls out on its own. Could that be a chassis problem or just a pmag issue? .....or should I be ordering the AI AtX mags? Im so confused on which mag That chassis takes. Thanks.
 
In a couple weeks you'll be able to get MDT metal mags for cheap. I've had several 10 rounders and several 12 rounders that have worked pretty great. Had one that had the binder plate fall out though, haha. Also have many AI, Accurate, and Pmags, and the MDT metal mags have been as good or better than the others.
 
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Anyone know why the PMAG keeps falling out? I can't believe dimensionally that it would be that much smaller then a AI metal mag...front to back and side to side..
Would a AW may be better?
 
Would a AW may be better?
That would depend entirely upon your action. What are you shooting?

Anyone know why the PMAG keeps falling out? I can't believe dimensionally that it would be that much smaller then a AI metal mag...front to back and side to side..
It shouldnt be, it should go up, lock in and hang on the mag catch. Does it go up far enough to clip on the mag catch? What action? Do it with and without action if you need to see and prove to your self how it works.
 
Lone peak Fuzion. ..I took the action off and push it all the way up to the stop.....it engages the catch...but just too loose and will fall out if i shake it.
 
I’ll try a PMAG tonight and report back. No fitment issue with MDT, ARC, and accurate mag for me.
 
I’ll try a PMAG tonight and report back. No fitment issue with MDT, ARC, and accurate mag for me.
Thanks...really appreciate it. The other mafs u have are all generic AICS mats? No AW or ATX Specific mags? AT, or AX?? Im very confused on the differences.
 
Correct.

For the Rem 700 platform and clones, the action determines which magazines you need to run and not the chassis/stock. Even then you may need to swap brands based on caliber.

The AW and AX are double stack/double feed mags designed for the the AI actions. Some aftermarket actions are designed to run them as well. AICS mags (Accuracy International Chassis System) is a single feed designed to work with Rem 700 platform originally, but has become the standard for the majority mag feed bolt actions.


The lone peak fusion actions are made to run the AW mags if you can find some but will work with AICS style mags.
 
I'm just getting a little overwhelmed on all these part numbers
Aics legacy AT
Vs
aX chassis...etc..

Screenshot_20231109_173205_Chrome.jpg
Screenshot_20231109_173159_Chrome.jpg
 
Is your action/chassis designed for AW mag cut? Maybe makes a difference? I just tried a AICS pmag in my ATX rifle and it doesn’t lock in. 🤔
 
again, pay attention to "aics". dont worry about the others, they arent for you.

View attachment 8268333

You can get an ai branded aics mag, you can get an mdt aics mag, you can get an accuratemag aics mag etc, they should all play together the same. Feed lip geometry to get them to feed whichever cartridge may take some bending but the body clipping in shouldnt be an issue.


Just measure your mags and allow for a definitive answer. Once we have your measurements someone can compare to theirs and let you know, I dont have one here with me to do so myself.
View attachment 8268334
Then compare your mag measurements to the inside of the chassis mag well, primarily the y dimension depicted. Subtract how much the mag latch hangs over from that y dimension. It should not be larger than the mags Y dimension. By you saying that it clips in at the stop I dont believe this is your problem.

Im curious if its the mag lips geometry and the two are at too subtle angle and not squared off?
View attachment 8268341

That’s not correct, ATX’s are designed to use the AX style mags with the lip in the front that catches and locks in, you can however use the mags without it too but they don’t lock in solid like the AX style. They should never fall out though.
 
If you have an ATX chassis would you please measure width and length, (not height), for us?
 
That’s not correct, ATX’s are designed to use the AX style mags with the lip in the front that catches and locks in, you can however use the mags without it too but they don’t lock in solid like the AX style. They should never fall out though.
That true for the ATX rifle. We are discussing the ATX AISC/chassis.
 
AT-X mag, .308 AICS pmag, and .223 AICS pmag all measure .970ish wide and 3.05ish long at the bottom of the catch. My pmags don't seem to be jumping out of the AT-X AICS.
 
That true for the ATX rifle. We are discussing the ATX AISC/chassis.

I’m well aware of that captain obvious, the chassis has the shelf for the AX style mag lip to lock into just like the rifle chassis. Just like the AX AICS has… that uses you guessed it… AX AICS magazines…
 

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Ok guys..I finally got it clarified from Mile High.
The guy helping confirmed with the gunsmith. The ATX chassis needs the mags listed under AX chassis if u re look at the parts listing I posted above .

The mags under AI legacy or AT AICS does not work.

Here is a copy of the email. Hopefully this clears it up.
Screenshot_20231110_065640_Yahoo Mail.jpg


For the mag part #3902 won't work

Screenshot_20231110_065615_Yahoo Mail.jpg
 
You definitely don't "need" AX (be they staggered or single feed) mags to function in the AT-X or AX AICS chassis. However the front lip will aide in feeding.

Have been running non AX aics mags fine in both chassis on several rifles. PMAGs just aren't as reliable as actual AI mags.
 
Ok guys..I finally got it clarified from Mile High.
The guy helping confirmed with the gunsmith. The ATX chassis needs the mags listed under AX chassis if u re look at the parts listing I posted above .

The mags under AI legacy or AT AICS does not work.

Here is a copy of the email. Hopefully this clears it up.View attachment 8268704

For the mag part #3902 won't work

View attachment 8268705

The AX AICS mag is the correct mag yes and it is optimal, but non AX mags do and will work too, they just don’t lock in as solidly. I’ve ran AICS mags in AX chassis many times and I’ve ran AW/AT mags in gen 1 AX’s, post 2014 AX’s, AXMC with SA mag adaptor, and PSR with mag adaptor and have never had a single issue.

Your issue is the POS magpul mag. I get that a lot of people think pmags are good mags, but they are not. Stick a quality metal AICS mag in there and I’ll bet you it works just fine.
 
Red
The AX AICS mag is the correct mag yes and it is optimal, but non AX mags do and will work too, they just don’t lock in as solidly. I’ve ran AICS mags in AX chassis many times and I’ve ran AW/AT mags in gen 1 AX’s, post 2014 AX’s, AXMC with SA mag adaptor, and PSR with mag adaptor and have never had a single issue.

Your issue is the POS magpul mag. I get that a lot of people think pmags are good mags, but they are not. Stick a quality metal AICS mag in there and I’ll bet you it works just fine.
Your the man! Thanks for for your wisdom...btw you mentions accurate mags...where do they fall under? ax or standard AICS type?
 
Red

Your the man! Thanks for for your wisdom...btw you mentions accurate mags...where do they fall under? ax or standard AICS type?

Accurate and all the other aftermarket AI pattern manufacturers only make standard AICS pattern mags.

If you want AX AICS mags (AICS with the lip) the sole source is AI. 6955 is the PN for the 10rd and 6852 for 5rd.
 
I have a few atx aics 700 actions, I've ran mdt, aw, arc, accurate and ai aics mags in it. To get aw mags to function in the atx aics chassis the rear mag height limiter block needs removed, it's circled in one my old pics above of my FDE chassis.
 
Just finished this build with an AW cut TL3 and the bolt rides right over the rounds with AW mags. Will try removing the mag block. Hopefully that resolves my issue. Also have AX mags to try.
20240409_154019.jpg
 
Just finished this build with an AW cut TL3 and the bolt rides right over the rounds with AW mags. Will try removing the mag block. Hopefully that resolves my issue. Also have AX mags to try.View attachment 8393884
I can't even get aw mags to latch unless I remove the silver screw and mag height block. Removing that should solve your issues. Good looking rifle by the way! Aw and ax mags have been very reliable after a slight feed lip tweak in my 65cm.
 
I can't even get aw mags to latch unless I remove the silver screw and mag height block. Removing that should solve your issues. Good looking rifle by the way! Aw and ax mags have been very reliable after a slight feed lip tweak in my 65cm.
Thanks man! Definitely very happy with how it turned out but really want it to run with AW or AX mags. I hope you are right. The AWs are latching in but won't feed unless I put some upward pressure on the mag at the rear.
 
So I pulled the mag height block and my two AW mags are slightly improved. Now the bolt makes contact with the rounds but still passes over them. With upward pressure on the rear of the mag they seem to work great so a slightly higher mag latch would be awesome. My three AX mags are slightly improved over the AW as they occasionally maybe half the time do feed. One of them feeds everytime but the bolt binds up as the round starts to leave the magazine and begins chambering.....

All three of these AX mags have already been sent in to AI since I was having occasional issues with my ATX.

Maybe some tweaking of the feed lips is in order or should I just move to the AICS mag for this? Really wanted to run AWs as I sold off all of my AICS mags after using AWs for the first time.
 
So I pulled the mag height block and my two AW mags are slightly improved. Now the bolt makes contact with the rounds but still passes over them. With upward pressure on the rear of the mag they seem to work great so a slightly higher mag latch would be awesome. My three AX mags are slightly improved over the AW as they occasionally maybe half the time do feed. One of them feeds everytime but the bolt binds up as the round starts to leave the magazine and begins chambering.....

All three of these AX mags have already been sent in to AI since I was having occasional issues with my ATX.

Maybe some tweaking of the feed lips is in order or should I just move to the AICS mag for this? Really wanted to run AWs as I sold off all of my AICS mags after using AWs for the first time.
What cartridge? Opening the lips for a bit more case head presentation would help, but do it in very small amounts, aw mags rely on the internal pressure of the two offsetting double stacked rounds as part of physics that keep them in the magazine. Aw's can be picky!
 
What cartridge? Opening the lips for a bit more case head presentation would help, but do it in very small amounts, aw mags rely on the internal pressure of the two offsetting double stacked rounds as part of physics that keep them in the magazine. Aw's can be picky!
6.5 creedmoor. I find it odd that AWs will seat in my chassis with the mag block installed but wouldn't in yours. Would suggest the mag latch in mine is shorter than yours...

I'm tempted to just order some mdt 10 rounders and run those.
 
6.5 creedmoor. I find it odd that AWs will seat in my chassis with the mag block installed but wouldn't in yours. Would suggest the mag latch in mine is shorter than yours...

I'm tempted to just order some mdt 10 rounders and run those.
I had some the very first atx-aics chassis that were available, believe late 22, early 23, they may have made some unannounced revision. I currently run 2 cdg actions with aw mags in my atx chassis(no mag height limiter in place), but they're designed around the aw mag, and run very well. I have also had a lone peak fuzion in one and it ran aw's fine. Never a tl3 though. I have a right tl3 now, and will install and test when I get home next weekend and give you feedback.
 
I had some the very first atx-aics chassis that were available, believe late 22, early 23, they may have made some unannounced revision. I currently run 2 cdg actions with aw mags in my atx chassis(no mag height limiter in place), but they're designed around the aw mag, and run very well. I have also had a lone peak fuzion in one and it ran aw's fine. Never a tl3 though. I have a right tl3 now, and will install and test when I get home next weekend and give you feedback.
Sounds good! Yea the Aws I have run very smooth even better than my AX mags if I give the rear of the mag probably a millimiter or two of lift.
 
The three lug actions with one at 6 o'clock while cycling, run AW and AX mags just fine, right? And, the actions with no lug at 6 o'clock when running need AICS mags, right?

There are AX AICS mags, for the actions with no lug at 6 o'clock to pick up rounds from the double feed mags.

If your action has no lug at 6 o'clock when running, it needs an AICS mag, right?
 
The three lug actions with one at 6 o'clock while cycling, run AW and AX mags just fine, right? And, the actions with no lug at 6 o'clock when running need AICS mags, right?

There are AX AICS mags, for the actions with no lug at 6 o'clock to pick up rounds from the double feed mags.

If your action has no lug at 6 o'clock when running, it needs an AICS mag, right?
Not necessarily. Impact, lone peak, zermatt, defiance all have aw cut action and lugs are 90/270 when running the bolt. As long as the aw mags high and tight to action, there will be case head presentation above the bolt face and they will run. Keeping that mag up high is key.
 
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