AICS Mag tough to feed

I got a PTG DBM, Badger bolt knob, and an AICS mag for my Rem700 build this week.

It was professionally installed and the bolt is right where it should be when feeding rounds from the magazine.

However, especially with a full mag, the bolt is pretty tough to cycle. I've read that it appears to be pretty common to remove some material/bend the feed lips for the first 1/4" or so of the magazine in order to smooth out the operations. I think this is pretty ****ing retarded considering I spent $80 on the magazine alone and $300+ on the DBM. Is this true? I mean, it has to be something because the bolt is no where near as smooth as I would like it to be.

Let's just assume for sake of argument the DBM is installed correctly - because it is.

Try leaving the mag loaded untill the next range session. A friend of mine has a 700sps in an element chassis that has the same issue when he fully loads his 10rnd AICS mag. It's getting better with time. Altering geometry on the magazine seems like a bad idea.

i also am shocked at how many long range guys futz with the feed lips on their magazines. i never have and think it's a horrible idea. granted, polishing them is reasonable. but i don't bend them.

there are actually some pretty nifty tools for bending feed lips.

i shot an ackley for many many years, and the straighter walls on that case made it somewhat stiff to put 10 rounds in an AICS mag. in combination, the early bighorn action i had wasn't machined correctly on the feed port, so it pushed the lips in and the result was for the first year or two i ran with 9 rounds in the mag. i returned it and got it fixed. and was able to run 10 comfortably. the top one is pretty tight though.

if you're using a standard tapered cartridge like 308 or creedmoor or whatever, and you're having trouble with the 10th round, something is probably not right. but normally there is definitely a little more friction with a full mag. it shouldn't be difficult to cycle though, just more friction.

Why not just cut a coil off the mag spring?

I just spent a while inspecting it. The magazine is straight. The round is pointed right at the middle of the feed ramp. Everything looks perfect, but I'm telling you that I barely have the strength to shove that first round forward. It is so damn difficult. It's not getting hung up on the rifle or anything, the round is just stuck in the magazine. In order to generate enough leverage I have to put the barrel on the floor and shove the bolt forward putting all of my body weight into it.

ETA: I just did some googling and ended up sanding the feed lips very slightly. No more gouges in my brass, appears to be feeding smoothly now, and no rounds are popping out when the mag is full. How irritating for a $400 setup.

The magazine spring is too long, not leaving enough room for all the rounds even when fully compressed. If you cut off a coil, it will solve your problem.

so polishing/sanding fixed it?

I'm not thinking its the coil spring because it is tough to feed until about half way down the mag and even then it left deep (you can feel them with your finger) gouges on all 10 cases.

Sanding the feed lips appears to have fixed both issues. I haven't had much free time, but it certainly was "shoulder cycle-able" when I did it this morning. I may take just a hair more off actually. I am using a grinding stone underneath the feed lips, if that makes sense.

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Originally Posted by Eurodriver

I'm not thinking its the coil spring because it is tough to feed until about half way down the mag and even then it left deep (you can feel them with your finger) gouges on all 10 cases.

Sanding the feed lips appears to have fixed both issues. I haven't had much free time, but it certainly was "shoulder cycle-able" when I did it this morning. I may take just a hair more off actually. I am using a grinding stone underneath the feed lips, if that makes sense.

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Seeing the same issue with AICS 10 rounders in my MDT HS3 chassis. I thought the same thing regarding such rough feeding from $80 mags. I have been going the route of shooting them in and hoping they improve. Also going to try Magpuls and see how they do.

I also get some good scratches on both sides of my 300 win brass. Both 5 and 10 rounders. I have just dealt with it up to now. I am going to give a stone a try and see if that improves things. I was just going to wait til the magpul LA mags hit the shelves, but I think Ill give this a go..

I was at the point where I had nothing to lose. If I ruined the magazine I'd just get another one. But I'm glad I did it. I didn't go ham with the sanding, just a light file back and forth underneath both lips.

The hardest part was loading and unloading the magazine to test for function as I made progress.

I would say it's slight tolerance issue with the DBM, mag and action. My guess is the mag fitment is tight, how it "rides" relative to the receiver. I would take a tight first round out verses the bolt overriding the round. Did you try another mag?

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Originally Posted by mark5pt56

I would say it's slight tolerance issue with the DBM, mag and action. My guess is the mag fitment is tight, how it "rides" relative to the receiver. I would take a tight first round out verses the bolt overriding the round. Did you try another mag?

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Can't speak for Eurodriver but mine are with each round. I often only load five at a time and have the same experience with them downloaded. The feed lips on them seem exceedingly tight. Mine are pretty new and don't have a lot of rounds through them yet so I am going to keep shooting them to see if they settle in but I am also going to try the Magpuls and see how they hold up.

These are double stack, SINGLE FEED magazines. They two things I can think of in the feeding cycle causing this the bolt riding on the magazine (top of) But unlikely. The other is excessive magazine spring tension which I've never experienced in the 5-6 various platforms I've had with a AICS. Since the bolt over rides the magazine and pushes the round forward, those are the two things having friction. The stoning of the underside of the feed lips may minimize the excessive spring tension if there's rough edges.

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Originally Posted by mark5pt56

These are double stack, SINGLE FEED magazines. They two things I can think of in the feeding cycle causing this the bolt riding on the magazine (top of) But unlikely. The other is excessive magazine spring tension which I've never experienced in the 5-6 various platforms I've had with a AICS. Since the bolt over rides the magazine and pushes the round forward, those are the two things having friction. The stoning of the underside of the feed lips may minimize the excessive spring tension if there's rough edges.

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I thought about mag height/bolt interference but there is no issue running it with an empty mag inserted. This is my first mag fed bolt gun so I may just need to run them in a little. I did expect them to be smoother out of the box. I am also going to have my buddy run them in a couple of his rifles to see if it is my set up or the mags.

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Originally Posted by georgeib

Why not just cut a coil off the mag spring?

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nobody likes this guy's idea

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Originally Posted by trinydex

nobody likes this guy's idea

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Because it doesn't apply, and the magazine was made excellent by sanding down the scoring under the feed lips.

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Originally Posted by trinydex

nobody likes this guy's idea

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Originally Posted by Eurodriver

Because it doesn't apply, and the magazine was made excellent by sanding down the scoring under the feed lips.

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Yup. I had assumed that the difficulty in inserting rounds was due to the mag spring being fully compressed and physically preventing additional rounds going in. Didn't realize that it was just poor quality fit and finish on the mag body.

Either way, something that should have been addressed before shipping to the customer. Especially on an $80 magazine.

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Originally Posted by georgeib

Either way, something that should have been addressed before shipping to the customer. Especially on an $80 magazine.

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No kidding! I thought for sure my smith messed up the install, but with PMAGs working great and the AICS working great after the modification I can't blame that. Additionally, Google will reveal many people saying they too had to sand their AICS mags on Sniper's Hide - where I got the idea.

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Originally Posted by Eurodriver

No kidding! I thought for sure my smith messed up the install, but with PMAGs working great and the AICS working great after the modification I can't blame that. Additionally, Google will reveal many people saying they too had to sand their AICS mags - where I got the idea.

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are the magpul aics style mags good to go?

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Originally Posted by trinydex

are the magpul aics style mags good to go?

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all of mine are

OP, I have cleaned up every aics mag I have, kind of just something I accept as needed and worth the effort, kind of like adjusting the feed lips for certain cartridges.

I have been traveling for work quite a bit. I am going to give mine a little TLC when I get back and have time to tinker.