Feeding problem with AI magazines in a Cadex Chassis

chalkriver2

chalkriver2

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Myself and another shooter are both are having issues with our 10 round steel AI mags in our Rem 700,s both mounted in a Cadex chassis.
I have 2 mags and both are doing this .
I was using Federal Gold Medal Match in 308 last weekend so its not due to my handloads being too long.
I have to play with the rear of the top bullet in the mag quite often to get it to feed correctly as it will jam the bullet below the chamber .
I am assuming the feed lips on the mags need to be bent out a bit ? Anyone have a mag that they can measure the width of the opening
Anyone else having this issue and any ideas whats up if it isn't the feed lips ?
Thanks
 
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I measured my 5 and 10 round AI mags.

10 round - .393"
5 round - .390"

I haven't had any issues in my 700 mounted in an AX AICS
 
Just cycled a few more mags through it and it is getting jammed sometimes while only 3-5 rounds left in the mag too so its not just the first one . I made sure the rounds were loaded all the way to the rear of the magazine as well. I had to push down on the 5th round to get it to pop up in the magazine enough to feed into the chamber. So that time it jammed inside the mag.
Mine measure .401 and .418 inside dimension at the front of the feed lip.
 
I think the main issue is that you have tolerance stacking when using a chassis system.

Cadex/MPA/AI work with all (pretty much at least) 700 foot print actions and considering all the different makers of chassis and actions and magazines we can't expect them to play nice all the time.

Is it possible that you have some debris build up in your magazine? I would start there first and if that didn't solve it I would recommend adjusting the feed lips a bit. A set of wide sheet metal locking pliers works great. I also find myself taking a fine grit sand paper to the lips to smooth things out.
 
chalkriver2 said:
Myself and another shooter are both are having issues with our 10 round steel AI mags in our Rem 700,s both mounted in a Cadex chassis.
I have 2 mags and both are doing this .
I was using Federal Gold Medal Match in 308 last weekend so its not due to my handloads being too long.
I have to play with the rear of the top bullet in the mag quite often to get it to feed correctly as it will jam the bullet below the chamber .
I am assuming the feed lips on the mags need to be bent out a bit ? Anyone have a mag that they can measure the width of the opening
Anyone else having this issue and any ideas whats up if it isn't the feed lips ?
Thanks
Click to expand...

So the bullet is nose diving when moving forward????

If yes, slowly open the front quarter of the feed lips... you are watching that the nose of the bullets start to point higher.

Mags are massed produced and get bashed around. Doesn't take much of a hit to "close" the front and nose diving results.

You do not want to open so much that the bullets start ejecting on a full mag so it is a balance... a bit of trial and error but once you see what you are trying to achieve, you can quickly tweak mags for this and any other properly aligned mag fed rifle.

Another very important check... with an empty mag fully inserted and the bolt closed, how close is the bolt to the feed lips. Ideally, the bolt should run through the top opening with the lips just clearing. Some chassis/mag don't allow the mag to sit high enough so the bolt can ride over the ammo. The result looks the same (nose diving) BUT mag lip tweak will not solve anything as the cartridge is too low in the feed cycle.

That can also show up in a very clunky feel as you try and coax the ammo into the chamber. The nose hammers into the feed ramp and feeding is far from smooth. All signs mag/chamber/bolt alignment is not proper.

Sometimes, some mags don't work in some chassis.. it is one of the most challenging fitments when setting up a mag fed rifle to run and gun.

Jerry
 
I'm curious if you have real AI mags or one of the AI style mags.
I have found that my real AI mags are much more reliable than the ones Cadex sells.

I got a couple Accurate Mags with my RPR and they don't feed right because the lips are too wide. I need to bend the feed lips inward somehow to get them to feed right.
 
BadAsMo said:
I'm curious if you have real AI mags or one of the AI style mags.
I have found that my real AI mags are much more reliable than the ones Cadex sells.

I got a couple Accurate Mags with my RPR and they don't feed right because the lips are too wide. I need to bend the feed lips inward somehow to get them to feed right.
Click to expand...

x2 Accurate mags I had were much lower reliability compared to my AI brand mags.
 
I had similar problem with my Accurate mags, don't bother playing with the lips, you wont get good result and just get frustrated.
Open your mag and change the angle of the spring so that it will put more pressure to the side you need. Open the rear for more front pressure and open the front for more rear pressure
 
I did some testing today by cycling a lot of mags through it while watching the feeding issue from above instead of while firing it during a match and cursing ..lol.
The mags are AI 308 mags that I got from MDT
Couple points on the testing . Mags are labeled silver mag and black mag .
The silver mag will drop free and the black one has slight resistance when loading into the magwell and is slightly thicker in dimension where the vertical mark is.
Silver mag is .886 in wide and Black mag is .902 in wide at that point .
Feed lips on silver mag are aprox .400 at the front and .410 at the rear
Feed Lips on black mag are aprox .420 at the front and .410 at the rear
The rounds sit a bit higher at the rear in the silver mag.
Both mags malfunction aprox the same amount even though the feed lips and mag bodies are slightly different so I don't think it is the feed lips or mag dimensions .
I started all tests with bolt to the rear and the mag all the way to the bottom of the magwell as there is a little vertical movement in the mag to allow inserting the mags on a closed bolt I assume..
Due to this I didn't get any first round malfunctions as happened in the past.
I number the rounds by how many left in the mag when the malfunction happens and ensured that the rounds were fully to the rear when loaded in the mag.
The results are below


Black - cycled entire mag OK
silver - #4 from bottom jammed
silver #4 from bottom jammed
silver - OK
silver - #8 from bottom jammed
black - #8 from bottom and # 4 jammed
black - ok
silver - ok
black - #7 jammed
silver - # 3 jammed
silver - #9 jammed
silver - # 5 jammed
silver - ok
silver - 5,3,2
silver -5,3,2
black - ok
silver - 3
silver - 3
silver - 4
black - 3 ,2
black - 7,6,3,2
silver - 3

So only 5 mags cycled correctly out of all the times I tried it with the bolt to the rear and it was about even as far as malfunctions went.
I did some more testing with the bolt forward before inserting the mag and the test results were worse.


When moving the bolt to the rear I can see the malfunction about to occur as the next round in the mag is slightly forward and jammed in a nose down and to the right position even before I pull the bolt fully to the rear.. The bolt wont be touching the round anywhere and I have to push the round down and to the rear to get it to reseat correctly. it seems to occur a lot when there are 4-5 rounds left in the mag.
 
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is the mag being pinched by the DBM?

Is there a dent on the mag body which hinders the movement of the follower?

Are there rough spots on the follower? From one of the pics... no anti dive for sure.

Is the mag spring in the wrong place or orientation or too weak.

Are the test cartridges bent from multiple cycles? don't laugh, I got a bunch of those from sorting out mis feeds.

Jerry
 
Mystic Precision said:
is the mag being pinched by the DBM? One mag has slight friction while inserting it and the other doesn't at all and will drop free if mag release is used .

Is there a dent on the mag body which hinders the movement of the follower? No there is a small vertical line on the one that wont drop free and the mags are clean inside.

Are there rough spots on the follower? No

From one of the pics... no anti dive for sure.

Is the mag spring in the wrong place or orientation or too weak. Not sure if its too weak but I am kind of thinking that may be the problem as if the round below the one being chambered is moving forward that may be it ...

Are the test cartridges bent from multiple cycles? don't laugh, I got a bunch of those from sorting out mis feeds. No , but I was getting pretty bent out of shape last match ..lol


Thanks Morgan
Click to expand...
 
Arrowhead said:
I had similar problem with my Accurate mags, don't bother playing with the lips, you wont get good result and just get frustrated.
Open your mag and change the angle of the spring so that it will put more pressure to the side you need. Open the rear for more front pressure and open the front for more rear pressure
Click to expand...

X2, this and some light sanding to the insides solved my issues.
 
I've got the same question ... are these genuine AI (Accuracy International) mags or are we talking about Accurate Mags which have been rebranded as Ruger Mags, Cadex mags, etc.?

I have a Cadex CDX-30 and have 2 Accurate Mags and one Magpul AI style mag.

None of my mags have fed reliably. My most common issue: the rear of the bullet is not pushed up against the feed lips so the bolt rides over it and does not push the bullet forward into the chamber. The Magpul mag is especially bad. The 5 round Accurate Mag is the most reliable and seems to have the best spring tension.

Any suggestions? Or should I just suck it up and buy proper AI mags?

I should note - The mags seat properly and there is only about 1mm between the mag lips and the Magpul mag and maybe 3mm between the feed lips and the bolt with the 5 round Accurate Mag.
 
Tikka223 said:
I've got the same question ... are these genuine AI (Accuracy International) mags or are we talking about Accurate Mags which have been rebranded as Ruger Mags, Cadex mags, etc.?

I have a Cadex CDX-30 and have 2 Accurate Mags and one Magpul AI style mag.

None of my mags have fed reliably. My most common issue: the rear of the bullet is not pushed up against the feed lips so the bolt rides over it and does not push the bullet forward into the chamber. The Magpul mag is especially bad. The 5 round Accurate Mag is the most reliable and seems to have the best spring tension.

Any suggestions? Or should I just suck it up and buy proper AI mags?

I should note - The mags seat properly and there is only about 1mm between the mag lips and the Magpul mag and maybe 3mm between the feed lips and the bolt with the 5 round Accurate Mag.
Click to expand...
Tikka223 read my preveous post, you will resolve your problems in minutes...
 
I have accurate mags... stamped on the mag body... run like a dream so it is not the design... but may be the QC of the mags you have.

Yes, follower spring pressure if weak will cause no shortage of problems. Too stiff, and pushing the rd out of the mag becomes a pain... or if the lips are not curved enough, you get self loading.

The mags are only as good as the mag well and alignment to the action, bolt and chamber. It all has to work in unison for smooth and confident feeding.

Find a mag with more follower pressure and see if that solves the issue. My first fix would be to open the front part of the lips and get that bullet tip higher. They look like they are really low in your pics.

Bullet shapes vary, OAL vary... throw that into the mix and even more fun. VLD/tangent ogive bullets are more likely to jam then Secant/rounded noses. but if the bullet is running into the ramp or below the chamber and stopping, you have an alignment problem and the only solution is either to just randomly change mags and test or try and make the mags you have work.

I have destroyed a few mags trying to figure out how to make things work but once you see what does what, it is not that tough to sort out.

Another thing to look for is how much of the bottom of the bolt nose engages the next cartridge. I have seen some really "thin" contact... they happened to run ok but if that cartridge ever dropped low, the bolt would ride right over it and you will see the jam as the bolt crashes into the middl'ish of the forward case.

Unfortunately, too many variables and tolerances for every stock swap to be plug and play.

I think a mag that locks up too low and/or not angled up enough are the two most common flaws I see in poorly running rifles.

Jerry
 
Mystic Precision said:
I have accurate mags... stamped on the mag body... run like a dream so it is not the design... but may be the QC of the mags you have.

Yes, follower spring pressure if weak will cause no shortage of problems. Too stiff, and pushing the rd out of the mag becomes a pain... or if the lips are not curved enough, you get self loading.

The mags are only as good as the mag well and alignment to the action, bolt and chamber. It all has to work in unison for smooth and confident feeding.

Find a mag with more follower pressure and see if that solves the issue. My first fix would be to open the front part of the lips and get that bullet tip higher. They look like they are really low in your pics.

Bullet shapes vary, OAL vary... throw that into the mix and even more fun. VLD/tangent ogive bullets are more likely to jam then Secant/rounded noses. but if the bullet is running into the ramp or below the chamber and stopping, you have an alignment problem and the only solution is either to just randomly change mags and test or try and make the mags you have work.

I have destroyed a few mags trying to figure out how to make things work but once you see what does what, it is not that tough to sort out.

Another thing to look for is how much of the bottom of the bolt nose engages the next cartridge. I have seen some really "thin" contact... they happened to run ok but if that cartridge ever dropped low, the bolt would ride right over it and you will see the jam as the bolt crashes into the middl'ish of the forward case.

Unfortunately, too many variables and tolerances for every stock swap to be plug and play.

I think a mag that locks up too low and/or not angled up enough are the two most common flaws I see in poorly running rifles.

Jerry
Click to expand...



It looks to me like the mag is sitting high enough so the bolt will contact enough of the round each time . It never skips over the round like you mentioned .
It jams when the round below the one I just chamber is sitting low in the front after extracting the fired round .
It is getting slid forward somehow and looks like the pic I provided before even trying to chamber it.
 
Arrowhead said:
I had similar problem with my Accurate mags, don't bother playing with the lips, you wont get good result and just get frustrated.
Open your mag and change the angle of the spring so that it will put more pressure to the side you need. Open the rear for more front pressure and open the front for more rear pressure
Click to expand...

What do you mean "open the rear" and "open the front"?
 
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