Feeding problem with AI magazines in a Cadex Chassis

Mystic Precision said:
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
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This.

Your nose diving is not a feedlip issue. The round is not getting TO the feedlips so the problem is deeper. With the mag out of the action, do all rounds feed easily? Can you thumb your dummy rounds out of the mag trying to imitate the action of the bolt moving forward? If any rounds nose dive, it might mean that your mag or follower or spring need tweaking. If the rounds don't nose dive outside of the action, but do in the action, check to see if anything is pinching the mag.

Also, is the OAL too long causing the bullets to catch? Would be nice to see a loaded mag top down to be sure.
 
curseyou said:
This.

Your nose diving is not a feedlip issue. The round is not getting TO the feedlips so the problem is deeper. I agree With the mag out of the action, do all rounds feed easily? Yes Can you thumb your dummy rounds out of the mag trying to imitate the action of the bolt moving forward? If any rounds nose dive, it might mean that your mag or follower or spring need tweaking. If the rounds don't nose dive outside of the action, but do in the action, check to see if anything is pinching the mag. I will try a few mags like that tomorrow . Nothing is pinching the mags and one will drop free if mag release is used as it sits loose in the magwell but still malfunctions.

Also, is the OAL too long causing the bullets to catch? No , as I have been using Federal gold medal match and the tips of the rounds are not touching inside the mag Would be nice to see a loaded mag top down to be sure.
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The rounds are fully inserted to the rear with the base of all rounds are touching the inside of the mag
 
I am using factory loaded ammo for the mag testing to make sure it wasn't that . Federal Gold Medal Match 175gn . The tips are not close to the mag at all .
 
chalkriver2 said:
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.
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Ok, then the problem is "lower" down. OAL is a good thing to check and shorten but you ammo doesn't look overly long???. Remember that the tips of bullets can vary and if you are right on the max length, that extra can cause a nose to drag/grab and mag walls and not rise properly.

2nd would be the follower dragging on the mag

3rd would be a weak or ill positioned spring. Once you reliably get the cartridge to the top of the mag, tuning the feed lips (if necessay) is the last step.

Consider using a dowel or pencil and push the follower into the mag. Does it move smoothly up and down? Can you feel it hang up on anything? Can you hear the spring "sproing" along the travel.. ie spring bind?

Maybe the spring is put in backwards?

This post has inspired me to fit the remaining mags to my Rem 783 project. I am going with the MDT polymer mags. Yes, they do get fat on the 10th rd but I have modified the DBM so the mags work just fine. Just need to widen the entry area of the mag well... very simple to do with a Dremel and sanding drum.

Some fitting here and there and the mags are working very nicely. 3 X 10rds mags and a couple of lower capacity ones for back up. The current production mags which I just got in seem to have a much stronger follower spring and were much easier to set up.

If all else fails, get new mags or borrow from someone else and test.

Jerry
 
My SWAG would suggest the spring tweak is reversed but you get the point.

Some followers will allow the mag spring to be put in either direction and some mag springs have a side with more pressure/lift.

Flipping the spring the right way will put addn pressure on the front of the follower to help lift the bullet nose higher... in AR mags they installed anti dive tabs to help resolve this

Good luck....

Jerry
 
Thanks for tips Jerry
The AI mags will only allow the follower to be installed in one direction and the orientation of the springs look good.
A club member just dropped off a NEW unused AI mag for me to try ...I will compare the dimensions and take some pics after trying it out tomorrow .
 
Shawn_338 said:
A buddy of mine was having the same problem, he called Cadex and turns out his mag well was out of spec. They are sending him a new one. Might be worth a call
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I got the AI mags from MDT . I will compare them to a new one I borrowed today.
Thanks for the info and if that's the case I will contact Cadex and see what they say .
I tried a plastic mag from MDT and it functioned worse as every round had to be jiggled to the rear a little to get it to feed.
 
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I compared and measured the new magazine and the only difference I can see is the upward spring pressure on the follower is actually a bit less and the feed lips at the front are a tiny bit narrower than mine.
It fits loose in the magwell and will drop free .It feels just like my silver mag as far as fitting into the magwell and has he same width at the vertical wear mark .
Feed lips are .385in at the front and rear .410in
Width at the vertical wear mark is Silver - .875in New .875in Black .885 in and the black mag has a very slight resistance when inserting but not enough to cause any issues and wont drop free.
Well the new mag is doing the same thing as my others and has the exact same issue with the 3rd round left in the mag getting jammed inside the mag in a nose down and to the right position below the bolt .
Also it has another issue as the last one or two rounds in the mag fail to feed as the bolt rides over them as well .
If I try and use it with one or two rounds in the mag the bolt will ride over as well.
After trying it a couple times I noticed a wear mark on both sides of the mag like mine have .







 
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Wear marks are normal.

If the bolt rides over a round it is because the magazine isnt seating deep enough. I am going through similar issues myself.

Can you push/pull your magazine up/down once it is locked in? If so how much does it move.

Also does the mag, when fully seated, sit against the receiver on the front and back?
 
Given that there is a wear line on the new mag, I would suggest that the mag well is pinching the mag and causing the follower to hang up. I can only assume when out of the rifle, the mags works fine. Try squeezing the mag by hand and see if you can get the follower to stick.

It is a fitment issue so you just have to find where things are hanging up and resolve.

Jerry
 
There is aprox 1/4 in vertical freeplay when mag is locked in and the bolt is to the rear .When the bolt is forward and loaded mag inserted the freeplay is gone .
There is no horizontal movement of the mag in the magwell . I couldn't get the mag to malfunction by squeezing it at the vertical wear mark . As 2 of the mags sit loosely in the magwell and drop free even if empty I don't think the wear mark is the issue .


 
That seems to be too much play up and down. How does it feed if you push and hold the magazine in the uppermost position. With the bolt closed the top round on the mag will push the whole mag down. I have the exact same prob.
 
Well upward pressure on it causes a jam immediately but forward pressure on the bottom of the mag ...Works like a charm !
It feeds smoother than it has ever done ...I ran a few mags through it as fast as I could as well with no issues .
I will start a thread on the Cadex forum here and see if theres a fix as I feel it is a problem with the chassis now.
At least I can get it to work now so some progress is being made ...maybe a plastic wedge :rolleyes:
 
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