Gunsmithing Mag Lips getting caught in bolt flutes

[slayer_21420]

Thanks for the info in my previous thread guys. I went ahead and bought a Manners, but went with the t3 w/mini chassis. Now i'm having issues with the mag feed lips getting caught in the bolt flutes when cycling the action, when this happens it bends the feed lips on the mag. I know that when this occurs with a standard DBM you just use shims between the bottom metal and the stock to lower it a bit but what can I do since i'm using a mini chassis?

I have both the accurate brand 5rd mag that came with the stock and an alpha type 1, the accurate mag binds about every time but the alpha only does if I push up on it.

Thanks in advance for any help guys.

Steve

 

[19Scout77]

I suggest you hop in the wayback machine and travel back to the day before you decided to screw up a perfectly good bolt by fluting it!

 

[slayer_21420]

:-D great plan! I'll just call and tell stiller to stop having PTG flute their bolts! What a helpful answer.. I've never come across a tac 30 without a fluted bolt, have you?

 

[ORD]

Got any pics by chance? I'm curious as to how much the mag feedlips are getting into the flutes, as well as the differences bw the two mag types it seems you have tried.

Have you tried any AI factory mags or just the one-offs you listed? Curious if that might be at least part of issue...I'd borrow or buy an AI mag and see how they fit/function before you get too crazy on modding anything.

Aside from that, since you can't shim up the DBM in your case, if the problem exists with all mags, including factory AI mags, then you are left with modding the locking tab/mag body to get them to sit a little lower in the action or modding the mini-chassis, but from the sound of things as you are describing the problem, it sounds like you may need more than a "little more" room to keep the flutes from damaging your mags and causing you problems (at least with respect to the Accurate mag...thus, I'd start with the Alpha were it my setup causing the problem).

 

[darrenk75b]

Take a little material off of the top of the mag release lever that hold the mags up into the action. Sounds like yours is a smidge too long.This will result in the mag sitting a bit lower, and the problem should go away. No biggie.

 

[Kebo57]

Slayer....washers from the hardware store work well as shims in the application you're talking about

 

[300sniper]

Take a little material off of the top of the mag release lever that hold the mags up into the action. Sounds like yours is a smidge too long.This will result in the mag sitting a bit lower, and the problem should go away. No biggie.

That will not keep the mag from being pushed up into the flutes though.

FWIW, my TAC30 in an AICS does the same thing with a 10 round mag but not AICS 5 round mags. I never use 10 round mags so I haven't dug into the problem yet.

 

[Kells81]

I have the same problem with my Stiller Tac-300 action and AICS 300WM modified to feed the 280AI. It doesn't happen all the time but it does. The only time I have been able to replicate it is when I would apply a little pressure to the magazine and work the bolt.

 

[smokebomb]

It's not clear just how much contact with the bolt your mags are making, but couldn't a guy just bed the action 1/16th inch (or whatever the clearance required) higher in the stock?

Shaving the top of the mag latch would work if gravity was greater than tension, but any upward pressure on the mag and the problem would still exist.

Either the entire mag latch needs a lowering, the action needs raising, or the mags need modification. Or email manners and see if they can drop the mini-chassis inlet...ie new stock.

 

[AccuSol-ERN]

Shims are ghetto and a lousy half-assed fix for any pillar height problem.

Since this is a mini-chassis there is little it can be. I would bet that someone installed an AW mag length latch in the minichassis before you received it. Or there is just enough tolerance stack that it happens with your current and limited mag supply. You can either drive the roll pin out that holds the latch in and then file the latch (be sure to hold the same angle on the little shelf at the top that engages the magazine bump out). You can also get ahold of Matt or Tom [MENTION=63001]mcs[/MENTION] and ask them to send you a new latch.

Either way it is a pretty simple fix.

 

[300sniper]

Shims are ghetto and a lousy half-assed fix for any pillar height problem.

Since this is a mini-chassis there is little it can be. I would bet that someone installed an AW mag length latch in the minichassis before you received it. Or there is just enough tolerance stack that it happens with your current and limited mag supply. You can either drive the roll pin out that holds the latch in and then file the latch (be sure to hold the same angle on the little shelf at the top that engages the magazine bump out). You can also get ahold of Matt or Tom [MENTION=63001]mcs[/MENTION] and ask them to send you a new latch.

Either way it is a pretty simple fix.

Again, the latch only controls how far down the magazine can sit, not how far up it can sit. The bottom of the receiver should control how far in the magazine can go. The latch is not the problem. I have a feeling it is the magazine(s) itself. Does it do it with 10 round AICS magazines?

 

[AccuSol-ERN]

The mags might have a variance, but I doubt it is large enough to cause this issue. Rather than have the headache of sorting mags, I personally would just set my rifle up that all mags would function correctly. There is a pretty big working tolerance in "pillar height" to have a functioning mag, just look at the contact between the bolt nose and head of the round when feeding from the mag.

Obviously use common sense and don't fit your rifle to function with a fucked mag, causing all other correct mags to fit sloppy cock.

As 300sniper insists, no option short of creating a "mag stop" is going to correct the issue of the mag inserting too far, however this is true with seemingly all AICS dbm options (except defiance) and that's why you don't see people shooting positional while resting their rifle on the mag while cycling the bolt (the bolt will not close over the mag lips). As to the receiver being a "mag stop"......well most custom actions including Stiller whose recievers are cut for AICS and/or AW mags have too big a cutout to act as a stop of any kind, especially in the rear where it is needed most.

You see this problem more severely with fluted bolts as the flutes try to chew the mag lips off rather than just contacting the bolt body.

Again, shorten the mag latch a little bit and don't put upward pressure on the mag while working the bolt. The spring pressure from the loaded magazine will always take up the slack of not having a "mag stop".

 

[slayer_21420]

Again, the latch only controls how far down the magazine can sit, not how far up it can sit. The bottom of the receiver should control how far in the magazine can go. The latch is not the problem. I have a feeling it is the magazine(s) itself. Does it do it with 10 round AICS magazines?

All I've got on hand are the alpha 10rd and the manners supplied accurate 5rd. The alpha works as long as you don't apply any pressure to the mag (and I mean ANY) but the accurate will not function at all. I bought the stock brand new and expected it to come with an aics mag but got the accurate brand with it which IMO is a pos. I'm going to try to get ahold of a factory ai mag and see how it works.

My biggest gripe is that this is a $900 stock and these are $50-$75 mags, why the fuck do I need to worry about whether or not I'll be able to close the bolt on the second round when I've got two or three coyotes in front of me? I don't want to have to carry around a feed lip tool in the field in case the damn mag gets twisted up. I think I'll try to weld a stop on the outside of the mag so it can only go in so far as to not let the lips contact the bolt flutes. Another idea is getting a new bolt body without flutes from ptg to eliminate the problem.

Thanks for the comments guys.

Steve

 

[Hennig]

Damn, what a pain in the ass. Gl with getting to the bottom of it mate.

 

[Pusher591]

I may have just had blinders on but does this occur with other action? I know GAP display all their guns with their Templar as fluted and I've never heard of that occurring with their actions. Just curious as I have a Deviant coming and I opted for a fluted bolt.

 

[LRI]

Shorten the mag release lever a smidge. Some, like the AX and PTG stealth, are heat treated and hard as wood pecker lips. A file wont do much. Youll have to either grind it or take a wizz pass with a carbide endmill. So long as you arent shooting the gun in zero gravity, upside down, or "operating" by using the mag as a monopod or broomstick handle it should work fine.

Before doing anything try a different magazine to see if the problem continues. Stuff happens. Feedlips get bent wrong, latch detents can be stamped slightly off, etc. Double check before blazing away.

Hope this helps.


C.

 

[slayer_21420]

Thanks Chad, definitely helpful. I do rather enjoy shooting upside down though...

I emailed Manners this morning and already got a reply from Tom, he will be calling me tomorrow with a solution. Great customer service as expected

I still would like to add a "stop" to the magazine so it cannot be inserted too far in the first place, relying on gravity is great and all but what if by chance some debris gets between the mag and inside wall of the DBM wedging it in a bit? Do any of you have experience with welding on a spot of material to keep the mag from being over-inserted? Doesn't seem like it'd be terribly difficult?

Steve

 

[300sniper]

There still needs to be some sort of positive stop or you will end up in a situation where your mag is being pushed by something unless you live on a bench or bipod. Ever shoot off a barricade? Ever shoot off your pack? Ever dropped down with your stock directly on a mound of dirt? I would never run a rifle in the field or competition that would lock up in those common situations.

 

[slayer_21420]

There still needs to be some sort of positive stop or you will end up in a situation where your mag is being pushed by something unless you live on a bench or bipod. Ever shoot off a barricade? Ever shoot off your pack? Ever dropped down with your stock directly on a mound of dirt? I would never run a rifle in the field or competition that would lock up in those common situations.

That's exactly what i'm trying to avoid, see my post above yours.

 

[doubled]

Many of us have the same problem - i found that a file to the sharp edges on the flutes fixed it for me. Now when there is contact 99% of the time it just rolls over vs. getting caught on the lip and bending the mag. It is the super-sharp edged on those bolts that rips up the mags when there is contact because it bites in and takes the lips for a ride. I filed my down just to knock off the sharp edges and hit it with a buffing wheel and all is well now.

 

[slayer_21420]

Many of us have the same problem - i found that a file to the sharp edges on the flutes fixed it for me. Now when there is contact 99% of the time it just rolls over vs. getting caught on the lip and bending the mag. It is the super-sharp edged on those bolts that rips up the mags when there is contact because it bites in and takes the lips for a ride. I filed my down just to knock off the sharp edges and hit it with a buffing wheel and all is well now.

You wouldn't happen to have a picture of your bolt would you?

 

[doubled]

I'll take one later - i just literally knocked off the edged with a file and hit it with a buffing wheel - cosmetically it doesn't look much differently but the sharp edges don't catch on the lips anymore.

 

[Texar2]

You could always use a tig or mig to add some material on top of the reinforcement plate on the front of the mag and file to fit. I had the same problem running the bolt while being suspended upside down. I had to fill in the flutes because of this and the fact that they would catch wind and make me spin clockwise when my chute deployed.

 

[LRI]

Many of us have the same problem - i found that a file to the sharp edges on the flutes fixed it for me. Now when there is contact 99% of the time it just rolls over vs. getting caught on the lip and bending the mag. It is the super-sharp edged on those bolts that rips up the mags when there is contact because it bites in and takes the lips for a ride. I filed my down just to knock off the sharp edges and hit it with a buffing wheel and all is well now.

Precisely why I use a different cutter geometry. One with no sharp edges as the flute has a 30* draft on each side.

C