Question about installing a mag catch

[Slatewiper]

I'm putting together an Anderson stripped lower with a Anderson LPK. After putting in the mag catch I noticed that it doesn't sit flush with the side of the lower. It sticks out roughly 1/16". Is that a sign of an out of spec lower or a bad mag catch?

[zombiescometh]

Does it function correctly?

[RocketScott]

Try tightening it one more revolution.

[Slatewiper]

Does it function correctly? Yes it does.

[Slatewiper]

Try tightening it one more revolution.

Tried that and it didn't help. The shaft started to stick out thru the hole in the release button.

[MrCleanOK]

If it functions properly, 1/16" sticking up on the port side is nothing worry about.


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[Slatewiper]

If it functions properly, 1/16" sticking up on the port side is nothing worry about.


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Thanks. Its just never happened before so I was wondering what might have caused it.

[MrCleanOK]

AR-15 parts come from all over the place, lots of different manufacturers. Unless you're talking about interaction between parts that are critical to the function of the gun (BCG, gas block, etc), it's unreasonable to expect that a part from one manufacturer will blend seamlessly with a part from another. There's just too much variation out there.


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[GH41]

If it functions properly, 1/16" sticking up on the port side is nothing worry about.


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You mean the red side?

[freefly]

I'm putting together an Anderson stripped lower with a Anderson LPK. After putting in the mag catch I noticed that it doesn't sit flush with the side of the lower. It sticks out roughly 1/16". Is that a sign of an out of spec lower or a bad mag catch?
If all parts are in spec, it should be flush (or even slightly under). I don't even see 1/16th above the frame when a mag is inserted (before latching) on my factory Colts and LMTs.

However, I too have run into tolerance-stacking issues with mag catches on builds before, to the point where the catch wouldn't even get past the "ears" let alone bottom-out in it's channel.

So, I would just make sure that it is properly seated in it's channel (and not binding/dragging/tight), and fully engaging the magazine. If you have any other lowers around to compare, it should be easy to verify by looking at the catch position in the mag well on both.

[Slatewiper]

If all parts are in spec, it should be flush (or even slightly under). I don't even see 1/16th above the frame when a mag is inserted (before latching) on my factory Colts and LMTs.

However, I too have run into tolerance-stacking issues with mag catches on builds before, to the point where the catch wouldn't even get past the "ears" let alone bottom-out in it's channel.

So, I would just make sure that it is properly seated in it's channel (and not binding/dragging/tight), and fully engaging the magazine. If you have any other lowers around to compare, it should be easy to verify by looking at the catch position in the mag well on both.

All my other Ar's it's either flush or slightly below flush.

[NeoNeanderthal]

Mag catches are extremely cheap. I'd buy a new one, or at the very least grind down the threaded pin end so you can turn it more until it sits flush.

[Smallblock]

Probably wont help but Here's how my Anderson lower with Anderson lpk fits. 3155031551

[MegademiC]

With the other parts removed will it fit flush?

[3 AE]

I think either the channel in the lower for the mag catch wasn't machined deep enough. Or the mag catch is thicker than it needs to be. As long as there is some tension on the spring the catch will only seat as far as the channel will allow.

[Slatewiper]

With the other parts removed will it fit flush?

No. I disassembled it to try just that. It sits the same either way.

[Slatewiper]

Probably wont help but Here's how my Anderson lower with Anderson lpk fits. 3155031551

That looks pretty close to mine.

[Smallblock]

Great,now I'm worried mine is wrong. lol

[Slatewiper]

I think either the channel in the lower for the mag catch wasn't machined deep enough. Or the mag catch is thicker than it needs to be. As long as there is some tension on the spring the catch will only seat as far as the channel will allow.

I'll bet you're correct. Unfortunately I don't have another mag catch to try out.

[pistolpete]

I just assembled a radical arms an anderson and dpms parts kits. I was able to get every one of them protruding the same amount. I did have to rotate a button 1/2 instead of a whole turn once though. Hope that helps.

[RocketScott]

No. I disassembled it to try just that. It sits the same either way.

I don't know what I was thinking telling you to screw it in more. Brain fart.

When I get to my shop I'll measure parts for comparison. I'm not sure if you can find specs online for the mag catch. I would bet it's the mag catch being too thick but could be the lower.

[NickySantoro]

I think either the channel in the lower for the mag catch wasn't machined deep enough. Or the mag catch is thicker than it needs to be. As long as there is some tension on the spring the catch will only seat as far as the channel will allow.

This^ or possibly some crap or flash in the slot preventing the catch from seating all the way. It might be worthwhile to remove the catch and inspect the slot.
FWIW
YMMV

[Iraqgunz]

I posted this in another thread.

I assembled an Anderson Manufacturing lower last night and I also had an issue with the magazine catch the front pivot pin. It appears to be a machining issue.

[RocketScott]

Sorry I'm Late getting back to this. The good news is that my van has a working transmission...

I measure a RRA lower with a Double Star LPK (I think, built it 10 years ago). The mag catch is .153" and the lower is .173". I also measures an Anderson mag catch and it was the same thickness.