Gunsmithing Magpul Magazines with Bighorn TL3 Long Action

[Midwestside]

I'm in the process of putting a build together with a Bighorn TL3 Long action with an AW cut mag opening
and I would prefer to run polymer Magpul magazines with the action because they are:
a) approximately a 1/3rd of the cost of AI mags
b) easier on the brass IMHO

It is apparent when mating the mag's to the bottom of the action that they will not seat or present the cartridges
high enough in the action to feed properly without modification of the feed lips.
(The pillar height was spot on for those quick to question that).
I contacted Bighorn explaining the conflict and they were quick to respond and were aware of the problem.

When I had contacted Bighorn, I only had the Magpul magzines in my possesion for reference.
I now have purchased an AI mag to compare the two feed lip configurations.

I am now somewhat confused at Bighorns' suggestion to modify the front end of the Magpul feed lips, because
when I compare two mfg's side-by-side, the Magpul lips are already a shorter distance from the back of the mag than the AI's?

So that is a long-winded explanation and I'm wondering if anyone (gunsmiths or otherwise) have encountered this combo (or possibly other AW cut customs)
and has pictures showing how they have modified the Magpuls to make this work?

It would be much appreciated before I go to "trial and error" and potentially ruin a perfectly good magazine. Thanks.

 

[ugsly308]

You can make a new latch that is longer that will allow the mag to sit higher. When I do a rifle I dam near want the bolt rubbing on the mag lips. That gives me as much case presentation as I can get.

Casey

 

[Midwestside]

The latch location will not remedy the problem. The feed lips conflict with the aw cut opening in the receiver and do not allow the mag to sit any higher without modification to the feedlips. I was just hoping someone had done this previously and could post a picture showing where and how much.

 

[m1k3]

I just finished a TL3 with MPA chassis and using a single MagPul magizine for now and so far it works fine. The only thing I thought might be a problem is that it doesn't seem to allow the round to angle up a tad and "aim" into the chamber. If I try to chamber a round slowly, it kinda jams up at an odd angle, if I run the bolt normally, it works fine. This is with 6.5 Creedmoor rounds which don't have the same taper as a 308, although that difference is only slight.

 

[Midwestside]

Yes, short actions are likely completely different. On the long actions there is definitely no way the combination of the Magpul magazine will work with the opening of the receiver without modifications to the feed lips.
They are too fat to insert slightly into the opening as the AI's do.
Again, I was hoping someone had a picture of a previously performed mod', but I will likely forge ahead and try to slightly bevel the outside edges of the feed lips of one magazine (without jeopardizing the polymer's structural ability to still hold the rounds) to the best of my ability.

 

[Habituallinestepper]

Wondering if you had any luck with this?

 

[bohem]

Wondering if you had any luck with this?

I run the Magpul Hunter 3006 mags in my Long Action Bighorn with out any issue. I had to thin out the magazine lip on a belt sander so that it would fit into the inlet. Once that was done I had no issues and the mags feed smooth as silk.

 

[Zermatt Arms]

Wondering if you had any luck with this?

The TL3-LA's have been updated since this thread started. There is now a cut in the magazine well to accommodate the Magpul magazines. We have had great feedback from this modification. There shouldn't be any magazine modification needed in order to run them in the long actions.

 

[Midwestside]

Wondering if you had any luck with this?

Nope, my receiver would need some additional machining as referenced in post #8.
Modding the feedlips was not working. I thinned the plastic composite as much as I could/ was comfortable they wouldn't not flex and be flimsy.

I should be clear, this thread was not created to shed any negative light on Bighorn. I think they rock and make outstanding products. But I do not feel it is their responsibility to make sure their actions are compatible with every magazine company out there that decides to start making AICS type mags, which is why I was asking if others could help me out with this particular combo.