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Gunsmithing Bedding a MPA chassis

I have personally witnessed a friend's rifle go from a scatter gun to tight groups by bedding an MPA. He finally resorted to bedding it after trying just about everything else multiple times.

That being said, his was an older model without the lug lock system. I have not experienced what he did with my MPA; but my MPA is a newer model with the lug lock system. Coincidence......I'm not sure.
 
If it's a newer one with the lug lock setup in there then you can eithe ruse the lug lock and skip bedding or you can tape off the bottom of the lug lock screw hole and fill it up bedding. The chassis needs to be roughed up where the bedding will go or the material is highly likely to just flake right off once cured.
 
I recently purchased a used MPA chassis. How does one tell if he has a lug lock or not. I think I'll try without bedding and tighten the action per manufacturers recommendations for torque, and if it doesn't shoot well will look at other options.
 
The lug lock is a little barrel with a threaded hole in the side and a ramp at the front of the recoil lug area. A bolt comes from the bottom up in to the barrel and when tightened it pulls the barrel between the ramp and the recoil lug, pushing the lug back in to the chassis.
 
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Assuming the recoil lug rests squarely on the shelf for it in the chassis, the Luglock locates the action back against the shelf and that together with the V-block geometry under the receiver fixes the position in the chassis the way bedding would in a stock.

I just found out that MPA does not make a Luglock barrel that fits standard Remington 700 0.1875" recoil lugs so I'm going to have to DIY for my Nucleus.
 
Assuming the recoil lug rests squarely on the shelf for it in the chassis, the Luglock locates the action back against the shelf and that together with the V-block geometry under the receiver fixes the position in the chassis the way bedding would in a stock.

I just found out that MPA does not make a Luglock barrel that fits standard Remington 700 0.1875" recoil lugs so I'm going to have to DIY for my Nucleus.
Simple solution.

Problem: The barrel can not contact and put pressure on the recoil lug. Since the barrel rides on a ramp in the front and should contact the front face of the recoil lug on the rear of the barrel.

All you need is the barrel to pull down lower in the chassis. I just filed .060" (to start) off the bottom of the barrel and it now contacts and applies pressure the way it was intended.

Hope this helps.
 
I filed a bit over 0.050" off of mine but realized if I file much further the contact point will be at the very bottom of the lug if it could tighten (I'm not sure it would because I still had at least 0.015" gap from the barrel to lug with the flat bottomed out.

I stuck a .45 ACP case between the lug and ramp and it looks like that diameter of 0.480" was a bit more than I need so I'll turn up a barrel that's about 0.450" with the top half cut off. That should grab the lug high which I prefer and I know it will work.
 
Using the largest barrel supplied (.395") I measured a gap of .004" with my standard rem 700 lug (.188). Removing .060" was good to go and only moved the contact point down that much as well.
 
Mine is different, my barrel measured at 0.385" and even filed 0.050" it still has that slop even when bottomed on the flat.

There is just no way it's going to clamp acceptably without a bigger barrel.
 
I just bought a used mpa that the seller neglected to say was bedded. I have not received the action that is going in that stock. How likely am I to have to redo the bedding and how much of a pain is it?
It is a rem700 action
 
Do you know what action it was bedded for?
Will ask tomorrow. He also modified the side and drilled a hole as seen in pic below.
I will be using this on an impact precision that is on the way.
 

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