Gunsmithing MPA Competition chassis + action installation

[ormandj]

When installing my Impact 737r into an MPA Competition folder, I realized the action was slightly canted when looking at my Spuhr mount's level vs. the MPA's level. I loosened the two action screws, moved the action until the levels aligned, held the rifle barrel-up as per MPA instructions, then torqued front then rear screw to the lower torque value, then repeated front and then rear to the higher torque value as per the directions. Everything seems fine, but I do wonder if this is to be expected. I worry about the action canting after repeated use/transport.

I appreciate any input people have regarding this, it's my first 700-style action and chassis system.

 

[Sheldon N]

My 0.02

First preference would be to bed the rifle if you wanted to force the action/rail/spuhr to match up perfectly with the MPA level. I also lean towards bedding just for stability.

If you aren't going to bed the chassis then I would suggest you bolt in the action into the natural postion rather than trying to force it level. I'd tighten it like this.. insert both action screws, rear tang screw barely bottomed out, just finger tight. Tighten front action screw to 20 in/lb, bang the but of the rifle stock on the ground. Tighten rear tang screw to 20 in/lb, bang the but of the stock on the ground again. Then front screw 65 in/lb, bang the butt on the ground, then rear screw 65 in/lb, bang again and done. That will ensure the stock is settled and the recoil lug is up against the chassis minimizing risk of zero shift.

As far as the level goes I'd rotate your scope in the rings so that it matches your Spuhr bubble level (check reticle with plumb line). Whether the MPA bubble level matches or not, I bet you find yourself using the Spuhr bubble.

Finally, adjust the butt stock cant so that it lines up comfy into your shoulder pocket. Mine is tilted over a bit to match my natural position (top screw moved one hole right on butt-pad).

 

[ScottDWallace]

You can tune the chassis level if you desire. There is a little open cell foam pad underneath each side of the level. One or two extra inch pounds on the high side, or a thin paper shim will get it close enough.

 

[ormandj]

Thank you for all of the guidance. @Sheldon N I'll give your method a twirl, scope already matches the level on the rings (used their leveling tool, which worked quite well). I do need to adjust the butt stock, I'll do that as well.

@ScottDWallace great tip, I'll go this route. That way there won't be any confusion regardless of which level I look at. Thanks!

 

[ormandj]

@Sheldon N do you suggest the use of the lug lock? I've heard mixed things with it, I'm just curious on your take.

 

[Sheldon N]

@Sheldon N do you suggest the use of the lug lock? I've heard mixed things with it, I'm just curious on your take.

My chassis are pre-lug lock versions. if I had a Lug Lock I'd personally not use it and just bed the chassis instead.

 

[abn31c]

FWIW, my comp chasis is in the shop right now getting the lug lock removed and bedded. I think lug lock was a bandaid for a lack of purchase between action and chasis. Love the chasis tho.