Anyone else with a MPA rat base experience sheering?

[SD Carpenter]

So after using with an Atlas for a couple range trips the base is actually sheering the lip and wedging it into the chassis rail.

I've even tried holding it back an inch and it still slides its way up pinning it, where I need a hammer to tap it back... Which kinda defeats the purpose of being able to slide it back and forth.

Anyone else experience this? I could less about the aesthetics really even though it's marring the crap out of the chassis.

 

[Fig]

I have the same thing and have never seen that...

 

[SD Carpenter]

I'm shooting a 6.5 so it's not exactly a heavy recoiling round to begin with

 

[FishDr]

I traded my MPA away so can’t look at it directly. If my memory is correct, the rail doesn’t go completely out the front of the forearm, it stops just a bit short. That’s why you are having this issue. Mount the base back a ways, or if you want it further forward, MPA makes a spigot to go in the forend.

 

[Ricker]

No damage on mine. Sometimes the RAT will loosen up and slide into the ending area of the dovetail cutout but it hasn't damaged anything.

 

[Mr.BR]

That doesnt look like shearing, it looks like your RAT slid onto the end of the dovetail and that slowly bent the jaw edge , without that dovetail ending it would have fallen off the rifle ,no fault of MPA here.
I always wandered how and why arca rail without any serrations became the next best thing

 

[Sheldon N]

Looks like your base was loose and you kept shooting it, with the recoil hammering it up against the end of the channel. My thought would be to pull it about 1/2" short of the end of the channel and tighten it down more, then watch for any loosening or movement when shooting.

 

[FishDr]

Looks like your base was loose and you kept shooting it, with the recoil hammering it up against the end of the channel. My thought would be to pull it about 1/2" short of the end of the channel and tighten it down more, then watch for any loosening or movement when shooting.

This !! And file those burrs down to prevent more damage. Those look nasty right there.
@MPA

 

[Lesco Brandon]

I traded my MPA away so can’t look at it directly. If my memory is correct, the rail doesn’t go completely out the front of the forearm, it stops just a bit short. That’s why you are having this issue. Mount the base back a ways, or if you want it further forward, MPA makes a spigot to go in the forend.

This ^^^^^^^

 

[SD Carpenter]

thanks for the replies guys,

I talked to MPA and the best I can figure I didn't hand tighten it enough and it slide off the end and started to curl back. When I first noticed it I held it back but it slide back up front again.

Next time I'm out I'll try cranking it down even more to see if it's still sliding.

 

[achalmersman]

Spend the money and get the RRS mount. That thing slides nice, and locks up TIGHT while fitting both the arca rail and pic rail. Get the SOAR release lever. Yes the price tag hurts. Oh well it's worth it.

RRS SOAR - Home

soar.reallyrightstuff.com

 

[b6graham]

That doesnt look like shearing, it looks like your RAT slid onto the end of the dovetail and that slowly bent the jaw edge , without that dovetail ending it would have fallen off the rifle ,no fault of MPA here.
I always wandered how and why arca rail without any serrations became the next best thing

the serrations on arca-lok came much much later than the original use of the dovetail

 

[Mr.BR]

Arca original use?you mean mounts for non recoiling cameras and stuff

 

[b6graham]

Arca original use?you mean mounts for non recoiling cameras and stuff

I meant in our sport in this case. But yes that too ha honestly I'm surprised more companies havent adopted the arcalok detects.

 

[ScottDWallace]

In addition to all the fantastic advice here, definitely consider getting the MPA spigot. It creates a much longer lever arm, effectively damping movements made back at the butt stock. Mine lives as far forward from the butt stock as possible. Certain barricades/obstacles benefit from brining the bipod back down the rail (culverts), but the great majority of time it's on the tippy top of the spigot.

RRS makes a Pic/ARCA combo mount, which is nice, although expensive. The new MPA spigots can be flipped over and just use a straight ARCA clamp, saving a few bucks.