Another MSH and Hammer Strut Issue

[GunBugBit]

I have put the Dawson Ice MSH+Magwell on four guns with no issues.  One of my newer guns, though, developed an issue after about 40 shots shortly after installing the Dawson Ice MSH+Magwell.

 

The issue was that the hammer would not fall at all, or it would fall to half-cock.

 

Looking under magnification at home, I saw that the top edges of MSH hole where the mainspring lives looked a little chewed up.  This gun's hammer strut has some squared off edges, not rounded toward the bottom like a lot of others.  So those steel edges not quite clearing - but instead rubbing on - the aluminum MSH caused some burrs that apparently made the strut hang up.

 

The issue manifested when the magwell was snugged down.  I only once saw the issue with the magwell loosened.  Apparently the snugging up just slightly tilted the MSH even though one might think the pin and tongue-in-groove interface would prevent all tilting, but not entirely.  The tiniest amount of tilt brought some newly formed aluminium burrs into contact with the strut, causing hangup.

The solution is pretty obvious, I'll post again after I have resolved the issue.

 

Haven't heard of this exact issue so hope it will serve as a reference for anyone who encounters it in the future.

 

 

[GunBugBit]

To avoid MSH tilt, realized the MSH bottom needs to allow the Dawson magwell to slide back in a straight line while riding the bottom of the frame (the gun's built-in magwell).  It wasn't.  The Dawson magwell was bumping into the MSH so I removed material from the MSH bottom until the Dawson magwell could slide all the way back.  Now the MSH does not tilt when tightening down the magwell screw.  This did the trick, Dawson magwell is solidly seated and hammer fall is consistent.