“The Modicum of Movement affair”
Posted by robertboyd2, May 4 2009, 01:33 PM
Despite the second trip back to Joe, the stock came back just the way I wanted. The wedge fit solid in the dovetail and the ball detent snapped positive in the both cutouts to lock it in an extended position.
Per my request, Joe also replaced the roll pin that attached the swivel plate to the main tube. While the substitution undoubtedly improved the overall esthetics of the stock (not to mention staying true to the original design,) it somehow lessened the tension required to lock the buttplate in the downward position. As a quick fix, rather than shim the spring, I decided to replace it with a trimmed mainspring from a 1911. Doing so solved the problem.
Then, I noticed something else when I attached the stock and shouldered the pistol. The action caused rearward pressure that pivoted the grip slightly forward. To make matters worse, the movement was just enough to bind the trigger bar’s movement and hinder sear reset once the trigger was pulled.
With only a single screw holding the grip in place, the discovery really wasn’t too surprising. While it offers tremendous credibility to my buddy John’s suggestion for a frame-mounted dovetail—no John, I still haven’t ruled it out—fellow U.N.C.L.E. Special builders Paul and Eric recently approached me with a possible solution to stop the grip from pivoting. They ran two small pan-head set screws from inside the mag well into the grip thereby pinning it to the frame.
Right now, the notion of this quick fix is much more appealing. However, to play it safe, I plan on compiling some dimensions in relation to John’s idea, should it become necessary down the road.
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Comments
stymie, May 4 2009, 05:28 PM
My concern relates to the amount of torque/ leverage that will be transmitted to the grip unit's dovetail during firing with live ammo as well as movement of the grip itself. The bracket pinned to the frame would alleviate all the worry. (NO stress to the grip at all; the steel frame takes the hit instead) Remember, that one screw in the grip will be under tremendous stress. A threaded bushing/ insert will prevent the aluminum grip from stripping/ fracturing as well.
Did you get a weight for the bbl assembly? (Check my comments in the previous thread) In that reply, I mentioned the P.38's/ P.5's ability to pull at least an additional 9ozs w/o a booster.
(Did you get my e-mail from last night? I got me an RFB!!!)
-John
Paul emailed me about the same grip problem with his grip. His fix seems like a really good one to me.
As I explained to Paul:
The problem is that there is a triangle that exists between the top inside of the grip, the screw hole, and the bottom inside of the grip. If everything isn't exactly right in all 3 of these spots you will have problems because each of those spots plays a different role in the fit and the play. I suspect there is no hope for that grip. The only way to stabilize it is to move it forward and take all the play out of the triangle in a way that the top and bottom of the grip properly contact the pack of the frame at the top and bottom inside of the grip. The starting point is to move the screw hole to the right spot toward the back of the grip. You may then have to file the inside of the grip at top and bottom for the proper fit. Not even I would attempt this as it is probably just an exercise in frustration.
Paul, creative problem solver that he is, found a way to make the grip he had work. Our grips from our new machinist fit with zero play, but even with them Paul's technique of anchoring the grip to the frame would be insurance against future loosening.