Smith & Wesson Radius Stud Package

[a5werkes]

Gentlemen,
I understand that the S&W revolver "radius stud package" was introduced ~1988 subsequent to their discontinuing pinning the barrel; the purpose of which was a safety measure.
Internet search name drops "radius stud package" by the zillions......no explanation offered and no photos of its appearance.
1. Is that true about safety upgrade.
2. Is the radius stud package visibly different than models without the package.

Thanks

 

[BBBBill]

I'm guessing that you are referring to the hammer and trigger studs. The "newer" guns have a radius at the root of the studs where they protrude into the frame cavity with a corresponding radiused/chamfered hole on the left side of the hammer and trigger. I was told that it made them less likely to be broken. I'm not sure how either radiused studs (or pinned barrel delete) would be considered safety measures other than ensuring that all parts are in place/intact so that the gun goes bang when it's supposed to. I do know that the pinned barrel delete has resulted in a ton of over tightened/over torqued barrels with sights canted to the left. At one time 7 out of 10 that passed through my hands had that issue.

 

[a5werkes]

^^^Thank you.

 

[a5werkes]

I have done some more investigating of this situation, so some additional thoughts.

Elimination of the the top sideplate screw in 1955 with substitution of a retaining "tab" required that the sideplate then be installed at a slight angle; this in turn required the sideplate pivot stud hole diameters be slightly enlarged for installation clearance. This was the first regressive design step of increasing part tolerances for assembly of pivot stud-sideplate.

In both prewar and traditional S&W M&P revolvers, hammer / trigger pivot stud tips fit into their corresponding sideplate recesses with minimal clearance, even after "tab" innovation. This minimal clearance design enabled the sideplate and its pivot stud recesses to bear 50% of action spring and operating component loads. It was also thought to be useful in preventing stud fractures in the event the revolver was dropped, particularly if the revolver impacted on to the hammer spur.

Radius Stud Clearance Package, affecting K, L, N frames, was introduced ~ 1988, with S&W ownership changing to Tompkins, PLC. Changes occurred to the geometry and thus clearance tolerances of hammer and trigger pivot studs, frame boss, hammer and sideplate changes. Tapering the ends with smaller tip diameters would allow for greater tolerances for production of the corresponding sideplate pivot stud hole locations, resulting in fewer part rejections during assembly due to ill-fitted parts. This was the second regressive design step of increasing part tolerances for pivot stud-sideplate assemblies.

Mechanical end result of the radius stud clearance package is that the tip of pivot studs (hammer / trigger) would essentially "float" within the sideplate location recess, re-purposing the side plate cover from a mechanical point of stability for the stud tips to that of a cosmetic only cover plate. Such a design no longer afforded the sideplate to prevent a hammer stud fracture if the revolver impacted directly on to the hammer spur, which may have been a digressive "safety" factor.