CtYankee,   I still have that ST article, and have referred others to it.   I've mentioned the higher observed velocities from revolvers on other forums. Some were skeptical, and of course it is logical that revolvers would have to be slower due to that leaky B/C gap.  I was glad to see it discussed in the ST article, so perhaps other forum members would not think I was quite mad;)

  FWIW, I have routinely seen higher chronographed velocities in 9MM and 10MM revolvers than in semi-autos with barrels of similar length. My 3" Ruger SP101 routinely produces velocities equal to or greater than my 4"-4.4" semi-autos. My 5" S&W 610 revolvers did the same. For instance, CorBon 135 grain tested some years ago was actually about 100 FPS faster in the 610 revolver than the 5" semi-auto.  Id' have to dig through old chronograph notes, but IIRC, the semi-auto produced ~1475 FPS, the revolver ~1585 FPS.  But it varies from gun-to-gun, and is not carved in stone. For instance a 5" Ruger GP100 demonstrated velocities a bit slower than my current 5" semi-auto.  My current 4.2" Ruger revolver is a little slower than the 5" Ruger.

I've reloaded 10MM for a very long time, know it does not equal .41 Magnum, and never tried to approximate top .41 Mag. ballistics with 10mm. I want my ammo to work reliably in both semi-auto and revolver, so have not tried the longer than standard overall lengths to increase usable powder space.  I prefer bullets in the 165-170 grain range for reloading the 10MM. I've used a bunch of powders since the '80s, but have settled on AA-9 for top loads in the 10MM. Using this relatively slow powder has produced top velocities with no unusual pressure signs, and very good consistency since it meters so evenly.  My reloads with 165 grain bullets demonstrate velocities quite similar to the Underwood 165 grain factory ammo. No undesirable issues encountered with either the Underwood or my reloads in my guns.

  JB, I'm more than a little  surprised that S&W would do any work on a long out of production 3rd. Gen semi auto. I'm a fan of both the S&Ws and the 10MM cartridge; had multiple 1006s, 1076s, 1026s and a couple 610s.  I acquired my last 1026 LNIB some years ago. I'm trying to hang on to this one. Nice used S&W 10MMs are not so common anymore.

Glad S&W is helping you out with yours.






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   Hello all, I've owned a succession of 10MM pistols and revolvers, pretty much since the first Bren Tens became available. Worked SHOT one year with Tom Dornaus and Michael Dixon, toured the factory, etc. Started reloading for the 10 as soon as dies became available.   I still have one 10 and am looking forward to discussion of all things 10MM.