model 69 barrel rifling specs?
- Thread starter Shuz
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Electro chemical machining vs. cut rifling on the older guns. I think Smith does all their barrels by this process except for 22 rimfire.
New guns have rifling made by EDM a type of electrical metal removal, while older S&W had cut rifling. Some contend that the EDM barrels don't shoot lead at high velocities as well as cut barrels. I don't know for sure myself. Smooth and uniform is always key. I think if you have problems with cast bullets the problem is more likely to be the bullets than the rifling. Some guns like some bullets some don't. Hapretty much always been that way.
Well, I compared the rifling on my new 69 to my 329PD which I bought about 2004, and it appears that the two riflings are different. The 329PD looks more like cut rifling like my 629-3 DX's and 629-4 Mtn Gun have. I shoot nuthin but lead boolits so this kinda concerned me. I fired the 69 the other day with .429 boolits and 7.0g of Trail Boss and the gun was comfortable to shoot and there was no appreciable leading. Groups were 2-3" at 25 yds from a rest. The trigger pull, since I went to the 11lb Wolff, has now dropped from 56 ounces to 48 ounces and I guess I can live with that. I prefer my 329PD to the new 69 so far. It is much lighter to carry and with it's 500X frame Hogues, and 32 ounce trigger pull, is much more comfortable to shoot. I'd trade straight across for another 329PD.
S&W's revolver barrels rifled with electricity instead of broaches vary a lot. Some appear polygonal, some look like old cut rifling with the corners rounded and others fall some where in between. From your description it sounds like S&W broach cut your 329PD's barrel. They still do that in some Performance Center (PC) Models. Perhaps S&W used up some left over PC barrels while the production line was turning out 329PDs.
I don't believe any of the two or three-piece barrelled revolvers have broached rifling. Like k22fan said, some EDM/ECM barrel's rifling looks more squared than rounded.
The forcing cones on all (my) EDM/ECM two/three-piece barrels look different, & better, than one-piece EDM/ECM barrels or my broach cut (625PC & 627PC) barrels. I suspect they're done all in one process rather than finished up separately on the assembly line.
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The forcing cones on all (my) EDM/ECM two/three-piece barrels look different, & better, than one-piece EDM/ECM barrels or my broach cut (625PC & 627PC) barrels. I suspect they're done all in one process rather than finished up separately on the assembly line.
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