New S&W rifling less sharp?

[newtonguitars]

While cleaning the 442-1 I noticed the rifling is a lot less "defined" than my older guns. I probably have 50 rounds thru it, so know I haven't worn it out, but that is what it looks like.
Do current Smith guns have a new rifling concept?

 

[Gunhacker]

Yep... it's no longer mechanically cut rifling, current method is called EDM - Electric Discharge Machining, and it does look shallower than the old stuff.

EDM Rifling

 

[shocker]

EDM or ECM?

I thought the rifling was ECM.

Electrochemical machining - Wikipedia

I believe Smith barrels, except for 22 LR, have been electrically machined since the mid 90's so it's not new.

Edit - here's a summary of how Smith does it.

Since 1993, Smith & Wesson has been using an electrochemical machining technique to rifle most of their revolver barrels. The only revolver barrels that are still broach rifled are .22 caliber barrels and ported barrels. The manufacture of electrochemically rifled (ECR) barrels begins with the same steps as conventional broach rifling. The barrels are drop forged from bar stock, annealed, and wheel abraded to remove scale. During the annealing process the barrels have a tendency to bend and are therefore put through a straightening operation. The barrels are next drilled and reamed using conventional machining tools and the forcing cone is made with a tapered reamer. The barrels are then ready for rifling.

The electrochemical rifting machines arc made by Surftran and were specifically designed for Smith & Wesson. Each machine runs two independent workstations, each one with a single electrode manufactured by Mechanical Plastics. They are constructed of a two-inch long plastic cylinder with metal strips spiraling down its exterior. The metal strips are in the desired dimensions of the grooves, are at the appropriate rate of twist (1 turn in 18.75 inches for .357 Magnum), and are slightly inset in the plastic cylinder. The barrel is placed in the machine and is held stationary. The electrode is placed into the barrel and both are submerged in an electrolyte (sodium nitrate). The electrode travels down the barrel and rotates at the desired rate of twist. As current passes from the negatively charged electrode (cathode) to the positively charged barrel (anode), the metal is removed by electrolysis to produce the grooves by duplicating the shape of the electrode. During this operation the electrolyte flows through the barrel under pressure to remove the reaction products. This prevents the build up of reaction products on the electrode. Because the metal strips on the electrode never come in physical contact with the barrel and reaction products are not given the opportunity to build up, the electrode does not require any cleaning or maintenance. In fact, electrodes are only retired when the plastic core, which contacts the barrel to provide proper spacing and centering, wears over time. An electrode will usually remain within the tolerance of 2 thousandths of an inch concentricity tier approximately 3000 inches of barrel. During our tour of the Smith & Wesson factory, they were rifling six-inch .357 Magnum caliber barrels and the ECR process took about 60 seconds per barrel.

 

[newtonguitars]

Thanks for the info! The 442 is plenty accurate too. My newest gun before this one was a 1990 made 640, and it had sharp rifling.

 

[LVSteve]

I thought the same with the 686+ I bought, but it's still way more accurate than me.

 

[Fish4bass101]

My LGS had a model 60-15 that I was interested in, but after checking it out it looked to me like there was no rifling in the barrel, just wavy etching, for lack of a better way of describing it. The salesman actually pointed it out to me. I looked at another PC 60-15 they had and it was the same. Needless to say I did not purchase either. The new rifling may be fine, but just not what I am use to seeing in my older recolvers.

 

[msauter]

My LGS had a model 60-15 that I was interested in, but after checking it out it looked to me like there was no rifling in the barrel, just wavy etching, for lack of a better way of describing it. The salesman actually pointed it out to me. I looked at another PC 60-15 they had and it was the same. Needless to say I did not purchase either. The new rifling may be fine, but just not what I am use to seeing in my older recolvers.

I have a 60-15, and the "rifling" isn't much more than a shiny swirl ... seems to shoot well though ... no key-holing, and similar accuracy to my 36 with real rifling. Still puzzles me some.

 

[joe44va]

My 60-15 Pro Series is on of my most accurate revolvers. Guess I got a good one. Thanks S&W.