S&W model 646 .40S&W

[MrMoose]

I picked up a nice revolver. Model 646 in .40 My only revolver with a titanium cylinder. My only revolver to use moon clips (that might change if I find a 940 in 9mm or a 925 in .45). Unusual 3-7/8” barrel. Frame mounted firing pin. No lock, no MIM. Round butt L frame with S&W by Hogue finger groove grips. Nice color case hardened hammer & trigger. This gun feels great in hand, balances beautifully. I just couldn’t pass it up. This particular example has been tucked away in a safe since new. Has not been fired since it left the factory. I got lucky - it came with the original aluminum case, outer box and all the original papers inside. Truly LNIB. Trying to decide if I should fire it. I think it is somewhat rare and perhaps collectible. I encourage those of you who know more about this piece to chime in and enlighten me as to its origins, purpose for existing, collectibility, etc. Is this one likely to be remembered fondly and appreciate in value over time, or go down in history as an unloved Frankenstein of a revolver?

[k22fan]

Hello Mr. Moose.

Yours looks just like mine. Both have MIM internal parts with hammers sloted for internal locks but no lock installed. Mine was $380 plus tax new. The gun store that I bought it from was a factory recognized S&W retailer. I was a regular. It's owner repeatedly told me that I should already know to buy a 625 rather than the 646. He got red in face pissed when I stuck to buying the odd ball then stomped off into the back. It had nothing to do with getting me to buy a more expensive gun. It was his opinion of the concept. Judging by the number sold most potential buyers must have shared his opinion. Depending on the source there were as little as 200 or as many as 300 of both the Performance Center and production line parts clean up 646s.

I had my choice of two 646s that were in different stores at the same price. Their rifling was different. The one I did not buy was rifled using electricity to erode away metal to create grooves. That's been S&W's method since around the mid 1990s. The one I bought has broach cut rifling, S&W's old method. my theory is that there were more cylinders left over then barrels so S&W had to make more barrels to complete the parts clean up.

During a S&W days sale with factory reps in the store I bought a new 3 7/8" unfluted 610 dash whatever from the same store for the same price. The owner did not like it either but he only said so politely.

I've fired that 610 in matches more than any other revolver. There is no doubt that 625 are faster to reload but I like being the only one at a match with the unusual revolvers. Also I some times skipped reloading and bought Win. white box .40 S&W at Wal-Mart for $16 a hundred. It was the least expensive centerfire cartridge that revolver suitable for matches were made for. Then came Obama and high factory cartridge prices.

[MrMoose]

Originally Posted by k22fan

The one I did not buy was rifled using electricity to erode away metal to create grooves. That's been S&W's method since around the mid 1990s. The one I bought has broach cut rifling, S&W's old method.

How can I tell what method was used to cut rifling in the barrel?

Did not know this model had MIM parts.

Thanks for the information...

[k22fan]

The lands and grooves in S&W's Broach cut rifling have square corners. I'll probably get the name of their modern rifling process wrong but it is something like electro chemical discharge or electro chemical machining. ECD or ECM? I'll go with ECM until corrected. S&W's ECM rifling has, in various degrees, rounded corners. Sometimes it looks like polygonal rifling and sometimes it looks more like regular cut rifling. Sharp square corners would be a good indication that your 646 has cut rifling. I'm not sure it matters. When their ECM rifling was new at least one prominent columnist in Handloader Magazine wrote he could not get cast bullets to shoot well in S&W's ECM barrels so I thought it prudent to not take a chance. Now 25 or so years later we are more comfortable with ECM. Some of our favorite cast bullet loads had to be tweaked but ECM was not the end of the world.

There are so few 646s that they are undeniably collector items. They are the only .40 S&W only revolvers that S&W ever made and since they did not sell I doubt S&W will ever make any more. None the less, I think you'll get more benefit out of owning it if you shoot it.

[BLUEDOT37]

Originally Posted by MrMoose

How can I tell what method was used to cut rifling in the barrel?

S&W started using the EDM/ECM rifling on standard production barrels in the middle 90s (1993-1995 ?)

Since the 646 came out in 2000 it's likely not broached rifling.

While it may be the only S&W .40 S&W revolver it's not the only S&W revolver that can shoot .40 S&W.

Some people like Ti cylinder & others not so much.

Being it's a L-frame has it's advantages.

IMO, if it had been chambered in 10mm Auto it would have been more versatile & could have a draw even today with the resurgence of the 10.

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[Bullet Bob]

Where's the pictures?

[epj]

Just wondering if these guns could be rechambered to 10mm. By no means suggesting, just wondering. Have no idea of chamber dimensions or cylinder dimensions. I know the GP-100 is chambered in 10mm and it is of similar size. Just wondering. I’m sort of wanting a L frame size 6 shot 10mm, and it would be even better if it were a S&W. More likely if I ever actually get one, it will be a Ruger.

[Bullet Bob]

It has been done. S&W says when you machine their titanium, you're destroying a protective coating that can lead to damage. You pays your money and takes your chances.

[reccpd101]

I'm a scardy cat reloader. Full power 10MM (like the Norma 170 gr.) is a very high pressure cartridge. Close to 37,500 psi. The 44 Magnum is 36,000 and available in an L frame only in a 5 shot. The 357 Magnum is 35,000.

If you bore out that 6 shot L frame 40 S&W to 10MM, please let me know where you are shooting it. I want to be at least 2 states away.

[Pizza Bob]

Originally Posted by BLUEDOT37

S&W started using the EDM/ECM rifling on standard production barrels in the middle 90s (1993-1995 ?)

Since the 646 came out in 2000 it's likely not broached rifling.

If we assume (yes I know) that K22fan's premise is correct, it could very well have broach cut rifling. Doesn't the PC use broach cut rifling, as opposed to the production guns ECM rifling? If this is the case, to make just a few barrels to come out even with the number of cylinders on hand, it may have been more cost effective to have the PC just broach cut the necessary number of barrels. I know enough to never say "never" when it comes to S&W.

Adios,

Pizza Bob

Used mine for IDPA - retired now...


Not going to dig it out of the safe to look down the barrel - sorry.

PB

[k22fan]

Originally Posted by Bullet Bob

It has been done. S&W says when you machine their titanium, you're destroying a protective coating that can lead to damage. You pays your money and takes your chances.

Their coating helps keep the titanium from being eroded by powder gases. Titanium is used to make parts stronger than the same weight of steel would be. It's used for aircraft parts that are not hit by the jet exhaust. Also it's used to make parts that need to be extremely resistant to oxidation. It's great for pipes that lay on the ocean floor. It slightly reduces double action pull by making cylinders lighter and lightens revolvers for concealed carry. Normal cleaning methods for steel cylinders remove S&W's protective coating so I'd rather have steel cylinders.

Originally Posted by reccpd101

I'm a scardy cat reloader. Full power 10MM (like the Norma 170 gr.) is a very high pressure cartridge. Close to 37,500 psi. The 44 Magnum is 36,000 and available in an L frame only in a 5 shot. The 357 Magnum is 35,000.

If you bore out that 6 shot L frame 40 S&W to 10MM, please let me know where you are shooting it. I want to be at least 2 states away.

SAMMI maximun average pressure (MAP) for 10 mm is only 2,500 psi higher than .40 S&W. Big US manufacturers do not make guns with a safety margin so thin that that small a percentage pressure increase will burst them. None the less, permanently altering a one of 250 S&W is down right stupid. At one point left over new 646 cylinders were available from one of the big parts sellers. If my memory is good it was Numrich? Altering a spare cylinder would be interesting but .40 S&W is powerful enough for my use for a 646 and it's my nature to be a "scardy cat reloader."

[S&WIowegan]

I owned one of the Performance Center 646s and a friend bought two of the parts clean-up 646s. These guns did not sell well and S&W let them fade away.

We bought them to use in revolver class IDPA. Factory full-house 40S&W ammo was a real hand full in these lightweight revolvers so we handloaded some real mild loads for these guns. Once the IDPA rule makers heard about this they decreed that the 40S&W ammo had to make major power factor. I sold mine to someone on this forum who was on binge to collect Performance Center revolvers. I explained every little mark on the gun and that it had been shot quite a bit. He bought it for $1K and then complained it wasn't pristine. He kept it and I had forgotten all about it until this thread.

[oldman10mm]

Saw one, standard non-PC, at the Medina Ohio gun show about 10 years ago, only one I have ever seen. Had a price of $1500 on it. The Medina show is a monthly show and for about a year, he kept having it on the table. One time he no longer had it on the table, I asked and he decided to return it to the safe.

[CHARLIE699]

I have a non-PC 646. It's really a joy to shoot as it handles any factory .40 with ease.
I will admit though, being a six-shot already, one DOES sometimes think of the possibilities.
I've toyed with the idea of picking up an unfluted 686 cylinder & having it re-chambered for the 10mm. Only seems a natural progression. I find it difficult to believe that nobody on this board has done this yet,,,,, or have they??
I thought of doing the same thing to my 617 (to .22mag) but,,,, that just gave me a reason to find a 648 instead.. The only thing better than a multi-caliber revolver, is TWO revolvers.
Guess I'll save my self-unemployment (retired) money & just keep feeding what I already have.

[MrMoose]

Thanks for all the great info on this unusual configuration guys.
I will try to make time and attach nicer photos soon.

[K Frame Keith]

I like it.

[Bill In Texas]

Congratulations! That's a nice revolver!

[Dieseltech56]

Does anyone have a picture of the barrel face/forcing cone on one of these 646s? I just wonder how thin it looks compared to a 686

[girvin02]

Originally Posted by Dieseltech56

Does anyone have a picture of the barrel face/forcing cone on one of these 646s? I just wonder how thin it looks compared to a 686

Here's what mine looks like.

[BLUEDOT37]

Originally Posted by k22fan

It's used for aircraft parts that are not hit by the jet exhaust.

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Related info from "How S&W Makes Handguns Today - S&W Handguns 2000" article.

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[jaymoore]

I also found one (non-PC configuration) back when they were unloved. It was much more of a handful than a 4" 686, so it didn't get much IDPA use. Reloading might be a little faster, but the 686 ran quicker with better "double taps", etc. Transitioning between targets? Eh, couldn't really tell a difference!

Safe queen for many years.

[k22fan]

girvin02's bore appears to be broach cut. Thank-you for the picture.

Dieseltech56 asked to see a picture of the other end of the barrel. I think he's interested in how thick the barrel is around the forcing cone. If you have nothing else to do maybe you can post another picture?

[girvin02]

Originally Posted by k22fan

girvin02's bore appears to be broach cut. Thank-you for the picture.

Dieseltech56 asked to see a picture of the other end of the barrel. I think he's interested in how thick the barrel is around the forcing cone. If you have nothing else to do maybe you can post another picture?

Oops, I wasn't paying very good attention to the request. Here you go.


And since I'm posting pictures. Here's a shot of the entire gun.

[Erocksmash]

these are really cool as I love the .40s&w wouldn't mind having eather variant....

[sigp220.45]

I found my non-PC version with all the goodies in a little New Mexico pawnshop. By a happy coincidence I had access to a large amount of .40 ammo. It was a match made in heaven, and I shoot it often.

[jaymoore]

Originally Posted by Erocksmash

these are really cool as I love the .40s&w wouldn't mind having eather variant....

I usually skip over the .40 S&W for either 9mm/.38/.357 or .45 ACP in carry weapons. But it seems a good match for the L frame. I'd probably prefer a bit more weight, though, given how i shoot. For some reason the titanium cylinder just isn't appealing either. "Regular old" stainless would be fine!
A full moon clip loads into the cylinder almost as easily as a .45ACP version, probably due to the short OAL cartridge length. So that's a plus.

If I was to wish for my "ultimate" L frame, it would be a six shot .41 Special. Just never wished (or spent the cubic dollars) hard enough to get one built.

[BLUEDOT37]

I'm of the opinion that the forcing cone is often a better indicator as to whether the barrel has broached or EDM/ECM rifling.

Sounds weird. Here's my take on it.

EDM/ECM rifling barrels appear to have the forcing cone formed at the same time. They are usually very smooth with a consistent transition & no tool marks.

Broached rifling barrels have the forcing cone cut as a separate step, show a definite angle at the rifling, & all too often have circular rings scarring their forcing cones.

I have broached barrels that don't "look the part" from the muzzle but when you illuminate the bore/forcing cone you can see the tell-tale signs of a cut forcing cone, usually rough & gouged.

Some broached rifling doesn't look as good as some EDM/ECM rifling.

As always, no theory is fool-proof, there always appear to be exceptions, but that's my general observations.

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S&W proudly says the 625PC has broached rifling.
Not too impressive looking from the muzzle.
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Not much better looking even after chamfering
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627PC factory muzzle
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Looks the part after chamfering
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329PD muzzle: a two-piece barrel with EDM/ECM rifling
Looks pretty sharp (except for the focus )
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Tool cut forcing cone
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Smooth EDM/ECM forcing cone
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