A Look Inside the New Mountain Gun 629-9

[686PC]

My Wolff’s Spring Pack Type 2 arrived yesterday and after enjoying the Mountain Gun at the range today, I cleaned it, inspected its action for burrs, and installed the lighter main spring and 14 pounds trigger return spring on the gun. Sorry for the ugly Hogue rubber, but that is a lot more comfortable for extended range work.

Opening the gun was easy to do as nothing was stuck. The only screw with a little loctite was the yoke screw. The inside of the gun was very dry and had several spots with a brown dust that was a little odd for a brand new gun. So I lightly oiled all surfaces with a brush and installed the springs. I noticed that this Mountain Gun comes with a trigger stop pin inside the trigger return spring, like some of the older N frames.

You can see what appears to be the remnants of the Internal Lock above the bolt. Does anybody knows if that is something else? That small part above the bolt is under spring tension.

I found no burrs on the bottom of the trigger return slide on this one. That’s an area I found burrs in the past on some of my PC guns that impacted the action.

After installing the lighter springs and lightly oiling all inside surfaces, the gun’s action is light and smooth. I’ll may go to a 15 pounds trigger return spring if the 14 pounds spring and main spring combo does not ignite the Federal primers consistently. The action is very smooth and light now... almost too light.

 

[RevolverJim]

You probably meant to say that the mainspring doesn't ignite the primers reliably......make sure that the strain screw is tight before shooting it again.

 

[SLT223]

I was going to look inside because I could see something in there that looked like half a flag but haven’t had time. You just saved me some trouble. Thank you for sharing!

 

[71vette]

The trigger return spring is most likely not your issue on light primer strikes. The Wolff “Power Rib” mainsprings usually need a longer strain screw, especially the reduced power. The other option is to “shim” the strain screw. I’ve done that before using a fired primer I took the anvil out of.

 

[686PC]

The trigger return spring is most likely not your issue on light primer strikes. The Wolff “Power Rib” mainsprings usually need a longer strain screw, especially the reduced power. The other option is to “shim” the strain screw. I’ve done that before using a fired primer I took the anvil out of.

Hi 71vette, thanks for the insight. I'm not sure I'll even have a light primer strike problem, but if I do, wouldn't a Power Custom extra length firing pin accomplish the same result?

 

[toroflow1]

It looks as though one could replace the cast hammer (MIM) & trigger with a set of forged parts from an earlier revision. That'd be the only way I'd buy. Otherwise, I prefer my originals.

 

[Bobbysixkiller]

What is the purpose of the flag. It seems un needed. Has a post like a lock flag. Hmm. Now I’m skeptical of these new no lock guns. Very strange indeed.

 

[schutz5]

Interesting to see a new model detailed. Thx!

 

[series guy]

The Wolff power rib spring in a round butt gun will more than likely need an adjustable strain screw for reliable ignition. I have found that setting the D/A trigger pull at 8 1/2 pounds works well.

 

[Baxter6551]

I’m not very knowledgeable on the inner workings but to me it looks like a filler for the space where the lock mechanism was - maybe to keep the bolt in place? Do this to avoid having to reprogram the CNC machines to eliminate that cavity ? I can’t see what mechanical function it might have.

 

[Beju]

Not sure why it would be necessary vs leaving it out, but the tab on the flag looks like it would ride in the channel in the top half of the hammer. Maybe it reduces play in the hammer when manually cocking. In the past, S&W has done things like put trigger play springs in the 3rd gen semiautos that are unnecessary for operation of the the pistols (a fun fact that gave me a sigh of relief when I broke one while swapping all the other springs on an LE trade-in 5946).

 

[686PC]

My take on this 629-9 so far:

I's GREAT to have a non-IL larger frame S&W revolver to shoot without any care for it. This is the one of the only 2 reasons I bough this revolver. The other is that I can shoot this without much worries since its yoke button has the newest design, which is stronger than the older pre-lock ones.

But I'm disappointed by the fact they kept the flag inside. It feels totally useless to me. Opening the revolver was revealing: every part except for the hand is MIM. I understand this is how things are now, but the new Colt Python/Anacoda parts are not all MIM.

Nowadays, my favorite DA revolver is the new Colt Pythons and Anacondas. Not only is their DA is both smoother and more refined, but more attention is paid to their inside, with all parts more polished and better finished. The only complaint I have with the new Colt Python/Anacoda, aside from their parts being unobtanium, is that Colt began shipping Pythons last year with MIM hands, as I found out when I went inside my 2.5" Python last December.

The pencil barrel of the new Mountain Gun is not my favorite for the 44 Magnum round. The recoil is more pronounced when compared to other 4" revolvers of the same caliber with a heavier barrel and you'll need a rubber grip for any serious 44 Magnum shooting.

I own several collectible S&W revolvers, all pre-lock, all dash 4 or less, most PCs and most unfired. I've been on the inside of a lot of them, so I was disappointed to see so many MIM parts on this Mountain Gun.

On the plus side, this is a gun you can abuse at the range without much care. I would not be uncomfortable shooting the older to 29s and 629s without any worries since most of them may develop yoke end shake due to the yoke button design of those older guns. All my shooting 29s and 629s have to had their yoke button peened. So, I will attempt to be content with this Mountain Gun, shoot it to my heart's desire, and keep my nicer S&Ws unfired. If this Mountain Gun does not work for me, I'll trade it for another Anaconda.

On the plus side, the way the new Mountain Gun has the brass bead installed toward the top of the front sight is very nice. It makes the bead very easy to pick up and allows for precision shots at distance a lot easier.

Hope this perspective helps. It's just my perspective.

 

[71vette]

“ Hi 71vette, thanks for the insight. I'm not sure I'll even have a light primer strike problem, but if I do, wouldn't a Power Custom extra length firing pin accomplish the same result?”

I installed one in a 625-8 JM that I tried to run a lighter mainspring in. It helped but did not solve the issue. I ended up going back to a standard mainspring with a 14lb Wolff trigger return spring.

I’ve successfully used light mainsprings on hammer mounted firing pin guns but have not had good luck on frame mounted guns. My standard is a 14-15lb return spring with a factory main.

 

[pokey074]

So they eliminated the lock cylinder, but left the flag so it can potentially engage under recoil and lock up the revolver??? Holy moly!

 

[joebuck]

To me the whole gun looks of less quality both inside and out compared to my 1994 vintage MG. The internals especially. Hard pass. Thanks for sharing the pics.

 

[Muley Gil]

So they eliminated the lock cylinder, but left the flag so it can potentially engage under recoil and lock up the revolver??? Holy moly!

Iffn' it were my revolver, I would remove that flag part and see if it makes any difference in the action.

 

[Bobbysixkiller]

I handled one the other day. Felt really good in hand. The sights are really nice. Just seems strange they left the flag. But like you said maybe it’s just a gap filler. If it shoots good I wouldn’t worry about it really. It just struck me as odd when I first seen it. Maybe it helps keep the cylinder from opening in heavy recoil. They are really nice looking for sure. The hammer looks like it has a couple notches it could stick in. Not knocking your gun. Just trying to understand the reasoning behind the flag. Congratulations on acquiring one. I wonder if the 10,19,&36 have this flag too. Curious.

 

[Bald1]

Is that a two piece barrel?

 

[Beju]

Looking at some other pictures online, S&W didn't machine the frame channels for the lock spring/plungers that the lock frames have. Given that, I would assume that S&W included the flag for some reason, as it's a potential part they could omit to save a small amount of money with (including installation).

S&W has been gradually making their revolvers simpler/easier/cheaper to manufacture since the late 1950s when they switched from what most people think of as forged hammers/triggers to swaging them. Swaging is still technically a form of forging, but S&W used relatively soft, low carbon steel that was subsequently machined and case hardened (so for all the talk of cheaper 'MIM parts with soft cores,' MIM replaced... case hardened parts with soft cores that were cheaper than what they replaced).

If I've got time on my days off, I can take pictures of one of my lock guns with the hammer removed. I'm not going to pull the lock parts from my 64-7 or the leftover parts from my 686-6, because I thought fiddling around with those tiny parts was a PITA.

I'll echo others statements on the Wolff Powerib mainspring. It seems like it really wasn't designed for the modern round butt guns. In my 686, the "standard" power spring didn't hit hard enough to reliably ignite harder primers like older lead-free Winchester primers, magnum primers, or Argentine Servicios y Aventuras primers with DA pulls. Those Argentine primers can give stock striker fire pistols issues, so they're pretty hard. This was with an Apex extended firing pin, mind you.

You can either get a set screw, adjust it to your liking, and use loctite to keep it from backing out, or you can do what I did and get an extended strain screw. I gradually shortened the tip of the screw using a dremel and files until I got close to the 8.5 lb DA pulls that series guy mentioned on my Wheeler digital trigger gauge. Works great now.

 

[BoulderTroll]

Is that a two piece barrel?

No. It would be impossible to make a 2-piece barrel strong enough with a pencil profile, as they said in their podcast. Of the five new “no-lock” revolvers (686MG, 629MG, 36, 10, and 19), the new Model 19 is the only one with a 2-piece barrel.

Not that it will sway anyone’s opinion, but 2-piece barrels are inherently better. The $5,400 Korth revolvers use 2-piece barrels, and nobody complains about it…