S&W 66 vs 686

[Steve Koski]

I saw a revo come apart at the world shoot in exactly that way. The shooter's eyes about popped out of his head.

[RePete]

I saw a revo come apart at the world shoot in exactly that way. The shooter's eyes about popped out of his head.

He forget the retaining screws for his eyes!

[Duane Thomas]

Just be sure to blue Loctite them in place after installation to avoid this: .

[RePete]

That's gonna leave a mark!

[eisenhow]

Actually, it's physics.

I'll preface this by stating it only matters if you intend to reload and fire quickly and a great deal. The average, casual user would never notice a difference between either the L and K frame firing 38 Specials in the course of several lifetimes.

The yoke assembly is essentially a lever arm. The crane is longer and the cylinder heavier on an L frame, hence more force is applied to to the system during a reload. All that leverage, coupled with the force of (vigorously) activating a speed loader on the end of the ejector rod, apply stress to the yoke end/screw mating surface. All things equal (design, screw length, etc.) there is more stress applied to the yoke end/screw surface during a reload in an L-frame compared to a K frame. With any given screw design and material attributes, the L frame system will fail sooner.

Do the current k-frames, like the model 67, have a the new style plunger yoke screw or the old style solid one? If they are plunger style have you seen any yoke issues with those?

The K frame action cycles faster at any given force applied to the trigger, or, conversely, it takes less energy to cycle the action at a give rate than in an L frame. The k frame cylinder is much lighter (esp. a 38 Special k frame cylinder) and the lock time faster. In fact, the L frame 6 shot 357 Mag cylinder is heavier than any other K, L or N frame cylinder of any caliber save the Model 27/28. All that extra mass creates additional torque when the cylinder is rotated. That force that has to be either applied or absorbed by the action components (hand, ratchet, cylinder stop, etc.). The bore axis is also higher on a L frame compared to a k frame.

OK, now the nit-picky mechanical engineer is coming out... It's really the moment of inertia of the cylinder rather than the mass that makes the difference. I'm sure an L-frame cylinder has a larger MOI than a K frame magnum so it really doesn't matter. I've got to get a better look at an N-frame cylinder, depending on the mass difference and the diameter it may have a larger MOI than an L-frame cylinder.

[Bones]

Mike,

You can get all the measurements you need with a set of calipers and the scale on your reloading bench and prove it to yourself. The 6 shot N frame cylinder dimensions are larger yet.

The new 67s and 10s have the 2 piece yoke screws. The -5 and earlier 66s, 19s, etc. and the like have the older, flat bottomed yoke screw design.

If the full lug L frame isn't slowing you down, maybe you're not going fast enough. You can certainly drive an F250 on a Formula 1 track, you just won't notice a difference between it and an F1 car until you step on the accelerator.

Craig

[eisenhow]

Mike,

You can get all the measurements you need with a set of calipers and the scale on your reloading bench and prove it to yourself. The 6 shot N frame cylinder dimensions are larger yet.

I'm convinced of the K vs L. I don't have an N-frame to measure.

The new 67s and 10s have the 2 piece yoke screws. The -5 and earlier 66s, 19s, etc. and the like have the older, flat bottomed yoke screw design.

Good to know, I'll have to keep that in mind while looking at used guns.

If the full lug L frame isn't slowing you down, maybe you're not going fast enough. You can certainly drive an F250 on a Formula 1 track, you just won't notice a difference between it and an F1 car until you step on the accelerator.

Craig

I know that I'm not going anywhere near fast enough. I've got an SSR, not a full lug 686. If I had it to do all over again I would have picked up a 67 police trade in from J&G instead of the SSR. I've contemplated picking up a 67 for SSR/ICORE or a longer barrel k-frame just for ICORE. However, I don't shoot the revolver I already have enough to justify buying all new loaders, holders, holster and gun.

[Gregg K]

The new 67s and 10s have the 2 piece yoke screws. The -5 and earlier 66s, 19s, etc. and the like have the older, flat bottomed yoke screw design.

Craig

The -5 and earlier model 19's have the old yoke retention system but for the model 66's my Smith book says that the -3 and newer have the new yoke retention system. I have a stack of model 66 -5 guns and they are all the new style yoke retention system.

I agree with the comments about the full lug L frames. I ran some drills with a full lug 686 and and an SSR L frame and found that I ran the SSR faster. The K frame still beat out both of the L frames. It may be just my preferences but the timer tells me to run a K frame.

[Aircooled6racer]

Hello: Listen to Gregg K He was the guy who suggested the Model 66 for SSR to me. I love the Model 66 over the model 686 I have tried. It just is a sweet shooter at minor loads of 38 special. Thanks, Eric

[lugnut]

You guys and your MOI and your partial lugs this and that... shesshhh! Just shoot already! Think about this guys.. Jerry can shoot a full lugged, heavy, 45ACP like a mad man.... Craig can shoot his Kframes like tac drivers... Most of us mortals will do just fine with either... provided we don't pop out our cylinder by mistake!! LOL

FWIW... I'm playing with my new 617 tomorrow for a while... then I'll switch to my 625 for a dose of reality!

[Duane Thomas]

What is the (theoretical, anyway) advantage of the new retaining system over the older one-piece screw? Why did S&W think we needed this?

[astephenson]

I heard it was because it requires less fitting. Could be gun-store fiction, though.

[RePete]

I heard it was because it requires less fitting. Could be gun-store fiction, though.

That was the reason given us at the S&W Academy.

[gr7070]

The only thing I do not like about my 686 is the readily available inexpensive backup guns the K-frame offers with 10s, teens, and 60-somethings.

That's definitely an advantage the 66 offers; not that it's one the clock would necessarily show.

[Bones]

For what it's worth, I ran a 67-6 (with the spring loaded yoke screw and well over 50K rd through it) at the World Championship in September without any issues.

I also really like the 2-piece barrel system of the new Model 67s. They far and away consistently deliver tighter groups @ 50 yd with my IDPA and ICORE loadings than any of my older 1-piece barrel 4" K frames (10, 19, 13, 15, 66, etc.). Additionally, I've found I can get much better (to my taste) actions with the frame mounted firing pin system (on the newer guns) compared to the hammer mounted firing pin system on older models. I personally like pinned sears and narrow serrated triggers, so I fitted these to my new 67s in place of the OEM trigger. Other than that, smoothing out the action and changing the front sight, I ran the gun as it came out of the box

I've worked with several folks who know a little about S&W revolvers on fitting solid yoke screws to the new system without any success. Our conclusion was it is better to leave it as it is and monitor wear, replacing as necessary. Again, the average user would not have a problem in several lifetimes, so the system functions and designed.

Last year I used my 19-3 at the Nationals in Tulsa (flat bottomed yoke screw, hammer mounted firing pin, P&R, etc.).

To me this means you can win matches with either system, they just have different operating characteristics to be mindful of.

Craig

[GlockCanMan]

Drat, I forgot the Major PF scoring for ESR. Thanks Merlin. Is there anyone that 'rent's a 625 for like 2 weeks?

If you are willing to pay for a round trip Air Fare and hotel accomendations (Decent motel) I will let you borrow my 686 & 625 for a classifier match so you can get qualified. Heck if you throw in free food, I will even bring the ammo out with me also.

Edited November 28, 2011 by GlockCanMan