S&W Model 19 and 66 follow up question

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I own one of each. A 19-4 and a 66-1, both 6 inch. Beautiful weapons and a joy to shoot.
Up til now I've been happily shooting and reloading 38 spec. very successfully.I keep the weapons spotless and well lubed to help ID mechanical defects, so far there have been zero in well over 600 rounds each.

BUT the itch to try my hand and my beautiful steel with 357 magnum loads has crept up on me. I have the brass and a load in mind using 125 gr JHP. Nothing overly hot, mind you, but a decent 1350-1400 fps is my vision.

Question: How "limited" should the firing of magnum loads be in a S&W K frame to keep the wear and tear manageable over time??

Thanks for the input!
 
I handload my ammo and likewise own both the 66 (no dash and -1) and 19-3. I load all my 357 ammo to 38 special +p or under loads. That said, I saved the following info. Some readers dispute it. Some no. Personally, I don't think a few hundred rounds of the loads you're describing are anything to worry about. A few thousand? Maybe could loosen the guns prematurely.

The 125 grain bullets driven to maximum velocities used large charges of relatively slow-burning powders. Handloaders know the powder types as WW296 and H-110, among others. The combination of slow ball-type powders and the short bearing surface of the 125 bullets allows prolonged gas cutting of the forcing cone and top strap area, accelerating erosion and wear.

Borescope studies of rifle, machine gun, and auto cannon chamber throats shows a lizzard-skin-like texture due to this gas cutting damage, called "brinelling". The results of brinelling are fine microcracks that weaken the surface of the steel, and further promote erosion. In machine guns and auto cannons, barrel life is measured in terms of "useable accuracy", and round counts that determine this are based on group sizes at engagement ranges.

In the K-frame magnums, the forcing cone dimensions combined with the barrel shank dimensions results in a relatively thin shank at the 6 o'clock position, where a machine cut is made to clear the crane. This is usually where the forcing cone cracks. The L and N frames use much beefier barrel shanks and do not have this cut. S&W intended the K frame magnums to be "carried much and fired seldom" service arms, designed to fire .38 Specials indefinitely, with light to moderate use of .357 Magnums. You notice that S&W has discontinued production of K frame .357 magnums, no doubt due to product liability issues and a couple generations of K frame magnum experience.
Click to expand...
 
The week spot on the K frame magnums is the bottom of the forcing cone. If you look, you will see a flat spot.
Large amounts of shooting Full Powered-high velocity .357 magnums using lightweight bullets (125 grain and ligher) can result in a cracked forcing cone.
Just use a heavier bullet and/or slow down the velocity.
 
I like 180 grain XTP's going about 1000 fps. Hardly a bleeding edge load but the increased weight and velocity over a .38 make them quite enjoyable out of a 2 1/2" 19-3. Plus with one of the longest bearing surfaces it gives plenty of time for pressure & temperature to drop before the forcing cone takes a hit.

11.5g of 2400 gives me the velocity and the accuracy I'm looking for.
 
As Lucky Derby has already noted, it's not the gun wearing out, but the forcing cone cracking you have to worry about. Considering that S&W has no more K Magnum replacement bbls, I'd not risk shooting a 125gr bullet with any magnum powder charge out of a K frame. I'd stay with 140gr or heavier for magnum powder charges in any K Magnum.
 
Again,

The key is to avoid the 125gr full power rounds. They are hard on all revolvers and with the design of the K frame magnum's forcing cone they are even harder on this terrific revolver. Shoot higher grain rounds with the velocity in the 1200 to 1300 fps and you should be ok. I own three K frame magnums and shoot 158gr rounds in them. I don't shoot as many as some of my other 357s. For the full power rounds I have a GP100 or Police Service Six. And even then I don't shoot that many full power 357 in them.

Watch the type of 357 rounds you shoot in your K frame and you will be ok.

roaddog28
 
Your revolvers should handle the load fine; however, keep in mind that repeated firing of hot 125 grain loads has reportedly cracked the forcing cone on the model 19 and 66. Also be advised that should you indeed crack your forcing cone, replacement barrels for the model 19 are VERY DIFFICULT TO FIND. I never shoot them out of my k frame 357s, but save the 125s for my L frame, which has no problem at all digesting as many as I can load:)
 
About 3 months ago I found a model 19-4 4 inch nickel plated, it looks like new..I mean it is beautiful and thats what attracted me to it I could not believe they only wanted $350 for it, I bought it and got out the door before they changed their mind,and then I started reading about the model 19 and its issues...after looking it over I found no cracks or for that matter not much wear at all,but dont know that I want it now, it sounds like it might be one to put up on the shelf...Like I said it sure is pretty to look at.
 
Workhorse, no reason to keep that model 19 in the safe. Just stick to heavier projectile weights, and it'll do fine.
 
One of the more classic bullet options for .357 is the 158gn weight in various styles. Stick with that sort of weight and there's no reason not to shoot a goodly amount of .357Mag loads. And if you're doing your own reloading you have the option of loading them to a velocity that is less than the max. Between the heavier bullet options and keeping the load recipe on the light side of the .357 rating you should be fine.
 
The only "problem" with the "K" frame is it is not intended to shoot lightweight ultra-velocity loads, nor is it designed to withstand mega-thumper heavy bullets at maximum loads.
110-gr and 125-gr hyper velocity loads will erode the forcing cone and gas cut the topstrap.
Huge thumper loads will eventually shoot the gun loose and out of time.

Stick to "service" style loads and you can shoot them as much as you want.
I have shot literally thousands of 158-grain lead SWC's loaded to around 1100 fps through my K-frame magnums with zero problems.
5.0 grains of Titegroup and a cast-lead 150-gr SWC sized to .358" gets you around 1100 fps and lots of range fun.
 
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