k frames and magnum rounds

I have a very nice shooter model 66-1 , I have heard numerous times that it wont stand up to a steady diet of magnum rounds as well as gun XXX. I am trying to figure out if this is a statement of fact or did someone look at it decide that since the frame size is small in comparison to the n frame so it must be true , The statement looks accurate and then is repeated until it must be true.
I reload for the 357 along with alot of others and seldom shoot full magnum rounds anyway , More just curious as to if there is any valid documentation to back it up.
If i want to shoot hot loads in 357 I have a Freedom arms and a Merrill that are two of the strongest handguns made

K-Frames can have issues if fed an excessive diet of full power .357. Whether or not that equals steady depends on how much you shoot it. The four I currently own, two dating back to recessed and pinned days have never even had a hint of an issue. Two of them have had maybe 1000 rounds of hot stuff through them over a few decades, one is a '70s duty weapon. The other two less. For keeping current I normally use .38+p class ammunition. Any K-Frame can handle light load .357 indefinitely.

There is a possibility of trouble if you shoot hot .357 Magnum loads through a "K" frame.

The problem is that the "K" frame had to have a flat spot machined on the bottom of the barrel in the forcing cone area to allow the cylinder yoke to close into the frame.
This causes a weak point where the forcing cone "Can" crack.

There are several factors that influence the possibility.
1. Is the use of the hot 125 grain full Magnum loads.
The very hot gas and the fast bullet striking the forcing cone can cause cracking from erosion and impact.

2. A dirty forcing cone.
Many of the Model 19 "K" frames that had cracks also had very heavily fouled forcing cones.
It's thought that the fouling contributed to the formation of cracks.

Ways to limit the chance of cracking is to limit the use of the lighter weight hot loads and shoot either heavier bullet Magnum loads like the 158 grain, use the lighter loaded "short barrel" Magnum loads made by Federal that are loaded with bullets in the 135 grain range, or just do most shooting with .38 Special or +P .38 Special ammo.

Second is to buy and use a Lewis Lead Remover kit from Brownell's. The kit includes a special cleaning head that cleans leading AND copper and carbon fouling off the forcing cone. Use the tool regularly even if you shoot only jacketed bullets.

Just HOW likely a cracked forcing cone is, depends on the gun and the ammo used. Some people report shooting thousands of full charge Magnum loads with no problems. Others report cracked or even broken forcing cones with much less shooting.

I have had a Model 65-4 Police trade in for a long time. I never shot anything but 158 grain factory ammo., JSP and JHP until this past Jan. The box of shells that came with it were UMC 125 grain JSP's that had one heck of a recoil. None of these rounds hurt anything. I have shot a couple of boxes of WWB 110 JHP's that were labeled "personal protection" and I believe they are a pretty low powered .357, and again, no damage. I keep the gun spotless in the forcing cone area. Possibly the heavy barreled stainless steel guns are stronger, but I don't know that for a fact. This past Jan. I finally tried some .38 special +p's and they shoot fine in it. Actually I think I hit a little better with the 38 +p's. In my limited experience with a K frame, I believe that keeping the cone very clean should greatly reduce the possibility of damage in that area. But then I have read about over tightened barrels and the little flat on the bottom of the cone being machined too thin. I have no idea about those factors, just what I have read. I can't remember what the link was on this topic but I figger that somebody on here will point you in the right direction.
Have a nice day,
gordon

The rounds that cause the most problems with the K frame 357 magnum revolvers are the ones with light bullets like 125 grain.

I picked up about 3 years ago a cheap beat up model 66 6 " to try out this theory we are talking about since I beleive these cracked forcing cone issues you hear about are from owners neglecting to clean their guns and oil them properly especially around the forcing cone. Anyways, I got this model 66 for 150.00 and figured I would try this theory out. I have been shooting nothing but 357 magnum rounds throught it mostly 125 grain 357's and am well over 15,000 rounds through it now and forcing cone still looks perfect, flame cutting yes, but no cracks.

Eric

I no longer shoot anything close to full power .357 Magnum rounds through any of my K frames' any longer, that is what L and N frames are for. I do though load full power .357 Magnum ammo for defense.

Cracked forcing cones can and do happen from time to time, see below. As it is not easy to find a replacement barrel for an M-19, I see no need to take the chance of breaking one.

My dad has a 66-2 that he bought new. He's put at least 3000 rounds of .357 158 grain rounds (power roughly equal to store bought .357s) through it with no problems whatsoever.

If it were me, I'd avoid loading more powerful rounds than typical store bought .357s. If you have luck like mine, any thing that can go wrong, will.

old bear said:

I no longer shoot anything close to full power .357 Magnum rounds through any of my K frames' any longer, that is what L and N frames are for. I do though load full power .357 Magnum ammo for defense.

Cracked forcing cones can and do happen from time to time, see below. As it is not easy to find a replacement barrel for an M-19, I see no need to take the chance of breaking one.

Click to expand...

Thats the same picture I have seen a thousand times, and yet so many people are worried about it, I have only heard of a handful that this has happened to.

Eric

I have a 66-7 with a two-piece barrel -- it differs from earlier models by not having the flat-spot on the forcing cone. It was an Aussie cop trade-in. Very nice gun. That being so, I still shoot mostly just 38 Special and +P.

fyimo said:

The rounds that cause the most problems with the K frame 357 magnum revolvers are the ones with light bullets like 125 grain.

Click to expand...

Of all the info I have researched this seems to be the point that is most consistent...stay with 158gr and you should be good to go. I have 3 66's and a 19. The 66's get shot about 2/3 38+p and 1/3 .357 158gr. They are all under 4" so I shoot the +p because I like that load better for snubbies at the range. I had a 66-1 4" for many years that was closer to 80% .357 158gr and it performed flawlessly after 1000's if rounds. I have never seen nor known anyone with a problem with the K frame. This is an old story that everyone talks about but no one seems to have any personal problems at all...always just heard about it. The actual occurrence of a broken K frame is very rare especially considering how many there are out there still shooting after 40+ years!

^^^^^^ This ^^^^^

This question comes up all the time. The issues are with K frames and lighter projectiles.

Your M66 will handle all the full house 158 grain rounds that you can throw down range.

Still confused on this issue. Are lightweight bullets (105gr, 110gr, 125gr) loaded to 38spl or 38spl+p okay, or do light bullets cause cracked forcing cones no matter the powder charge?

.38 in ANY weight is fine. Issue is with .357 light bullets.

I have asked about model 66 problems shooting 357's, on this, and other boards, for years.

I use to ask in those posts if anyone had ever seen or even HEARD of a cracked forcing cone on a model 66. After all those years of asking, I finally got one taker. About four years back a fellow posted a picture here of a cracked forcing cone on a 66. He said he did it with factory 125 grain 357's.

He didn't say what brand and IIRC didn't respond to follow up questions. From the photo I discerned that the revolver was dirty with carbon buildup around the forcing cone.

If you don't clean your revolver properly, and allow it to build up lead and carbon in and around the forcing cone, AND you shoot high volumes of lead followed by untold high volumes of hot 125 grain jacketed 357's, you MIGHT crack a forcing cone on a model 66. Of course by the time you do, you could easily have purchased a replacement pre lock 66 (at todays prices) with all the money you spent on ammunition.

I have 13 model 66's. If the design was as "weak" as alleged on the internet gun boards, I would have seen it in over 44 years of shooting K-frame magnums. Could it happen? Sure. Has it happened? Yea I'm sure it has. Does it happen with any frequency? I havent seen one scintilla of evidence that it does. To the contrary, it appears to be an extremely rare event.

The high time examples in my herd are both former LE guns with untold amounts of 357 through them. The 4 inch 66-2 has over 25,000 125 grain 357's through it from its service career with a Chicago cop. He was a shooter and told me what he'd run through it.

I've used it in IDPA, carried it on duty, qualified with it several times and taught new shooters with it. I have put at least another 4000 357's through it and untold numbers of 38+P over the years. It has only started to exhibit a slight bit of endshake over the last few years. Very little rotational slop. Trigger is smooth and sweet. There is some flame cutting on the top strap as you would expect. That is self limiting in my experience and not a concern, to me. The gun locks up tight and is a tack driver.

I may send it off to Sandburr Ranch for a tune up and to remove the endshake. I also may not as the gun operates perfectly and locks up tight.

So OP, go and enjoy that 66-1 shooter. It is a fine example of what S&W was capable of building. Possibly the finest revolver to come out of Springfield. There won't be any more as nice either. Keep it clean, shoot what you can handle/want/afford, and your great grandkids will be enjoying that fine revolver. Good luck! Regards 18DAI

Oft repeated Internet gospel...



Here we go again...

My position is that you have more to worry about from an alien invasion from outer space than if your 66 (or 65, or 13, or 19) is going to fall apart using factory magnum ammo of any sort, including the hot 125 JHP's.



Witness this 66-2. It belonged to a Police Officer who was a dear friend and had a DOCUMENTED 13,000 rounds of Federal 125 JHP's through it during it's long police career. I took it in trade in my shop when the local PD switched over to SiG 226's. I knew this gun and kept it for myself.



When I got it I round butted it, replaced the hand and cylinder stop and it's shot untold numbers of Magnums and Specials since then. It's still my favorite field gun...



Baby it if you want to, but these are great guns with a brilliant service record and I would think that you should shoot whatever you want out of it.

Drew

I had a Model 19 whose cylinder notches showed evidence of being pushed out after firing very hot Norma ammo. While attending the revolver armorer's course at the S&W Academy, an armorer told me that they've had occasional failures in this area. The evidence I refer to is that when holding up the cylinder to light, after cleaning, the light reflected differently at the chamber side of each of the six notches, indicating to me that the notches were no longer in the same plane as the surrounding metal.

I have a Model 65 that I don't need for SD. After my experience with the Model 19, I just feed it .38 SPL +P

gumpys said:

I picked up about 3 years ago a cheap beat up model 66 6 " to try out this theory we are talking about since I beleive these cracked forcing cone issues you hear about are from owners neglecting to clean their guns and oil them properly especially around the forcing cone. Anyways, I got this model 66 for 150.00 and figured I would try this theory out. I have been shooting nothing but 357 magnum rounds throught it mostly 125 grain 357's and am well over 15,000 rounds through it now and forcing cone still looks perfect, flame cutting yes, but no cracks.

Eric

Click to expand...

Are you one of the mythbusters guys?

Given the discussion this topic continues to get, I suppose it's understandable the question is repeatedly asked.

But multiple threads here cover the same ground -- for this the search function was made.

That said, the information in this thread is good. I'll add that most reports of cracked forcing cones seem to come from the '60s and '70s, before SAAMI specs were lowered and ammo was hotter all the way around; I think that all of today's .357 is likely fine in K-frames, even in very high amounts.

I must be the only person in the world who is too lazy (extra recoil) and too cheap to shoot enough .357 ammo to worry about it.

I do wonder however, are the K-frame .357's the only guns to ever crack a forcing cone? Does it ever happen to N frames? To Colts? Ruger's? Taurus'? If so is it more often or less than with a K-frame.

And that's acknowledging that apparently it doesn't happen often even with K-frames