J vs K frame .357s

[jford1]

Which gun/frame is actually stronger? If using the same full power .357s (say normal Remington 125gr.) which gun would likely fail first? I'm mostly interested in just comparing the gun designs not materials so think steel vs. steel. Are the beefed up .357 J frames better suited for the round or does S&W just assume you wouldn't shoot enough full loads to find out? Are K frames weaker because of barrel, cylinder, top strap, or forcing cone design despite their larger size? I'm not willing to shoot either until they break but assuming it was someone else's hand and ammo supply, which would come out on top?

 

[texas bulldog]

the forcing cone on a K frame is much thicker than the J frame. the others aspects i don't have enough knowledge to speak confidently on, but i would believe the K frame to be stronger overall.

 

[jford1]

That's what make sense to me but I hear so much about how Ks can't digest .357s and how Js can.

 

[lawboy]

K frame is stronger.
You hear a lot about K frame forcing cone issues with 125-grain magnum loads because that was an issue historically during the law enforcement career of the K frame magnum. Also, people actually shoot magnum ammo out of K frame guns so there is a body of experience out there. Who do you know shooting magnum rounds from a J frame on any remotely regular basis? Yeah, me either. That is why you don't hear about it, because it is not an issue as nobody even wants to do it!

 

[jford1]

Maybe I'm weird but I actually enjoyed shooting 125gr. magnums out of a 2" 640. I was plenty accurate with them also. Sure it barked pretty good but it wasn't that bad on the hands either. I wouldn't want to shoot the same load out of any of the lighter ubertanium alloy guns, however.

 

[DawgFvr]

Ruger SP101 is only a tad bit larger than a J frame...has the same size forcing cone of a K frame and can shoot .357 mags til the cows come home. It has been called a J frame on steriods by some.

 

[jford1]

So how many rounds did cops shoot to cause forcing cone problems? Was it only the forcing cone or did any of the guns just shoot loose? S&W did replace the K .357s with L .357s so I'm assuming this isn't just one of those police dept. gun myths. Did Smith ever do a scientific study or did they just update the guns to appease their clients?

 

[Will5A1]

What I've read indicates the K frame Smiths did not have problems digesting full bore 158gr .357 loads, the problems with cracked and/or eroded forcing cones and top strap flame cutting was traced to the lighter (125 gr) loads from some, but not all, ammo companies. Its my understanding that this damage was often caused with very few rounds fired. I would also point out that Smith continued to produce the K frame 65 and 65LS until 2004 IIRC. I've fired a fair amount of full power .357 (factory and reloads) thru my 65's and 66's and have not noticed any errosion or cutting yet, but to be honest I shoot mostly .38 Special level loads in them, its a lot cheaper and allows me to shoot more.

You might use the search function here and at the Smith and Wesson forum and see what you can find, I recall seeing photos of examples with errosion and flame cutting.

 

[GP100man]

ive read in a rag some where that certain powders cause higher erosion than others ,one i remember was loads with blue dot & 125gr bullets.

GP100man

 

[CMcDermott]

The problem K-frames have with light (125 grain and less) bullets is caused by the clearance cut on the bottom of the forcing cone that allows the crane to close. If any of the chambers in the cylinder let the bullets come out so that they hit on the bottom side of the forcing cone first, then that forcing cone will crack. There just isn't enough metal left after that clearance cut is made. Heavier bullets don't accelerate as fast as the light bullets, and just don't hit as hard when they do contact the forcing cone, so they don't cause this problem.
J-frames, even though they have a smaller diameter barrel, don't need or have the clearance cut; and they don't have problems with the forcing cone cracking.

 

[jford1]

Interesting. Is there a simply velocity limit (say 1200-1300fps)? 158s can have very close to the same energy as 125s but with a lower velocity. It sounds like the relieved section of the K frame barrel could crack from any ammo if it was hit wrong. Is the 125gr ammo just more prone to cause this or is it unlikely to happen below a certain velocity at all?

 

[pinkymingeo]

The 125gr bullet is too short. In the brief interval when it clears the case before entering the forcing cone there's a gap which allows superheated gases to escape past the bullet, causing rapid erosion and plasma cutting in the forcing cone area. Since that part of a K-frame is weaker than on other revolvers, there have been some problems. Shooting longer bullets stops the problem. You can shoot full-house .357 158's in a K-frame until the cockroaches inherit the earth. I personally have never seen a need for 125gr magnum loadings. I use them sometimes for +p-level stuff, but go with 158's and heavier with hot loads.

 

[DawgFvr]

Use the "larger" copper top DPX bullets and have the best of all worlds. Also...the article explains why the 125 gr is the man stopper vs the 158 gr hunting bullet.
http://www.hipowersandhandguns.com/Corbon 357 Magnum 125 gr DPX Ammo.htm

 

[jford1]

So 125gr bullets are ok with lower pressure/velocity 38 or 38+p loads but not full magnums. What about Buffalo Bore 38+p (or similar loads) with low pressure but high velocity 125gr projectiles? Would such loads still have the flame cutting and cone cracking potential of a similar velocity .357 that use higher pressure?

 

[pinkymingeo]

Not if they don't have the pressure. The S&W Airlite J-frames have a 120gr bullet minimum for the same reasons, but that only matters with magnums. Anybody who thinks lighter bullets are more effective for stopping large animals, two- or four-legged, needs to talk to a hunter. They know better.