Is this forcing cone erosion bad?

[epags]

I stand corrected, my dad has some feeler gauges so we checked it.

.004 will pass between the two. .005 will not.

Not sure what acceptable limits are.

My Dan Wesson 357 with removable barrels call for a .006 shim.

 

[dfariswheel]

My Dan Wesson 357 with removable barrels call for a .006 shim.

Any modern revolver should have a barrel-cylinder gap of between 0.004" and 0.008" with 0.005" considered to be perfect.
Colt held this standard, but S&W allowed it to slip a good bit. Recently S&W is passing revolvers with 0.012" gaps as "good" and sometimes even more.
To be fair, unless the gap is large enough to spit bullet metal it's not a huge issue. Even a wider gap won't loose that much velocity.

 

[243winxb]

Barrel steel- When comparing early Colt Trooper 357 to S&W M28-2, 357, the engraving tool easly marked the Colts barrel & frame. Very soft steel compared to the S&W.

Why use soft steel? Why surface harden hammer and sear? Machining time is shorter & cutters last longer.
For Colt, faster production time, more profit, to keep the company out of bankruptcy.

Sorry Colt lovers.

 

[GeoDudeFlorida]

Why use soft steel?

Elasticity. Heat hardened steels are more brittle and crack/shatter versus deforming under stress then coming back to shape when the stress is relieved. And, speaking as a machinist, I know from experience it's cheaper/easier to harden post machining than use harder alloy vanadium steels, so it saves money to make the steel brittle by hardening post-manufacture than to machine harder alloys that won't get brittle and crack.

Sorry Smith lovers.

 

[GeoDudeFlorida]

That Colt barrel at the forcing cone looks like there is a slight step to the outside diameter. Which makes it seem like lead could be piled up on it?

I'm used to the face of a new forcing cone being machined flat, not a stepped outer diameter. Is this normal for older Colts?

The pic below is forcing cone wear, in my experience. The face has been blasted concave. This gun has only had jacketed ammo fired through it.

View attachment 1083830

That picture doesn't look like a Colt, though. Ruger?

 

[243winxb]

Easy barrel replacement on my 337PD, if needed.

 

[chicharrones]

That picture doesn't look like a Colt, though. Ruger?

Yep! GP100 mentioned in post #22.

 

[tightgroup tiger]

Barrel steel- When comparing early Colt Trooper 357 to S&W M28-2, 357, the engraving tool easly marked the Colts barrel & frame. Very soft steel compared to the S&W.

Why use soft steel? Why surface harden hammer and sear? Machining time is shorter & cutters last longer.
For Colt, faster production time, more profit, to keep the company out of bankruptcy.

Sorry Colt lovers.

This is my GP100, I suspect they are using soft steel like Colt does also.

Notice there is no flame cutting, it hasn't been shot enough for it to happen. Or the frame is hardened and the barrel isn't. What ever the case, I don't know. This damage was done with shooting midrange lead bullet loads. Shouldn't have happened. Not enough loads through it.
Many of my S&Ws are much older and have been shot alot more with hotter loads and they don't look like this. (They are Model 28s)
Accuracy on this one is going South.

 

[JohnKSa]

Notice there is no flame cutting, it hasn't been shot enough for it to happen. Or the frame is hardened and the barrel isn't.

Interesting. My 1990's vintage GP100 shows easily noticeable flame cutting but just the slightest bit of forcing cone erosion--right around the inside lip.

 

[tightgroup tiger]

Interesting. My 1990's vintage GP100 shows easily noticeable flame cutting but just the slightest bit of forcing cone erosion--right around the inside lip.

I don't know if Ruger changed something on the later models, or if mine is defective. (no heat treat). I didn't like the fact that Ruger wouldn't talk to me about why it went bad so fast. I've never even heard of lead, midrange loads hurting a forcing cone.

 

[Drail]

Forcing cone erosion is caused by one thing - use of very light bullets with certain powders that burn at a very high temperaure. That flame is only in the cone for a micro second but it is hot enough to cut steel until the bullet passes and the barrel vents. Don't use lightweight high velocity loads and your forcing cone will not erode. I learned that lesson the hard way.

 

[GeoDudeFlorida]

Forcing cone erosion is caused by one thing - use of very light bullets with certain powders that burn at a very high temperaure. That flame is only in the cone for a micro second but it is hot enough to cut steel until the bullet passes and the barrel vents. Don't use lightweight high velocity loads and your forcing cone will not erode. I learned that lesson the hard way.

I stay above 140gr. with jacketed in "hot" .357Mag loads. Seems to be working just fine.
I've never been a "fan" of The SuperVel Cult so, there's that, too.

 

[chicharrones]

This is my GP100, I suspect they are using soft steel like Colt does also.
View attachment 1084123
Notice there is no flame cutting, it hasn't been shot enough for it to happen. Or the frame is hardened and the barrel isn't. What ever the case, I don't know. This damage was done with shooting midrange lead bullet loads. Shouldn't have happened. Not enough loads through it.
Many of my S&Ws are much older and have been shot alot more with hotter loads and they don't look like this. (They are Model 28s)
Accuracy on this one is going South.

Same with my GP100 earlier in the thread, plenty of cone erosion but no flame cutting of the top strap. I bought it new in 1993.

 

[Palladan44]

Here's what I KNOW:

Heavy jacketed magnum loads (eapecially 110 or 125 grain bullets) will cause the most damage to a 357 revolver. These are what damaged all of the LE issued model 19s back in the day. Apparently a 125 grain bullet going 1,550 fps was necessary then? I never put any hot magnum loads through my Python. No need.
I use cast lead 158gr. loads going around 1000fps at most.

Here's what I THINK:
I think your gun looks like a serviceable shooter, and finding a competent gunsmith to verify this may be difficult or impossible to find these days! I'd stick with light to medium spiced ammo and ENJOY shooting that gun!