Is carbon ring theory a myth? Let’s try prove / disprove

A revolver carbon ring is supposed to “sneak up” and cause a pressure spike. Revolver, 38 special shot in 357 Mag and then the shooter switches to 357 Mag, carbon ring, pressure spike. Or 44 special 44 Mag. Or 45 Colt 460 S&W. Etc.

My contention is that you will need to forcefully push the longer cartridge into the cylinder pushing into/past the carbon ring before any pressure spike will occur. And having to push in a cartridge where it normally drops in will alert the shooter. So there will be no “sneak up”.

The only user experience fact I can provide is this: I’ve shot hundreds of 38 special in 357 magnum guns, between cleanings, and the 357 cases drop in fine, two different guns S&W 586 and Kimber KS6, and both seem to fire fine. The extracted cases always have straight, smooth sidewalls.

Maybe it is possible to see after thousands of rounds, no cleaning?

Proof of carbon ring pinching should be seen in slight bottle neck appearance in fired cases, I think.

How many rounds have you fired, what gun, caliber, such that the longer cartridge would no longer just drop in?

Have you seen fired cases that have a bottle neck shape due to the carbon ring?

I’ve asked “debunking” type questions before, looking for facts beyond my own experience, and sometimes the threads result in “It’s an accepted fact but I have no proof”

kmcdonou said:

Just curious how often you clean your 586 or KS6? Are you cleaning often enough to where the ring doesn't have time to develop?

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Edited my OP to clarify, thank you.

I’m not advocating not cleaning a gun, quite the opposite. However, I have experimented for hundreds of rounds, with no evidence to support the carbon ring theory.

My experience is that the carbon ring pressure spike theory is a myth. All of the posters so far seem to agree as well because they clean their guns and have no experience to prove a carbon ring pressure spike is a thing.

Thanks for the input so far.

Often in our threads, we repeat things like, “If you shoot 38 make sure to remove carbon ring before shooting 357.” Sounding more and more like BS, but we’ve only had a few responses so far.

reddog81 said:

I never had any problems until I started using a Lyman lube sizer and after a couple range sessions of shooting lubed lead .38 ammo without much more than a wipe down of the guns and bore afterwards. Eventually try to get a .357 in the chamber got difficult. I cleaned the cylinder real well and the problem went away.

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Good info, thank you. So maybe a hundred rounds and bullet lube had built up enough to make 357 difficult?

CraigC said:

This isn't really a safety issue with standard production .357's and .44's. When it does rear its ugly head, it's just a matter of inconvenience. It only becomes a safety issue in Freedom Arms guns when you combine a minimum-spec chamber and a 65,000psi cartridge. Different animal altogether.

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Still unproven without facts. Have any proof? Any experiences?

CraigC said:

Do you need to see a blown up Freedom Arms to believe it?

Do you need pictures of one with an egged bore to believe that some idiot was able to do that an FA .357? Or is second hand word from Wayne Baker good enough?

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No not really. Just some facts like shooter was shooting 38 a bunch, switching to 357 without cleaning and then overpressure due to the carbon ring. I’m betting if you have a picture of a 357 FA with an egged bore it was caused by a double or triple charged case, handloads, and not a carbon ring.

And if Wayne Baker has stated how a carbon ring caused the overpressure condition, and that it was in fact not a double charge, all the better.

Once the gun goes off with a double charge, maybe it’s better to save face by claiming carbon ring, especially if they were your hand loads?

CraigC said:

The egged bore was caused by poorly made cast bullets.

The over-pressure condition is caused when the crimp can't open, because it has nowhere to go. FA 83's are immune to double charges but folks aren't typically loading them to 65,000psi with Bullseye.

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Good info, thank you. And as with the carbon ring theory, your example should be similar to a pinched case by carbon ring.

But, no one has issued proof of carbon ring over pressure yet. The only proof I can think of is a fired bottle neck looking case 357 / 44 Mag / 45 Colt / 22 LR, etc.

Speedo66 said:

Is this some theory postulated by interweb "experts"?

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That’s what I’m thinking. I’ve seen it posted so many times as a comment and a caution in gunboard posts (not just THR) that I’d thought I’d challenge by asking for data and information.

@CraigC has some info and manufacturer recommendations (FA 45 / 454). However, Freedom Arms is in the business of making money selling extra cylinders, so maybe that drives their recommendation.