doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Warped action

Incorrect tempering of receiver surface metal is the inherent flaw in the use of the high heat bone charcoal process when applied to shotgun receivers. A dangerous situation may develop as a result of incorrect tempering of the receiver surface metal after the high heat bone charcoal coloring process is completed. This is particularly true of older shotgun receivers, made prior to ww2. Factory tempering specifications were inconsistent, as receiver metallurgy formulas changed from time to time. Unfortunately, much of the original factory hardening and tempering specifications have been lost. Even the best of mechanics are only guessing when they attempt to correctly re temper a shotgun receiver after subjecting it to a high heat bone charcoal hardening process.

Quality case coloring should provide cosmetic enhancement without endangering gun integrity or shooter safety....Be careful if you are contemplating sending your prized shotgun's receiver to a high heat bone charcoal mechanic.. He is going heat it up to around 1600 degrees F... Make sure that you get it in writing, that if the receiver warps in the heating and tempering process or that if it cracks after firing, then the mechanic will assume full financial responsibility for the destruction of your gun and/or your personal injury.

A low, controlled heat process, combined with specific chemicals is the safest way to recolor a shotgun receiver. So long as the heat is kept low and controlled, the original receiver metallurgy and heat treatment is not changed. No harm is done to the gun nor is there any potential for danger to the shooter, as a result of the re coloring process.

In summary, shotgun receivers should never be re hardened in the vain interest of restoring the cosmetic effect of case colors. Case hardening is a high heat process which alters the surface molecular structure of the receiver metal. Re hardening a receiver can warp it. Subsequent efforts to straighten the metal, either by bending or filing can only harm the fine original metal-to-metal fit and adversely alter the workings of carefully aligned internal shotgun parts. In addition, if the receiver surface metal is not correctly re tempered after the hardening process, then the receiver metal may be too brittle and as a result, may crack upon firing.

I dunno... maybe a torch is the answer.

Just based on what little description that was given on the annomoly, I'd say the warp was something that could be very small and the resultant hammer misfit is magnified by the geometry. It sounds like the fix could be very simple: slight bending of the hammer and possibly some side clearancing/polishing. But, I'm doing a diagnosis based on very little information.

To me, trying to twist or bend a frame would be scarier than refitting parts.

Friends:
Ed good is most wise. A good gun should NEVER be re-cased for the sake of vanity or perceived "aesthetics." There is simply too much that can go wrong. Especially with certain "well-known" US re-case shops.

Best, Kensal

Ed

With all due respect… you are full of it, or more precisely …you clearly don’t have a clue, the temps and process you cite are proof of that.

The heat treatment of steel is well understood by many that practice the art.

Faking true case hardening with the judicious application of a torch and some cold blues or Tincture of benzoin is kinda like restoring the Mona Lisa with crayons.

Mike

Serious problems that can occur during the case hardening process namely distortion and cracks. For example in my early life [50 plus years ago] I was considering recase hardening a gun of mine.To this end,I visited a well established Birmingham gunmaker and asked for a quote for recase hardening the action.The reply from the owner was;"only if you accept full responsibility for any distortion or cracks that may develope during the hardening process." Then to reinforce his position,he went back to the workshop and returned with the actions of a pair of Boss sidelocks that had been recase hardened.One action appeared sound the other had cracked during hardening.
Case hardening of parts such as the action of a shotgun that have many variations in section thickness and have sharp corners present, pose a significant challenge.The packing of the parts in the hardening box,protection of thin sections to prevent their conversion into high carbon steel, temperature controls and quenching methods are all critical if cracks and distortion are to be avoided.
For the above reasons I have avoid guns that have been re hardened.

Most people are adding to this and it's all positive. I've been researcing the art of CCH for a while now and only do it on my own guns. I operate at proper temperatures for low times and thus my colours are not deep but I risk less by doing this.

Everyone to their own. I don't CCH everything but some things...depends on what I feel about a particular gun.

T

removed

I'd seriously question the word of your friend's "gunsmith". Parker hammers have the firing pins cast as part of the hammers. They are not separate parts. Either he does not know what he is talking about or has been misquoted.

He probably meant to say that the firing pins would no longer align with their respective holes in the breech face. But, I'm giving him the benefit of the doubt.

Stan