Cryogenically treating (CT'ing) your gun will not improve its accuracy. It might increase barrel life, depending on the alloy and heat history of the gun. It can also increase brittleness, making the gun more likely to break if it's dropped (again, depending on alloy and heat history).
When an alloy steel is quenched, the crystal structure goes through several phase changes. These phases have varying densities. The phase changes might not complete if the quench stops at room temperature; there's nothing wrong with that because subsequent tempering will provide the right hardness and toughness for the application. Because quenching is more rapid at the surface of the part, the phase changes will be more complete there than they will be at the core of the part.
If you CT such a barrel the phase changes will continue and the barrel will become harder, and the volume of the material at the core of the barrel will increase which will cause tensile stresses at the surface of the part. The part will then be more likely to break unless it's stress-relieved. Stress relieving requires temperatures high enough to risk distorting the part, has to be done in a controlled atmosphere to prevent oxidation, and afterward the gun will have to be completely re-blued and re-bedded to the stock due to dimensional changes.
Notice what else this means: CT can't relieve stress in a part. If it does anything, it will increase stress.
CT does nothing to a gun that can reasonably be expected to improve accuracy. None of the articles I've seen that claim otherwise (and I've seen many) involve a properly controlled, valid test; every one of them is fundamentally flawed and the results are meaningless. Don't waste your money on CT, you'll be much better off spending it on ammo at the range, working to improve your breath control, sight picture and trigger squeeze.
For further detailed information, ask a metallurgist. Or find these two articles in Precision Shooting magazine: Meanwhile, 17,224 rounds later..., (September 1998), and Cryogenic Treatment of Gun Barrels, (March 1999). I'm the author of the second article.
When an alloy steel is quenched, the crystal structure goes through several phase changes. These phases have varying densities. The phase changes might not complete if the quench stops at room temperature; there's nothing wrong with that because subsequent tempering will provide the right hardness and toughness for the application. Because quenching is more rapid at the surface of the part, the phase changes will be more complete there than they will be at the core of the part.
If you CT such a barrel the phase changes will continue and the barrel will become harder, and the volume of the material at the core of the barrel will increase which will cause tensile stresses at the surface of the part. The part will then be more likely to break unless it's stress-relieved. Stress relieving requires temperatures high enough to risk distorting the part, has to be done in a controlled atmosphere to prevent oxidation, and afterward the gun will have to be completely re-blued and re-bedded to the stock due to dimensional changes.
Notice what else this means: CT can't relieve stress in a part. If it does anything, it will increase stress.
CT does nothing to a gun that can reasonably be expected to improve accuracy. None of the articles I've seen that claim otherwise (and I've seen many) involve a properly controlled, valid test; every one of them is fundamentally flawed and the results are meaningless. Don't waste your money on CT, you'll be much better off spending it on ammo at the range, working to improve your breath control, sight picture and trigger squeeze.
For further detailed information, ask a metallurgist. Or find these two articles in Precision Shooting magazine: Meanwhile, 17,224 rounds later..., (September 1998), and Cryogenic Treatment of Gun Barrels, (March 1999). I'm the author of the second article.
