What it does in a nutshell is relieve the stress in the steel of a rifle barrel by freezing at about 315 degrees below zero, subsequently changing the molecular structure of the steel. This process not only straitens out the grain of the steel, it makes the barrel more heat resistant and in the case of a machine gun it would require less barrel changes in combat. It slicks up the bore increasing muzzle velocity and in many cases increases accuracy up to 50%. Bluing on fine firearms becomes more rich and lustrous, while the firearm is just plain more durable and easier to clean. Much like a caterpillar going into a cocoon and emerging as a butterfly.
Uncle John
Cajun Cryogenics
No
colt
H&R and I believe Rossi have single shot rifles with interchangible barrels.
Heavy Barrel
Rifle Muskats Sub Mrines Rifle Barrels Cannons
You will need a gunsmith to know for sure.
rifle barrels may have a different external diameter. A rifle that is carried for hunting will usually have a "sporter" barrel- slender, to save weight. Target rifles will have more massive, stiffer barrels for accuracy. Those are "heavy" barreled rifles.
Rifle, handgun and shotgun can all have "long" barrels
If you have the money, they can be made.
How much Remington Armory 1918 bolt action rifle barrels are worth will depend on their condition, overall state and wear, and can range from $200 to about $800.
Because it is a pistol, not a rifle.
It depends on what they're being aimed at, and also the point of reference.