Hi, I would like to know how many round is too many round in short time period, which could lead to ruin the barrel.

You can ruin a barrel in short order if you get it hot and keep it hot. What exactly are you concerned about? Are you talking about a semi auto, a full auto, a bolt action?

Key word is "Depends"

On what cartridge, what barrel material, what powder, what bullet etc. A real overbore will do damage quicker than one that's not. To many factors to say.

My view is don't shoot enough to heat the barrel past the point I can't hang on to it. The hotter you get it the quicker the damage is done.

There is no hard and fast rule on ruining the throat of a barrel.

It depends on the intensity of the cartridge (e.g., .30-30 or .300 Weatherby), the quality of the steel, and the frequency and duration of the 'exercise'.

George

Ok some more info

Shot 20 rounds in about 20 minutes 7 mm rm, 139 hornady with r-22, and the barrel was getting really warm!
I

quote:

Shot 20 rounds in about 20 minutes 7 mm rm, 139 hornady with r-22, and the barrel was getting really warm!

A one time thing I wouldn't worry about it. Not something I would choose to to on a daly basis. LIke I said I don't normally heat my barrel up to the point I can't hang onto it.

Mr. Ackley wrote of a .244 H&H Magnum, the .300 case necked to 6mm, and losing barrel accuracy in less than 250 shots. Now that was a long time ago and barrel steels have improved... 500 rounds? 400 Rounds?

Basically, you question is too "general." In a .22 Hornet with a couple grains of powder... you would have trouble firing fast enough to heat the barrel. .22/250 with 2 to 5 times as much powder (aqnd higher performance)... 3 or 4 or 5 shots will get the barrel real hot. Then there is the "weight" of the barrel. If you have a pencil barrel, light of weight and easy to carry but easier to "heat up"... Now the heavy, HEAVY bull barrels of the target guns... they don't heat up as fast.

Mr. Ackley also wrote of turning down a barrel, as an experiment, to about 1/8 inch thick. It fired just fine. You could collapse this tube with your fingers, totally not useful/practical, but shootable. Obviously, he mentioned that it would heat and the rifling deteriorate rapidly...

Little problem to the deer hunter who might fire 20 rounds in 5 or 10 7years. Varmint shooter, i.e. prairie dogs... find a friendly barrel replacer you like and can afford... (ha, ha). luck.