When varmint or target hunting with my vssf, sometimes I get carried away and the barrel will get pretty hot. I know this is bad.

Why is it bad?

Once the heavy ull barrel heats up, does it wear faster? It shoots accurately regardless if the temp.

Hi, Badon:
Machine gun barrels don't last very long. The hotter the barrel, the sooner the barrel steel reaches the critical temperature where erosion starts on the next shot. Barrels for low intensity cartridges last a long time. Ever shoot out a .22 rimfire? Someone reported that he shot out a 7mm Ultra Mag in 300 rounds.

Bye
Jack

badon,
Jack is right on the money here. The hotter a barrel gets, the more it WILL wear. The more overbore the cartridge, ie Weatherby mags in general and all Ultrmags, save the .338 perhaps, the shorter the barrel life will be.

When the barrel is too hot to hold in your hand for a solid 5-10 seconds without causing you to let go of it, it's too hot for it's health. The previous statement was not invented by me, but has been a general guidline for longevity that I follow with good results.

Different barrel materials help to negate the effects of erosion, but none eliminate it. If stainless stopped erosion at higher temps you would see every military rifle with a stainless barrel. Chromed bores, common to military rifles, seem to minimize this effect and also help to prevent corrosion, but I've seen precious few bolt action rifles with a chromed bore available for sporting purposes.

To address the heavy barrel issue, the main benefit is that it heats up more slowly, so you don't have to worry about erosion and heat as soon as you would with a lighter barrel. There are other possible benefits to a heavy barrel, but once it's too hot to hold, it'll erode just as fast as a pencil thin sporter barrel. Heavy barrels have a greater diameter that increases the surface area available to cool the barrel, but they also have more barrel steel to cool, so a sporter barrel will actually cool quicker than a heavy barrel rifle once it's hot, but the sporter will get hot much quicker. The fluted barrels, with the greater surface area for cooling, are supposed to cool more quickly. Many shooter say the actual effect is not great enough to be observed in the field. Marketing hype is only good to a certain point outside a scientifically observed laboratory I guess. :) A fluted barrel of equal weight to a non fluted one, ie greater diameter and more surface area for the same WEIGHT barrel, will cool faster, but it's debated if it can be readily observed under field conditions.

Hi, Badon:
Machine gun barrels don't last very long. The hotter the barrel, the sooner the barrel steel reaches the critical temperature where erosion starts on the next shot. Barrels for low intensity cartridges last a long time. Ever shoot out a .22 rimfire? Someone reported that he shot out a 7mm Ultra Mag in 300 rounds.

Bye
Jack

I have had a 7mm Ultra Mag for over two years now. I know I have put well over 300 rounds through it. It still shoots great. Any rifle will burn out, even 22's. It depends on how you shoot it. Keep pumping ammo through it at a high rate and the barrels gone. Take care of your rifle and it will last a long time, even the so called overbored cartridges. Shoot slow and make each shot count.

Hi, Gents:
A 300 round barrel life is usually low, even for overbored cartridges like the 7mm RUM. If that report is correct, the shooter was doing a bit of rapid fire. The late Bob Milek did in a .220 Swift in one day. Too many prairie dogs in one place.

Bye
Jack

Guys have it right...barrels don't wear out, they burn out....the more heat, the faster they erode.

Not just pressure (but for the split second of a shot, pressure and heat are pretty much interchangeable), but duration. Big cases may run at the same pressure level as small cases (22/250 vs. 223), but the big case has more powder...slower powder...so a longer burn time. Just one way of saying the more powder your burn at a given pressure, the more erosion.

Bring two rifles...swap off as one heats.