Sounds silly to me but a mate is buying a rifle and is adamant a bull barrel will help reduce throat erosion(came up as he said a thin barrel on a 22-250 seemed pointless). Can anybody in the know clear this up?
Cheers
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Sounds silly to me but a mate is buying a rifle and is adamant a bull barrel will help reduce throat erosion(came up as he said a thin barrel on a 22-250 seemed pointless). Can anybody in the know clear this up?
Cheers
The only thing that is proven to prevent throat erosion in any caliber rifle is to not shoot it!
I wonder if he thought the bull barrel would act as a kind of heat sink, and greatly delay the temp rise in the area of the throat.Quote:
Originally Posted by superdiver
Until its hot & then its hot for ages & ages......Quote:
Originally Posted by Max Headroom
No is the answer. Throat erosion is caused by the high gas velocity and temperature caused by the propellent.
Hot gas at around two and a half times the melting point of steel at 55,000 or so psi travelling at around 1km per second is quite erosive bit like a plasma cutter. Thankfully its only for around 2 thousandths of a second per shot. So theres no way the temperature can be heat sinked away by a heavier profile.
Heavier barrels are good because they have less harmonic movement so are more predictable shot to shot and take longer to heat up, and longer to cool down.
A major factor in throat erosion is heat, obviously.
There is an argument that a heavier barrel resists throat erosion better as its harder to heat it (the throat) up to the same temps as a lighter barrel; before the heat is wicked away to the remainder of the barrel.
As always it will depend on how its treated, though I have no doubt if a person took a light contour barrel and a heavy one, and fired one shot down it every two minutes or something till the throat was shot out - I think the heavy barrel would do better as it has more mass to wick the heat away from the throat area.
I think as Marty says the issue is not heating causing erosion, its the plasma effect of the superheated gases. I dont think a thicker barrel will help much with this.
Its commonly accepted that if you shoot a gun hot and don't let it cool between shots it will wear the barrel faster then if you did let it cool. I don't think anyone would dispute this. eg. you could wear a 7mm mag barrel out in a few hundred rounds if you didnt let it rest, but that same barrel might do 1500 rounds if allowed to cool between shots.
This is because, generally, as metal gets hotter it gets softer. As metal gets softer, it looses abrasion/wear resistance.
This means a hot barrel will wear quicker than a cold one, and it takes more rounds in the same period of time to heat up a heavy barrel to the same extent as a light one.
If both were given as much time as needed to cool properly between shots, I think they would have the same barrel life, but if both were shot continually till one of them died, or with less cooling allowed between shots, the heavy barrel would come out on top.
Heat kills barrels. Heavy barrels are slightly harder to heat to the level where wear is increased.
Basically, IMO, a bull barrel helps manage heat. And managing heat extends barrel life. So I think the answer to your question is both yes and no depending on how you look at it or how it will be used.
Chris is right as well. Shooting a hot barrel will help kill it as you have to factor friction into the wear as well.
Interestingly I believe copper jackets cause more wear than steel jackets do, something to do with copper and alloys being "sticky". I do know that the Germans in ww2 discovered soft iron driving bands prolonged the life of artillery barrels compared to copper when they were looking at ways of saving copper for rifle ammunition.
So how is it that a target rifle barrel that fires 10 to 15 rounds in a short session can have a barrel life of 4000 rounds?
And these are generally high up in the PSI stakes driving 155 grain bullets at the 3000 fps mark.
I get it that they have heavy profile barrels but it cant all be about heat sink or the last few shots in a 15 round string would be way off the mark?
There are several factors that cause throat erosion, pressure, heat, type of barrel steel, choice of powder, etc, etc. High intensity cartridges (eg; magnums) are the worst for it, the bigger the case and the smaller the bore, the worse the problem becomes. Cartridges that are 'balanced' (ie; sensible case capacity to bore ratio) such as 6.5x55, 7x57, 7-08, .308, .30-06 etc all give excellent ballistic performance and barrel life. Most stainless barrels have less resistance to throat erosion than chrome-moly because they are much softer. Chrome-plated bores and chambers give a noticeably longer life from throat erosion, but nothing will prevent it completely. If you buy a new hunting rifle and shoot 50 animals a year with it, cleaning it properly, it will last your lifetime without worrying about throat erosion. If you wish to run high intensity cartridges at maximum velocities than you have to accept a shorter barrel life as an acceptable expense.
50 animals per year, shit lately I'd be happy with 15.