Barrel life has a lot to do with several factors, and one of the main factors is how much freebore was cut in the new chamber. A bullet will only jump so far before it gets started crooked in the barrel, and throat dia is also critical in this equation also.
When the barrel seems shot out, go to a sierra Semi point, flat base bullet that has more bearing surface on it. The Sierra 55g and 63g semi points are VERY accurate bullets in a 22/250 with a 1-14 twist. I went to these two bullets when my 22/250's and 220 swifts(1-14's) had the throats completely shot out and accuracy was always restored for another 800 rounds(approx.) with the 55's and even more when I went to the 63's.
I bought a new Howa Varmint in 1990 that had a throat so long you could not touch the lands in the brand new rifle. I started off the 63g sierra with 39.0g of IMR 4350 with a win primer an the rifle shot a ragged hole to 1/2" at worst.
The whole craze of everyone wanting to shoot a boat tailed bullet with a plastic tip in guns with long throats will not make for long barrel life(3500 rounds). So, Reloaders have to learn to adapt as their throats wear or replace the barrel. When you do replace the barrel, be DARN sure you know the amount of freebore on the gunsmith's reamer or you may find yourself repeating the whole episode all over again with short barrel life.
I order my reamers with zero freebore with std bullets, and I am not afraid to stuff them down in the case achieving super accuracy. Of course you have to take into consideration the case capacity like a 223 AI shooting the 75g A max for example.
I can not stress the importance of having short freebore on a custom chamber. This is one area that leads to GREAT misunderstanding in terms of barrel life. The bullet has to get started straight in the barrel in order for it to be accurate.
In the 22/250 and 220 Swift, I found that IMR 4064 EATS throats while Win 760(and aa2700) is MUCH easier on throats. So, powder types can and do make a difference!
Those with ears, let them hear!!!
When the barrel seems shot out, go to a sierra Semi point, flat base bullet that has more bearing surface on it. The Sierra 55g and 63g semi points are VERY accurate bullets in a 22/250 with a 1-14 twist. I went to these two bullets when my 22/250's and 220 swifts(1-14's) had the throats completely shot out and accuracy was always restored for another 800 rounds(approx.) with the 55's and even more when I went to the 63's.
I bought a new Howa Varmint in 1990 that had a throat so long you could not touch the lands in the brand new rifle. I started off the 63g sierra with 39.0g of IMR 4350 with a win primer an the rifle shot a ragged hole to 1/2" at worst.
The whole craze of everyone wanting to shoot a boat tailed bullet with a plastic tip in guns with long throats will not make for long barrel life(3500 rounds). So, Reloaders have to learn to adapt as their throats wear or replace the barrel. When you do replace the barrel, be DARN sure you know the amount of freebore on the gunsmith's reamer or you may find yourself repeating the whole episode all over again with short barrel life.
I order my reamers with zero freebore with std bullets, and I am not afraid to stuff them down in the case achieving super accuracy. Of course you have to take into consideration the case capacity like a 223 AI shooting the 75g A max for example.
I can not stress the importance of having short freebore on a custom chamber. This is one area that leads to GREAT misunderstanding in terms of barrel life. The bullet has to get started straight in the barrel in order for it to be accurate.
In the 22/250 and 220 Swift, I found that IMR 4064 EATS throats while Win 760(and aa2700) is MUCH easier on throats. So, powder types can and do make a difference!
Those with ears, let them hear!!!
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