300 saum,or 7 rem mag. barrel life???

[OlRounder]

thinking of having a frien build a rifle for me. I am wondering about barrel life in 300 saum with a twist to shoot 190 to 220gr bullets and the same question for a rem 7 mag. With all I will have invested in this rifle I would like to get the most out of it that I can. these arent my only choices of course but something right along these lines is what I'm looking to shoot. thanks!

 

[Louis Boyd]

thinking of having a frien build a rifle for me. I am wondering about barrel life in 300 saum with a twist to shoot 190 to 220gr bullets and the same question for a rem 7 mag. With all I will have invested in this rifle I would like to get the most out of it that I can. these arent my only choices of course but something right along these lines is what I'm looking to shoot. thanks!

What you should consider is how much it costs to rebarrel compared to the cost of the ammo to burn the barrel's throat out. If you look at it that way barrels are relatively inexpensive for just about any cartridge other than the really overbore ones like the 264 WM, 7mm RUM, and 30-378 Wby. I have three rifles in 300 SAUM and I'm not concerned about barrel life, at least not compared to the cost of the ammo. Barrel life for the 300 SAUM is similar to a 300 Win mag, and that's a little better than a 7mm Rem Mag. I don't consider any of those as barrel burners. Of course you pay for performance. There's a reason barrels are threaded onto receivers rather than welded. It's not so you can easily replace the receiver.

Barrel life is determined by the pressure, temperature, velocity, and duration of the propellant gas blowing over the barrel's throat. At the throat all four of those parameters are larger than in any other part of the barrel. Wear from barrel friction including the effect of twist is usually negligible compared to throat erosion.

 

[OlRounder]

Yes, a good point on ammo cost. I currently am going thrue a barrel on a .22 6mm ackley. Its going pretty fast. I'm already planning to " move it up". Thanks for your help. I'm leaning hard towards the 30 cal SM. I think its just what I want to end up with. Thanks again.

 

[Louis Boyd]

Something to think about. From the time of ignition until a bullet exits the barrel is typically 1 to 2 milliseconds. Very high performance rifles can erode their throats in 1000 shots. Low velocity rifles may have 20,000+ shots of useful life. Ether way the time the barrel is actually in use over it's life will be from about a second to less than a minute.