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29 Jul 2012
@ 08:15 pm (GMT)

jason rushton

Hi am new to site and would appreciate any advise on expected barrel life of a 300 weatherby mag?



30 Jul 2012
@ 10:06 am (GMT)

Nathan Foster

Hi Jason, much depends on how you use the rifle. If you keep the barrel cool and keep it well polished between shooting sessions (keeping the pores of the steel closed), you can push barrel life out to 1200 rounds. But if you shoot long strings, especially with a thin barrel, the throat will erode.

With any of these potent cartridges, accuracy often falls off at around 500 rounds, even with careful use of the barrel. At this point the loads can be reworked (usually requires an increase in powder charge) then away you go again. The next time accuracy begins to wane, its time to start planning to rebarrel.

You know its ironic though. We tend to think of the magnums chewing barrels yet in the last three months I have had a few chrome moly rifles through here that have lost accuracy in as little as 100 rounds, simply from being used in harsh NZ environments, surface rust formed during the course of the hunt, goodbye bore. Like I say, Ironic, a .308 Win gone in 100 rounds. Bore care is always the key.
14 Aug 2012
@ 12:54 pm (GMT)

Bruce Holler


I wonder is stainless is the way to go?
Also, TC makes rifles with 5 groves instead of 6. Your comments are welcome.


15 Aug 2012
@ 04:44 pm (GMT)

Nathan Foster

Depends on where you live as to stainless versus Chrome Moly Bruce.

In NZ and as mentioned above, I have guys turn up here with rifles on a regular basis with near new but completely stuffed chrome moly bores from rust. The typical example is that the guy went away during the roar/rut, stayed in the bush for 2-4 days, came home, cleaned the rifle, just a basic oil and pull through, went to go out again a few weeks later and the rifle won't shoot.

What has happened, is that during the bush trip, it rained a lot. A hunter is never really that far from a coast line in NZ so salt is a problem. The bores rust during the hunt, perhaps just overnight. By the morning or the end of the hunt, the rifles are stuffed, good for a 100 yards or so, no good for mountain work or long range.

On inspection, I will find corrosion at the intersection of the lands and grooves. If the hunter has cleaned the rifle, the colour of the corrosion will not be orange but a rough grey. Sometimes a muzzle chop will do the business, other times the corrosion extends too far into the bore.

Thats the key difference with stainless, the polished stainless bore offers corrosion resistance. Its certainly a lot more work with chrome moly. Chrome moly polishes well but is prone to corrosion and once it starts, the pores in the steel open right up. You could possibly push for a correlation between this and throat porosity following high temperatures if you were inclined to study such things. I found a definite correlation between cleaning procedures and throat wear in the magnums. Basically, if the throat is not kept polished, the pores not kept closed, the throats erode rapidly.

Personally, the less grooves the better for me. 4 is my optimum. The less the barrel is worked, the better. I prefer to see minimal deformation of the bullet. Grooves tend to be market driven more than anything though. Customers will rave about the latest 6 groove bore, then the barrel makers have to go off and buy 6 groove tooling to keep everyone happy. In reality, they all seem to work, 4,5,6 grooves, it doesn't really matter. But I do like to keep things simple, less work means less potential deformation / malforming.


We are a small, family run business, based out of Taranaki, New Zealand, who specialize in cartridge research and testing, and rifle accurizing.