Anyone have 338/300 RUM data?

[rost495]

I'm working on saving for rebarreling a 300 wtby to 338/300 RUM. I've got some decent data off longrangehunting site.

Wondering if anyone here has this wildcat and any load data they'd share.

Mine will have polygonal rifling. We'll see if we can pick up a bit of extra speed and ease of cleaning that way. The Special Forces shooters running 338 Lapua are very happy with polygonal rifling and now my buddies at the AMU at Fort Benning are trying it for their 1000 yard rifles.

Thanks for any info.

Jeff

 

[MrBaitnFish]

Rost,
Just out of curiosity, why do you want to go through the pain (cost) of a wildcat when there's already the .338 ultra out there in a factory chambering. I doubt you'll get an extra 100 fps with the case capacity difference. I don't have any data on that cartridge. I went the other way with the 300 ultra and had a 264/300 ultra made. That is one fast & fun cartridge. Who makes barrel blanks with polygonal rifling?

 

[studpile]

Try reloadersnest.com, they generally have lots of wildcat cartridges...even if they're relatively recent. Could you explain polygonal rifling...not wanting to sound dumb...but curious.

 

[MrBaitnFish]

Polygonal rifling is just as the name implies. Rather than lands and grooves pressed or cut into the barrel it is a polygon twist. It is more common in European handguns, also H&K rifles are polygonal rifled. Also, Hexagonal, & Octagonal rifling. Same thing, just different number of surface grooves. Glocks use this type of rifling as do baby eagles. It is thought to provide a smoother surface, making a faster barrel and also easier to clean.

 

[studpile]

Gotcha,..thanks

 

[rost495]

Poly also seals better, usually providing up to 100 fps more than a regular rifling job. The army teams and snipers are very happy with them so far.

Pac Nor offers them in poly. And I've won so many trophies with PN barrels, I think this is a good road to try.

On the caliber choice, from most of the folks I have talked to you gain up to 200 fps, add another 100 with the poly rifling, I'm in the land of the 338 lapua and its easy to load for. With less headaches than the 338 Lapua can cause in small actions like the Rem 700.

I'll be able to end up with powerful round, and in a manageable weight gun. 28 inch #6 contour fluted.

The addition of the extra FPS is important to me for a few reasons. You can never control where your next barrels sweet spot of harmonics will lay load wise. So if I have a 300 win mag done and it shoots best 100 fps from max, then I've got the same as a hot 06. So I tend to go for a bit more room, just in case. If it shoots with top end loads great, if not, I've still not done all the work for nothing. If that makes any sense.

Thanks for the thoughts, Jeff

 

[rost495]

Oh yeah, I should add, I'm going to a custom barrel and tune up anyway so its no extra pain or expense. Save the die set. Which I am fairly sure I can just have a set reamed with my reamer and be fine. Probably 75 bucks total. Not any more than a good factory die. And that should include neck bushing setups.

This is supposed to be my only ever big game powerful reach out and touch something good. So I'm trying to do it right.

If I ever need bigger it'll have to be elephant round big.

Next thing after this is what you have there the 264 wildcat. In a lightweight rifle. But thats a few years out. Other guns just beggin to be bought. Its like a disease.

Jeff

 

[Boman]

Jeff,

Sounds like a great project. I know there is a custom gun maker out here in Colorado that chambers the 338/300 RUM, there was an artical in Eastmans a few months back that featured a guy shooting this cartridge. I'll see if I can get you the number or website for this smith..

Also for your lightweight project I'd highly reccommend Rich Reilly out of high tech custons in colo sprgs. he built my .340wby for me. It weighs about 7lbs scoped and ready to go. Its also a tackdriver. I should bughole groups all day long with it. He specializes in extremely accurate lightweight rifles that dont brake the bank.

 

[Boman]

Jeff,
looks like the smith I was thinking of is Kevin Weaver of weaverrifles.com. ph 719 683 3024. Give him a call and see what he says. I'm sure my smith could chamber this for you also and his chambers are pretty unique and very well done. his name is Rich Reilly ph 719 667 1090. Good luck and let us know what you decide.