6.5 ultra mag

Pros: Fast
Cons: Burns barrels, large amounts of powder, overbore, hard to get components for, not very practical
 
If you want a 6.5 go with a smaller case. Nothing bigger than the 264 mag.

The RUM case is too big for anything under 7mm. The 7mm RUM using 180-195 grain Bergers will be vastly better at long range than anything of 6.5 caliber.

The only advantage I can see is less recoil at 6.5 caliber vs 7mm or 300 RUM.

For my money the RUM case is best at 308 caliber shooting 230 Berger. That's vastly superior at range to any 6.5 caliber and longer barrel life. You can shoot the 230 Berger in a standard 10 twist barrel. The 195 Berger in 7mm requires a faster than standard twist. Sometimes the original is best and that includes 300 RUM.
 
What type of performance are you looking for with this rifle? I have all the RUM's and a RUM wildcat. I can't even imagine anything coming out of the case smaller than a 7mm. My 14 year old shot a whitetail buck, and 2 goats this year with his 7 rum. 190 matrix on top of 102.5 grains of 33. It shoots a easy mid 3200 fps. We had to slow it down for fear the jackets would shred off. If you did decide to do this, your limit will be bullets. Jacked bullets will end up being too slow ( shedding the jackets) or you will have to shoot a solid bullet. I'm just not sure if I could be done...but if it can, I'd LOVE to see it!!

Jayson
 
I have a wildcat based on the 338 RUM Improved that's very similar to the 6.5 Allen Mag. A straight 7mm RUM necked down to 6.5 would likely get you very similar results without the need to fireform, which is a good thing! Its a great caliber if you understand what you're getting in to.

Focus on the heavy for caliber bullets like the 160gr Matrix. I get 3450 fps with the 160 from a 30" barrel. It shoots as flat as a 338 Edge with the 300gr OTM and as flat as my 7mm RUM did with the 200gr Wildcat bullets. But it does it without the recoil. Mine doesn't have or need a brake. The 140 and lighter bullets just don't make sense with that much capacity if you ask me. The only powder I'd recommend is US869. There are some stick powders with slower burn rates but you'll probably end up with powder bridging issues.

Barrel life will be pretty short if you don't take care of it, and not exactly spectacular even if you do take good care of the bore. It's the cost of velocity. Mine is built on a large shank Savage so barrels are relatively inexpensive to replace once they're burned out.

I also have a 270 RUM that I haven't done much with. It should be in the same league with the 165 Matrix VLD.

Build your 6.5 RUM and have fun with it. Barrels were made to be burned out and replaced. That's why they're threaded on and not welded.

Andrew
 
thinking about building one whats the pros and whats the cons thanks

One pro is you do your own thing. A con is folks will think you are crazy and complain about how quickly YOUR barrel will wear out. Like one of our .com friends says, Barrels are threaded so they can be replaced. A pro is you can match .264 Win Mag velocities at a lower pressure. This will allow your barrel to last longer.

I made a sorta 6.5mmRUM. In fact I made two; one for me and one for my son-in-law. I rented a 6.5-.338 RUM reamer and a 6.5mm neck reamer. I had the 'smith run the reamer in as though I were using .338 brass and then extend the neck with the other reamer so I could use 7mm RUM or .300 RUM brass to give the barrel longer life.

Both of us used our new wildcats to kill a couple of pronghorns at the end of last month. His was loaded with Nosler 140 AB and mine was loaded with Barnes 127 LRX.

If I were doing it again, now that there is a factory 6.5-.300 Weatherby, I would merely use that reamer. The neck on that one is even longer. Also, I wouldn't have custom made loading dies. And, I could use factory dies and find brass more readily available. You could use .300 Wea or .340 Wea brass.
 
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