13 twist ultra mag?

[Gerbil boy]

So I've recently bought an Obermeyer Palma barrel fir cheap. It's 13 twist cut rifling barrel that will finish at 30" or longer. I've got a gunsmith buddy that has a short throated 300 remington ultra mag reamer and a bunch of brass and dies from a failed christensen arms rifle project. Anybody ever built a light bullet ultra mag? I think it will stabilize a 168 sierra or berger and I should be able to get them around 3500 fps. I also have a bunch of 155 bergers too. (Maybe 3650fps) I'm in VA so we don't have any elk of grizzly to deal with. This thing should make a lightning fast whitetail hammer. I've got a shilen DGA magnum single shot that will work perfectly for this.

 

[dkhunt14]

A 13 twist might be on the edge for stabilizing a 168 fully. The speed you get will help. Hopefully the reamer is throated right for it. If short, you can always throat it out a little. It might get pretty ugly on whitetails at that speed. Barrel life won't be great. Guys have done it and maybe they will reply. Matt

 

[KMart]

I had a 13 twist in a 308 Win. It would reliably stabilize up to a 175 Sierra MK at normal 308 velocities.

 

[Kurz]

Gerbil boy,

I have built a couple of RUMs on slow twist barrels, notably a 300 RUM with a 13" twist Krieger last year.

The 168s will need 13.6 to keep the bullet stable depending on the construction and velocity of course. I was using the Tipped TSX (they are longer) by Barnes to keep the bullets together at the higher velocities. They are excellent for deer hunting.

I didn't go up in weight because that wasn't the part of the experiment. I did go down to the 150 TTSX though and they were awesome on deer. I stayed with the solids even though some of the cup/core bullets might be satisfactory, in order to conserve meat. We used to run the big .30-378 Weatherby cartridge with cup/core light weight bullets but the damage was massive on deer.

H-1000 was excellent in nearly all cases that I can remember, not nearly as much heat generated as with some of the more active powders.

Enjoy the experimenting!

Regards.

 

[dkhunt14]

I went to the Berger stability chart. I ran a 168 VLD at 3300 and it said Marginally stable. The SG was 1.38. Then I went to 3400 and the SG was 1.39. They recommend a 12.3 twist to be stable. Matt

 

[Gerbil boy]

Thanks for the help. I was curious as to what powders to run. I see reloader 25 was the speed king on nosler reloading data. I've got the old benchrest shooting primer and it talks about the hunter class benchrest setup. They almost all ran a .308 with a 14 twist and ran 168 sierra matchking @25000 fps. I don't care about barrel life. I've got another 300 weatherby barrel for this gun that loves 200 grain ELD-X hornady bullets @3100fps(under 1/2") A couple guys that I shoot with have Richard Franklin Varmintators. 300 wsm 15 twist with 125 noslers running 4000fps. They are devastating on whitetails so I figured this gave me a little more horsepower and b.c.

 

[M14AMU]

Go ahead an order you a couple extra barrels also!!

 

[Todd DuBose]

Here the smartasses and Order Your Barrels comes out. I don't pick on you guys for being a snail and just making the hours go by so why not button your upper lips unless you have a dog in this fight.
Currently, I'm running aBartlein 31" 1-13" twist on myWeatherby 30/378 Weatherby and shooting the Nosler 125 grain Ballistic Tip over both my Chronos, I'm running 4,130 or thereabouts. With a -or+ of 20 fps on 5 rounds. Oh, I forgot, this is within astronimical amount of IMR-4350. I could give two $hi!!'s if the barrel lasts 250 or 500 rounds. Whatever it does, I will know I had fun in doing so and to be able to say to you stick in the mud safety boys. Your done. Rainbow arches?? Not me. Have fun with this. Todd DuBose

 

[ebb]

Sounds like fun to me. Shot 162 Amaxs out of my 7 rum at 3695. Many did not make it to the target. I like the idea of the Barnes bullets, let me know if you can blow up one of those. I don't think you can, but that might be a fun experiment.

 

[Eric Leonard]

I had a factory 700 BDLSS 26 inch 10 twist,,with 96 grs RL22 the 150 Sierra SBT would avg 3610 fps and shoot .500-.600 at 100 yards,,I could get 3500 with the 168 and 3390 with 180 Noslers,,


with a 26 inch factory bbl,,30 inch bbls should be some faster,,

 

[Clavius-Walker]

Will this barrel be used on any gerbils?

 

[M14AMU]

Only monsters! But he's not quite there yet as monsters require fps in nanoseconds!