.257 Weatherby & IMR 4831

300winnie

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Joined
May 18, 2005
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133
Has anyone loaded the new 110 grain Nosler Accubond with IMR 4831 in the .257 Weatherby Magnum?

Thanks.
 
some buddies of mine shoot the 257 weatherby. They swear by IMR 7828 for 100-115gr. bullets. except for the 120 gr bullets which they like RL25.
 
Re: .257 Weatherby

I have had several custom 257 Weatherby's with no freebore. I tried IMR 4831 with the 100 and 115g partitions, but the powder proved to loose 250 fps when the temp droped from 75* down to 45*.

I have had fantastic luck with R#22 with both 100's and 115's, but feel there could be improvement with H4831sc.

Good luck!
 
Re: .257 Weatherby

Keith, did you find that the 257 WBY was allot slower and hit pressure signs quicker with no freebore? Could you shoot factory ammo with this setup?

I'm asking this because I am going to rebarrel mine in the very near future. However, I haven't been able to decide on SAAMI chamber specs or remove the freebore. Granted, I reload almost exclusively, so that's not an issue. However, it's the rare instance that I may have to use factory ammo, or that someone else does that bothers me.
 
Re: .257 Weatherby

250fps from 75 down to 45 degrees??? According to Ackley and my own chronograph data it's more like 1 foot per second for every 1 degree. I have chronoed ammo that was 150+ degrees that was sitting on the dash that had IMR-4831 in it and then chronoed again at around 45 degrees and it was only about 100 feet per second slower. I chronograph almost every shot when I am target shooting. Same results with Varget, H-380, RL-19, RL-22, IMR-7828, and IMR-4350 . I think all this extreme powder stuff is just a gimmick to sell more powder The extreme stuff varies just as much from what I can tell. I carry an infrared heat sensing gun when I'm chronographing to see how warm my barrels are or when I am doing any kind of volume shooting. I don't want to melt my 257Wby while shooting varmints with it.

I use RL-22 for the 75 grain V-Max's to get 3960 fps and IMR-7828 for 100grain Partition's to get almost 3700fps. The 110's I tried RL-25 and IMR-7828 and they were about the same thing powderwise but couldn't get any speed or as good of accuracy out of them. In my gun the 100's fly faster, shoot flatter and hit harder out to 1000 yards than the 110's. I might still try them on Elk because they are a heavier bullet.
 
Re: .257 Weatherby

Sorry Hired gun, I'm just reporting what my Ohler 35P said. Needless to say, I was as shocked as you are. In my rifle with the 3 groove Pac Nor bbl, the velocity fell unbelievably!
 
Re: .257 Weatherby

You can figure +250 fps more out of a 257 Weatherby with no freebore. I hand load my ammo and would never even consider shooting a factory round.

In a chamber with no freebore, you can not shoot factory round, bullets have to be seated for that chamber.

Accuracy is in the high 2's and low 3's for three shot groups using 100g nosler partitions. Sierra 100g spt bt are a little bit better with velocity at 3750-3850 depending on the bbl. I do believe that 3 groove bbls are faster than 6 groove bbls, at least on the bbls that I have had.
 
Ive used IMR4831 only with the Speer 120 SPBT. The load is in the Speer book, max was max in my Lghtwt. Excellant accuracy though. I have not shot the 110's only the 115 Baltips w/H1000. The 100 Sierra's w/RL-22.
 
Re: .257 Weatherby

I just sent a reply to your email, Keith.

All I can contribute to this is that I have a 25'06 Ackley and use 100 Grain Noslers with 57 gr. of R22. (barrel length is 28½) Comparing my velocity (3650fps) with most published data on the 257W, my load will run right with it, but not with the heavier bullets. And, this is with 10/12 grains less powder than the Weatherby; which certainly has more potential, set up correctly.

Good hunting. LB
 
Re: .257 Weatherby

Thanks for the info on the 25/06, man that load is smok'en!

It ought to turn a yote inside out at 300 yards!

nice talking to you!
 
Re: .257 Weatherby

Yeah, I have dumped a few Nevada coyotes with this gun. I always have it handy for the long ones; this rig makes it almost routine. Doug did a heck of a job. Now, it's a bit of a shame, all he works with is his Paints. (horses) He doesn't hunt, at all.

Good hunting. LB
 
Re: .257 Weatherby

What's your twist rate? My .257 Wby. custom has a 1 in 10 twist but I can't get it to shoot 100 Nosler ballistic tips and I'm thinking I need a 1 in 9 twist. What do you think?
 
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