.257 Weatherby Mag Build

[Left Hand Dave]

Ok so I have been looking at the .257s with the Black Jack Ace bullets. Wanted something fast in .257 so I looked at the 25 SAUM and the .257 Weatherby. I think the .257 Weatherby is a better choice for me because it seems to be the fastest and I never get the velocities that everyone else get so that should at least put me at fast if not fastest. This is a hunting rifle build. My questions are as follows.
1. is a Remington 700 magnum action a good choice for a .257 Weatherby build?
2. Does anything need to be changed on that action to get the Weatherby rounds to feed properly?
3. Is there any reason I should not choose the .257 Weatherby?

Thanks
Dave

 

[Canhunter35]

A 257wby will work great in a 700 action.
As long as it has a magnum bolt face and say feed rails from a 7mm rem mag it'll feed perfect.
One thing I would consider if ur wanting velocity from a small bore magnum is barrel length. I would go 28" or 30" of barrel and that sucker will be fast

 

[cape cove]

The longer barrel length would be great and a faster twist, say 8 or 8.5 would be good to be able to use the Hammer bullets or others longer ones that may come along. Depending what you hunt, the 257 WM is a great round and choice JMO

 

[sable tireur]

I've been running the Weatherby in a 26" barrel for hunting and don't find any reason whatsoever for longer barrels. My reamer is made to my specifications for seating this bullet out simply because of the extraordinary length of the bullet. Seated over Retumbo, I'm running around the 3250 mark which is sufficient for 1,000 yards if you want or need that distance. You can get some more velocity by switching to VVN-570. I chambered a 1:7.5" twist barrel just in case although you can get away with the 1:8" at the higher velocities but you give up a little in the BC department.

Enjoy!

 

[Left Hand Dave]

I've been running the Weatherby in a 26" barrel for hunting and don't find any reason whatsoever for longer barrels. My reamer is made to my specifications for seating this bullet out simply because of the extraordinary length of the bullet. Seated over Retumbo, I'm running around the 3250 mark which is sufficient for 1,000 yards if you want or need that distance. You can get some more velocity by switching to VVN-570. I chambered a 1:7.5" twist barrel just in case although you can get away with the 1:8" at the higher velocities but you give up a little in the BC department.

Enjoy!

What freebore did you use on your reamer? I would like to compare to Black Jacks reamer if I could.

 

[sable tireur]

The freebore (0.289 - 0.292") used by Blackjack on the reamers they designed to sell on their website are just fine for each of the cases. There is still room to adjust the seating for each cartridge based on your powder choices. Mine is a different design not just a length change so no I'm not going to discuss it yet.

 

[Ronald W Schaefer]

You're gonna love that .257 Wby. My wife has a factory Mark V I got her 43 years ago with a 24" #2 contour barrel in 1:10 twist. It still shoots great and has put many a critter in the freezer. We get about 3300ish FPs in that pipe using 69 grs, IMR 7828, WBY brass and Fed 215 primer and 117 SGK, 115 Barnes TTSX or 120 Nosler partition or 120 A-frame...so IDK about all that 28-30" barrel business. One thing about it though, you gotta shoot slow on the bench--after three rounds you cant touch the barrel.

 

[cjhunts_alot]

No reason not to get a 257wby for the 131 blackjack.

Mines a 1:7 twist 26" McGowan Howage i put together myself. It's got a saami chamber and I'm loading them at 3.48". That puts the base of the bullet at the neck/shoulder junction, and there's still plenty of bullet in the neck of the cartridge. I have no idea how far I'm off the lands, but it's shooting just fine.

I used 117 Sierra Gameking load data to start with and it seems to work just fine.

Yes, I use old priority boxes for targets... They're free and I have a billion of them.

 

[Aoudad shooter1975]

For a hunting rifle I would not exceed a 26 in barrel...

1. A 700 will work great...start with a magnum...300 win mag,338 mag, 7 mag...will be great
2. No
3. One of the best rounds ever...even better with a heavy bullet and fast twist....

 

[25WSM]

Everybody told you the truth right here. I'm a master gunsmith of 30 yrs and until the last couple yrs the 257wby mag in a 700 long action had been my go to gun. I've had over 1 dozen of them that customers talk right out of my hands. I shoot a 26 and 24 inch for my hunting rifles. Expect well under half moa. Most of mine did 3 shot
. 25 moa groups. I use custom spec on my reamers and will give you the specs in a second if I was not currently in the hospital. I have the Sammi reamer and a tighter neck shorter throat reamer. The custom does shoot better by the skin of it's teeth the Sammi still hammers under half moa. If you reload go custom spec. My custom spec has never had too much pressure with factory loads. I shoot bib 110 in mine. These are 520 bc and even shoot lights out from a 12 twist I built. I'm looking at selling one now to build a fast twist barrel for the 131bj. I'm looking to put a 25 on my 1000 yard rifle this yr too.
I don't think you can go wrong on this build.
Shep

 

[Canhunter35]

I'm surprised how many guys recommend 26" or shorter. I just had a 28" 7mm plus muzzle brake built and I really like it. It Handles fine and with a proper sling it carries just as well, but maybe I hunt differently I don't know

 

[sable tireur]

I'm surprised how many guys recommend 26" or shorter.

Variety is the spice of life. That's why I'm so grateful to have custom barrel makers available to make what I want in the conformation I want. Short or long, it makes no difference, I just call and order.

 

[25WSM]

I've had a few 24 inch barrels keep up with the 26s. I look mainly for the balance of the rifle, looks and obstruction come second. A 24 inch in a classic looking stock handles well and a 28 in an a3 look fantastic. With these fast twist barrels I don't know how much speed is there per the different lengths. I pretty much look for 3650 with a 100gn and 3450 with a 110. It's funny how someone said they would go longer to help get speeds
everybody else gets. I'm in his boat for sure. I must get all the slowest barrels made because people here get 100 to 150 more than me with same loads all the time. But good news is a slow 257 wby mag is still fast as crap. My current crop of 3 have a 26 in Lawton barrel and a 24 inch Jarrett. And I built an encore from a prohunter 2506 and cut it to 24. That's my little blind gun. The Lawton shoots quarter moa easy.
I kind of backshelved the 257s in favor of a 6.5/257wby and a 6.5saum took place of my 25wsm.
Hopefully this 131 will remedy this.
Shep

 

[Quintus]

I am still kind of old school and love the .257Wby, but I still look at it as a sprinter not a miler. I don't worry about BC but just let raw velocity beat the wind to 450 yards or less. With a 100 grain TSX at 3690 or a 110 Accubond at 3540 it is an absolute "lazer". I have had several of them in custom and factory configurations on the Mark V, 700, and USRAC 70CRF actions and my favorites have all been on the Mark V, but they were all very accurate except the first which was a Mark V sporter. Currently I am shooting a Factory Ultra Lightweight with a 26" and it is just over 1/2MOA to 300 and very easy to shoot.