257 Weatherby with 131gr Blackjacks?

The website says 1:7.5 - 1:8 for magnums so I am hoping that I will be fine.

If not I will drop back to 121gr Hammers or my old friend the 115gr Berger.
 
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I have a 1:7 twist McGowan and I used load data for the Sierra 117 spbt as a starting point. Everything seemed to line up pretty well, and the velocities were very close to the same. I eventually settled on using 7977
 
You can contact Blackjack for the particulars, but he put up some photos today, of finalizing loads for a shoot. Impressive! A good 500 FPS faster than I can get my 25CM!
1589695754802.png
 
I have emailed them multiple time while working on my 25-06AI and always gotten a response. I have a finnicky barrel and for some reason it did not like H1000 of Retumbo. Finally found some luck with H4350. Its not the speeds I want its accurate and pretty close. I used the data from the Sierra 120. If I remember correctly BlackJack said the bearing surface was almost the same and I could try the powders recommended for that bullet. Thats how I ended up with H4350

I don't facebook. I did email blackjack awhile back asking for starting data, but they never replied. I assume for liability reasons.
 
I have emailed them multiple time while working on my 25-06AI and always gotten a response. I have a finnicky barrel and for some reason it did not like H1000 of Retumbo. Finally found some luck with H4350. Its not the speeds I want its accurate and pretty close. I used the data from the Sierra 120. If I remember correctly BlackJack said the bearing surface was almost the same and I could try the powders recommended for that bullet. Thats how I ended up with H4350

I emailed them again last night. I will see if I get anything back this time.
 
In my 257 Vanguard I get the best combination of accuracy and velocity with RL-22. I've used many different slow burners like RL-26, RL-33, MRP, Retumbo, etc but always came back to RL-22. I've gotten my highest velocity with RL-33 (3389 ft/sec- 24" barrel)) with 117-120 gr bullets but just couldn't get the accuracy I was looking for. The load was also fairly compressed which I'm not crazy about. JME
 
I emailed them again last night. I will see if I get anything back this time.
You might want to call. I had problems making contact via email. Phone seemed to work better. They both have full time jobs and a phone let's you know someone is looking for you.
 
Has anyone loaded this combo yet, and what worked for you? I am going to try some soon hopefully and I want to start tracking down the right powder for the load.

My 1:8" twist barrel arrived earlier this week. Once it is fitted it will be time to burn some powder.
I've been thinking abt buying the 257 but have a 25-06 already. Wanted to ask if you have an opinion on the difference between them? And would it be worth buying. Going to use it on hogs at night mostly.
 
I've been thinking abt buying the 257 but have a 25-06 already. Wanted to ask if you have an opinion on the difference between them? And would it be worth buying. Going to use it on hogs at night mostly.

I wouldn't say it is worth the extra velocity to go weatherby if you al ready have that. A 25-06 or 25-06AI will move bullets along plenty well. The weatherby will burn barrels faster and burn more powder. If this rifle wasn't setup on a magnum bolt face I would probably have built a 25-06AI or 6.5-06.

Don't get me wrong, I love my 257 weatherby, but your rifle will get it done. You are having the same debate I had when I chose this. I almost built this rifle in 264 Win Mag instead of 257 Roy, but I already have a 6.5x55. They both shoot 264 caliber bullets, and my 6.5x55 will do just about anything I need. Making a 264 Win Mag would have been cool, but would not have served me as well IMO.
 
One last bump. Has anyone loaded this yet? Blackjack gave me a few starting loads, but none with H1000. They really like Rl26, but good luck getting ahold of some. I have 1/2 lb., but dont want to develop a load, then have no more powder left.
 
One last bump. Has anyone loaded this yet? Blackjack gave me a few starting loads, but none with H1000. They really like Rl26, but good luck getting ahold of some. I have 1/2 lb., but dont want to develop a load, then have no more powder left.
You're going to be best off with Retumbo, IMR8133, RL33, N570, H50BMG. That's an 86gr capacity case and a small bore size, slower will be your friend unless you want a poor case fill %. I just ordered an 8 twist barrel myself. Either going to do a 257 wby or Miles' new 25-7 blaser, it has 84gr capacity 30° shoulder 0.320" neck and will be around 3.34" coal.
 
You're going to be best off with Retumbo, IMR8133, RL33, N570, H50BMG. That's an 86gr capacity case and a small bore size, slower will be your friend unless you want a poor case fill %. I just ordered an 8 twist barrel myself. Either going to do a 257 wby or Miles' new 25-7 blaser, it has 84gr capacity 30° shoulder 0.320" neck and will be around 3.34" coal.

I'd like to know more about that 25-7 Blaser. Googled and found nothing. Can you point me in the right direction?
 
I'd like to know more about that 25-7 Blaser. Googled and found nothing. Can you point me in the right direction?
Facebook unfortunately, I'll dig up some info for you. That's an image of the parent case, essentially a 7 saum stretched about 0.330" the long neck only requires 0.126" to keep bearing surface above neck/shoulder junction at all times.
 

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