131 Blackjack bullet experiences

djfergus

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Dec 25, 2015
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Weatherby usually have long freebore throats already. I am sure they would work fine.
I'm thinking the saami freebore on a 257 wby is around .380". I may be completely wrong. I was looking aro for 257 wby reamers a while back & all that was on the shelves were saami or zero freebore versions. I guess a fellow could go with a zero freebore and throat it with a throat reamer or try their luck at jumping it in a saami chamber but I haven't had much luck jumping bullets much more than .120" or so.
 

Hoss50

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Arizona
I have just started working up loads for my 257 weatherby with the 131gr blackjack. It is a standard chamber reamer. With the bullet seated as long as I felt comfortable with I am .02 off the lands. I am using H1000 powder right now. During the first round of load development it got this group.
 

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djfergus

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Dec 25, 2015
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I have just started working up loads for my 257 weatherby with the 131gr blackjack. It is a standard chamber reamer. With the bullet seated as long as I felt comfortable with I am .02 off the lands. I am using H1000 powder right now. During the first round of load development it got this group.
What twist barrel?
 

Left Hand Dave

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Who's run these in a 257 Roy? What's the availability of a 257 wby reamer throated for these?
Because the SAAMI reamer has longer freebore than the Blackjack reamer it can be reground for shorter freebore.
I called Manson up to order a Blackjack 257 Weatherby reamer, I think I talked to Dave, very nice fella. He pulled a SAAMI reamer off the shelf and they reground it to the Blackjack spec. There is a little upcharge but it comes out about the same as the price through Blackjack.
Just an option
Dave
 

elkaholic

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Because the SAAMI reamer has longer freebore than the Blackjack reamer it can be reground for shorter freebore.
I called Manson up to order a Blackjack 257 Weatherby reamer, I think I talked to Dave, very nice fella. He pulled a SAAMI reamer off the shelf and they reground it to the Blackjack spec. There is a little upcharge but it comes out about the same as the price through Blackjack.
Just an option
Dave
Dave is good to work with!
 

Dollarhyde

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Dec 4, 2009
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BFE, OK
Our Blackjack Spec 257 WBY reamer may not allow for as high of velocities as the SAAMI but it was designed with our bullet in mind and with consideration for magazine length.

I have ran the 257 WBY in 1:7.5 to speeds I cannot publish online and the bullets arrived at 1336 yds with no issues. I have also ran the 131s out of 1:7.5 twist at 3570 fps to 1946 yds with no issue.

These were premium Blake Barrel and Rifle Barrels so I cannot say ALL barrels and all chamberjobs will allow such high MV and RPM.

3570 x 720 / 7.5 = 342720 RPM. We recommend < 330k RPM as a general rule but the 131 ACEs have survived much more punishment and in some button blanks have survived over 350k RPM. I hesitate to say all of this since someone will have issues no doubt - that's just a fact.

Twist for 100% BC throughout your expected conditions and realize the extra MV of say the difference from 3405-3470 to 3570-3600+ isn't really worth the risk in terms of the 100-150 fps reward.

257 WBY and the upcoming 257 Blackbird are true low recoil lasers.

I managed 16th place with my 257 WBY at NF ELR and I rarely get to shoot to have feel for the wind.

For those that have not seen the data or trends the 131 ACE likes right off the lands, 0,018" off the lands, and 0.035" off the lands as the 3 primary starting points.

Personally I recommend doing a 60-80 round break-in, doing a Powder-MV window also known as the Satterlee Method, and then taking these long-seated bullets to the range and using a hand-press to try "off the lands", 0.018", and 0.035".

If you get good ES and pretty good accuracy (day 3 bullets touching or stacked out of 5) tune with your clamp-on muzzle brake or tuner.

I have 5-6 rifles currently and have other test rifles moved through that have had zero issues getting a truly competitive load in 2 range trips with that method.
 

lancetkenyon

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Jun 3, 2013
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Arizona
The .257 131 Blackjack is OK for accuracy.

Last weekend, getting my final zero before pronghorn season.

200 yards, 9 shots total.
1st was right (pointing it out). Moved .1MIL left. Shot two more. Waited 30 minutes, shot 3 more. Waited another 30 minutes and shot 3 more. Dropped one of the 8 out of the group, making it about .5" group (.24MOA), but I will take it. 25SST @ 3225fps suppressed.
20200725_092700.jpg
 
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