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duckhunter175

High BC, Fast Twist .257...

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Anyone running 131gr Blackjacks or the 121/128gr Hammers in any Quarter Bore???

Curious about reduced bearing surface and increased velocity. I've settled on .257wby as a 'do all' Texas rifle but if I can run a higher BC bullet at 3300+ and with 20-30% more mass I'm all for it.

I did see that the .257wby reamer for the Blackjack has significant reduced freebore to reduce jump-- is that a bullet alignment issue b/c of reduced bearing or is it a jacket strength issue??

I'm taking a hard look at a 7.5 twist which Blackjack seems to say is ok for the 131, but Hammer says a 7t is needed for their 128gr (0.10" longer than the Blackjack).

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I wonder why they recommend such a high twist rate for their bullets.    That is a bit faster than most bullets in the same weight/BC category.   It would be hard for me to put another barrel on my gun just to try those bullets.    Seems a bit crazy to me.  

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I am running a 25SST 26" 1:7.5" Proof Sendero.  So far, the 131 Blackjacks are screaming at 3268fps with only about 50 rounds down the barrel, and zero pressure signs.  Had them up to 3312 so far with H1000 final fire forming the brass.  I got a compressed load of H1000 @ 3312, so might try RL23 to free up some case space.  They shoot pretty good too....

200 yards, 3 shots, 3268 fps, 8ES, 3.4SD.

POA was green dot.  Still working on loads, so not necessarily worried about zero yet. (Photo is actually sideways, shots were above green dot, but that doesn't matter in the photo)

20191006_113736.thumb.jpg.ff190602522349b2d7216fc73d92f38c.jpg

Some other 200 yard 3 shot groups during fire forming/load testing so far as I started to dial.in for 200 yard zero.

20190928_123808.thumb.jpg.4e1c23d208170c558fefb7f52cf935ad.jpg

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Looks promising!!! Assuming this is going to be a hunting gun Lance?

 

I'm still puzzled by their reamer and the reduced Weatherby Freebore-- haven't been able to get them to answer the phone at Blackjack. I'm concerned if I go with a 1-7T for the 128gr Hammers that I will overspin the 131 ACE. Just not sure if that reamer was designed for better accuracy or to reduce jacket separation at Wby velocities.

 

My thought is a 7.5T Proof might be the way to go so I can use the 131 or go to 121HH. Now gotta sorta out the reamer.

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I think I would stick with the 7.5 twist. I'm assuming the recommendation for 7 twist from hammer bullets is so they could be shot at lower velocities from smaller cartridges. 

As far as the weatherby freebore my guess would be that they shortened it up so handloaders can get the bullets closer to the lands for accuracy purposes. 

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For the 131 Blackjack, I think a 1:7" would be a bit too fast at 3300+fps.  Blackjack actually recommends a 1:8" twist for 3300+.  But, I would go 1:7.5" myself, allowing a bit more flexibility and stability if you want to run them a bit slower with a good lower end node.  The 1:7" is recommended for cases like the 25CM, .250AI, 25x47L, .257 Roberts, etc.  

Yes, mine is going to be a hunting rifle for deer/antelope sized game.  If I can get the 121 Hammer shooting well in the next couple weeks, it will be a backup for Kaibab. 

I know a guy with a 1:7.5" shooting the 128 Hammers with great accuracy so far.  Just depends on where all you plan to shoot it to see if the 121 or 128 would be a better fit.  Only high elevations, the 128 might do just fine.  Dropping down low, the 121 might stabilize just a bit better.  But even if the 128 loses a bit of BC, still might beat out the 121 at higher velocities at distance.  

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How is the performance on game with these bullets?   Not just great but how was the expansion?   Did the bullets get recovered?   Exit hole sizes?  Weight retention?   ECT?  

 

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On 10/21/2019 at 10:13 PM, lancetkenyon said:

For the 131 Blackjack, I think a 1:7" would be a bit too fast at 3300+fps.  Blackjack actually recommends a 1:8" twist for 3300+.  But, I would go 1:7.5" myself, allowing a bit more flexibility and stability if you want to run them a bit slower with a good lower end node.  The 1:7" is recommended for cases like the 25CM, .250AI, 25x47L, .257 Roberts, etc.  

Yes, mine is going to be a hunting rifle for deer/antelope sized game.  If I can get the 121 Hammer shooting well in the next couple weeks, it will be a backup for Kaibab. 

I know a guy with a 1:7.5" shooting the 128 Hammers with great accuracy so far.  Just depends on where all you plan to shoot it to see if the 121 or 128 would be a better fit.  Only high elevations, the 128 might do just fine.  Dropping down low, the 121 might stabilize just a bit better.  But even if the 128 loses a bit of BC, still might beat out the 121 at higher velocities at distance.  

Only at 650' here in Texas but I plan to use this gun in the same manner as your 25SST. Our DA is often 3000+ because of the heat so I feel I can probably get a 128 stable enough... then when I'm in WY, CO, AZ above 5000' I think they will be golden.  Did you have to throat ream your 25SST for the 128 HH? It looks to be 0.10" longer than the Blackjack!

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On 10/22/2019 at 11:18 AM, recurveman said:

How is the performance on game with these bullets?   Not just great but how was the expansion?   Did the bullets get recovered?   Exit hole sizes?  Weight retention?   ECT?  

 

I've seen a few threads posted with animals taken by blackjacks on LRH and on their facebook.

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I've been shooting the 25 Creedmoor that southernexpress built for me for a few months now. I'm loving the 131 ACE. Seen it do a perfect job on an Antelope and hopefully we will see what it does this weekend on a Colorado mule deer. 

 

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1 hour ago, WHT_MTNMAN said:

I've been shooting the 25 Creedmoor that southernexpress built for me for a few months now. I'm loving the 131 ACE. Seen it do a perfect job on an Antelope and hopefully we will see what it does this weekend on a Colorado mule deer. 

 

What barrel / twist are you running and what velocity are you seeing?? The guys at blackjack said to expect 3350-3450 from a Wby--- which is incredible considering that is where I'm at with a 115 Berger right now.

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My 121 Hammers came in last night.  Should be testing them on Sunday.

I know other Hammers I have tried have been crazy accurate.  These are the 131 Hammers in my 6.5SS from this week.  No pressure yet, but I am not chasing speeds with accuracy like this.20191023_123122.thumb.jpg.3d230f2c243adc14dda3d34deff5fd2f.jpg

20191023_123137.thumb.jpg.1cfeedb123423a40947ff5271d7e9fe7.jpg

20191023_123119.thumb.jpg.5e7928d0940bc4495777373715224716.jpg

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1 hour ago, duckhunter175 said:

What barrel / twist are you running and what velocity are you seeing?? The guys at blackjack said to expect 3350-3450 from a Wby--- which is incredible considering that is where I'm at with a 115 Berger right now.

x caliber 1:7  very little to no pressure at 2900fps 

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