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257 Blackjack

My latest project, the 257 Blackjack. A SAUM based cartridge shortened to run in a SA DBM, pushing the 131 gr Ace at 3200 fps with a BC of .340-.345. supersonic past 2000 yards and only 5.3 MRAD to 1k.

Built on a 700SA, Iota Carbon chassis, Proof 24" 7.5tw, US Optics TS 20, PVA Jetblast brake, A TT Diamond, and Hawkins bottom metal.



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I love what you're doing leading the way getting the .257 Cal back in the mix of competitive (hunting as well) cartridges that are completely capable.
 
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Looking at "Project Quarter Horse" led me to the conclusion that .257 is the optimal bore size for the Creedmoor case based on the combination of projo mass, velocity and aerodynamics. Obviously, not an opinion shared by many. Seeing folks jump down to shoot 130 grain 6.5 CM loadings cemented that thought. That said, with little factory support, I'll hang onto the 6.5 CM for now.

It's interesting to see the .257 getting stretched waaaay out there. Every time I look at 6mm loadings, the BCs just fail to impress...I know they're popular comp loads because of the mild recoil and high velocity. I feel like this might be to ELR what the 6 CM is to PRS. Thankfully, as a "poory," I can at least get a .25-06 and bask in some small amount of the quater bore glow if I so choose one day. ;-).
 
Ouch, Its not meant for a poor man I guess. Completely stupid question but how much is brass running for it? What kind of life does it get?

The wsm? It was made from 300wsm because they didn't have the 25 at the time.
 
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I was wondering what the parent case may be. What steps are involved in forming brass from GAP 4s to blackjack?
 
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I was wondering what the parent case may be. What steps are involved in forming brass from GAP 4s to blackjack?
Several courses of cut,trim, anneal, turn.

Any hope of factory brass?
I believe that Blackjack is working on getting one or more reputable manufacturers on it, but until I see it I wont speculate.
 
@coldboremiracle I really enjoyed your article on the 25 Creedmore.
It cost me though. I now have a PVA shouldered Tika prefit 25 Creed, KRG Xray, & a 419 Hellfire sitting on my bench. Just need to order the tools to pull the stock T3 barrel.

So what is the difference between the Blackjack and the SST?
Blackjack COAL with 131 Ace = 2.855............. Shoulder angle? Is it 35?
SST COAL with 131 Ace = 2.860..........Shoulder angle is 30

I chose to go with the SST mainly due to the support and brass availability from Sherman. Load and shoot brass is the ticket for me.
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This thread reminded me. SST brass is on sale 24% off. Just ordered another 100 25 SST for $145 shipped.
200 should be enough to due in the first barrel.
I was going to rent the SST reamer, but LRI bought one;) Mine was the first cut with it. ARC Nuke 1.1 SA + 25" Bartlain M24 7.5T is done and test fired by LRI, but the heart wants what it wants & I requested a new fluting design. Patiently waiting on LRI to get programing done and tested on some practice barrels.
 
I don't get on the forums as much as I should but I've been poking my head around here and there after having a badass time at the NF ELR 2020 match in Wyoming a few days ago.

I just wanted to let interested parties know, 257 Blackjack production brass will be available December 2020 or January 2021.

Of course reamers and a few types of dies will be available at that point.

Projects like this have a tendency to lag a few months and with the election year it is prudent to say that Q1 2021 is most likely a safe bet for those naturally inclined to some dose of skepticism. I definitely fit into that group. : )

For those considering barrel life of the 257 BJ, it was designed to supersede SA performance but not be so hot as the 25 PRC/SAUM/WBY or even the 25-06 in terms of Overbore Index. A simple design goal of 3200 fps was set with the understanding some headroom would be nice. The 131 ACE likes to run 3140 and 3170 fps but upcoming releases to the high performance 257 realm like the upcoming release from Berger may indeed enjoy the headroom. Quickload calculates max pressure around 3260 fps and real world testing correlates this.

At 60 gr H2O capacity the 257 BJ shares the same exact OI as the 257 Roberts Ackley Improved which somehow happened fortuitously. You can see below that the 257 BJ will fall into the zone of cartridges that are a bit spicy but not completely overbore, akin to 284 Win. It lies nearly perfectly on the dividing line between the Yellow and Orange qualitative indicators of the original author.

For those who prefer simplicity, 257 BJ will equal or better 25-06 performance in a SA with 10% less powder or simply, a 257 Roberts AI in a SA.

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We believe the design goal of 131 gr (0.340 G7) at 3200 fps suits the mountain hunter and the long range competitor very well offering high performance, ample energy at 1000 yards without unnecessary recoil, and I believe the market is as accepting of balanced cartridges as it has ever been. The magnum craze of the 2000's has passed and people want to enjoy shooting their rifles.

The recoil to performance ratio of 257 BJ is perfect for me at 170 lbs with a Carbon/Carbon rifle setup.

Anyhow, I'll be counting the days to the end of 2020. Selected 257 BJ testers will be receiving the brass soon enough and further reports should be trickling out in the coming months.

If you know of someone with rigorous data keeping and/or a philosophy of use prime for 257 BJ testing please let me know so we can review.

CBM will be getting the earliest of the production brass to test of course!
 
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Super cool for sure @257 Blackjack. CBM turned me on to the quarter bore creedmoor (25 creedmoor) sometime ago in my desert tech. I love the cartridge. I’ve been reading his findings with the 257 blackjack and I’m very intrigued. Nice to see the .257 class of bullets getting some much needed attention. I look forward to future updates.
 
257 Blackjack, Will there be a Gunsmith recommended to chamber barrels, that will have the reamers for the Blackjack cartridge ?
 
That’s awesome! I can’t wait to see more results from the 2020 hunting season with these bullets. After seeing coldboremiracle 25 creed I built one myself and absolutely love the caliber!! Would like to maybe do a little testing myself!

maybe next will be the 257 blackjack of brass becomes available
 
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If you're interested in seeing what the Blackjack can do, here is our latest adventure. You can see a doe pronghorn get "Jackt"


 
What velocities are you getting with the 131’s in the 25 -06 ?

A respectable 2940 grouping a little over .3 MOA carefully at 100 yards. I'm actually thinking on coming down about 100 fps. Shoots great but primer pockets start getting loose after 5 reloads. Not enough to retire the brass yet but enough to tell me to back off a little. This rifle started as the Model 700 Long Range model in 25-06. All I did was put the basic Timney trigger set at 3# and put a Remage barrel on it for this bullet. This is by far the best bullet in the wind I have ever experienced. It is the shit on the Plains and mountains.
 
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Thats almost the same as my Creedmoor.

How far off the lands? I'm running .006. Today I was getting 2888 MV getting .4 MOA at 550 yards in fucked up mirage. No heavy bolt lift. I may just back off to .01 off the lands. By off the lands I mean measuring from jammed into the lands. I really don't know where the lands start.
 
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Sure there will, but until we get a good source of brass its not gonna take off.

This is one of the reason I stuck with 25-06. It has to work in the '06 and Roberts because that is what is mostly out there right now. The BC negates getting over 3000 fps as mandatory. It is a heavier bullet and really shouldn't be pushing it beyond the manuals out there that have 120 as the heaviest bullet with these older cartridges. That doesn't mean people shouldn't take advantage of the 131 if that is all they have. Of course there is the Wetherby Magnum. :). Looks like the majority want magnum performance without the magnum though.
 
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A respectable 2940 grouping a little over .3 MOA carefully at 100 yards. I'm actually thinking on coming down about 100 fps. Shoots great but primer pockets start getting loose after 5 reloads. Not enough to retire the brass yet but enough to tell me to back off a little. This rifle started as the Model 700 Long Range model in 25-06. All I did was put the basic Timney trigger set at 3# and put a Remage barrel on it for this bullet. This is by far the best bullet in the wind I have ever experienced. It is the shit on the Plains and mountains.
What load? I'd consider going to a slower powder. Reduce overall pressure. You've got a long barrel on yours, IIRC?
 
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What load? I'd consider going to a slower powder. Reduce overall pressure. You've got a long barrel on yours, IIRC?

26" barrel. 53 grains H4831. CCI match primers. I got the barrel early when they were recommending 1:7.
 
26" barrel. 53 grains H4831. CCI match primers. I got the barrel early when they were recommending 1:7.
I agree with Sandwarrior. Try a different powder, Im getting the same velocity with 4 inches less barrel and 10 grains less powder. My Blackjack is a 24" and using a grain more powder than your 25-06 it is giving me over 3200 fps. I'll bet you could get it significantly faster with a different powder, that is of course if you want to.
 
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26" barrel. 53 grains H4831. CCI match primers. I got the barrel early when they were recommending 1:7.
I love 4831. But, in your case a move to RE-22/23 would help I think. Double base vs. single base. -23 is as, if not more, temp stable than H4831.

The big caveat sometimes is whatever you can find for powder. And, ya just gotta do with what you can get.
 
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I agree with Sandwarrior. Try a different powder, Im getting the same velocity with 4 inches less barrel and 10 grains less powder. My Blackjack is a 24" and using a grain more powder than your 25-06 it is giving me over 3200 fps. I'll bet you could get it significantly faster with a different powder, that is of course if you want to.

I agree with you and @sandwarrior

Maybe VV N560?
 
The H4831 is pretty forgiving in as much as I have more than a few flat spots to choose from but will never get any efficient speed based on volume of powder. But regardless of burn rate charts out there here are the QL burn rates for powders I'm considering. The %s are based on the H4831 burn rate.

H4831 .4301
RE22 .3860 -10%
RE23 .4090 -5%
N560 .3710 -14%
N165 .4236 -2%
N170 .3250 -24%
 
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MV per QL based on 53 grains 25-06

H4831 3011 Near Maximum
RE22 3024 Near Maximum
RE23 3003 Near Maximum
N560 3027 Near Maximum
N165 2923 Near Maximum
N170 2670

The highest I measured H4831 @53 grains was 2966 within 3% of QL prediction. I'm beginning to think it won't make much difference if I change to slower powders just under the range of H4831. I'm going to go out on a limb here and say since Hogdon has the 120 maxed at 2856 with 51.5 H4831 that if they did publish a 131 grain bullet it will be in the high 2700 fps range for the 25-06 at around 49 grains. I'm getting good accuracy with the 131 ACE in 25-06 but it is as predicted based on the published reloading data if you estrapulate to a heavier bullets. So, the 25-06 is limited but in a predictable way that doesn't take away from the cartridge itself. I'm okay with that because the accuracy is good and I mainly shoot under 600 yards. If I want to make it difficult I just shoot a smaller target.
 
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Checked the bore after 500 rounds and had a fair amount of copper fouling from one end to the other and the beginning of a carbon ring. Got that cleaned out fairly easy. It's a wonder it was shooting as good as it was. I checked the measurement jammed into the lands and it has grown to .013. So, basically my bullet jump had doubled. It is pretty forgiving on bullet jump to. This is an Xcaliber prefit. So, turns out it is a good time to back off with a slower load. I'm waiting on a Redding competition seating die with a VLD stem. Believe it or not I have been seating with a regular Lee seating die, lol. It's also pretty forgiving on concentric seating.
 
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I am getting 3160 with Retumbo in a custom 25-06 reamer to allow me to seat them appropriately. Shot a 4 inch group at 900 yards with mine. I also have a 25 SST. I shot a cow elk at 665 yards this year. DRT, didn’t take a step. I have been very impressed with accuracy and bullet performance in the 131 BJ’s.

I really would like to do a 25 Sherman. Would love to see ADG do headstamped brass in 25 Sherman (or 6.5).
 
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I have also been very impressed with 25 Creedmoor. It has the velocity of the 6cm, but shoots flatter and kills better than the 6.5 imho.
 
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