remington 700 | Coldboremiracle

You may have read my piece on the 25 Creedmoor from a while back, if you haven’t then make sure you go read it after this. In that article about the 25 Creedmoor, I detailed how my nascency in precision rifle shooting began with a twenty-five caliber rifle, and that I had returned again to the quarter-bore. There’s more to that story, however.
One of the main reasons I quit shooting that old twenty-five 0’six, was because there was never a good bullet selection for it. The biggest bullets available were one hundred twenty grain, and they were hardly long-range bullets, with ballistic coefficients not much better than anything else designed in the sixties. That was all about to change, and change for the better. I couldn’t have known how far down the quarter-bore hole I was going to fall when I first made contact with Blackjack Bullets.

The 257 Blackjack next to its larger parent, the 6.5 SAUM

That first conversation I had was with Miles Johnson, the brains behind Blackjack Bullets. Like me he had often hungered for a better bullet for twenty-five caliber cartridges, but he had the intellect and drive to do something about it. Miles is a smooth-talking guy, with very unequivocal purpose in conversation. The kind of guy you could sit around a fire with a bottle of whiskey and watch the stars, and before you know it he might be talking so deep about drag and aerodynamics that you have to start reading the bottle to find words you understand.
Our initial contact began my twenty-five Creedmoor project, Miles’ company Blackjack Bullets was producing the 131 Grain Ace bullet, and I intended to make it the crown jewel of the project. Which has been an extremely superior performer for me lo these short two years, it leaves its six-point-five cousin in the dust. But Blackjack had been working all along on something even more threatening and treacherous, it was their own cartridge that was purpose-designed to make the 131 Ace sing a tune that nobody could touch. That project was the Two-fifty-seven Blackjack, a short action magnum cartridge based on the SAUM case. It would fit in short action rifles, feed from AI patterned magazines, and push the Ace beyond thirty-two-hundred feet per second. It falls somewhere between the old 25WSSM and the 25SAUM wildcat.

The 131 Ace has an advertised G7 BC of .330, my personal experience and testing led me to believe that number is a tad conservative and that the number is more like .340. With an immaculate profile like that, the Ace when launched at these speeds is as flat as most available cartridges you can get, and it cheats the wind from its deviant influence.
Since the twenty-five Creedmoor had been such an outstanding success, I decided that I must indeed have the two-fifty-seven Blackjack as well, I figured it would be an amazing Rocky Mountain hunting rifle. So as soon as Miles had a reamer, we got started on the project.

The Pit Boss. Sporting a 24 inch Proof Research carbon wrapped barrel, and a YHM suppressor adorns the muzzle.

With weight in mind, I decided I would spend the extra cheddar and get a Proof Research carbon fiber barrel with a 7.5 twist. My 25 Creedmoor is a 7 twist, but with the much faster Blackjack I needed a slightly less agressive twist. It was matched to a lightweight carbon fiber stock from Iota Outdoors. Both would be connected with a simple Remington 700 short action. I swapped the factory trigger for a superior one from Trigger Tech, this has been a pretty standard practice for me. On top I mounted my US Optics TS 20X, which I think is perfect comapnion for this lightweight but long range hunting rifle. That said, I have a USO Foundation 25X on the way that might go for a ride on the Blackjack as well.

Trigger and magwell detail, all a perfect fit.

Next, it was time to start load development. Which requires making brass from something else, the easiest seemed to be Hornady 6.5 4S cases, they were cut, sized, annealed, then cut again, sized again, turned, and annealed. The finished product is a beautiful fat and short little case, it looks like the X47 after an all you can eat 24 hr buffet.
Mine is only the third rifle chambered in the Two-Fifty-Seven Blackjack so load data was based entirely from what Blackjack bullets had tried in theirs. I tried several different powders, including H4350, H4831SC, but I ended up getting the best velocity with Alliant RL 26. With 56 grains of powder, I was getting just shy of 3300 feet per second. Fireforming these fat little cases gave some slight variation in velocity, but that didn’t surprise me. I did quite a bit of testing with loads back and forth, which is a tedious process with such a limited supply of brass in which I was so heavily invested. Magnum primers seemed to give the cartridge too much of a pressure spike, and excessive wear to the cases, so I backed down to just a Large Rifle primer, which significantly softened the blow. This change still gave me adequate velocity, but also saved my brass from being ruined prematurely, and eased in extraction from the chamber. The Ace likes to run right around 3200FPS from the Blackjack, and that’s just fine with me.

A typical group from the 257 Blackjack, including a true coldbore shot (left) and four followup shots.

With no shortage of space here in the Rockies, I decided to get the Blackjack out to some significant ranges. I wanted to see how well my projections panned out, and see how close the trajectory lined up with my ballistic computer Trasol. My first distance conquered was 1025, this after confirming a fairly rough zero in the dirt at 150 yards. From there I dialed the indicated 5.3 MRAD, and closed the bolt. One of my favorite things about shooting that far, is the nice delay you have to get a good clear sight picture to watch the impact. The first impact was a touch low, so I corrected the .2 and fired again, making perfect elevation on impact. I then shot it at 1250 yards where it was slightly ahead of the predicted dope, and I had to dial back down half a MIl to get on target. I then stretched it out to just a few hundred feet shy of a mile, and 12.8 MRAD was just the ticket for that range. For the naysayers, that is two MIL’s ahead of the 220 grain 300 RUM I was testing a few months back. And at 1600 yards, the Blackjack is 300FPS faster than the RUM, and only 60 pounds of energy less than the RUM. These are of course estimations made by my ballistic calculator, but they appear to be spot on based on the data I’ve shot to within a reasonable margin of error.

Shooting these 25 caliber heaters through this carbon wrapped barrel can heat it up quick. This rifle was purpose-built to be a hunting rifle, so barrel heat is of little concern. Rare is the occasion that I shoot more than a couple shots, so the weight savings are far more valuable to me in a hunting rifle.

The recoil on the Blackjack is not bad at all, but for a short action I would call it sharp. Obviously, there is going to be some kick from something this spicy, but its certainly not bad, I would compare it to a heavy 308 load, keeping in mind the eleven-pound rifle weight.

One of the many concerns I am hearing from people about this project is the old “barrel burner” comment.
Yep, its gonna get roasted. If it gets to 1200 rounds I’ll consider myself lucky, and then I’ll get another barrel cut and threaded and screw it on in too. That is if I haven’t found something even sharper than the Blackjack by then.
Another concern I have heard from many is about feeding. Short and fat cartridges tend to have feeding issues, especially with steep shoulders like the Blackjack. But to my gratification, I have yet to have a single malfunction. It smoothly feeds from an old beater AICS magazine, which will hold seven of these handsome dandies. Whether the first, or last round from the mag, these hop right into the chamber without any hangups. And single feeding is no problem either, if you just toss them in with a bit of forward motion, so they clear the blunt breach of the barrel, the bolt closes smoothly.

Bolt knob detail. The 257 Blackjack was initially to be called the 257 Pit Boss, I decided to honor the original name by memorializing it here.

A wildcat cartridge is an adventure wrapped in hundred dollar bills, but it is not without its fun and excitement. I am not even close to being done with the 257 Blackjack, hunting season is just around the corner, and I fully intend on putting the Blackjack’s talents to work. With both deer and elk to harvest this fall and winter, the downrange energy, and resistance to wind, this lightweight but potent little rifle is a perfect candidate for these rugged Rocky Mountains that have become my winter range. With any luck, brass will be commercially available within the next few months from at least one reputable manufacturer. Reamers and dies will also soon be available from Blackjack Bullets website, so it may not be too long before this little cartridge is made an honest one.

The Pit Boss has since received its scope upgrade, the US Optics F25X

In the meantime, I will continue to prepare and practice for the hunting season waiting for the next best thing. Miles may have some mad scientist things going on at the Blackjack Lab somewhere in the hills of Oklahoma. The best news of all perhaps is that big names like Berger and Hornady are following the lead, coming out with better bullets for the quarter bore fans like myself. So the future of the 257 Blackjack, as well as my 25 Creedmoor, and any fast twist 25 caliber cartridge will be bright and long-lived.

Donald Trump Junior stretching the 257 Blackjack out to 1230 yards

-CBM

Precision Rifles are just my cup of tea, and watching the technology around them progress over the years has been exciting. While they are still relevant, and in many cases beautiful, traditional and wooden rifle stocks are being overtaken by modern chassis systems.

A chassis system essentially serves the same purpose as a rifle stock, but the difference between them is quite stark. Stocks are generally made of wood or a synthetic material like glass filled nylon. Rifle chassis are almost uniformly manufactured from non-organic materials, such as aluminum, plastics, and more and more often from cutting edge composites like carbon fiber.

Rifle chassis bring modularity, customizable options, and other modern conveniences to the user’s rifle. As well as providing one of the most important foundations for precise shooting, a rigid and firm structure from which successive shots can be launched with meticulous control. Naturally, modular rifles like the AR-15 have been gleaned over, and some of their best features have been merged into precision rifle chassis.

And that brings us to the current subject, the Yankee Hill Machine MARC Sport Rifle Chassis is one of the latest to join my fold. Yankee Hill has long manufactured AR-15’s and their components, so it seemed a natural progression to build the similar parts of a precision rifle chassis.
YHM has a new division specifically geared towards the precision rifle market, suitably named Graham Brothers Rifleworks, I look forward to see what else they bring to the shooting bench.

The Remington Model 700 has long enjoyed a position as the one to use for custom rifle builds. As such, most rifle chassis are built to accept the 700’s footprint and its many clones, the MARC Sport is no different. Other footprints such as Savage Long and Short actions are also available as well. And I wouldn’t expect it to end there, surely others like Howa, Tikka, and other popular models will follow.

The MARC Sport comes as just the heart of the chassis, it uses an AR-15 style buffer tube in the back. The simple reasoning behind this is that you can easily attach any buttstock made for the AR-15 family of rifles. The modular design allows the end user to configure the chassis to their liking, an ownership feature that many gun enthusiasts are quick to take advantage of. The chassis also uses AR-15 patterned pistol grips, so you can pick and choose from the bountiful variety of grips to fit your hand and shooting needs.

The handguard of the MARC Sport is similar to an AR-15 freefloat handguard, obviously it attaches differently, but it shares familiar features. The handguard has MLOK slots on all eight facets, this allows the user to add accessories such as bipod mounts, cartridge quivers, support bags, or tripod interfaces, all great accesories for competition shooting.

The handguard attaches via four screws along the center of the chassis, steel thread inserts assure durable strength over time. It also features QD sling cups at the front and rear of the handguard tube. The chassis also has a series of threaded mounting holes along the bottom of the fore-grip area, to attach likely a tripod mount, or the available YHM Arca Swiss rail.

The chassis accepts AICS pattern magazines, I have tried several different manufacturers magazines and they all work perfectly. One suggestion I would give YHM would be perhaps a slightly longer mag release bar, or a wider one. Either option would give the user a better purchase when trying to strip a magazine from it. And if you twisted my arm for another complaint, it might be that the handguard is a little too intrusive in the objective area of the scope. This didn’t allow me to install the sunshade on my scope, not a huge deal, but one you may want to know about.
The MARC Sport chassis will accept both right or left handed actions, it comes with a small adapter plate that uses a screw to hold it in place. The plate is mounted over the unused bolt handle recess on either the right or left side.

The MARC Sport shown with optional Arca Swiss rail, mounted on the tripod.

In the very rear of the chassis is the buffer tube adapter, there are two different options when purchasing the MARC Sport. These are to accept the different types of buffer tubes and the buttstocks that go with them.

My little 16 inch 260 Remington was a perfect fit, the aftermarket trigger also had no issue fitting into the chassis

The chassis is built intuitively, a thumbshelf comfortably bedded in the right place. A comfortable contoured grip area under the center of gravity for carrying, and rounded edges in all the right places. And it comes with screws of the appropriate length to mount your Remington barreled action.

I used one of the many Magpul buttstocks available, mainly because I had them. It was very convenient to have the collapsable buttstock, it made the overall rifle more compact and easy to store. But with so many great options out there, you can surely find one to fit your needs.

The MARC Sport chassis system is a perfect addition for a good rifle. Most of us love to customize our guns and this chassis allows you to do it at a great price without giving up any quality. It does exactly what a rifle chassis should do, it gives the rifle a solid platform, that the user can adjust and customize to fit his skill level and needs. It has rekindled my love with my custom Remington’s, I have another one finishing up at the gunsmith now, and it too will soon be paired up to the MARC Sport chassis for a little match shooting.

-CBM