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Discussion Starter · #1 ·
I shoot IHMSA Big Bore 200m silhouette seeking a better round to shoot from the T/C Contender for production standing (P) class I did lotta research then did this....objective knock rams over without hitting my self in the face shooting the Taco hold. Lots of shooters shoot 30 calibers, 30 Blackout, 30/221 etc. I wanted to use 7mm bullets for superior ballistics. Thought of 7mmTCU but velocity and case capacity to much for Taco hold. Then there’s the 357Max case transformed to 7x357max which is almost clone of TCU with short neck. So i studied reload manuals looked at 357 magnum, case capacity seemed more to what I was after. So looked at 256WM compared H2O volumes figured ok. So called Bullberry in Utah talked to Troy told him to make me a wildcat 7x256 use same dimensions as 256WM with neck expanded for 7mm bullets. So Bullberry Had reamer made and did a 10 3/4” bull barrel. Meanwhile I worked on dies! Die makers said $250+ and year or 2!! So I ordered a full carbide 19/64 drill bit soon drilled neck out on a standard 256WM full length die and exchanged expander to 7mm. Then ordered a Hornady 7mm short neck die which I ground off the bottom 3/16” for proper length. Ok! Reamer production took about 3 months then Bullberry produces barrel so from order in 10/2020 to received 4/2021 right smack in bullet powder primer shortage! So loaded 139gr with IMR 4227 started at 10.5grs (1115fps) worked up to 13grs @1408fps ES of 17. Recoil little much hit knickle on chin every shot but took every Ram hit. So then loaded 160gr bullet with 10.3 gr Imr 4227 @ 1060fps this load has Momentum of .678 at 200m with nice long bullet for good push, ok with same result took every Ram hit even 2 hit low in belly. Haven’t benched this load for group size because shortage of bullets. So will update soon as now have bullets and bad weather. None of these loads showed any signs of high pressure. With the home engineering of dies cost of this project, dies $95 drill bit $16 reamer $185 barrel $350 after shipping, total $646. All smiles on this end.
 

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Interesting project, I like the experimenting spirit! I have a 10" TC barrel in 7mm Super Mag. (what you referred to as a 7x357Max.), which indeed has a 'nasty' short (about 1/8") neck....fun to form! Haven't shot it much, but seems to work OK.
I'm not a silhouette shooter and am thus not familiar with the 'taco hold'.
The reason I'm responding to your post is your comment about bullet shortage being a limiter on your group shooting testing. I have no solution to the primer shortage, but I'd like to suggest you try cast bullets. In the 1980's I had good results in a 7mm-08 with two RCBS bullets, the 145 grain (1 lube groove) and the 168 grain (2 lube grooves). At the velocities you are shooting, cast bullets are very appropriate and may solve a problem or two, as you can [somewhat] control your destiny. Buy Bullet Mould 7MM-168-SP 531 and More | RCBS

And: https://www.adorama.com/rcbs82150.html

Due to the short neck on my 7mm Super Mag, cast bullets are definitely not a good fit.

BTW, I like the 256 Win. case too, I have a Marlin Model 62 lever gun in 256 Win. and, in reference to your 'handle' name, I have a 10" octagon barrel in 22 K Hornet for one of my Contenders, neat cartridge!!:)
 

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How funny. I was digging through some of my Dad's notes from my Speer #8 and came across the 256 Winchester and thought about how it was kind of a cool cartridge.

How are you getting your brass? That manual (1970) talks about forming it from .357, and some of the difficulties seeing that it is a rimless cartridge.
 

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I looked up the 'taco hold', and now understand it, and your desire to have a chambering of less recoil. I'd hate to try it with my 35 Rem., 30-30, or 375 Win., or even 6.5 TCU barrels! I'll leave that stance to the 'pros'!
Besides, with my luck, I'd likely be sending my left pinky finger downrange with the first shot!:eek:;)
 

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Discussion Starter · #5 ·
Interesting project, I like the experimenting spirit! I have a 10" TC barrel in 7mm Super Mag. (what you referred to as a 7x357Max.), which indeed has a 'nasty' short (about 1/8") neck....fun to form! Haven't shot it much, but seems to work OK.
I'm not a silhouette shooter and am thus not familiar with the 'taco hold'.
The reason I'm responding to your post is your comment about bullet shortage being a limiter on your group shooting testing. I have no solution to the primer shortage, but I'd like to suggest you try cast bullets. In the 1980's I had good results in a 7mm-08 with two RCBS bullets, the 145 grain (1 lube groove) and the 168 grain (2 lube grooves). At the velocities you are shooting, cast bullets are very appropriate and may solve a problem or two, as you can [somewhat] control your destiny. Buy Bullet Mould 7MM-168-SP 531 and More | RCBS
I dabbled a bit in cast bullets about 20 yrs ago, bullet situation ok now it’s primers! For normal year of silhouette shooting and practice I need 4,000+ sitting on 1,700 now, name in hand all over.
And: https://www.adorama.com/rcbs82150.html

Due to the short neck on my 7mm Super Mag, cast bullets are definitely not a good fit.

BTW, I like the 256 Win. case too, I have a Marlin Model 62 lever gun in 256 Win. and, in reference to your 'handle' name, I have a 10" octagon barrel in 22 K Hornet for one of my Contenders, neat cartridge!!:)
My 22KHornet shot 3/8” @ 100 but who ever did it botched the chamber so hard on cases so sold it, but nice round.
 

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Discussion Starter · #6 ·
How funny. I was digging through some of my Dad's notes from my Speer #8 and came across the 256 Winchester and thought about how it was kind of a cool cartridge.

How are you getting your brass? That manual (1970) talks about forming it from .357, and some of the difficulties seeing that it is a rimless cartridge.
I used 360 brass from Starline because 357mag wasn’t available only .125 longer I’m thinking so some trimming, actually considered trimming 357max brass as had 200 but I shoot Ruger 10” 357max too!
 

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How funny. I was digging through some of my Dad's notes from my Speer #8 and came across the 256 Winchester and thought about how it was kind of a cool cartridge.

How are you getting your brass? That manual (1970) talks about forming it from .357, and some of the difficulties seeing that it is a rimless cartridge.
It is not a rimless cartridge, it is a 357 Mag. case with a .257" bullet. I'm assuming Winchester didn't want to call it the 257 Win. Mag. to avoid any confusion with the already existing 257 Weatherby Mag. (who knows?).
I bought my cases years ago and I don't shoot mine much, so....
I'm interested in 22Khornet's response.
 

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Discussion Starter · #8 ·
I looked up the 'taco hold', and now understand it, and your desire to have a chambering of less recoil. I'd hate to try it with my 35 Rem., 30-30, or 375 Win., or even 6.5 TCU barrels! I'll leave that stance to the 'pros'!
Besides, with my luck, I'd likely be sending my left pinky finger downrange with the first shot!:eek:;)
I do modified Taco really, I grab barrel instead of bbl scope combo, feels more natural or comfortable for me and raises sight line higher to get head up for proper vision.
 

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Discussion Starter · #10 ·
It is not a rimless cartridge, it is a 357 Mag. case with a .257" bullet. I'm assuming Winchester didn't want to call it the 257 Win. Mag. to avoid any confusion with the already existing 257 Weatherby Mag. (who knows?).
I bought my cases years ago and I don't shoot mine much, so....
I'm interested in 22Khornet's response.
It’s not a rimless cartridge. It’s regular 357magnum case which is rimmed.
 

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My 22KHornet shot 3/8” @ 100 but who ever did it botched the chamber so hard on cases so sold it, but nice round.
Mine is a TC factory barrel, not a converted 22 Hornet. Pretty rare, I think (?), bought it in 1971, RCBS dies took about 12 weeks to get back then.
 

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Discussion Starter · #12 ·
How funny. I was digging through some of my Dad's notes from my Speer #8 and came across the 256 Winchester and thought about how it was kind of a cool cartridge.

How are you getting your brass? That manual (1970) talks about forming it from .357, and some of the difficulties seeing that it is a rimless cartridge.
Not rimless! Uses standard 357 brass just necked and little body taper.
 

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Years ago, had a TC Contender 10" chambered for the 256 Win. Formed cases with a Bullberry custom forming die, ruining about every 4th case going to the salvage box. A very tempremental case to work with. Used Hornady 75 gr HP's over either H110 or IMR 4227 and averaged about 2150 fps with both powders. A pretty darned accurate little cartridge. A friend brought a out of town gunsmith to the range and the 'smith was most impressed with the setup. He bought the barrel, dies, brass on the spot and was happy going down the road. I've retained the loading data from the 90's when I was chronographing a lot of my firearms.
Still have the 22K Hornet in a Ruger 77/22 rifle. Shoots from 35 gr to 50 gr Hornady tipped bullets with JBelk's recommended AA1680 powder. Was using Li'l Gun powder until he taught me the benefits of the AA1680. Little tiny 100 yd groups with the 45 gr Hornadys.
 

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Discussion Starter · #15 ·
Years ago, had a TC Contender 10" chambered for the 256 Win. Formed cases with a Bullberry custom forming die, ruining about every 4th case going to the salvage box. A very tempremental case to work with. Used Hornady 75 gr HP's over either H110 or IMR 4227 and averaged about 2150 fps with both powders. A pretty darned accurate little cartridge. A friend brought a out of town gunsmith to the range and the 'smith was most impressed with the setup. He bought the barrel, dies, brass on the spot and was happy going down the road. I've retained the loading data from the 90's when I was chronographing a lot of my firearms.
Still have the 22K Hornet in a Ruger 77/22 rifle. Shoots from 35 gr to 50 gr Hornady tipped bullets with JBelk's recommended AA1680 powder. Was using Li'l Gun powder until he taught me the benefits of the AA1680. Little tiny 100 yd groups with the 45 gr Hornadys.
I haven’t had any issues forming using new starline brass didn’t lose any! Start with redding form dies 1 & 2 then full length 256wm die I drilled with 19/64 which gives proper diameter. Then the Hornady 7mm short neck die. 5 steps then prime powder and seat bullet. Then all reloads have been neck sized only.
 

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Discussion Starter · #17 ·
I think those extra couple of steps from .284 down to .256 is where the case mortality sets in.
CCrk the redding forms stop just few thousandths from .284 neck If remember correctly at 290 so then I use 7mm short neck size so never fully go to 256 maybe that’s why I have no loses.
 

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CCrk the redding forms stop just few thousandths from .284 neck If remember correctly at 290 so then I use 7mm short neck size so never fully go to 256 maybe that’s why I have no loses.
Probably so, the extra steps for kdub to get down to the 256 Mag. case likely contributed to his 25% loss rate. I've never had to form any for my Marlin 62 since factory cases were still avaiable at the time I bought the rifle, and I have enough to last till I'm gone.
I did have to form brass for my 7mm Super Mag. Contender barrel from 357 Max. brass. I bought 500 357 Max. cases, and still have about 425 left after tiring of forming the 7MM Super with that ridiculously short neck!
 
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