Varminterror
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@Nature Boy - what's your freebore in that Shilen? Longer CBTO for the 80.5 or the 90? I'm thinking about doing something silly next year.
Favorite 6mm?
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Nature Boy
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I believe it’s 0.169”. Take a look at the ISSF .223 reamer print to be sure. I don’t have one
Litetrigger
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A pair of 6mm's built for long range target and varmint shooting. Top is a 6BR bullt for 600 yd benchrest competitions with 30" Krieger barrel fitted to stiff BAT right bolt, left load, right eject action. Fitting and chambering by Terry Leonard who also made the specticular fiddleback cedar stock. B&A 2oz trigger and Leupold 45X Competition scope in BAT mounts. Below: .243 Catbird built by Jerrett Rifles, Hart barrel in tuned M-700 action bedded in McMillian M-70 target style stock. B&A trigger, Swarovsky 6-18X50 scope in Talley mounts. Purpose of .243 Catbird is long range varmint shooting with custom 65 gr BT benchrest bullets at 4000+FPS. Amazing to watch.
Nature Boy
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Wow. I bet it eats barrels like a fat kid eats Snickers
small town life
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The only reason for my 243win vote is that's the only 6mm I have and it's an AR. My next hopeful build will be in another AR is either 6dash of 6br. Limit will be 2.260" which will keep the bullets around the no more than 90grs. If I have a lonely caliber I like to get a companion for it. While I'm not a 7mil fan I built an AR7-08rem for a friend that lead me to build a 7saum AR. I also have a 5.56 and need/want something in the 22-250 range, but not 22creed.
I remember seeing one at a gunshow as I recall… (at a “boutique” booth with a lot of really nice stuff waaaaaaaaay out of my budget!) it’s a necked down 270 win with the shoulder blown out a bit if I recall. And like 1500 rd or less barrel life?
Varminterror
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Not a chance in hell it gets 1500. I’ve burned up a lot of 6mm barrels - I’d bet it wouldn’t get 1000, most likely smoked by 750.
Those numbers were kinda my thoughts, but I recall reading the 1500 figure somewhere.
Varminterror
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I didn’t get 1000 out of a couple dozen 243win barrels. I don’t get 1500 out of a dozen 6 creed barrels now since converting. I had a 6.5-284 which would still be a smaller case than the Catbird and didn’t get 1200 - guys aren’t getting 1000 out of the 6-284’s.
But the Catbird wasn’t necessarily meant to be a high volume cartridge with everlasting life. We don’t expect get 100,000 miles out of top fuel drag racers - but they DO expect extremely violent acceleration for the ~3 miles they run the engines before totally rebuilding. Any time we’re pushing bullets up near 4,000fps, we’re not worrying about barrel life.
troy fairweather
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Werent the early wssm getting like 300 rounds a barrel in 223 before they chromed the bores.
Varminterror
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I think that would be gross exaggeration if anyone made that claim. I had a 243wssm and a 25 WSSM, and both were stainless Shilens, no lining, and I shot a lot more than 300 out of both of these. I shot the 243 more than the 25, and both were hunting rifles so I wasn’t tracking velocity as tightly, but an educated estimate would be that I had 1200-1400 on the 243 when I sold the upper - it likely was spent by then, but still holding sun-MOA. The 243 WSSM case has about the same capacity and overbore ratio as the 243win, pretty close in powder consumption, with a bit better shoulder angle for in-neck inflection… so I’d bet heavily a 243wssm would hang tough for about 750-900, then start slipping speed, almost exactly the same as a 243win.
troy fairweather
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I think they only chromed the 223wssm barrels
Varminterror
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There’s nobody in the world who knows the WSSM’s better than Mike Milli, and he’s still building stainless Shilen barreled 223wssm’s. It’s the same capacity of 22-243, less than 220 Swift Or 220 Improved, less than 22 Clark, WAY less than the 22-06 mentioned in Ackley’s book…
Yes, 223wssm will burn barrels quickly, but we’re doing something super silly if we think it’s only 300 rounds. 650, probably, and it PROBABLY still holds sub-MOA at that mark, it’s just losing ~15fps per 100rnds for a while…
Jim Watson
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Because Remington was using .244.
Confusion caused by the Internet Generation calling groove diameter the "bore."
lysanderxiii
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So promising . . .
Litetrigger
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A pair of 6mm's: At top, 6mm Rem 40-X Remington with Leupold Vari-X 6.5-25X50. Bottom .243 with Douglas XX (8"twist) barrel on Remington M-700 action in H-S Precision stock. Leuold 24X scope. The .243 Has a 8" twist ordered for testing loads with Berger 95 and 115gr VLD's and Sierra's 95 and 105gr MK's.
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OP
OP
1948CJ2A
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This is my 6mm Rem. Nothing fancy but it shoots very well.
Varminterror
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Right for what? It's a an oversized case for the slow twist it was designed to have, folks were making faster twist versions of the 6-08 before it was even standardized...
OS/N
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In 1955 the mdl 70 in 243 was released with a 10 twist bore and was a true duel purpose rig firing 80-105 grain bullets. Wildcating started in 52 with the release of the 308. It was correct as released in 55. Velocity with less than 80 grains is too fast and more than 100 is too slow for practical use.
Varminterror
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I think 70+ years of wildcatting and new cartridge development which improved upon the slow twist, sloped shouldered, light bullet, tapered case 243win design might disagree with this. Specifically that last claim, that velocity with bullets over 100 grains is too slow for practical use seems absurd to me - the fact that SMALLER cases have proven to be quite practical for decades with these heavier bullets disproves that idea, let alone all of the successes of the fast twist 243win...
The 243win was THE cartridge I considered to be "nearly perfect" for around 30yrs of my life - but recognizing it could be a lot closer to perfect if offered a fast twist barrel and a steeper shoulder angle. I STILL prefer a fast twist 243AI over all others, but I recognize that I can do everything I needed with a smidge less powder and no case forming by using 6mm creed and Dasher. "Nearly perfect" is still pretty good, but there's been a lot of improvement to the 243win in the last 70yrs, starting even before it was standardized.
I gotta go 243 Win because it just works. These are some huge bodied mulies and my boys aren’t even interested in shooting anything else. It’s a browning xbolt shooting Sierra 85 grain BTHP GameKings on top of about 37 grains of IMR 4064. This is just this past hunting season. These two have made enough one shot kills with this combo out to a shade past 300 yards that I don’t even worry about it.
tark
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Hey! Where is the .244 H&H magnum? The most insanely overbored cartridge in existence? ( A 375 H&H necked down to a .243 caliber )
Go look it up in Cartridges of the World.
Go look it up in Cartridges of the World.
Litetrigger
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Thank you Mr. Tark for mentioning the .244 H&H, it's an interesting cartridge. I've never seen a rifle is this caliber and can't remember how I came to have the sample shown in pic. I expect very few rifles and ammo were made. Another British 6mm cartridge is the H&H .240. I've hunted deer in Scotland with a .240, with a pretty Holland &Holland rifle they had loaned me in hopes I would buy it. Which I didn't. The 240 ammo I hunted with had a Norma stamp on primer so I assumed they made the whole catridge.. It is quite similar to the .240 Weatherby Mag and I suspect it gave Roy Weatherby the inspiration for his 6mm Mag, even borrowing the name. Guessing, but Norma may have also made the .244 H&H, as the sample I have has a steel jacketed bullet like Norma once made. Attached is a comparison pic of the two British 6mm, note Norma stamp on primer of .240.
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