6mm 1-12 twist short barrel caliber ?
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I had my 6-284 built with a 12tw and shoot the 75gr Vmax. It was a miscommunication, mostly on my part, with the smith that built it is why it ended up with a 12tw but for that particular rifle I never really planned on shooting anything but the mid weight bullets anyway and it shoots those 75's crazy good.
If you already have a bunch of 6XC brass and the brass is good stuff I guess I don't know why you wouldn't hit the easy button and build one of those.
If you didn't already have the brass and you were starting from zero and had to buy brass and dies, for me, it would be hard to not go with something like a 6 Creedmoor simply because there's at least three companies, Lapua, ADG, Alpha, that sell top notch brass, it's always easy to find, dies are easy to get, and they always feed well through everything. That's not to say any of the others on your list aren't equally as good but with all the different Creedmoor cartridges product support seems to always be very high.
Another hot rod 6mm that seems to be gaining in popularity is the 6 PRC, 6.5 PRC necked down, but they tend to be more geared toward slinging the 105-115's so a 12tw 6PRC may not be the best choice.
If you already have a bunch of 6XC brass and the brass is good stuff I guess I don't know why you wouldn't hit the easy button and build one of those.
If you didn't already have the brass and you were starting from zero and had to buy brass and dies, for me, it would be hard to not go with something like a 6 Creedmoor simply because there's at least three companies, Lapua, ADG, Alpha, that sell top notch brass, it's always easy to find, dies are easy to get, and they always feed well through everything. That's not to say any of the others on your list aren't equally as good but with all the different Creedmoor cartridges product support seems to always be very high.
Another hot rod 6mm that seems to be gaining in popularity is the 6 PRC, 6.5 PRC necked down, but they tend to be more geared toward slinging the 105-115's so a 12tw 6PRC may not be the best choice.
Dultimatpredator
Well-known member
That’s a pretty slow twist meant for light bullets. I wouldn’t be going with a caliber that needs a long heavy bullet sticking out of the case. I own four 243’s and the slowest twist is 1/10. They shoot 55 and 60 grain bullets in super small groups. Thats like old school 244 and 6mm twist rates. Guessing that’s why he’s sitting on those barrels. Meant for 55 to 70 grain bullets. That’s why the 244 and 6 mm went obsolete because they had that twist rate and wouldn’t stabilize the “heavier for caliber” hunting bullets to hunt deer. The 243 did at 1/10…that’s why it’s still popular today. Imo the 243 is the only caliber you you picked that might possibly work with that slow twist and your best accuracy will be with light projectiles. All the rest you picked out need long heavy bullets which need faster twist rates like 1/8 to 1/7 to stabilize them.
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alf
Well-known member
6x47 Lapua.......
Austin Laughlin
Well-known member
nightcaller
Active member
I'm not following the logic here. 12 twist 6mm is very common. Why would any of these cartridges "need" a long bullet? Why is it that the 243 is the only one that would work? I would think any of them will work you just need realistic expectations.
I'm a fan of 6mms and shoot different twists in the same caliber, 243 and 6 dasher, both in different twists both are very accurate when matched to a bullet that is optimal for that twist.
My 6 dashers are my most accurate guns with bench stocks and heavy barrels. My 8 twist shoots 105s and my 14 twist shoots 68s.
Maybe I'm misunderstanding something. I think you could pick whichever caliber and barrel you want and then find a bullet that's optimal for the twist.
Dultimatpredator
Well-known member
The 1 in 12 was used for a 6 mm or 244. The slow twist was designed to shoot light for caliber projectiles. It’s what killed them off to the deer hunting crowd back in the 60’s because the slower twist would not stabilize 100 grain bullets. I have to ADMIT I’ve never tried personally to shoot a heavy for caliber bullet in a slower 1/12 twist. I have 2, 1/10 twists, 1, 1/9 twist, and 1,1/8 twist all in 243 rifles. They all shoot 55 to 100 grain projectiles at .2” to 3” at 200 yards pretty consistently when I do my part. Everything that I’ve “read” says that the reason the 243 survived and is still up and running today is becuase the factory rifles they were chambered in back in the day came with is a 1 in 10 twist to stabilize heavy for caliber bullets in the 90 to 100 grain size. So, I’m just one guy with one opini… The OP can do what he want and asked for opions. But, I’m guessing that anything over 75 grains probably isn’t going to group with “superior“ accuracy with the slow twist. I like shooting 55 to 70 grainers for coyotes so the 1/12 twist would be zero problems for me. The 1/12 twist was designed back in the day for varmint hunting with 55 to 70 grain .243 bullets. The OP asked what he should do and I gave him my opinion. But it’s up to him make his own mind up. I will say out of all the calibers he's chose 243 brass is as common as mosquit’s and always will be. They rest I’ve never seen on the shelves for sale in my 30 years of reloading. I can even pick up 308 bass and neck down…not that i ever have. But it’s also a common caliber you can find everywhere. Good luck. Keep us posted on what you get and how it shoots OP.
So yes, just like nightcrawler said I’m sure all the calibers will work but you’re gonna need to stick to 70 grain bullets and under to get your best accuracy. Just depends on what the OP is gonna do with the gun. If he has in his head to go shoot all the modern, super long, 105 to 115 grain target match bullets that have come to the market in the last 10 years “i’m guessing” he’s gonna be pretty disappointed in his groups.
So yes, just like nightcrawler said I’m sure all the calibers will work but you’re gonna need to stick to 70 grain bullets and under to get your best accuracy. Just depends on what the OP is gonna do with the gun. If he has in his head to go shoot all the modern, super long, 105 to 115 grain target match bullets that have come to the market in the last 10 years “i’m guessing” he’s gonna be pretty disappointed in his groups.
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AWS
Custom Accessory Maker & Retired PM Staff
I'd say whatever one you want. Have your guy throat it to the dummy rounds you give him. Or have your own reamer made to your specs.
I'd go with the case that has the smallest capacity of those listed to have the most efficient with the short barrel and lighter bullets.
Personally if I were building a 16.5" 12 twist 6mm I'd go with a 6x45, 6x47 Rem, 6mm-204 or one of the 6s on the Grendel case, oh I have a 6x45 and 6mm-204.
I'd go with the case that has the smallest capacity of those listed to have the most efficient with the short barrel and lighter bullets.
Personally if I were building a 16.5" 12 twist 6mm I'd go with a 6x45, 6x47 Rem, 6mm-204 or one of the 6s on the Grendel case, oh I have a 6x45 and 6mm-204.