jasent
Well-Known Member
Barrels are like tires, you go through them faster on a hot rod
A gain twist in something this fast would shred bullets and probably lead to very dangerous pressures.Answer is yes it has been done. Google it, not a lot of info available.
Barrel life gets tossed around like "you'll shoot your eye out kid". A barrel is dead when it no longer perform the tasks it was intended for. Some are dead on arrival, we replace them, dump them, make excuses for them, and move on. Some of what we consider accuracy comes from 5-10 shot groups used in other disciplines. This type of rifle likely should be judged base on first round hits, a second on top of that, and rarely a 3 round group. 3 rounds seems where the ELR folks are going.
Bullets are the real issue. You'll need one heavy enough to develop decent pressure for a consistent burn, and provide a decent BC. Presumably long range is your intended use.
The 155 Berger is coming-it would be interesting to see it severely tested. Steve from Hammer has a pure copper in his head, probably in hand this summer.
Barrels-you'll need one with enough twist, and could be a place to try gain twist.
You'll need a Weatherby sized action.
The end product will be very specialized.
It's about having fun. if it's a process you enjoy go for it.
I'm with the others, the 6.5x300wby is probably as far overbore as you want to go.I was out on the range watching a shooter hit steel after steel with his custom rifle chambered for the 30-378 Weatherby.
After looking at the cartridge and spent shells, I wondered if anyone had already necked this round down to make a 6.5-378 Weatherby?
If anyone has, please let me know how it performed, both good and bad.
Harper I looked into them a great deal when they first came out and found particularly that with high velocity rounds they were frequently tearing bullets apart.Interesting-never had a gain twist. I did look into them lightly when last ordering a barrel. It seemed in my reading and conversations with barrel makers, the intent was to aid a bullet in surviving this transition, and reduction of initial pressures. Ultimately decided on a non-gain twist just to avoid a variable.
Curious to hear more of your thoughts on the subject.
.....If I were ever going to try one I think would have to shoot exclusively mono's through it to be safe.....
A gain twist in something this fast would shred bullets and probably lead to very dangerous pressures.
I think a gain twist would do exactly the opposite.
From the studying I did on the subject the big problem is going from a very slow twist like a 1:14- a very fast twist like a 1:7.I have seen both sides discussed and advocated. Which is more correct I don't know. Which factors make it more, or less feasible I can't say.
I did look seriously at it, and decided it's known to be an unknown. For that reason I decided against it for the initial effort. For essentially the same purpose stated by the OP. A heavy, 6.5 mono-metal, driven hard from a large case.
We're looking at a 160ish grain 6.5, that will need a 1-6" twist to stabilize.
As far as I can tell the purpose is to reduce those initial engraving issues. In my mind I can't visualize trading the initial stresses, for stress the length of the barrel, being a good thing. Bartlein refers to this as the bullet never going to "sleep".
There are shooters saying it works, and some military applications I'm told. Maybe it works in certain situations, but not in others.
For myself I'm curious enough that at some point I could try it, just for a learning experience if nothing else.
From the studying I did on the subject the big problem is going from a very slow twist like a 1:14- a very fast twist like a 1:7.
I'm not sure you'd see enough of a difference going from say a 1:10-1:7 but essentially as the twist gets faster widening out the grooves in the bullet there's a tremendous amount of shearing force on the jackets.
Still being addicted to speed myself the incredibly high velocities you can achieve with the gain twist barrels really appealed to me but the negatives just convinced me to stay with conventionally twisted barrels.