Thread: Terminator Products calibres

Originally Posted by Bremic

Can you explain this a bit more, please, for the uninitiated. Is it because some projectiles usually need to be jammed in the lands in order to be accurate, and the lands end up burnt out for a good way down the barrel?

Yes that can be part of it.

As I understand it....
Quite often with the big overbore cartridges it will be all good for 50-150 rounds then it can start to turn to custard.
The heavy, high bc pills can be quite delicate in the jackets.
So generally they will work fine for a while then they need to be retuned, generally longer o/a length & slowed down a little, then when that stops providing the answer a new bullet needs to be used like a SMK or Accubond etc which have a lower BC, this retuning can be as often as every 50 rounds on some of the biggest 7mms .....
Basically the bullets get "hurt" when forced into the barrel at extreme pressures & speed especially as the barrel ages, it gets very rough with heat cracking etc, some of the bullets cope better than others with this & some barrels wear less than others but it is very hard to determine exactly how much by, just like the effect of different powder types.

The newer 180 Berger jackets are thicker & stronger to help minimise this but the trade off is the bullets don't expand on game as well as they could & will often pencil through beyond say 800 yards, which is where you want them to work & is why you are pushing high BC bullets fast in the first place......
Some people have started annealing the jackets to soften the bullets which could be the answer ?

This isn't such a problem with the bigger calibres as they don't tend to get such a hard time, except say the 338/408, but the GenII & SMK handle well but the barrel still won't last say 850 rounds, often much less.
The GenI 300 Berger was a huge embarrassment for Berger, they made it nice & soft for the little 338s but the big 338s launched it too hard & it couldn't cope, so they made a thicker jacketed GenII which solved the problem.
The 30, 338, 375s etc will generally last longer because of the bore size, a bigger bore will always resist wear better than a smaller one because it is easier for the powder/heat to get through it.

There will always be a place for the smaller calibres, but it is much easier to shoot at long range with a big high BC projectile, the bigger the better generally.
The 300gr 338s have such a high BC & can be sent at 2800 fps easily in a portable lightweight rifle.
They kill well & have a lot of energy, the extra weight helps with wind a little more than the BC implies in my opinion.

With the newer generation of muzzle brakes & hearing protection they are very easy to use with minimal recoil & ground disturbance

A case in point would be my GF, the first two animals she shot were rabbits at 190-200 yards with my 204, then she shot a Red hind at 525 with my 338 Lapua imp.
She has shot steel before on several occasions out past 1000yards but would only have fired 50-100 rounds total.