OzFclass

Okay, to help settle a club discussion/argument;
does giving the projectile jump (say 0.010") lead to excessive and/or quicker wear of the throat and lands.

Bart wrote:Okay, to help settle a club discussion/argument;
does giving the projectile jump (say 0.010") lead to excessive and/or quicker wear of the throat and lands.

I believe so, and it stands to reason - more leakage of superheated gas at very high pressure past the projectile will increase the rate of erosion.

Would have thought considering most projectiles have a fairly long bearing surface that the projectile would be pushed forward enough initially that the gas couldnt get past it. Either way your going to have hot gas and pressure no matter what. Hot loads and faster burning powder would wear quicker than mild loads and cooler burning powder. And best of all, poor cleaning technique will probably wear a barrel out quicker than a jammed or jumped load.

Bart wrote:Okay, to help settle a club discussion/argument;
does giving the projectile jump (say 0.010") lead to excessive and/or quicker wear of the throat and lands.

No!!! it will not lead to any more throat wear as opposed to a 10 thou jam...

Brad Y wrote:...the projectile would be pushed forward enough initially that the gas couldnt get past it...

That's debatable. Projectiles are heavy, gas is good at leaking .

This is a debatable point, any difference in throat erosion rates between jam and jump cannot be measured and will forever be open to debate. Any difference would be so slight and would be lost in all the other factors pertaining to barrel life in general. My observation is that no two barrels of the same caliber shooting the same ammo ever have exactly the same life. For the record, my opinion is there would be no difference in throat erosion between jump and jam.
Keith H.

Well, I'm running a 280AI at the moment and on my second barrel. First barrel lasted 2000 rounds and I used VLD bullets jammed exclusively. Velocity hovered around 2800fps. Second barrel I'm running hybrids, jumped about 30 thou and so far this barrel looks to be on track to achieve a very similar level of barrel life, with around 1400 down the tube and it's shooting very well. So I guess if there's a difference, it's almost imperceptible to me.

I believe that jump may speed up throat wear somewhat
but things like incorrect cleaning, powder type and barrel brand have a far greater impact on barrel life than jump or jam
RB