142 SMK

[paperpuncher]

So for the guys shooting these what sort of seating depth do they like. Do they need some jump / jammed. This is in a 260 AI, IDK the freebore but the boat tail bearing surface junction is just forward of the neck shoulder junction when just touching the lands

 

[shoot4fun]

I always have better luck jumping them. And it seems like they don't really care how much.

 

[FatBoy]

I like to jump .015", but as long as jump is pretty consistent they do seem to shoot well jumped longer.

 

[germanlongbow]

Not sure on the sierra matchkings. My buddies 260 AI loves the 139 scenars jammed 0.060. 30 inch tube with velocities at 3020 fps. No pressure. Scott

 

[Zero333]

I tried everything from 10 in to 30 out and the results were VERY close...
but 10thou in (but not jammed) was most consistent with 20 jump almost as good.

Tested 3 groups of 5 shots with each seating depth... 10in, kissing, 10 out, 20 out and 30 out.

 

[paperpuncher]

Thanks for the information I will load some ammo tonight based on your exp. and see how it goes. Ill try to post some results tomorrow

 

[germanlongbow]

I shoot the 142's with 0.015 jump out of my last two 6.5x284's. Always found the sierra matchkings liked to be jumped. Never had any luck with jamming them. Scott

 

[perry42]

I seat mine out .015 in a 6.5x55AI. Started at .015 in and ended up out changing .005 at a time. Good Luck.

perry42

 

[alphapygmy]

Criterion barreled Savage in 260AI. Mine liked .015" jump like most everyone elses.

 

[paperpuncher]

Got out to try it today They shot a little better jumped than they did jammed. The difference was not huge but enough to notice. Thanks again to all that replied