Jump or Jam the 155 Palma???

[WB300]

Folks,

Developed a load using Varget, Win brass, CCI BR-2 primer, and Sierra 155 Palmas. Just trying to tweek seating depth now. The throat on my Rem LTR is loooong, so seating close or into the lands isn't possible. Farthest seating depth I can load safely still gives me about a .13" jump while single loading. If I load to max internal magazine length, I have about .2" jump. Do the 155 Palmas like to jump that much? Or do they like to be jammed in which case I am wasting time and ammo?

Bill

 

[AtOne]

The thing we've seen with the 155 palma's is either your rifle likes them or it doesn't. Between a 700 5R 1-11.25 twist and a 700P 1-12 neither shot them well but I do have a Savage 1-10 twist that loves them.
If you've found a load that looks like it will work well then its worth trying varying seating depths.

 

[WB300]

Thanks AtOne.

OCW got me to 46.6 grains of Varget, which is right in the node for 155 grainers. I can shoot anywhere from 46.4 to 46.8 grains at the same target and get MOA in the same location. When I shoot groups of individual charges at different seating depths, I still get the same results. I have a feeling wither my LTR doesn't like them, or they don't like to jump too much. MOA isn't bad, but this rifle shoots many factory match loads and some of my other hand loads (game kings) sub MOA, so I think there is room for improvement.

Bill

 

[xcDave15]

I have mine seated at 2.775 and saw an increase in accuracy over the longer seating depths. This was with IMR 8208 XBR powder.

 

[427Cobra]

Jump them at least .080 and push them hard.

 

[cdparker]

Sierras seem to like being jumped. 0.020" seems to be a good starting point.

 

[mdmp5]

you need to jump the palmas, because they cannot be loaded long enough to touch the lands, unless you have a custom cut chamber, and I'm not certain that a reamer exists for this purpose. The bullet does not have enough surface bearing to load long. I haven't loaded them in a while, but I remember seating them as far as 0.12" from the lands. Accuracy has always been great for me with these bullets regardless of the jump. If you can get them past 2850 fps, that is optimal. I use H4895 to get me to about 2880 fps out of a 20" barrel.

 

[Nortex]

They jumped a good bit when I loaded them in my FN with great accuracy. The velocity is the key to having any advantage with them over others at least past the 500 yard mark.