140 vs 142 SMK data

[Unknown]

I have been shooting 140 SMK's in my 260, and have a great load worked up for it. At one time, I had loads and data for the 142 SMK, and the 144 Lapua. Now, I can't find the data, and I'm hoping someone else has worked with these two bullets, and can tell me if I have to work up a whole new load.

I realize that every rifle is it's own rule, and that pressures will change a bit. My loads are conservative with zero pressure signs using the 140 bullets, and if memory serves me right, I used the same load with the 140's that I used to use when I was loading the 142's, but I can't be 100% sure without finding my notebook. I moved, and the notes are nowhere to be found...

Does the hive mind say that I'll need to work up a whole new load over 2 grains more bullet..or is the chance of the 140 grain loading working well with the 142 grain bullet high enough to warrant going with the same load as used for the 140? Maybe reduce the powder charge by .2 grains??

 

[PDXGS]

What powder?
What brass?
For reference only:
I use 43.7 gn of H4350 in Lapua brass with Fed. 210m primers seated at 2.850" COAL for my pet 142SMK load. No pressure signs.
With another batch of powder my sweet spot was at 43.5 gn

 

[Unknown]

Brass is Winchester 7mm-08 necked down to 6.5mm, primer pockets uniformed, flash holes de-burred, trimmed, and annealed.
Powder is H4350, primer is CCI-BR2, bullets I have used have been 123 scenar, 140 Nosler, 120 spitzer, 142 smk, and 144 Lapua BTHP.

The rifle is a bolt gun with a Defiance machine action, and a 27 inch Obermeyer 5R barrel with a RWS 3 port muzzle brake on it. Manners stock, rifle basix trigger set at 2 pounds. Action is pillar and glass bedded, with a floated barrel.

I did find postings I made in the thread about loads for the 260, where my data was enterred on 02-07-2011, and 03-22-2011. So because I entered the info on that thread, I was able to recover the data, and it is now on the inside of the box of 260 dies.

I had been using 43.8 with the 140 Nosler, and 42.7 with the 144 Lapua, but the velocity with the Lapua was only about 2750 fps, and I was getting 2880 with the Nosler bullet with absoutely no pressure signs.

I ended up going with 43.5 grains of H4350. Length to ogive is 2.30 inches. giving me about 10-15 thou jump to the lands. I'll post the velocity after I chrono it. My 260 seems to be very forgiving and easily shoots well. More to follow.