I am calling upon the collective experience of the many Swede fans on the site - Mats and others.
The problem is that I cannot close the group size below 1.3 inches with Nosler 125 partitions, but the rifle is capable of shooting into half an inch with 100 gr Ballistic Tips.

The Rifle in a custom stutzen 21" barrel with 1:9.5 twist. So far I have tried N160 and H4831 - 48.4 grains producing the best group. I am thinking about trying Rel 19. The C.O.L. is 2.950 which is 0.030 off the rifling. New Lapua brass, CCI 200 primers.
I have cleaned the bore, checked the scope and mounts... you name it. If the rifle is tight with 100 gr BTs ahouldn't it be tight with 125 gr Partitions? Thinking about a load based on a Barnes 140 gr next. Thanks fellas.

Well I'm no expert given the fact that my Model 96 won't shoot groups under 4", but just what is wrong with 1.3". After all the proper use of the Partition is game not small varmints at extreme range. There is an alternative in the 129 grain Hornady Interlocked bullet. Works fine in my .260s.

The partition will generally not be as accurate as the baltips. It is a question of inherent balance in the manufacturing process.
Some lots of partitions are better that others, but 1.25 inches at 100 yards is about the best I ever average with them in my 308.

Try them at 300 yards, I'll bet you are still under three inches there. Both my 308 bolt actions act this way with the partitions. How fast a bullet "goes to sleep" is a function of symmetry in the rifle and bullet.

Don

Oops, missed this one... Sorry.

Well, what velocities were you getting? Consistent? Is the group stringing in any particular direction? ANY signs of instability? Lightly seated primers, perhaps? The CCI's need to be bottomed out firmly, the exact opposite of Federal's who can start spraying if you seat them too hard.

What Don says has merit (all of it), further than that it might be that you'd have to chase them pretty fast in a 1:9.5" twist. If velocity spread was high I'd opt for CCI 250's or WMR's to light everything - given that they were seated well.

I'd bet that the 129 Hornady would shoot great though... It and its big brother, the 140 IL, work great at shorter distances.

-- Mats

well Mats, The group was stringing horizontally.
On ther primers, I use a RCBS hand priming tool which I am not convinced is sitting the primers square. Sometimes they feel as though they have one side higher than the other. You can't see it with the eye - it is just the feel to it.

Velocity - pass on this one. It was an indoor range and too dark for the chrony.

Maybe I should try those CCI250s...??

I'd try some other way to seat the primers. I use mostly CCI for my loading and the 200's normally work just fine with N 160, although they need a firm seating: Press them in until you feel them bottoming out, then a bit more. The pockets should be cleaned every loading, without exception.

Is your RCBS tool bottoming out? One reason for the apparently crooked seating could be a bent case holder, or one of the incorrect size. The only other option is an out-of-square seating rod.

-- Mats

Mats
Sorry for not getting back to you. I have loaded up some 125s and 129s. Headed for the range in a couple of weeks. I'll let you know if the primer thing makes any difference.

I had all kinds of problems with mine not wanting to shoot 120 grain anything. Load I settled on was 48 gr of imr 4831 with 140 gr sierra's or 150 AMAX at 47r of imr 4831. See what happens.

It's not necessarily fair to compare 100gr BTs with anything else. My 6.5x55 is definately more accurate with them than even 120gr BTs, I did wonder if the decreased muzzle flip might have something to do with it.

Now that I think about it, the most dramatic improvements to accuracy in my loads have come from finding the seating depth that the rifle perferred. As long as the cartridges feed, you might get better accuracy seating the bullets closer to the lands. That is pretty difficult in the old military rifles, but with the heavier bullets is not likely to cause your cartridges to come apart.