Narrowing it down
Made it to the nearest 100yd range today. I've been playing with a variety of powders under the Nosler 168 trying to get something that would shoot less than the 3 moa I was averaging. I've narrowed it down to a couple, finally. Best of the day was a Swiss made powder, same stuff I've been using in the cast load above, SPP210. It's supposed to burn at 4198 speed. Loads in my 6x45 indicated it does, but there are fellows on castboolits.com having problems with it, one says he gets 200fps less with the SPP210 than he does with an equal charge of 4198, another says he has to reduce his charges of SPP210 to get the same velocity as 4198, and others say they're getting hangfires. Anyway, I decided it try 28gr of it today under the Nosler and shot a 5 shot 100yd group with the 1902 sight that was 1.9" wide x .75" tall. Three X's and two tens on the SR-1, two of the three shots in the X ring touching. I don't know how fast it's going, targets don't care anyway, but 2.3gr less gives me 2000fps out of my K31 with a 164gr cast bullet, so I'll guesstimate 2100-2200fps out of the smaller case of the Krag. I also got some good results with IMR4007SSC, 41.8gr of it under the Nosler gave me a nice 1.6"wide x 1.4" tall 5 shot group that dropped about an inch less than the SPP210 load, so I'm guessing it might be going 2300fps. I'll continue to work with these two powders. Eliminated from the competition were Russian 4895, AA2015 and some surplus flake powder for 50BMG plastic training ammo that burns about Blue Dot speed.
I think I can get a little more accuracy out of them by neck sizing only, all this testing has given me plenty of fireformed cases. After I had a couple jams in the match a few weeks ago I did some work on the magazine and it feeds spitzers better now, so I think I can also seat the bullets out further and get a little less jump to the rifling. Weighing and sorting cases might improve things too.
Griff, I had several model 92 or 96 carrier and follower assemblies. Comparing them, I could see that the rear of the carrier, the little tab in the center of the follower, had been modified, ground down. This allows the carrier to contact the rounds higher on the case, raising the nose of the round that's ready to feed up. I picked out the one that had been ground the most and it raises the sharp nose of the Nosler above where it was getting stuck in the crack between sideplate and receiver. Feeds like a dream now. Could be these were being modified by unit armorers and led to the changes made to the 98 follower. I had several heights of tab to chose from, the one that was in it hadn't been ground on at all. Too much up might be the cause of the dreaded "bullet catches on the chamber edge" syndrome.
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