dougduey
Well-Known Member
I've been lurking on this thread for several years trying to learn what I can about a great cartridge. I've been reloading for a a Sako 85 for some time now. When I first started loading for it 15 years ago, I used Remington brass and IMR7828 with 140 and 160 Accubonds. Groups with nearly every load were MOA or better. The best were 5/8". Chronograping the loads it was apparently a fast barrels, routinely shooting faster than manuals suggested. It also has had nodes with heavier than book loads. 140s shot nearly 3500fps. 160s shot nearly 3400fps (this was what original STW loads suggested was obtainable). Both shot without any pressure signs.
Fast forward 15 years, I decided to start playing with the rifle again. Because my reloading supplies sprouted legs moving across the country, I had to start over again. I was surprised to see the only available brass was from Nosler. Whether because of different brass, or a change in powder lots, loading was now a real challenge with most groups in the 1.5" range. I did find a load in the MOA range....but nothing like before. Although less accurate than before, velocities were in the 3300fps range with 160s and 76g of 7828 (with a COL of 3.625). Increasing COL did not improve things, nor did reducing loads.
I've since tried loads with H1000 and RL26. H1000 did no better through 5 different powder charges. 80.5g of RL26 also shoots <1" but no better.
My practice with cases of this capacity is to load in 1 grain increments, then move to .5g increments once I'm on to something. Perhaps I skipped over a node.
Any other suggestions on what I might do to return the gun to its former accuracy level? I've been careful about letting the barrel heat up. I'd guess the tube has seen 300 rounds or so.
Catskills,
Do you have or have access to a chronograph?? If not, get one. It will save you a ton of time in load development. The 6.5 Guys have a great video and write up on how to do load development using a chronograph. Once you find where max is in your rifle for a particular bullet and the powder you are using, drop down about 1.5-2.0 gr from there. Then load up one round in 0.2 gr increments and fire them using the chronograph. You'll find a velocity node (or flat spot) where the velocity levels off and doesn't really change much. This is what you are looking for, and they tend to be 0.4-0.8 gr in powder increase. Then pick a spot in the middle of that node and load up 5 rounds and shoot them over the chronograph. You should have a pretty decent ES with this found load (hopefully single digits, but anything 25 fps or less is very good and very very stable). Now load up 5 more rounds and see how they group. If it's not as tight as you like, you will need to play with seating depth to dial it in.
As far as powders go, I mainly use H1000 in 150 gr bullets and above. Haven't found a bullet that didn't like H1000. I'm on my second barrel now, and H1000 gets the call for most of my loads. I use RL25 in the 140 gr bullets. RL26 is great in all bullet weights and I've used Retumbo in the 175 gr bullets
Good luck
Doug