Hi guys I posted this question on one of the varmint boards, but it can't hurt to have a couple more brains on it.
I have a savage 110 6mm rem. Douglass xx 26" 1 in 8 twist barrel. I am loading out to just touch the lands. 210M primer, sierra MK 107 bullet. I am useing 3 powders RL19, RL22 and IMR 4350. With all 3 powders, lite loads group well. At speeds 2500 to 2700fps it shoots more one hole groups than not with all 3 powders. Once I get over 2750 the groups open up. I have tried about 40 different loads and not one groups under 1/2 at a speed over 2700 (most 3/4 to 2"). Very few group bigger than 1/2 under 2700 with any of the 3 powders.
I also loaded some 100 gr. btsp sierra bullets with the same results.
I only had a few thousands clearance between my stock and barrel, so I releived that a bit. Thought maybe the mounts were loose, pulled them and remounted them with new screws and locktite.
Checked the burris signature rings. Retourqed the stock(SSS pillar bedded with larger recoil lug). The scope a Bushnell 4200 I checked on a 7mm mag seem fine.
The yesterday I was at the range I started with a clean bore fired about 70 rounds with loads 2800 to 3200 never got a deceint group, put in a load with 40 grains of RL22 got one ragged hole @ 2625 fps.(that is shots 71 to 75 without cleaning)
The second to the last group I fired was 48 gr of RL22 at about 3200fps. It was the most constaint speed I have ever shot over a chrono with any firearm ever. The high to lo for 5 shots was 5 fps. Now if I could only get them to group like the slow ones. Ken

That's a tricky bullet to stabilize at those speeds. The first thing I'd check is runout of the loaded rounds. You may find that excessive runout is the culprit. If you don't have a concentricity gauge, you can shoot the fast loads at 300 yards and see if they don't tighten up. If they do, it may be because of excessive bullet runout, and it's taking the bullet that long to stabilize.

Another suggestion. Seat the bullet a bit deeper on these fast rounds. This will allow a slower drag (release) from the case, and limit bullet deformation when the bullet enters the throat. (This may solve your entire problem, and I think I'd try this first. Go in about .020" or so and see what happens).

The second thing isn't likely, but I'll mention it. Check your bolt lugs for even facing. Savages don't often have this problem, and the installation of the custom barrel almost certainly came with a truing of the bolt, but you may want to check this anyway.

Take a permanent marker and mark the rear faces of both sides of the bolt's locking lugs. (Degrease before marking). Then chamber an empty case. Remove the bolt and see if the marked areas are smeared pretty evenly. If one bolt lug shows scoring in the marked area, and the other doesn't, you will need to have the bolt lugs lapped. (You can also easily do this yourself, just don't tell your local gunsmith!)

Uneven bolt lugs can cause higher pressure loads to act funny. When the lug that isn't touching slams home, groups will open up.

Let us know how things go...

Dan Newberry
green 788

I suggest you change powders. Although it would seem that the 4350s should be good powders for the 6mm Rem., they've never given me good accuracy in mine. The only thing that I've found that works well is IMR 4064. H380 also gave me good accuracy, but seemed to give hangfires sometimes.

Thanks for the replies, I will give your suggestions a try. I hope I can find a 300 yard range around here. Thanks, Ken

That excellent advice re5513. I hadn't thought about overstabilization, but that's certainly an issue.

Try the deeper seating (which should ease the release and possibly limit obturation on contact with the lands, and see what happens.

I'm curious now!

Dan Newberry
green 788

I freely admit this is second hand but here is what I was told about VLDs in tight twist fast rounds. BASE pressure is crucial. The reason why a max velocity load with these never works is because the pressure on the boat tail is causing distortion. Back off until the base is not distorted and things are OK. This was for Bergers and J4 jackets I think the Sierras are slightly harder but maybe it's still applicable.

Also isn't 4350 slightly fast? I would have thought 4831 or N165 would be more in line?

For what it's worth I have found a similar situation with my 257 Ackley Imp. using Sierra 100 gr. boattail, Speer 100 gr. boattail and 100 gr. Nosler Ballistic tips. They shoot wonderfully in the 3000-3050 velocity range. Speed them up and groups open . A one grain difference between best load and next highest translates to a 1" jump in group size. Flat base bullets are not so fussy although a similar situation occurs with them to a lesser degree. A gunsmith whose opinion is well respected told me that he believed barrel harmonics enter the picture here and some barrels just perform best at particular pressure and velocity levels. I think I'll be looking for a new barrel after hunting season as top end standard Roberts velocities were not what I was looking for when I got an Improved chambering. May have the old one set back and rechambered for the standard case and put it on a different action.

Now we are getting some more thing to concider. I could shoot these at 2700, I will probably be limiting the range to 500 yd. at least for a while.
I am not the best at reading the wind and an extra 400 fps would come in handy, for less drop and less wind drift.
4350 is a little fast for these heavy bullets, I have just used it with great success for the lighter bullets, so I gave it a try. I may try some 4831. I really want to use RL22 it seems to be less temperature sensitive than the IMR's, have you guys noticed that? Also I like the shorter kernels of RL22 they seem to flow better.
Thanks for the input, keep them comming. Ken

I would suggest IMR-4895 From 30.7 grains to 35.6 grains with a Remington 9-1/2 primer.

7828 shoots real good with that bullet in my VLS at about 3050.

Thanks again to all those who gave all the great advice. I am loading some 105 A-max bulets up to see if that will make a difference.