300 meter shooting - 6BR load development with Sierra 107 MK

[Frank]

Need some advise to get me started. I am using Sierra 107 MK Moly with Lapua cases. Am using 27 gr of Varget which chronos at 2535 fps. This load is OK @ 100 yards but starts to spread out at 200+ yards.
How fast can you push the 107 gr. in this 6BR case?
Is 3000 fps too much to ask?
What powder brands are favored? Powder loads?
Primers used?
.43443.0

[Øyvind]

Hi, the average speed of that bullet with a 1:8 twist barrel would be around 830-860m/sec.The powders used in Europe are N-150/N550/, N-140/N540,Norma R-11.
Loads with N-150/N550/Rp11 are usually from 30 grains up to no more than 33grains with that bullet. With the quicker N-140/N540/and maybe IMR4064 I would start around 25grains and stop before 29 grains.In that area you will find velocity and accuracy with those powders and bullet connection.I use those with my rifles, both standard and free rifles, all Borderbarrels.
For caps, I use all kinds.Just make sure the flash hole is of the right size and uniform.
oesir-at-c2i.net.43445.43443

[Eric U.]

Frank,
I use Berger 105 VLD's. They have a different bearing length than the Sierra 107's, so I'm not sure what your max velocity should be. Much better than 2535fps, I would guess.
So far, I've only tried two different powders in my 6BR...Varget and N540. I settled on N540 because I was worked up my loads for the World Championships last summer in Finland (Vihtavouri is Finnish, and I knew I could get it there). I ended up with 31 grains of N540 that put my velocity at about 2925fps. That is a pretty hot load, so don't start anywhere near that. Also, don't try it without coated bullets. I used CCI BR4 primers. They are harder than Federal, so can stand a bit more pressure. When I was using Varget, I had quite a bit more than 27 grains (31.5 if my memory serves me). That was a VERY hot load and probably was on the verge of being dangerous. Good thing the days I shot that load were pretty cold. I don't know what the velocity was.
As with all VLD type bullets, try to work up your loads at the distance you will be shooting at. Since I didn't have any 300m ranges to develop loads, I had to settle for 200yds. I did then confirm that it still grouped at 300yds before going to Finland. I would suggest against doing any of your development at 100yds. VLD's take some distance to stabilize, and will probably give you a false reading at the closer ranges (that is partially why benchresters don't use them, even at 200yds).
My rifle and load that I finally settled on: a BAT benchrest action, 3 groove 26" long Lilja 1-8" twist barrel, Anschutz trigger and stock. The chamber was cut for a .262 neck (yes, I had to neck-turn my brass). My load was 31 grains of N540, CCI BR4 primers, Berger 105gr VLD's seated into the lands by about 0.020". As stated before, I neck-turned my brass to give about 0.0015" clearance between my brass and the neck of the chamber (0.00075" per side). I also deburred the flash-hole and uniformed the primer pockets. I used Wilson hand dies for bullet seating and neck-sizing, and a Redding body die for when the brass started getting tight in the chamber.
Hope this helps,
Eric
.43453.43443

[pdeal]

Eric: You mentioned that you used a BAT benchrest action w/Anschutz trigger. Does this action support the Anschutz trigger directly or did some adaptation need to be done?
pdeal-at-mylanlabs.com.43457.43453

[Eric U.]

I used a Briley adaptor to fit the trigger to the action. Additionally, some modifications had to be done to the action to make it all work...
1. An additional action screw hole was put just in front of the trigger mounting area. This is because there is no room in the stock (pistol grip is in the way) for using the rear action screw.
2. Remington style pin holes had to be machined into the action to accept the Briley adaptor. I was hoping the trigger hanger that BAT supplies with their actions would work directly with the Briley adaptor, but it just wasn't to be. Problem is that an Anschutz trigger is much longer than a "standard" Remington trigger, and wouldn't fit the trigger hanger. Bruce Thom (Mr. BAT) made the action modifications for me.
Good Luck!
.43459.43457

[pdeal]

Thanks. With the popularity of the Ans. trigger I'd have thought that a few of the custom action mfrs. would offer versions of their actions that would accept the ans. trigger directly. Have not found one yet though.
pdeal-at-mylanlabs.com.43460.43459

[ge]

: Thanks. With the popularity of the Ans. trigger I'd have thought that a few of the custom action mfrs. would offer versions of their actions that would accept the ans. trigger directly. Have not found one yet though.
pls send pictures...very interested
res74ilv-at-virizon.net.43503.43460