Range trip #3 with new 6BR. Post bedding.

[MDM]

I guess I'm going to have to disregard the info from my first two range trips since the first was with a bipod, and the second trip was prior to bedding. Still haven't found that sweet spot yet. I do think the bedding helped with consistancy. I'm getting 5 shot groups at a fuzz under .75". I want to knock atleast another .25" off somehow. All testing is with Varget and 107 SMK's. I think it is time for me to try a different powder, but I want to keep working on the 107 SMK's because I have a few hundred of them. Going to try some Re15 and H4895. What is a good starting point with these two powders?

Top two groups are 29.8g Varget, 107 SMK with a .010 jam.
Middle two are 30g with a .010 jam.
Bottom left is 30g with a .015 jam.

The barrel was clean, and I fired two foulers. Seems like it may need about 5 foulers before it really settles down.

 

[dieselten]

did you try 30.0 grains Varget with a jump? The Sierra 107 isn't afraid to jump .040 or .060.

 

[MDM]

I tried a .020 and .010 jump, but have to disregard the results because I was shooting off a bipod, and the rifle had not yet been bedded. I was going to give the Varget one more go around and try jumping at .040, .030, .020, .010 before I went ahead and switched powders. I was going to do this a 30g because I'm getting the most consistent results there. Any rec's on how I should proceed?

Can seating depth change grouping by .25"? This is the first time at I've really messed with seating depth as all of my other rifles shot well enough without tinkering with seating depth. I do need to wring some more accuracy out of this rifle though.

 

[smack01]

This a group with my 6BR using RL15 and SMK 107's at 20 off the lande using 30.0 grains, Lapua brass and CCI 450 primers. I tried Varget which gave me .5 to .75 groups but the RL 15 was the ticket. The 2 shots at 5oclock are fouling shots with the bullseye being a 10 shot group. Kepp trying different combinations and you will find one that works. That is half the fun.

 

[bheadboy]

MDM, seating depth can change groups greatly,not unusual tosee +1/2 "
one reason is a .010" increaSE in jam can up pressure as much as 4000psi,you must reduce loads if you jam, and find the pressure good level for your throat by doing so,

Otherwise, jump and find the pressure sweet spot there

Bob

 

[Josh11]

I had the same problem. I was shooting lapua 105 and h4895 but I was getting around .75 inch groups. I switched to Sierras 107 and RL 15. That was it. I got my smk 107 jammed about .05 or so. Ive shot 2 inch groups at 600 yards with this load. I havent tried closer than that yet because I see no need. This is my long range load. H4895 just couldnt do it for me.

 

[z4lunch]

Steve here... My 6br likes 107mk's 20 off with 30.3 Re 15
I shot a 1.3 and and 1.5 group at 600yds a few weeks back
Steve

 

[allenn]

You are going to burn up a lot of ammo going the way you are. The first thing you need to do is a ladder test.

 

[MDM]

Scope is a Vortex Viper 6.5x20. Trigger is a SSS competition trigger set at about 14oz. Going to keep working at it. I have so many different recommendations, I don't really know what direction to go.

 

[MDM]

That 6BR is shooting very badly.
Your seating depth increments are too large!!!!! You need to seat the 107 Sierras as long as possible and let the bolt closing finish seating the bullet.
This will be your maximum jam length and you need to work in only one direction only.I would use 0.005 increments for your seating depth.I would also use 3 shot groups until you narrow it down.There is a sweetspot for seating depth and it runs about 0.005 wide meaning bullets seated in that narrow 0.005 window will shoot well.Start with your bullets loaded as long as possible using 30.0 grains of varget and a Fed 205M or CCI 450 magnum primer.Shoot two 3 shot groups then seat your next 3 shots 0.005 deeper into the case without changing anything else.
I have a half dozen 6BR's and a couple 6Dashers and any load I use is better than the groups you have posted.
Are you shooting off of a good solid bench? What scope,trigger and stock are you using?
Does your brass now chamber easily?
Lynn

So, if I go this route and find the sweet spot for the seating depth, then I can experiment with powder charges? Once I find the sweet spot with the 30 g charge, that seating depth sweet spot will remain the same for that bullet at different charge weights?

 

[allenn]

This is a very good read. Take a look, I hope it helps.
http://www.6mmbr.com/laddertest.html