First day of real load development with new 6br
- Thread starter Roger M
- Start date
sorry for the lack of info. Shooting 68g accumax bullets over varget off of a rest and rear bag at 100yds. Rig is a rem action with a singleshot floorplate with a heavy mofo mclennan barrel in a rem 40x stock. not interiely a benchrest rig.
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nice rig I am doing the same to a savage model 12 LRPV in 22-250. I am using right now 60gr a max and I have settled on 35.8 and 36 gr of Varget.So far so good and now I have moved the bullet 3 thousands of an inch back off the lands and then after that I will move 6 thou and see how that works. Also I am going to try 37 gr up to the max charge what ever that is I do not have the manual in front of me. And when I have settled on a good round there, I am going to try 53 gr HPBT and then 75 gr A-max. I love this load develpment. Mind you its hunting season and this will take me months hehehehe
P.S. I hope to post some pics of my rig too
Dam fine rifle you have there
P.S. I hope to post some pics of my rig too
Dam fine rifle you have there
What twist is your barrel? I am guessing it's a slow twist considering the light bullets you are using.
That 31gr load looks like a winner but the 34gr load would buck wind a little better.
If you have a faster twist (1:8) then try some 107gr Sierra MK's over 30-33grns of Varget.
With 30.5grs Varget and 107gr SMK's I am getting 2860fps and nice little bugholes at 100m.
That 31gr load looks like a winner but the 34gr load would buck wind a little better.
If you have a faster twist (1:8) then try some 107gr Sierra MK's over 30-33grns of Varget.
With 30.5grs Varget and 107gr SMK's I am getting 2860fps and nice little bugholes at 100m.
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
Retest in smaller increments starting at 32.0 to 33gr. I would go up in 2 tenths. Shoot at 200yds/m. That will make a number of your groups fall apart which is normal. Watch for any signs of stringing especially vertical as in your final group.
Personally, I wouldn't bother with seating depth. Adjust powder small increments does the same thing and is not subject to as much change as the throat wears.
What primers are you using? how far do you intend to use this rig?
Jerry
Personally, I wouldn't bother with seating depth. Adjust powder small increments does the same thing and is not subject to as much change as the throat wears.
What primers are you using? how far do you intend to use this rig?
Jerry
i am using federal match primers. I dont plan to do any long range with this setup it will just be a 100 200yd bench queen. I will try your suggestion from 32 to 33g what brought you to that conclusion? One problem i have is interpreting targets to decide what to do next. i plan to do further testing at 200yds. just trying to find time when all the once a year shooters arent at the club.....
Roger,
Turn your rear bag around when you shoot, the slope will match the slope of your stock better. Your targets have the least verticle between 32-33 grains.
Thats why you should trest in this area.
I shoot 68 grain bullets at 33 grs in my fast twist 6BR with good results.
NormB
Turn your rear bag around when you shoot, the slope will match the slope of your stock better. Your targets have the least verticle between 32-33 grains.
Thats why you should trest in this area.
I shoot 68 grain bullets at 33 grs in my fast twist 6BR with good results.
NormB
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
The groups are most round in this powder range.
Assuming that shots were done consistently without wind, you can see that the groups started vertical, went horizontal/circular, then vertical. This would be very obvious at longer distances.
There is also little point in going to the absolute max as this will be a very touchy load as temps change and barrel wears.
I like to keep my loads in the widest sweet spot for my set up.
Now to go up in very small increments and at longer distances to eliminate any stringing. My guess is that around 32.0 to 32.7gr will be your load for this bullet.
Big thing now is to call your flyers. You are looking for very small variance that can come from wind or you, as well as the load. You are looking for the load where the bullets just drive themselves into the same hole with no flyers.
The rifle can shoot very well. Good luck.
Jerry
Assuming that shots were done consistently without wind, you can see that the groups started vertical, went horizontal/circular, then vertical. This would be very obvious at longer distances.
There is also little point in going to the absolute max as this will be a very touchy load as temps change and barrel wears.
I like to keep my loads in the widest sweet spot for my set up.
Now to go up in very small increments and at longer distances to eliminate any stringing. My guess is that around 32.0 to 32.7gr will be your load for this bullet.
Big thing now is to call your flyers. You are looking for very small variance that can come from wind or you, as well as the load. You are looking for the load where the bullets just drive themselves into the same hole with no flyers.
The rifle can shoot very well. Good luck.
Jerry
From my own experience with many 6 BR's I personally feel that seating depth IS the holy grail of 6BR accuracy. The bullets will work across a wide spectrum of speeds, but they are extremely sensitive to the right seating depth.
Take your best powder load and start at soft jam and work your way to 20 thou into the lands in 2 thou increments.
Take your best powder load and start at soft jam and work your way to 20 thou into the lands in 2 thou increments.
for sure i'm going to work charge in finer increments. if after that i change seating depth will that warrant re developing my charge weight as the case volume willl change? I guess my goal in all this is to truly understand load development to get the most out of my toys and range time. i appreciate the input i have received thus far. Thanks to all.
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
My experience is that changing the seating depth is akin to changing the powder charge as you are changing the combustion chamber volume. You are also changing the pressure curve as that is directly related to how jammed the bullet is relative to the lands.
I work with powder charges as I usually have mag fed rifles where the mag determines the OAL.
In my match rifles, I want a stable set up which can shoot accurately over many rds. If I work up my load based on OAL, I will need to constantly adjust my load. The throat is constantly moving and changing. With some of my boomers, you would need to adjust your load every 50 to 100rds. That is not much fun...
Jerry
I work with powder charges as I usually have mag fed rifles where the mag determines the OAL.
In my match rifles, I want a stable set up which can shoot accurately over many rds. If I work up my load based on OAL, I will need to constantly adjust my load. The throat is constantly moving and changing. With some of my boomers, you would need to adjust your load every 50 to 100rds. That is not much fun...
Jerry
