6x47 Bizarre Seating Depth Results

[Badbob]

Folks

I've been doing load development for my 6x47 using Barts 105 Hammer. The gun is a Criterion 26" heavy varmint on a Defiant Tenacity action, Vortex GenII Razor, Manner's composite stock. I'm working on two nodes, one at 2870fps and another at 2940fps. I've comparing my targets and I see that my vertical and horizontal strings are very similar. Have you seen this before? I've also notice that .013" off the lands produced that best group size and lowest SD/ES for both 36.5 and 37.3 H4350. Further, all three of the best groups were at the same seating depth for both powder charges (nodes). Is this normal? Sure would like to hear your thoughts on this? Thanks BB

 

[Badbob]

Here is comparison of the best groups at .013" off the lands.

 

[JEFFPPC]

Shoot the 1.140 and 1.141 again and if one or both repeat then go up down .1 at a time for a couple of tenths with powder to see if it gets better. Once you have settled on a load ck for ES , if it is not single digits try various primers. I tuned all 3 of my competiton rifle from high teens ES to 5 or less with primers. All three did best with Fed 205M, I had never used them before in 50 plus yrs of competition. Never to late to learn something

 

[Badbob]

Shoot the 1.140 and 1.141 again and if one or both repeat then go up down .1 at a time for a couple of tenths with powder to see if it gets better. Once you have settled on a load ck for ES , if it is not single digits try various primers. I tuned all 3 of my competiton rifle from high teens ES to 5 or less with primers. All three did best with Fed 205M, I had never used them before in 50 plus yrs of competition. Never to late to learn something

Thanks Jeff! So, just to clarify, you are suggesting:

1) reshoot both 1.140 and 1.141 seating depth in 37.3g of H4350 with BR-4 primers
2) then change the powder charge by .1 grains up and down to see if anything changes or looks better.
3) check ES for single digits and if not single, then check primers to see ES improves.

Is this correct?

Do you have a suggestion for the primer test?

Huge help, thanks BB

 

[Ranger188]

BB, what are you going to do with it?
Since your running a Manners and Razor, this isn't a BR rifle and your groups
look to be sub .25 MOA
If you think it will shoot better than, adjust the powder like JEFFPPC said, just up and down .1
Or adjust the seating .002 in and out. Or the primers, if you have 205M's or CCI 450's
and keep the same load, just swap out the primers.
Only do one thing at a time and test it before doing anything else.
Other wise, your GTG. Most tactical rifle shooters would be happy with those groups
if it repeats..
Love my 6x47 too.

 

[JEFFPPC]

Thanks Jeff! So, just to clarify, you are suggesting:

1) reshoot both 1.140 and 1.141 seating depth in 37.3g of H4350 with BR-4 primers
2) then change the powder charge by .1 grains up and down to see if anything changes or looks better.
3) check ES for single digits and if not single, then check primers to see ES improves.

Is this correct?

Do you have a suggestion for the primer test?

Huge help, thanks BB

Shot back to back 5 shot groups to find your current ES. If its 10 or less your good. If not do the same thing with different primers. As your doing this if your first 5 have an ES of more than 11 or12 I would not bother with the second group. You can do this if testing groups or drop beyond 100yds since the ES is not related to target distance. What ever you find always be sure it repeats before excepting it as gospel. Rangers advice on testing one thing at a time is good advice. As far as it's as good as you need since its not a dedicated Benchrest gun that is personal preference, that would not be my thought. If you miss steel at 900 yards by a ants eyelash, well maybe a gun that shot in the middle ones instead of middle 2s just might have been a hit. You need to decide what works for you. Good luck.

 

[Badbob]

Shot back to back 5 shot groups to find your current ES. If its 10 or less your good. If not do the same thing with different primers. As your doing this if your first 5 have an ES of more than 11 or12 I would not bother with the second group. You can do this if testing groups or drop beyond 100yds since the ES is not related to target distance. What ever you find always be sure it repeats before excepting it as gospel. Rangers advice on testing one thing at a time is good advice. As far as it's as good as you need since its not a dedicated Benchrest gun that is personal preference, that would not be my thought. If you miss steel at 900 yards by a ants eyelash, well maybe a gun that shot in the middle ones instead of middle 2s just might have been a hit. You need to decide what works for you. Good luck.

Thanks Jeff . . . it is a PRS gun, not a BR gun. .25moa is plenty good for PRS and range time has far more impact on scores than tight groups. However, I'm finding it personally enjoyable to see how well it shoots. Seeing the occasional .1 is very obsessive!

I loaded up different primers this morning: 6 1/2, 7 1/2, 205M, 405 all at 37.3g of H4350 and a seating depth of 1.141" That combo has repeated produced single digit ES and SD with BR-4 primers. I think this will be it for me or until I get my 6mmBR back together and my Barts 80g Dominators show up in the mail and I can start playing with that rig. That gun will be a dedicated BR gun. BB

 

[4xforfun]

I would go up and try the next two nodes......just to see. I find them at 3050ish and 3140ish. Now, I shoot the 108 Berger...don't know if that matters. If they aren't any better, go back down.

Tod

 

[mgunderson]

It is common for the seating depth to be the same or very similar. That is why people often talk about setting the seating depth first before working the powder.