What went wrong? May have figured it out?

[ckaberna]

So, I have a new to me 6BRA went out and shot a ladder at 391 yards last week. See target. Based off what I have learned 31.8 grains is where the “node” is..... well once I got home I loaded 3 sets of 6 for grouping and seating testing. These were fire at 200 yards. Obviously this is not the node so what am I missing?

1” orange dots
105 hybrids
28” Brux 8 twist
Bat “B”
2907 avg. with Oehler 35
SD=9
ES=20

Fired some more trying to find a maximum for this rifle from 32.1 to 33.2 grains with velocities from 2930 to 3032 and the resulting cluster at 200 were a smaller group than the sets shown? No pressure signs ever seen?

Frustrated

 

[JMayo]

31.8 is near max. I shoot a bart w bat. Jumping 3thou.
I found 30.5 and 31.8 shot near the same.
I went with 30.5. So many things can cause a spread like that.
One day it's all One hole The next it's all over the place.
The poa width of a crosshair can be the difference.
Hand tension, trigger pull. Tension on forearm, setteling of rear bag.... The list goes on and on.

We shoot dots at 100 ...unreal what the bullets do.
One guy out of 15 hit 50 out of 50 dots.
.... Fantastic shooting everyone said ....

 

[Steelnecktie]

H4895 is what your missing
My 6BRA was same way, best groups with Varget were at 3100
Best groups with H4895 were around 2960. 1/2 the size of Varget groups

 

[ckaberna]

I also ladder tested 4895 the same day but couldn’t find a node. All loads seemed to keep increasing. I suppose I could try the 31.3 load?

 

[ttfreestyle]

H4895 is what your missing
My 6BRA was same way, best groups with Varget were at 3100
Best groups with H4895 were around 2960. 1/2 the size of Varget groups

Same here with varget, terrible groups

 

[ckaberna]

31.8 is near max. I shoot a bart w bat. Jumping 3thou.
I found 30.5 and 31.8 shot near the same.
I went with 30.5. So many things can cause a spread like that.
One day it's all One hole The next it's all over the place.
The poa width of a crosshair can be the difference.
Hand tension, trigger pull. Tension on forearm, setteling of rear bag.... The list goes on and on.

We shoot dots at 100 ...unreal what the bullets do.
One guy out of 15 hit 50 out of 50 dots.
.... Fantastic shooting everyone said ....

Why would you say 31.8 is near max when I have went as high as 33.2 with no signs of pressure. I agree I thought 31.8 was max but at 2908 FPS I expected more?

 

[ckaberna]

May be this lot of varget does not play well with this barrel? Will try the 4895.

 

[KenOath]

Try 30.7 to 31gn Varget.. I know someone else having problems with a BRA he’s also using Hybrids?.

 

[HTSmith]

Don't know what elevation you are at, but Berger suggests faster than 8 twist for hybrids. I'm at sea level and my 7.5 Brux shoots the hybrids better than my 8 twist Brux at 300 yards. I'm certainly no expert.

 

[ckaberna]

Elevation about 750’
Coil humidity do this? It was 87% the day I shot these. Temp 85F

 

[dbduff]

Stay with it. Like any endeavor, the more you do,the more you learn. Save your targets, write it all down. At some point,"eureka" how could I have missed this? We've all gone through a variation of this. Think how you learned to catch a ball, or throw a spiral. Over and over.

 

[BartsBullets]

View attachment 1057027 View attachment 1057028 So, I have a new to me 6BRA went out and shot a ladder at 391 yards last week. See target. Based off what I have learned 31.8 grains is where the “node” is..... well once I got home I loaded 3 sets of 6 for grouping and seating testing. These were fire at 200 yards. Obviously this is not the node so what am I missing?

1” orange dots
105 hybrids
28” Brux 8 twist
Bat “B”
2907 avg. with Oehler 35
SD=9
ES=20

Fired some more trying to find a maximum for this rifle from 32.1 to 33.2 grains with velocities from 2930 to 3032 and the resulting cluster at 200 were a smaller group than the sets shown? No pressure signs ever seen?

Frustrated

I think you need to work on your seating depth. That should help tighten it up some.

Bart

 

[ckaberna]

I think you need to work on your seating depth. That should help tighten it up some.

Bart

Thanks Bart but I have done that too. I am thinking “scatter node” but looking at the ladder? These are 3 shot groups at 200 starting with .008” jam all the way to .035” off in .003 intervals, may need more? The .0 is the only thing promising to me but I don’t like just “kissing” the lands.

 

[Steelnecktie]

Maybe give you something to work with, this is where I’m at
.002” neck tension
CCI BR4 primer
Lapua Brass
Once rifling makes a mark on bullet, .010” more jammed into rifling.
30.6 Gr. Of H4895
105 Gr. Bullet @ 2960 FPS.
Brux 4 groove
Don’t know if this will work for you, but it shoots 1.5” 20 shot groups at 500yds for me.

 

[mikecr]

I think you should start over with Berger's recommended full seating testing, at a reduced charge that you feel would be worst for powder(nowhere near a node). Find your best coarse seating, and move on with that for your ladder testing.

 

[dkhunt14]

I never could get the hybrid to shoot at 1000 yards in my 8 twist Dashers. I have also seen alot of other guys struggle with 8 twists. The 108 BT and 105 VLD have always shot better for me. Matt

 

[BartsBullets]

Bart
As a bystander to BRA I've seen several competitors move away from hybrid to a 108 Berger and beyond ' other than custom Bullets such as yours how much more seating test would you do prior to moving on in this case?Edit- and which projectile would you try next?
Just wondering
Jim

Jim,

I agree about the hybrid 105s. They tend to to be a good bit longer then say the Berger 105 VLD and that makes them a tad harder to stabilize. I’d try some Berger 108s or the Berger 105 VLD. If that doesn’t work give a shout out to Tommy Jacobs or myself for a custom bullet.

Bart

 

[ckaberna]

I have got 15 more rounds loaded with the hybrids and 4895 before giving up. I have 400 or so of the old Spencer 103’s I may try while waiting on the 108’s.
Thanks for all of y’alls advice and ideas. Will update results.

 

[riflewoman]

During your ladder test did you also measure velocity? You’re shooting .3 gr increments. A standard deviation for ammo is often 13 fps or higher. Hodgdon lists 26 grains/2367 fps starting and max 29 gr/ 2620. The total increment is 253 fps in 3 grains. Or 25 fps in your incremental charges. So the 13 fps SD can wipe out all or most of your velocity gain with this method. You really need to shoot 3 examples of each charge and if you do that, you might as well shoot groups. Ladder tests are just that way. Especially with smaller charges.

 

[Alex Wheeler]

.3 in a br case is huge. You wont find a node like that. .2 is a course ladder which will tell you where to load your .1gn ladder. Use 3 shot per charge as well. If if doesnt look good, pick something that looks ok and work seating depth, then re visit the ladder. If still no good change powders. At this point with what we spend in the shooting hobby I cant imagine not shooting a custom bullet. Either the 103 vapor trail or Barts hammer. 105 vlds and 108s are great IF you get a good lot and sort them.