Group Pattern Question

[dashender7]

I'm seeing a pattern repeating shooting groups.

6.5 CM Weatherby Vanguard "Meat Eater" with 24" spiral fluted light barrel. No modifications. About 140 rounds on the rifle now. 143 ELD-X with Lapua brass CCI 400 small rifle primers RL-26 2,735 avg. with about a 12 ES. Maybe the very beginnings of light pressure near top of published powder around 46.0

I can back off powder and get about .8" groups consistently, but I'm wanting to chase these almost tiny groups.

Pictured below is at 100yds. Have seen similar results at 200yds with the expected group size comparably.

4 or 5 shot groups with small cluster and one bad flyer up to 1.5" to 2"" out of the group that are otherwise all touching. Pictured below is the worst one. Unless I'm crazy, I feel like the wild one is shot 3 after the first 2 starting with a cold or cooled down barrel. I also might be waiting longer after that flyer for the barrel to cool before shot 4 thinking the barrel is warming up too much. Haven' been able to confirm again yet.

Hoping for ideas and insight to consider as I troubleshoot load development. Dumb to think I'm on to something good with this load given the bad one that happens in every group? Barrel heating up or wrong powder charge? Where might I go from here? Thanks in advance!

 

[nealm66]

That looks more like something mechanical, scope, mounts, stock, you. If you get that figured out, that's a definite shooter

 

[L.Sherm]

Try sorting your bullets base to ogive.
Are you measuring all your rounds CBTO

 

[dashender7]

That looks more like something mechanical, scope, mounts, stock, you. If you get that figured out, that's a definite shooter

Thanks for the feedback. Will check everything. Not sure what to do about the stock - just check the action screws?

 

[dashender7]

Try sorting your bullets base to ogive.
Are you measuring all your rounds CBTO

I am measure all CBTO with a comparator yes. The seating depth is consistent to a thousandth. I haven't checked bullets by themselves but I think if they seat and measure seated consistently I should be good to go right?

 

[Stammster]

2735 fps with 143 ELD-X and RL26 out of a 24" bbl should not be close to excess pressure unless you are jammed. You should be ok to at least 2900 fps - which is roughly 63kpsi.

 

[L.Sherm]

2735 fps with 143 ELD-X and RL26 out of a 24" bbl should not be close to excess pressure unless you are jammed. You should be ok to at least 2900 fps - which is roughly 63kpsi.

Just because one gun might do it doesn't mean the next will.

 

[Stammster]

I know. But there is a direct relationship between velocity and pressure for a give bullet, powder burn rate, and barrel length.

My comment was specific to the 143 ELD-X, 24" and RL26 out of 6.5 CM. I would expect to just start seeing pressure signs with H4350 at that velocity (2735 fps), but not a slower burning powder like RL26.

Just wanted to let the OP know that it's possible he might possible go slightly higher on powder charge to solve his issues. Carefully of course.

 

[nealm66]

Thanks for the feedback. Will check everything. Not sure what to do about the stock - just check the action screws?

Well, I'm not really sure if I'm being honest. What throws me off is your solid groups at a lesser charge. That flier to me sure doesn't look like harmonics. What is your shooting platform? 1 piece or 2 piece rest? Bipods? Is the flier always horizontal from the group?

 

[dashender7]

Well, I'm not really sure if I'm being honest. What throws me off is your solid groups at a lesser charge. That flier to me sure doesn't look like harmonics. What is your shooting platform? 1 piece or 2 piece rest? Bipods? Is the flier always horizontal from the group?

I always shoot prone from a harris swivel bipod in the dirt with a rear bag. I was taught to load my weight a little into the bipod. I'm not a competitive shooter but probably enough experience to say I don't think it is me. I should add that not all lower powder charges give solid sub MOA - some are opened up to over 1.5" but a more consistent scatter. Flyer seems to be horizontal or diagonal never straight vertical.

 

[dashender7]

I know. But there is a direct relationship between velocity and pressure for a give bullet, powder burn rate, and barrel length.

My comment was specific to the 143 ELD-X, 24" and RL26 out of 6.5 CM. I would expect to just start seeing pressure signs with H4350 at that velocity (2735 fps), but not a slower burning powder like RL26.

Just wanted to let the OP know that it's possible he might possible go slightly higher on powder charge to solve his issues. Carefully of course.

Thank you for the input. Seems I read and have experienced Lapua brass is a good bit lower volume than some others like Hornady? This might have something to do with reaching pressure sooner? By pressure signs I should say slight primer cratering and flattening of primer, some carbon on outside of case neck, no marring of the case head.

 

[dashender7]

I should add too that I don't believe I'm jammed. I measured jam at 2.242 CBTO and these groups are all tested at 2.220

 

[nealm66]

Are you single feeding? Have you tried off a bag? That might eliminate a couple possibilities. I think vanguards have a bedded spot out a ways on the stock that could play havoc off a bipod. Usually when I see horizontal I blame myself and I can tell it there before I even look at the target. Hopefully your not sensitive as I'm just trying to throw possibilities out

 

[dashender7]

Are you single feeding? Have you tried off a bag? That might eliminate a couple possibilities. I think vanguards have a bedded spot out a ways on the stock that could play havoc off a bipod. Usually when I see horizontal I blame myself and I can tell it there before I even look at the target. Hopefully your not sensitive as I'm just trying to throw possibilities out

Oh man no pride there at all brother. It could be me I shouldn't rule that out, but normally I'd know if I pulled one like that and easily call it right away without even needing to see it too. I am single feeding and I will take the suggestion to shoot off a bag this next time. This is the first rifle I've ever had with such a light barrel and non-free floated. I truly appreciate the help brainstorming so I can make the most of my next time out to shoot and figure this out.