What causes a group like this ?

[KyleR1985]

16” 6 dasher

I got 95tmk to shoot ok with Varget and lever.

108 eldm shot great with both.

I just tried 8208xbr with both of those bullets

The 108’s shot ok with it, they seem indifferent to powder in this gun (though not as good as Varget and lever). Still a round group, just slightly bigger than Varget or lever (sub moa versus just over moa).

But Look at the groups I got with the 95tmk. It tightened up significantly horizontally, but strings out vertically. I ran into pressure the first group, so I backed down a little and shot the second group. It got rid of the heavy bolt lift, but still the vertical stringing. And the ES/SD opened up a lot.

I shot a quite a bit after these groups with different bullets/powders and nothing strung like this, so I’m pretty confident it’s not me.

Is the bullet/powder combo just not going to work? Or should I try a different primer?

The red target was the too hot load first at 200, orange bull reduced that load .3gr at 100 yards.

 

[coyotekilla]

This is my tikka 22-250 and I doing load development. It was stringing horizontal or vertical depending on powder charge, but the happy place was found. I usually find accuracy a touch below max loads. Did backing the powder off .2 or .4 affect anything?

 

[KyleR1985]

This is my tikka 22-250 and I doing load development. It was stringing horizontal or vertical depending on powder charge, but the happy place was found. I usually find accuracy a touch below max loads. Did backing the powder off .2 or .4 affect anything?
View attachment 891103

Yeh the group on the orange bull was .4gr less.

That’s why I posted.

 

[coyotekilla]

Yeh the group on the orange bull was .4gr less.

That’s why I posted.

Humm, next question... both groups show simular pattern / group shape...

Assuming its a chassis rifle...

maybe maybe your nodes are very narrow. I've heard that about short barrels.

Personally I haven't experimented with different primers. Basically either 205 or 210 feds

 

[wind gypsy]

Is the bullet/powder combo just not going to work? Or should I try a different primer?

Heck if I know but if I already had 2 powders that worked acceptably, I dont think id spend much time chasing the one that didn't.

 

[KyleR1985]

Heck if I know but if I already had 2 powders that worked acceptably, I dont think id spend much time chasing the one that didn't.

Agree 100%. Feel stupid for asking for exact reasons you describe.

But this is a learning experiment for me too with reloading and ballistics.

I’ve been an archery guy my whole life - there’s not much about a bow or arrows I don’t know or understand. I’m trying to crash course as much as I can with firearms.

I know how they go bang. But I’m running two tracks at same time - get efficient useable results quickly without fuss ; learn as much as you can in the process. It’s costing me a few hundred dollars in range fee and components. But seems worth it - and I could hunt tomorrow if pressed.

 

[wind gypsy]

Agree 100%. Feel stupid for asking for exact reasons you describe.

But this is a learning experiment for me too with reloading and ballistics.

I’ve been an archery guy my whole life - there’s not much about a bow or arrows I don’t know or understand. I’m trying to crash course as much as I can with firearms.

I know how they go bang. But I’m running two tracks at same time - get efficient useable results quickly without fuss ; learn as much as you can in the process. It’s costing me a few hundred dollars in range fee and components. But seems worth it - and I could hunt tomorrow if pressed.

It's a legitimate question and I'd love to hear someone with answers on why it might be doing that. I'm just afraid there might not be a sure fire answer?

I spent a fair bit of time down the various precision reloading dogma rabbit holes and found I couldn't replicate or find anything consistently true so I've tried to dumb it down to save myself some time and sanity.

 

[rickyw]

Could it be inconsistent cheek weld??

 

[Firth]

I've typically heard people blame bedding for vertical stringing, but it obviously doesn't make sense that the bedding would be good for one load and not another. You could try shooting a bunch more shots and see if it fills in and ends up "round".

Maybe barrel harmonics? I've read a bit about it but generally favor the keep it simple route on reloading.

 

[greyghostnw]

Vertical add more powder

 

[Castle Rock]

I would try shortening the OAL , ideally to about .05 to .06” off the rifling

 

[KyleR1985]

I would try shortening the OAL , ideally to about .05 to .06” off the rifling

Thoughts on why?

My groups tightened up with the 95tmk when I got it closer to the lands (.02-.03” off) with the other powders.

Definitely open to trying

 

[KyleR1985]

Vertical add more powder

I had heavy bolt lift with the group at 200 (black and red target).

I backed down .3gr and bolt lift eased up and dropped velo 30fps, and shot the group on orange target at 100.

I’m not comfortable going up in charge weight given that.

 

[MallardSX2]

16” 6 dasher

I got 95tmk to shoot ok with Varget and lever.

108 eldm shot great with both.

I just tried 8208xbr with both of those bullets

The 108’s shot ok with it, they seem indifferent to powder in this gun (though not as good as Varget and lever). Still a round group, just slightly bigger than Varget or lever (sub moa versus just over moa).

But Look at the groups I got with the 95tmk. It tightened up significantly horizontally, but strings out vertically. I ran into pressure the first group, so I backed down a little and shot the second group. It got rid of the heavy bolt lift, but still the horizontal stringing. And the ES/SD opened up a lot.

I shot a quite a bit after these groups with different bullets/powders and nothing strung like this, so I’m pretty confident it’s not me.

Is the bullet/powder combo just not going to work? Or should I try a different primer?

The red target was at 200, orange bull at 100 yards.

View attachment 891071View attachment 891072

Just curious, what was your velocity ES and how are you measuring that?

 

[KyleR1985]

Just curious, what was your velocity ES and how are you measuring that?

Chronograph.

On the group shot at 100(orange target), ES/SD was 71/19. I had one shot way slow. If I take that one shot out, the ES/SD both got cut to 37/12.

One of my suspicions was that my charges were too variable. I’m throwing the 8208 with a harrels. So I loaded up 10 with everything the same, but stopped short and trickled up until one grain getting dropped caused me to hit the charge weight. Not exactly scientific, but surely will tighten the thrown weights up a bit. I’ll shoot these next range trip.

This is speaking to @wind gypsy ‘s point. If I don’t have a clear simple path to correct it with this powder, I’ll move on. But I’m willing to try a couple of things to learn.

If that tightens the group, I’ll probably move on from the powder. I don’t have the time or equipment to trickle up charges. Especially when two other powders work fine.

 

[Wrench]

Vertical on a 6br would have me looking at the action torque and checking bolt / scope screw clearance.

A 6br should shoot considerably better.

 

[wapitibob]

In my amateur opinion, that combo isn't going to shoot and in the off chance you get something close, it won't be consistent. There are bullet/powder combos that are inherently accurate, shoot one of those, it'll be consistent and easy to tune.
When I finally went that route, it was easy. This was my initial 7.0 grain spread, r to l, then fine tuned; done and verified at 81.7gr out to 600 in less than 25 shots.

 

[KyleR1985]

Vertical on a 6br would have me looking at the action torque and checking bolt / scope screw clearance.

A 6br should shoot considerably better.

Would you do this even if multiple other loads shoot round groups before and after that vertical group? And repeats twice with same bullet/powder, but no others.

Seems like if I missed on assembly, it wouldn’t be isolated to a single load out of a session.

I did build gun from ground up and follow protocol of getting everything disassembled, degreased, loctited and torqued. Across around 300 rounds or so, the only two groups to string vertically were 95tmk’s with 8208xbr

 

[KyleR1985]

In my amateur opinion, that combo isn't going to shoot and in the off chance you get something close, it won't be consistent. There are bullet/powder combos that are inherently accurate, shoot one of those, it'll be consistent and easy to tune.
When I finally went that route, it was easy. This was my initial 7.0 grain spread, r to l, then fine tuned; done and verified at 81.7gr out to 600 in less than 25 shots.

View attachment 891937
View attachment 891938

My guess is that you’re correct that it isn’t worth spending time or components on generally.

This question is mostly a learning experience for me.

I’m reasonably certain the gun is tight. I’m reasonably certain the bullet will shoot round groups with other powders. I’m reasonably certain the bullet shot best at current OAL with other powders. I’m reasonably certain the powder shot round groups with a different bullet.


This leaves charge weight and its precision. This seems to me to be “it just won’t work” and I’ll move on. I can’t think of anything else it may be, that’s why I asked.

 

[5811]

I had a load do this when I was searching for a 100eld-vt 6.5 cm recipe. I chased charges and seating depth from jam to +140.

Never did get it to shoot.