Vertical shot string

[Redmt]

Question for all the reloading wizards. I've heard of vertical shot stringing but never paid much attention to the threads. I'd never seen it until now.
I broke in the barrel on my custom 6.5 bored #1. I figured I would start with a known load that produces excellent results with my Ruger Predator. I've been shooting the same load for years. So same load, completely different rifle and I got an S shaped vertical string about 6-8" with 5 rounds. What do I even start with looking for the WTF?

 

[Coule stalker]

what is your shooting position? The S shape sounds like potentially a combination of trigger pull and breath… I recommend starting completely over, it doesn’t sound like the new rifle likes your pet load. I’m no expert, but I always start with new brass, or shoot some higher quality factory ammunition and keep that brass for that gun. If you like your pet load components, back off to the book minimum and work up from there.. sometimes just a primer change makes big changes..

 

[Coule stalker]

I should have mentioned in my first reply, when I see vertical I start thinking about increasing powder charges… if there is a lot of horizontal, I start playing with seating depth.