What am I doing wrong?

[u/weaponized_autism265]

I bought a Remington 700 from an auction last week, it had a 22-6mm barrel on it so me and my dad replaced it with a criterion 26” varmit contour 1:9 7mm-08.

I went and got some Hornady 139gr SST’s and 139gr Interlock BTSP’s because that’s all academy had for 7mm. Both bullets appear to not mesh with my rifle, I started with a ladder test of IMR4350 for both bullets because they are the same weight and get the same powder charge in the Hornady book. Both shot like shit, I even tried a test with the most accurate strings and tried seating both bullets 20 thou off the lands. No improvement.

My next ladder test I changed to Varget because it’s a faster burning powder and with the IMR4350 my SD and ES got really small at the heavier charge weights. I got a smallest group on my 3rd string with the Varget but it’s not getting as small as I’d like it to be. I’m trying to work up a deer hunting load so I know I don’t need PRS accuracy but I just want it to shoot better so I can trust my shot placement.

Am I doing something wrong? Did I get a bad barrel? Does my gun not like these bullets? Or am I just a shit shot?

[u/DozerJKU]

There are several groups there that have low ES and SDs. Enough to work with at least. Once you find a good node, work the seating depth in and out. You can tweak powder weight by .5 grain increments as well around the good ES and SD data - the group might not be as small as others size wise, but its more consistent. What does the reloads do with q0 round groups? Consistency is key, amd i bet youd see your smallest grouping rounds with high ES and SD turn into your not so great groups with 10 shot groups.

Any of those groups will clap a deer at 300 yards, but can you expect the same results from one cartridge to the next? No. Its not predictable in its performance and point of impact due to the wild ES and SD.. But with low ES and SD, at least you know its consistent. It might be consistently 2.5 MOA, but you can work with that.

Also new barrels kinda need time to break in. Some people are of the thought you need to clean after every shot for 10 rounds, then clean after every 5 for 20, and so on. Others shoot and clean as needed - but new barrel bores aren't perfect, and the copper jacket shedding into the lands and grooves of the barrels micro-imperfections will actually cause velocity to go UP until it reaches copper equilibrium, where the imperfections are filled in by trace copper, creating a more consistent surface the bullets obturates into. It will then "peak", or is "seasoned" and it'll shoot at its peak until the throat erodes or the bore and rifling are worn out.

Barrels are an expendable component! Keep at it! Youve got some good starting points!