Promising load went to sh!t?

[Xringer07]

I'm somewhat new to reloading (Jan 2020) and have been working on load development for my Rem 700 in .243 Win. (Factory walnut stock, glass and pillar bedded, Zeiss V4 3-12, Talley Lightweight rings). Settled on a 95 gr NBT over 46.5 gr of RL26, 0.020 off the lands. This load was showing ~0.6 - 0.75 moa on several different range trips.

Decided to try some different seating depths to see if I could get things any tighter (why not). This is where I seemed to run into trouble. Loading up the same exact load (as a control) showed dismal results on two different range trips. Nothing inside 1.5 MOA. Tried cleaning the bore with Butch's Bore Shine, then three foulers and very similar results.

I've checked action bolt torque, ring torque; nothing has changed. At this point I'm suspecting my brass is getting tired (5 loadings), but there are no outward signs of failure that I can see.

I'm at a loss for the sudden decrease in accuracy and was wondering if any of you folks have experienced something similar? Any suggestions are greatly appreciated!

P.S. The rifle has (maybe?) 500 rounds through it so I'm not suspicious of a worn out barrel.

Thanks a ton in advance!

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[wildwilderness]

you need a chronograph. You have to know what the bullet is doing. Usually they speed up. I have had to drop almost 1 grain of powder to get a load back to shooting well. Also temperature will affect RL 26 more than the other touted temp stable powders.

In my limited experience the group depends on the fps more than anything else.

 

[rayporter]

how many three shot groups did you get under an inch?

serious question.

 

[Xringer07]

you need a chronograph. You have to know what the bullet is doing. Usually they speed up. I have had to drop almost 1 grain of powder to get a load back to shooting well. Also temperature will affect RL 26 more than the other touted temp stable powders.

In my limited experience the group depends on the fps more than anything else.

My initial workup was showing an average of 3023 with an ES of 20 and an SD of 10. Haven't chrono'd it since, but temps are only about 20° different. I'll run it through the chrono again tomorrow to check velocities. 0.2 grains above and below the selected load were +7 and -8 fps avg respectively.

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[Xringer07]

how many three shot groups did you get under an inch?

serious question.

Well, the only two I've tested with that particular load on separate sessions. I found accuracy on a lower charge as well, but wasn't satisfied with velocity. Don't get me wrong, I'm no accomplished marksman, but I believe I have the fundamentals down and don't have much trouble with other rifles ( I worked a load for my dad's .270 that routinely shoots 1/2 MOA... and my BCM AR shoots 3/4 to 1 MOA) . The sudden change is what's throwing me off. Maybe it is me? I honestly don't want to believe that though lol

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[rayporter]

ok, you can shoot a .270 into a half inch often and under an inch all the time. it is not you.

there is a saying in bench rest that goes something like this, "the wind blows them out and the wind blows them in"

2 groups does not show true capability.

 

[Xringer07]

What happened between the two photos you posted? Aggregate looks to be a little over 1.5MOA

View attachment 223388

That was a scope adjustment from .75 group to .6 group

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[Erict]

Try less scrubbing unless accuracy falls off. A soaked solvent patch to remove powder residue and a clean dry patch followup every now and then as needed. Good luck.

 

[MidGAHunter]

Assuming no changes in lots of any components (bullets , powder, primers), I'd load up 10 rounds of the load you felt was your best load. Shoot those through the chrono and see where your group is. That 10-shot group will give you an idea of the capability of that load in your rifle. If the lot of any components changed you may need to do a re work of your load to get it back to the velocity node. Also, do you anneal your case necks? If not and you have 5 firings on your brass you may have inconsistent neck tension, which can open up your group as well.

 

[Xringer07]

Thanks for the replies everyone. Turns out I had a wonky box of bullets. I annealed enough of my brass to run a few tests. I opened up a fresh box of 95 gr Ballistic Tips and loaded up 5 each of 46.5 gr RL 26, 0.020 off and 0.080 off respectively as those two showed good results initially. Both printed 5 shot groups under 0.9 MOA. Not comp level, but closer to what I expected. I also loaded up 5 with non-annealed brass and they printed a real similar group. Goes to show a different lot of the same exact bullet can show some drastically different results.

Thanks again for all the input, this forum and community are tops.

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[Sean.mcvicker]

Just stumbled upon this post. Having a load that shoots right SD’s does not mean it will group. Period. Most likely the lands on your barrel finally wore past the accuracy node (seating depth) you were in. Do a seating depth test starting at .010 off the lands. Shoot groups of 3 seating your bullet in .003” each time. You will find the seating depth your rifle likes. After finding the best group. Find your powder charge with an OCW test. If a wonky batch of bullets changed your load that much, you didn’t have a stable load to start with Look up reloading videos by long range only, or Eric cortina.