Help improving my group’s. What needs changing?

R

Rickyd1

Private
Minuteman
Mar 3, 2023
10
3
England
#1
I’m working up a load for my 6.5 creedmoor AT-X. I have really good extreme spread of 6.8fps and standard deviation of 2.9fps. Im also happy with the velocity of 2772fps I’m now altering the seating depth - I have a range of depths already tested, but ideally I’d like them tighter. I started off with 25 thou off jam, then worked my way back. I have gone from 2.3280 down to 2.2720. Do I need to still keep going with the seating depth?
I have a barrel tuner that I haven’t yet touched, as ideally I wanted tighter groups first, or would you be happy with the results and start adjusting the tuner ?
 

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#2
I would do a finer seating depth adjustment. .030 though is a lot between adjustments. Some people go as low as .003 to .010 adjustments. Find the 3 groups that are close in size and pick the longest one.
 
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#3
5 shots is way too small to get an accurate representation of what your true ES/SD is (unless you already confirmed this over a larger sample size). If you haven't already, I highly recommend you review this Hornady podcast:

The only thing you can glean from 3 shot groups is immediately identifying bad ones. I would set a desired threshold...say 1/3 moa (if that's even possible), throw out the shots above that, and keep gathering data for the potentially good ones. Rinse and repeat.
 
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#4
Sorry, my first post wasn’t very clear- yes adjustments are .003
Also I have done a 20 shot string prior to this, the the results being very very similar- just slightly higher.
And yes I do plan on doing larger groups than three shots, it’s just that I wasn’t too happy with the results I currently have, so don’t want to waste more bullets
 
#6
Rickyd1 said:
Sorry, my first post wasn’t very clear- yes adjustments are .003
Also I have done a 20 shot string prior to this, the the results being very very similar- just slightly higher.
And yes I do plan on doing larger groups than three shots, it’s just that I wasn’t too happy with the results I currently have, so don’t want to waste more bullets
Click to expand...
Curious....what bullet
 
#8
I’m using 140g eldm
Yes those two targets are acceptable, I was just hoping that there would be a few more similar to those either side (was hoping for around 4 good continuous groups)
 
#10
Shoot a couple of 10-30 shot groups with what appears to work, select the best out of those and stop chasing your tail. Three shot groups prove nothing. If you don't believe try shooting five three shot groups without changing anything. You'll notice they are still drastically different.

Also it looks like it groups just fine. It's not a candy-colored benchrest rifle.

Stop worrying and fiddling with the load, instead start shooting and practicing.
 
#11
When fine tuning seating depth, you should consider what the throat erosion rate is.

For example, let's say you observe that 0.025 jump produces poor precision, but 0.015 is great. Then, you loose 0.01 to erosion over a 150-round match. You've got two issues, the later rounds shot during the match are in the "poor precision" bucket, and you're back to load development b/c seating depth ...

+1 @Shawny "Stop worrying and fiddling with the load, instead start shooting and practicing."
 
#12
MvHTjy said:
5 shots is way too small to get an accurate representation of what your true ES/SD is (unless you already confirmed this over a larger sample size). If you haven't already, I highly recommend you review this Hornady podcast:

The only thing you can glean from 3 shot groups is immediately identifying bad ones. I would set a desired threshold...say 1/3 moa (if that's even possible), throw out the shots above that, and keep gathering data for the potentially good ones. Rinse and repeat.
Click to expand...

Shill
 
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