Help me understand...



  • Ok, since the availability of the 140gn bullets I use for the matches (Nosler CC 140gn) is sporadic, and since I've had good luck with Hornady AMAX bullets in the past, I decided to swith over to the 6.5 123gn AMAX bullets since it seems those are always available.

    Long story short, I did my ladder test, found some nodes, and loaded 7 rounds of the middle of each of those nodes. During the ladder test, one of the loads had really good velocity spread of 6fps. When shooting the 7 rounds for that load my ES was 63fps and the group for that load was 1.5" for all 7 shots.

    My best load gave me between .5-.75" at 100yds for 7 shots, but the ES was 72fps. And here is the interesting part, my average velocity for this load is 3097fps. How can a load with a little worse ES and SD shoot with about 2X the accuracy of the other load?

    Another observation...I was looking at the loads section of the site and I find that someone has a load of 44.5gn of H4350 and that is flying at 2785 on a 6.5 CM. My most accurate load is 45.2gn of H4350 which gives me an AVG velocity of 3097fps with the 123gn AMAX. I am shooting mine out of a 26" barrel. for a .7gn increase I am getting a little over 300fps more velocity. Does that look rigth?



  • Because I just read this https://www.primalrights.com/articles/load-development I think I have a clue of whats going on here. But if I'm wrong, I'm sure Greg will beat me down and shame me publicly.

    Your load that is most accurate despite the ES, because that is the node where the bullet is leaving the barrel at the same point each time in the wave of the barrel.

    On the 300 FPS faster, different barrels, different speeds.



  • benchmark barrel?



  • @ramirojpc said:

    Ok, since the availability of the 140gn bullets I use for the matches (Nosler CC 140gn) is sporadic, and since I've had good luck with Hornady AMAX bullets in the past, I decided to swith over to the 6.5 123gn AMAX bullets since it seems those are always available.

    Long story short, I did my ladder test, found some nodes, and loaded 7 rounds of the middle of each of those nodes. During the ladder test, one of the loads had really good velocity spread of 6fps. When shooting the 7 rounds for that load my ES was 63fps and the group for that load was 1.5" for all 7 shots.

    My best load gave me between .5-.75" at 100yds for 7 shots, but the ES was 72fps. And here is the interesting part, my average velocity for this load is 3097fps. How can a load with a little worse ES and SD shoot with about 2X the accuracy of the other load?

    Another observation...I was looking at the loads section of the site and I find that someone has a load of 44.5gn of H4350 and that is flying at 2785 on a 6.5 CM. My most accurate load is 45.2gn of H4350 which gives me an AVG velocity of 3097fps with the 123gn AMAX. I am shooting mine out of a 26" barrel. for a .7gn increase I am getting a little over 300fps more velocity. Does that look rigth?

    That post generates more questions than answers. It paints a picture of someone that needs to slow down and follow the instructions in my article. It may seem time consuming to read, and even more time consuming to perform, but if you follow my directions... it will lead you to a load. Simple as that. Read the pressure article too, because I'm struggling to see how you're getting 3100fps with 123's in a 6.5CM. So either you're running hot as hell, or your chronograph is out to lunch. Either way, at the stage of the game you're at, velocity shouldn't even be entering into the equation.



  • @orkan said:

    @ramirojpc said:

    Ok, since the availability of the 140gn bullets I use for the matches (Nosler CC 140gn) is sporadic, and since I've had good luck with Hornady AMAX bullets in the past, I decided to swith over to the 6.5 123gn AMAX bullets since it seems those are always available.

    Long story short, I did my ladder test, found some nodes, and loaded 7 rounds of the middle of each of those nodes. During the ladder test, one of the loads had really good velocity spread of 6fps. When shooting the 7 rounds for that load my ES was 63fps and the group for that load was 1.5" for all 7 shots.

    My best load gave me between .5-.75" at 100yds for 7 shots, but the ES was 72fps. And here is the interesting part, my average velocity for this load is 3097fps. How can a load with a little worse ES and SD shoot with about 2X the accuracy of the other load?

    Another observation...I was looking at the loads section of the site and I find that someone has a load of 44.5gn of H4350 and that is flying at 2785 on a 6.5 CM. My most accurate load is 45.2gn of H4350 which gives me an AVG velocity of 3097fps with the 123gn AMAX. I am shooting mine out of a 26" barrel. for a .7gn increase I am getting a little over 300fps more velocity. Does that look rigth?

    That post generates more questions than answers. It paints a picture of someone that needs to slow down and follow the instructions in my article. It may seem time consuming to read, and even more time consuming to perform, but if you follow my directions... it will lead you to a load. Simple as that. Read the pressure article too, because I'm struggling to see how you're getting 3100fps with 123's in a 6.5CM. So either you're running hot as hell, or your chronograph is out to lunch. Either way, at the stage of the game you're at, velocity shouldn't even be entering into the equation.

    You are probably right. With how difficult it has been to find the "ingredients" that work well readily available, it always seems like I am in a hurry to develop a new load for the next match. With that said, I have read your article, and i followed your instructions on load development for both my 6.5x284 and my 6.5CM. My problem is that unless I am wrong in what to look for, I don't see pressure signs on my loads for 6.5CM. I get no sticky bolt, I get no cratered primers (I even look with a magnifying glass), I get no swipes on the case heads, etc. The Lee manual I am using claims a 44.8gn max load with 2950fps out of a 24" barrel, I am already running .4gn over that with no pressure signs at all. I started my load development at 41.5gn and went up from there in .5gn increments to find the max like you suggest, but didn't find it, better stated, I didn't find a max based on how far I wanted to go over the stated max in the Lee manual. It was the same thing when I was developing a load for my 6.5x284, and after I had gone about .5gn over the stated max, I asked in the SniperCentral forum if I should keep going since I saw no pressure signs. So I stopped at 45.2gn of H4350 for my 6.5CM. Then I went back and loaded 3 rounds each from 41.5 in .3gn increments up to 44.7gn, just below the stated max per Lee's manual. When I saw I had no pressure signs, I did 2 more loads, 1 at 44.9 and 1 at 45.2. The 44.9gn load is the one that gave me the 6fps ES between the 3 shots of the ladder test. However, I did have other close nodes in the 42-43.5gn range, but not as good as the one between 44.3-44.9. So I loaded 7 rounds each of 44.6, 44.9, and 45.2 and shot a group measuring velocity for each shot. The 45.2gn load gave me the smallest group of all 3 of them. I guess the biggest difference between how I do the ladder test is that I shoot the 1st string low to high charge weight looking for pressure signs, the 2nd string I shoot high to low, and the 3rd string low to high again. I use a spreadsheet with the table and I label the columns 1, 2, & 3 for the shots, and the charge weights i label a, b, c, d, ...etc. I then pasted a picture of my target on the right of that table and printed it and as i am shooting I am marking the shots on the target: 1a, 1b, 1c, etc..

    That is technically what I have been doing to try and find a good load. I already have a little over 350 rounds down the pipe on the gun so the barrel should be well settled, hopefully. But after this match, and since I am not competing on another one for another 3 months or so, I am going to take the time and follow your load development article and see what I come up with.


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