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Questions on load development at 100yd for Long Range?

dmoran

Donovan Moran
Many say they load develop at 100yd, then confirmation at the desired distance.
From which I have 3 pertaining questions:

1) Are you after best possible accuracy or acceptable accuracy?

2) Say you get what you’re looking for at 100yd, but when confirmation testing you do not get the accuracy you desire, what do you do and how do you proceed?

3) You get what you’re looking for at 100yds, confirm at desired distance and get acceptable accuracy, how do go about tuning it better/smaller/tighter yet?


I would appreciate answers to all 3 questions from each reply....
Donovan
 
1, Aceptable for the work I wish to put into the cases, loading components and rifle. To get the "best" is like an ongoing saga that never ends.

2. Cry. Sometimes conditions change from one test to another. I try to figure out variables that may have clouded the original test and be honest with myself.
Then I try again and sometimes again. If not, I make a change in some component or rifle factor.

3. I like to play at longer ranges with minor seating depth, and component changes. Changing range conditions again make trouble, especially mirage at longer
ranges. One thing I sometimes try is a "round robin" sampling of changes for each shot on different targets. That way range conditions are maybe amortized.

Had something like that just this past Friday. 300 yard seating depth test turned into a mess. Mirage and wind made precise sighting impossible. Picked what I thought was a good compromise, moved to a gong at 600 years and proceeded to hit 15 in-a row with all I could see clustered near the center of the thing. For now, "good enough" and I refer to #1 and #3.
 
Try 300yds. I was originally using 100yds and when I pick up my rifle after having it rebarreled, we started talking about load work up. He told using 300yds works much better. At 100yds you are to close to the target to get a real feel for what the load might do down range. I started using it and it works quite well.

Good luck on your load work up.
 
1- Best possible Accuracy
2-At 100 yards I just work on a load that Chronographs well, with bullets into the lands
3-If it looks good I then go to 1000 yards to see what group and vertical I have if there is vertical I try a different seating depth if there is to much horizontal I may change powder charge. Or possibly a ladder test!
4- I like at least 200 yards

Joe Salt
 
Donovan

I'll start this by saying if I had access to a 1,000yd range I would do my load testing at that distance but the closest option for me is Deep Creek (500 miles from my house). Funny thing is I work on US Army ranges and have access to 1000 yd ranges but I can't bring private firearms on them.

Next are the answers to your questions:

1. Best possible is the goal
2. Adjust powder + or - .2 gr. Seating depth is next then neck tension
3. Same as #2. If it won't shoot small I'll start back at the begining with different powder, bullet and or primer. I haven't had to do this yet but I'm still new to this sport.

Below is how I develop my loads.

- All my initial load development is on a 100yd range. I load and shoot all at the range like the short range BR shooters to include shooting over flags. Process is similar to what Erik Cortina has discussed at length on this forum.

- Start out with the bullet in the lands and shoot 3 shot groups with a .3 grain increase in powder weight for each group. I'm looking for the rise and fall of the individual groups on paper and look for when the different groups line up vertically. Out of the powder charges that line up vertically, I'll select the middle one no matter what the group looks like.

- Then start adjusting seating depth out in .003 increments looking for the best group(s).

- Neck tension is then tested.

Once the above is done I feel I have a baseline to work with. Next step is to shoot it at a 600yd range (monthly local match).

- Each target I shoot at 600yds will have different powder charges and seating depths that all hover around the 100yd baseline load. Each time I've done this (4 Dasher barrels and a couple tactical type guns) they all required my initial baseline load to be tweeked a bit but not much.

I'm still new and learning BR load development, shooting, etc but the process outlined above has worked okay for me.

Hope I answered your questions.

Good Shooting

Rich
 
Many say they load develop at 100yd, then confirmation at the desired distance.
From which I have 3 pertaining questions:

1) Are you after best possible accuracy or acceptable accuracy?

2) Say you get what you’re looking for at 100yd, but when confirmation testing you do not get the accuracy you desire, what do you do and how do you proceed?

3) You get what you’re looking for at 100yds, confirm at desired distance and get acceptable accuracy, how do go about tuning it better/smaller/tighter yet?


I would appreciate answers to all 3 questions from each reply....
Donovan

Donovan,

Great question and I am looking forward to other shooters answers.

I can only partially answer since the only time I get to see what a load is doing is at distance at a match.

1) So far I have only been able to tune at 100 and 200 yards. I would say I'm looking for the best possible accuracy that produces consistent results with nothing crazy. I am trying to get the gun to shoot as small as possible with acceptable speed and ES.

Side note: I do feel like I've had a tuning break through. I have my gun shooting exceptionally well without it throwing shots. Below is a pic of four groups of three shots at 100 yards. If that doesn't work I don't know what will!


2) As soon as I find out I'll let you know. So far my load testing at distance has been when the range officer says commence fire! My load/tune was OK. Good enough to place but not good enough to win.

3). TBD
 
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1) Best possible accuracy (which sometimes appears at more than one node)

2) I move out to 200 yards and try one of the "best" loads, then the other (if there is an "other")
If the results are less than desirable I can usually find the sweet spot with small seating depth adjustments.

3) "If it ain't broke, don't fix it" works for me here. You can keep testing loads until you wear out a barrel if you become obsessed with this stuff. But I do sometimes play with the seating depth adjustments when close isn' good enough


.upload_2016-2-14_20-38-38.png
 
What works well for me is to keep my load consistant but make very slight changes with my tuner at the start of each match and later in the day if needed.
Ben
 
I have several guns that shoot better at 200 than they do at 100. One day a buddy of mine shot about a 1" group at 100 and 10 minutes later had two of three shots in the same hole for a sub 1/2" group at 200. 100 yards is a good distance to test, but fine tuning needs to take place, IMHO, from 200 and on. For the last few years I have been putting my loads on paper to 100 and then on steel to 300-400 yards..If I can keep them grouped on my swingers, I am good to go. Paper punchers and those shooting for score at 1000 will need to fine tune all the way out.
 
To be honest and this is only in my findings. But I've yet to find a group that I thought was the best one testing at 100 yards perform as it should at 600 yards.

Here's an example of my 100 yard testing last summer from my HG. Looking at the target I would had chosen the 36.2 grain charge but further testing at 500 showed I would had chosen the wrong charge if I hadn't tested this at 500 yards.

BB5BA051-C215-4DC5-BEA8-3406E7522F21_zps3i919brx.jpg


Here are the 500 yard groups shot same day. I went out afterwards twice more to confirm and with that lot of powder I went with 36.0 grains. Now I'm shooting 35.8 grains

FDEE8F77-97C4-42A3-90A3-713C32E8D297_zps2hvyjzya.jpg
 
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James

Did you have any chrony numbers with that test at 100?
Chrono numbers don't make any difference. A lot of times the small ES numbers don't do well at distance. I had a Dasher that would shoot ES of 3 and group under .250 at 100 yards. It would not shoot under 13 inches at 1000 yards. It was all vertical. Another load in the same gun shot ES of 10 plus and would shoot 10 shot groups in the 4 inch range at 1000. I have seen this many times in many guns. Matt
 
I would also point out that deciding on a charge weight solely on the basis of a single 3-shot group is inherently risky, especially when all of the groups are a single ragged hole (very nice shooting by the way!). It's very difficult to say one is better than the others when they are that small unless you shoot multiple groups and compare the averages.

As an aside: Has anyone got a link to a technical essay on the statistics and probability of 3-shot vs 5-shot vs 10-shot groups , and related issues in group analysis? I've looked for some time and can't find one.
 
I was struggling with my HG finding that perfect load. I have read where another shooter was using H4350 in a BRX so as my last resort. I loaded up a few rounds and sat down at my backyard range and did a quick test. My first group was the 36.0 grains and then I went and shot 35.8 and decided to try 36.2 each powder charge I got up and went back to the shop and loaded three. Once I saw the results I went back and loaded three of each and drove to my local range and setup at 500 to test. Results were what I posted. So I got excited and went home called into work I'm not coming in and later that evening I went back out and did the same test with same loads again. I had a match on Saturday and was leaving for St Louis Friday. So Friday morning I loaded the exact same loads once again and headed to the range and once again the results showed the same. So in three tests at 500 yards based off of what I shot at 100. Also not note of those three 500 yard tests the temps varied from mid 60's Friday morning to 75* Thursday morning and then 85* Thursday evening. So I had a 25* range that I shot in and came up with the 36.0 grains being my best of all three tests.
Now back to 100 yard testing. I never went back and did any more tests at 100 as I mentioned I was out of time and just thru those together in hopes it would work. I don't do any testing at 100 yards. I'll start at 300 if the wind is switchy and not steady. If I have a good day with little to know wind I'm going straight to 500 yards. I've never had luck at 100 in the past even doing multiple tests as I do now at 500. Some guys may have luck testing at hats fine. I'm a firm believer one needs to do his load developing at the range they are shooting in.
Why do I choose 500 vs 600 on my testing? Simple is wind. I find at my local range the layout allows me to have the better wind conditions at 500 over 600 yards. The way the range is layed out I have a solid wind break all the way down to 500 yards. where the 600 yard berm is at the other end of the range is more subseptible to wind turbulence again due to layout of the range.

My results for the St Louis match for HG got me 1st place in group based on the testing described above.

http://internationalbenchrest.com/results/long_range/2014/BR St.Louis/810/StLouis810.php
 
I find this interesting:

4. Extreme Spread and the other Range Statistics, which increase with number of shots per group n, do not have any useful functional forms. The characteristics of these measures have to be derived from Monte Carlo simulation. They are the least efficient statistics but are also the most commonly used because they are so easy to measure in the field and so familiar to shooters.

Nice to know our common approach is the least efficient of the four described. :cool:
 
Nice rest !.!.!
Looks like a swivel top front on a big base that extends to a rear swivel rest as well?
Where'd you get it?

I want to see the 2-shot 100yd groups...
Donovan
 

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