• This Forum is for adults 18 years of age or over. By continuing to use this Forum you are confirming that you are 18 or older. No content shall be viewed by any person under 18 in California.

load testing are there newer more efficient methods now?

I load my rounds to the absolute longest c.o.l. that I am willing to tolerate. Whether that is magazine length, kiss the lands length, or boat tail at base of the neck length. Then I load two rounds of each charge in .2 grain increments. I shoot them over a chrono looking for the top end of speed and pressure.

When I find that stopping point, I back off 2% in the medium 308 class cases. I use the resulting powder charge and start seating bullets deeper in .005" increments until the groups tighten up. So far, I haven't had to go more than .050" till a group came together.

The reason I do this, is because I'm looking within a fairly narrow performance window. I don't care if there is a node 2 or 3 grains off of max. I am looking for a load that works at the top of the pressure curve, with just enough room to keep it from being over pressure in the summer time.

By backing off the charge by 2% you are bringing the pressure back from the edge. By seating the bullet deeper, you are simultaneously adding that pressure back in and looking for a good barrel timing node. The incidence of those two curves is where I want to be.

The appearance of that incidence in relation to the top pressure will tell me if this combo is optimal or even viable for what I am doing.
 
Last edited by a moderator:
single step ladder then three shot strings and then 5 shot strings. more if your discipline requires it..10 or 20 shot strings.
bestest fastest PROVEN method
next is to shoot every combo( rich bench rest shooter's do this,i think bart posted a 5 shot 5x5 ( depth/powder) matrix. you may shoot loads you can see will not work

ocw waste of time money
 
I don't know about newer methods but the one that has almost always worked for me in 40+ years is to select a powder / bullet combo load from one the manuals that they report as the one they tested which was the most accurate. Sierra and Nosler manuals have such data. Also the Lyman Manual is a good source for selecting a powder for a given cartridge / bullet combo. I normally start at the mid point of that load and work up or down if necessary.

I start by setting the COL at .020" off the lands. Assuming you are using a powder that's appropriate for the cartridge you are loading I've found that the single biggest accuracy factor is the bullet. Also make sure the bullet weight is appropriate for the twist in your rifle. If you using good equipment (i.e. scope / rifle) finding an accurate load isn't difficult.

Don't try to do too much load testing in one range session. Fatigue will set in and you may get sloppy in your technique skewing the results. Take your time and don't rush it.
 
There are two things that I can recommend, loading at the range and using some flags so that you can have a better handle on the wind variable. The flags do not have to be fancy, something as simple as a couple of wood stakes that come up to the line that the bullet takes to the target, with surveyors' tape hanging from their tops to the ground give a great advantage over nothing at all. Heavy triggers, scopes that do not adjust for parallax, wobbly benches and poor rest setups are to be avoided. I run a one shot per load pressure series with steps suitable to the case size, on a single target trying to have the same condition for all shots, up to the point where I get pressure signs, at which point I stop immediately. I like to test with light marks on the bullets to start. I usually start out a couple of grains under the top manual load. As I shoot the test I take note of how the bullet holes are located and take note of any clustering. After that I load the middle charges of the clusters for three shot groups and go from there. Doing all of this, with a chronograph set up, I will usually come up with a decent load is relatively short time, no more than a couple of hours, if the rifle is a good one and conditions are good. Friends who load at home usually take several trips to the range and may still be going around in circles several weeks later. If a rifle has not had its action bedded and the barrel floated, I do not usually waste my time.
 
K22 said:
I don't know about newer methods but the one that has almost always worked for me in 40+ years is to select a powder / bullet combo load from one the manuals that they report as the one they tested which was the most accurate. Sierra and Nosler manuals have such data. Also the Lyman Manual is a good source for selecting a powder for a given cartridge / bullet combo. I normally start at the mid point of that load and work up or down if necessary.

I start by setting the COL at .020" off the lands. Assuming you are using a powder that's appropriate for the cartridge you are loading I've found that the single biggest accuracy factor is the bullet. Also make sure the bullet weight is appropriate for the twist in your rifle. If you using good equipment (i.e. scope / rifle) finding an accurate load isn't difficult.

Don't try to do too much load testing in one range session. Fatigue will set in and you may get sloppy in your technique skewing the results. Take your time and don't rush it.
Click to expand...
This ^
The projectile and powder manufacturers have paid staff that do nothing else !
If a powder/projectile combo isn't listed it probably doesn't work or isn't worth documenting.
Going way back to an early Lyman book I have there were also 2 additional loads listed, a factory duplication load and an accuracy load. these can be helpful to home in on what'll work for you.
Don't try and reinvent the wheel instead do lots of study of any powder and bullet suppliers recommendations and then tweak from there.
An evening's study and a few notes taken can save a heap of time at the bench.
 
retired said:
single step ladder then three shot strings and then 5 shot strings. more if your discipline requires it..10 or 20 shot strings.
bestest fastest PROVEN method
Next is to shoot every combo (RICH Benchrest shooters do this ),i think bart posted a 5 shot 5x5 ( depth/powder) matrix. you may shoot loads you can see will not work

ocw waste of time money
Click to expand...
Another back handed slap in the face to the Benchrest community and Bart
 
First, I'm a hunter, not a BR shooter. I'm still concerned with accuracy of my rounds. I've been shooting since I was in my early 'single-digit' days and reloading since college (some 30 years ago).
I have tried many of the various methods, from shooting groups (3,5 and 10 shot) to OCW to looking for 'flat spots' shooting singles over a chronograph. All will work for my goals. I have noticed that for some cartridge/rifle combination, one version is 'better' or more exact than others. The smaller bores - .223 and the like - seem to do well enough for my purposes using either OCW or 'flat-spots' version. Once I get up to my magnums, it's OCW. In between it varies.

If you have your preferred method, great. I just enjoy shooting for the sake of shooting and to put meat in my freezer.
 
Essentially all of the methods I have seen are "ladder" tests involving charge weight and seating depth (ignore other variables for the moment). The major disagreement in technique is between those who shoot for group size, and load 5 or so shots and judge results by group size. Vs those who shoot long range and judge results by minimal change in poi and therefore shoot 1 to 2 shots per load. Of course these are generalizations and you get the point. The general consensus is evaluate only one variable at a time, i.e. charge or depth; ie the "scientific method". Occasionally the Tony Boyer method is noted, which involves loading 3 loads each of 5 different charges x 5 different depths = 25 load combinations. He then looks at the groups to select the best.

While I am classified as high master in mid range Ftr, I know much more about statistical analysis than the loading intricacies used by BR shooters; my techniques are simple and I am quite particular concerning load develop to get the most out of the least. In this regards there are several conclusions I will share based on the statistical perspective.

First, with limited sample sizes (shots) it is much easier to find a node based on changes in poi than by using group size. Poi is well behaved like averages of numbers, and detecting stable poi is not difficult when reasonably small changes in charge weight are made.

Secondly, the paradox of judging based of group size is that excellent shooters shooting small groupd require more shots to detect an improvement. Conversely fewer shots are needed for an average shooter to reliably detect a 0.5in group is better than all the other 2in groups. More shots are needed to differentiate minute differences in excellence. Meaning there is no universal answer when it comes to "how many" shots to establish statistical significance when it comes to group size. My personal guideline is 10 shots, and calculate the standard deviation of the distance of each shot from the group center; this is much more robust than group size.

Finally, the notion of the "scientific method" one variable at a time was out of date when I was a kid in the 60's. The question of how do I learn the most with the least work is the focus of volumes of statistics books. Back to Tony Boyer matrix; it looks at all possible combinations. Do you believe the optimum is simply 1 of the combinations out of the 25, and that those loads which are neighbors of the optimum are not any good? That is visualize a barren ocean with a small remote island. If so then many, many shots are necessary for any statistical significance.

On the other hand consider the appearance of a horse saddle, where the bottom of the seat is the node as defined by a stable poi. Looking at the saddle from the front, the node is at a high spot; while from the side it is a low spot. It is unlikely you would find this type of optimum region using one variable at a time without many, many loading trials and time. While the Tony Boyer matrix can find this, since the saddle surface is well behaved a statistical design involving 9 (vs 25) loads can reliably evaluate these 5 charges and 5 depths in short order.

So the short answer is that there are many efficient statistical experimental strategies to carry out more thorough load development trials using fewer loads if one is inclined.
 
I find shooting groups to be mundane I do a ladder test twice at the longest distance I can at least 500+ yards look for the charges that match up vertical then load up and shoot at my local club in match conditions adjusting charges as needed.
I just look at the vertical spread each weekend that way I'm getting more value for my money I feel and not boring.

Cheers Trev.
 
CharlieNC said:
So the short answer is that there are many efficient statistical experimental strategies to carry out more thorough load development trials using fewer loads if one is inclined.
Click to expand...
What's your opinion on tests of 7,62 NATO M118 match ammo at 600 yards shooting 270 shot test groups like this? Rings are 6 and 12 inches....

IMG_0170.JPG
 
Bart B. said:
What's your opinion on tests of 7,62 NATO M118 match ammo at 600 yards shooting 270 shot test groups like this? Rings are 6 and 12 inches....

View attachment 1047787
Click to expand...

I believe in the old adage "seek first to understand", and since I do not know the context or objectives associated with the target it is difficult to have a specific opinion which would address your question. Observations are that the shots are well centered, with comparable normal variability in the horizontal and vertical directions. 270 is a lot of shots and obviously a lot can be going on during that time. But a simplistic view is that if you calculated the standard deviation of 20 shots it would probably be indicative of the overall result unless the other long term factors involved with shooting 270 played a major role in the outcome (wind, barrel heating, etc certainly had some influence).
 
That 270 shot group was shot with 173 grain FMJBT bullets made from 3 or 4 machines. Barreled bolt action in a Mann rest. Military teams often pulled them to seat Sierra 168 or 180 HPMK bullets from a single lot and got 20 shot test groups no bigger than half that 10 inch extreme spread.
 
rockwind1 said:
so i read this great article by jason baney but noticed it was dated 2010

http://www.accurateshooter.com/technical-articles/long-range-load-development/

are there any newer technologies or techniques that have made this easier or faster? or has a different technique gained acceptance since.

i dabbled with the 10 shot technique and the ocw,,,always looking for a more efficient way.

hard to argue with someone who has won a bunch of championships though
Click to expand...

I have changed my load work up process a great deal within the past 15 years. I started with shooting lots of groups at various charge weights. Then tried the shot impact ladder like Mr. Baney uses. I found them to be cumbersome, frustrating, time consuming, and expensive.

A year and a half ago I purchased a LabRadar chrono. I have worked up loads for 4 barrels since that time using a velocity ladder rather than a shot impact ladder like the one Jason Baney uses. I load my rounds with a 0.5 grain increase between shots and usually start about 100fps or more slower than I would like to end up with. I shoot one round of each powder charge. I start with the slowest round (lowest powder charge) and increase by .5 GR until I reach a pressure max. When I see a velocity level off and not increase relative to the power increase then that is an indication of a node. I don’t need to shoot at a target or have access to a range with long distance to complete this test. It has proved to be very fast (can complete the test in 20 rds or less).

For example: in a 308 Win I have to shoot the 155gr Bullet at a minimum of 2935fps to stay supersonic at 1000 yds. This is how I conduct my test...

Powder. - Velocity
41.5- 2820
42.0- 2850
42.5- 2880
43.0- 2920
43.5- 2950
44.0- 2960
44.5- 2990
45.0- 3028. *node between 45.0&45.5
45.5- 3030
46.0- 3060

In the hypothetical example you see that the velocity did not increase as much as the other shots fired even though the powder charge was increased by the same amount. With 10 rds fires I found the node with that barrel. I have repeated this test on different days to try to replicate results and I have found the Results are repeatable.

I would then load some rounds at 45.2 and 45.4 GR to shoot for groups to see if either one of those charges shot best and meets my accuracy requirements.

Hope this helps,

-T
 
CharlieNC said:
I believe in the old adage "seek first to understand", and since I do not know the context or objectives associated with the target it is difficult to have a specific opinion which would address your question.
Click to expand...
Accuracy specs are mean radius 3.5" max. The velocity at 26 yards, 2550 fps +/- 30 fps.

After all shots were fired, group center found then radius to each shot used to calculate mean. That group had a 1.9 inch mean radius. I doubt it got significantly bigger after the first 50 shots were fired. That was the 1965 National Match lot of M118 ammo.

People have put 30 to 40 shots downrange in half as many minutes starting with cold barrel without accuracy degradation. Good barrels properly installed do that.
 
Last edited:
You must log in or register to reply here.

Similar threads

New load development combo method, what do you think?
Replies
13
Views
2,245
Alex Wheeler
Alex Wheeler
New Dasher Brass Testing Results
2
Replies
26
Views
3,474
Chfcemerson
Competition BR Loading - Newer Stuff
2 3
Replies
43
Views
11,290
StephenPerry

Upgrades & Donations

This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.


Click Upgrade Membership Button ABOVE to get Gold or Silver Status.

You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.


To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.

Classified Ads

Forum statistics

Threads
166,984
Messages
2,226,235
Members
80,084
Latest member
H3NN13

Share This Page

Back
Top