I am unorthodox when doing load development

[WVELK]

Or, I think I am. I just got a new 6.5 PRC from a member here. I have 5 different bullet options that came with the gun or that I had. I also have a ton of powder options in stock.

Here is what I do. Step one I record all the max loads published by bullet manufactures for each of the powders I would consider using with that bullet. Next I do a fairly extensive search on line to look for most accurate loads for the bullets and powders I am considering.

Step 3 - I pick a powder weight for each bullet and powder combo that I want to try. I pick something that is below max and close to loads preferred by others. Then I load each round .03 off the lands for the bullet being load. Three rounds loaded for each bullet powder combo I am considering.

I shoot and almost always I will have two combinations that really shine above all others. From there I load those two again and do a ladder test at 500 yards. Some will say that is not far enough but it is what I have easy access to and works for me. I look for a node within one grain of powder give or take.

Then I play with weights usually .3 grains at a time until I get the best group. Finally I play with seating depth. My only deviation is at times I will load 3 rounds .01 off another .04 off then .08 off and .120 off. If I find a sweet spot which I normally do then all of the combos are loaded that far off to start. But, honestly the end result seems the same if I just start with everything .03 off then test bullet seating last.

Any suggestions as to how to improve my unorthodox approach?

 

[Marbles]

Nothing other than what is contained in the thread below.

Painless load development (mine)

I have had multiple people ask me to lay out how I do load development being that what I do is different. Since Shaen @Shooter71 just rebarreled a Tikka 595 in 6XC I thought it would be easy to show how I do it. It’s a Master Sporter with a T3 lite profiled 20” barrel- keep in mind it is a T3...

rokslide.com

 

[SDHNTR]

1. Quit concerning yourself with what worked in other’s rifles. Meaningless in yours.
2. You are playing with fire starting with loads that are real close to max.
3. As you appear to have found, the seating depth step is largely unnecessary unless you’re a bench rest competitor.

I do something similar but I start a healthy amount below max. Book max is just what was max for the test rifle. It’s no universal standard. Your max could be a considerable amount lower (or greater) than what’s in the book. YOUR rifle’s max is all that matters, end of story. Only one way to safely find that and it’s to start low and work up gradually, not start high and hope for the best.

I’ll work up to find pressure and then back off by a full grain. Then shoot that load for groups. If I like what I’ve found, I’m done. If not, I change the powder or bullet and do it again until I find a good combo. Generally, I select the bullet I want to use and two, maybe three different powders. One of the two or three usually works. If not, I go to bullet choice number 2 and try again.

I mostly shoot monos so I seat them .050” jump (assuming mag accommodates), or Bergers with .005” jump. It either works or it doesn’t. I’ve never seen seating depth turn a bad group good. It may turn a good group great, but I’m a hunter so I don’t bother myself with that level of precision.

 

[WVELK]

1. Quit concerning yourself with what worked in other’s rifles. Meaningless in yours.
2. You are playing with fire starting with loads that are real close to max.
3. As you appear to have found, the seating depth step is largely unnecessary unless you’re a bench rest competitor.

I do something similar but I start a healthy amount below max. Book max is just what was max for the test rifle. It’s no universal standard. Your max could be a considerable amount lower (or greater) than what’s in the book. YOUR rifle’s max is all that matters, end of story. Only one way to safely find that and it’s to start low and work up gradually, not start high and hope for the best.

I’ll work up to find pressure and then back off by a full grain. Then shoot that load for groups. If I like what I’ve found, I’m done. If not, I change the powder or bullet and do it again until I find a good combo. Generally, I select the bullet I want to use and two, maybe three different powders. One of the two or three usually works. If not, I go to bullet choice number 2 and try again.

I mostly shoot monos so I seat them .050” jump (assuming mag accommodates), or Bergers with .005” jump. It either works or it doesn’t. I’ve never seen seating depth turn a bad group good. It may turn a good group great, but I’m a hunter so I don’t bother myself with that level of precision.

Very valid points on max loads and will note that going forward. I have had a bad habit of operating under the belief that published max loads by manufactures are conservative. While they may be in some cases, as I think about my prior work I know that to not be true. I would venture to say their max loads have probably been what I found to be max approximately 85 percent of the time.

The point I was placing too much weight in until reading your post, is that I have never had a situation where the max load in my rifle was lower than published by bullet manufacturers. However logic and common sense dictates that it only takes one time to be a bad time.

This is exactly why I put the post out there. We all become complacent at times and I was guilty here. Thanks again SDHNTR!

 

[Harvey_NW]

Very valid points on max loads and will note that going forward. I have had a bad habit of operating under the belief that published max loads by manufactures are conservative. While they may be in some cases, as I think about my prior work I know that to not be true. I would venture to say their max loads have probably been what I found to be max approximately 85 percent of the time.

The point I was placing too much weight in until reading your post, is that I have never had a situation where the max load in my rifle was lower than published by bullet manufacturers. However logic and common sense dictates that it only takes one time to be a bad time.

It can start to vary when you change things like COAL, and also different actions, brass, etc. seem to handle pressure a little differently. Max charge at SAAMI length might be fine, but could exhibit pressure signs if you seat the bullet touching the lands and change the pressure curve.

In all my Tikka actions with bullets seated 20-40 thou off the lands, they pretty consistently start to show pressure signs like ejector marks at or just above max charge. A gunsmith I use theorizes Tikkas show signs a little earlier than beefier actions because the lugs aren't as robust.

I'll echo what's been said about keeping it simple. I do the painless method, but I like to seat .030" off the lands in shorter throats, or bearing surface fully seated in the neck in longer throats. Then to be safe I still shoot a pressure ladder from 2gr below max up to 1gr above max in .5gr increments, and look for pressure signs. This group usually gives a good indication if the combo wants to shoot or not. Drop 1gr from where signs started to show up, and shoot 10. If it goes around 1", I load them all. If it doesn't, rinse and repeat with a different bullet or powder. When I do this on a new barrel, sometimes I have to back the charge off again later as the brass is fireformed, and the barrel stabilizes with fouling and starts to develop firecracking, and speeds up.

 

[SDHNTR]

The point I was placing too much weight in until reading your post, is that I have never had a situation where the max load in my rifle was lower than published by bullet manufacturers. However logic and common sense dictates that it only takes one time to be a bad time.

Yep it only takes once. I once had a barrel that would pressure up 2.5gr below book max. Drove me nuts. Was never very accurate either. That same gun now wears a new barrel and pressure didn’t start until 4 grains more than the previous load, or 1.5 gr over book max. Same powder, same brass. I now always start low. It’s sometimes annoying, and yes, usually seems like a waste of time and components, until it’s not.

Every barrel is different, sometimes very different. When in doubt, start lower.

 

[N2TRKYS]

I start all my testing at half a grain below book max and work up in half grain increments to half a grain above book max.

I’ve never had to adjust seating depth longer or shorter than the tested COAL on the load data to get accurate loads.

I don’t know or care how far off the lands I am. Chasing the lands is dumb.

 

[Mike 338]

You know what's fun? Listening to a guy reinventing the wheel who has 2-1/2 fingers and one eye.

 

[WVELK]

Yep it only takes once. I once had a barrel that would pressure up 2.5gr below book max. Drove me nuts. Was never very accurate either. That same gun now wears a new barrel and pressure didn’t start until 4 grains more than the previous load, or 1.5 gr over book max. Same powder, same brass. I now always start low. It’s sometimes annoying, and yes, usually seems like a waste of time and components, until it’s not.

Every barrel is different, sometimes very different. When in doubt, start lower.

I went back and looked at my notes for all my rifles. I also looked at my message above, because I knew I normally start below max as noted above. However, I could not remember how much below max and from my notes I never started higher than 1 grain below max for the bullet and powder. But, after reading this useful thread I think I will just plan on starting 2 grains below max. Heck maybe 2.5 what is a few more shots.

 

[JGRaider]

1 grain below max is where've I started for over 30 years. I also use a chrono when developing new loads. I start at max mag box COAL and adjust if necessary, but seldom have to unless it's a mono.

 

[seand]

last load dev was picking middle of the book charge weight and shooting 10 for velocity. Looked in the book to see velocity change per gr of powder in the reference rifle. Then just added the powder I estimated needed to get the velocity I wanted to shoot at.

Shot 10 for velocity and was within 5fps of estimate. Satisfactory group size. Done.

Book Charge weights may not match your rifle very well and don’t mean much. Easy to start at what you know will be a safe load and adjust charge to the velocity/pressure you want to run.

 

[A382DWDZQ]

I think about my prior work I know that to not be true. I would venture to say their max loads have probably been what I found to be max approximately 85 percent of the time.

I think it is very safe to say that manufacturers are basing their max loads on a much larger data set than yours. While your data might be providing different results so far, there may come a point when that fails. That’s why you start low. There are other data points that you can use, but this isn’t one. For example, if you are going to try a new powder in a rifle that you have already loaded for, and you have already done load dev on a different rifle with that powder, specifically that batch or bottle, you will know both the performance of that powder and the rifle already and you can make some calculations from that. But if you are using a new batch or powder and a new rifle without knowing how either performs, I’d start with a minimum load and see how it goes. I wouldn’t start close to max because you’re just gambling that all your variables fall into spec.