Round Robin or Groups When Firing Test Loads?

Just curious what other people do when trying to find the best handload.

I do Round Robin firing mean I fire 1 round from each charge weight group then repeat the cycle until I am out of handloads. Each group has its own target. I was told its important to do this because the rifle could be shooting better or worse at different times during the load process.

I have met other people that just fire entire groups. If group 1 has a charge of 38 grs of powder, they will fire all the rounds in that group, find how it shoots, then move on to group 2.

Do y'all prefer one method over another?

Never used the round robin method. I always shoot one entire load and move on to the next.

Entire group. 1 group at a time, then move on to the next group. The round robin never makes sense to me. Also, you need to be in 1 position throughout the entire 3-5 shot group. Round robin, you will be out of position from the next shot to the next group. If you are working up loads at or above max, then you need to be able to feel and see what the rifle and brass are telling you.



^^ The rifle will do what you tell it to. How does the rifle shoot better or worse at different times?

Yeah, it didn't make much sense to me either. I just went off what he told me. I am doing some load development this weekend so this is good info. I will definitely just fire groups.

One more questions, how long do you usually let the barrel cool between shots?

I'll wait about 45 seconds or so. The barrel is going to get warm, not matter what. You just don't want it to get too hot. I normally have 3-4 rifles with me doing load work up. So, I'll shoot 1 group, then go to the next rifle and shoot 1 group, so on and so on. I'll let the rifle sit about 15-20 minutes at least before I shoot the next group. Also, I do a very light cleaning before I start my load work up. I will put a few wet patches followed by some dry ones. Then shoot a few foulers rounds while zero'ing at 100, then shoot your groups. Once you start shooting groups, don't clean the rifle.

Thanks Chad, this is a big help and I appreciate it!

Welcome! Also, check out what I wrote in this thread below. It's more info on groups.

http://texashuntingforum.com/forum/ubbth...nal#Post5654357

One thing that I have noticed can throw fliers is if you have a hot chamber and you let a round sit in it for an extended period of time. I try to close the bolt and let fly in short order. That also goes back to what Chad mentioned earlier about not rebuilding your position for every shot.

-ww

When I first started out I would load up 5 rounds each of various powder charges typically incrementing charge weight by .2-.4grains)and shoot each load one group at a time. Then I would pick the best group and try to fine tune. Later I learned of Dan Newbery's OCW load development method (aka Round Robin)and the Audetet (Ladders) method. The objective of each of these methods is basicaly the same and I think both methods work well. I have found that Dan Newberry's method works best for me. Unlike the Audette method, one bad shot from a bad mount,wrong cheek weld,ect. does not skew the whole test when using Dan's method.
Irregardles, I have found that I can develop a better load while sending less rounds down range using each of these methods.
Here is a link to Dan Newberry's method. http://optimalchargeweight.embarqspace.com/#/ocw-instructions/4529817134

I agree with the idea of shooting an entire group so as to maintain shooting position. One variable that is not accounted for, however, is barrel warming. Unless you wait a very long time between shots, the barrel will continue to warm throughout your shooting session and each successive shot will be slightly faster than the previous one. By the time you get to the third or fourth group, you are no longer firing at the same barrel temperature as the first group. Depending on barrel harmonics and where you might be at or near a node, you could reach an incorrect conclusion for your testing.

When I'm shooting over my chronograph to determine velocities for different loads, I use the round-robin method so that the velocity for the last group isn't artificially higher than the first group. Mathematically, this spreads out the barrel-warming effect over all the groups and still allows me to determine the relative differences in velocity. (I typically incorporate the OCW method along with the velocity testing, the objective being to find a node where changes in load/velocity produce minimal POI shift.)

Ladder test.

Look up the minimum and maximum charge for a given powder and bullet weight. I start in the middle and work up to max, even .3 to .6 gr above max.

Take the latest rifle and load, the 7mm-08 with 162 gr A-maxes, and H-Varget I loaded one round at

39.0 gr
39.3
39.6
39.9
40.2
40.5
40.8
41.1
41.4
41.7

It can be done at 300 yards, but with a very good shooting rifle it can be hard to read. If the wind is low I like 500 yards better. Once you hit the node they will group. I chronograph each shot and, of course want them as fast as possible. But consistency trumps velocity. In this batch 39.3, 39.6, 39.9 grouped. So did 41.1 41.4, and 41.7. I went with the faster node and suspected 41.4 would shoot the best. I loaded 5 shot groups of 41.1, 41.4, and 41.7. Sure enough all of them grouped sub-MOA, but 41.4 was the clear winner. It also had an ES of 17 fps on virgin brass. That's the load I go with.

That is until a student shot that rifle and load during a class. The conditions were very wet and the load over pressured. I called Chad to verify if I was right that the load overpressured because of damp conditions, he said that is correct. But due to the volumes of information I got from the ladder test I can zero back in on 39.6 gr since it grouped with 39.3, and 39.9.

Chad is a loading encylcopedia. He knows where most cartridges will shoot because he has so much experience. I don't know all he knows so I lean on the ladder test. Every single cartridge I have ladder tested has given me clear data in less than 14 shots. That's 22-250, 243, 260 Rem, 6.5 Creedmoor, 7mm-08, 308, and 7 Rem Mag both with 168 gr and 180 gr. Bergers.