Group sizes while working up a load?

[ultralight]

I worked up a batch of 35 gr bergers with benchmark and CCI BR4's COAL: 2.240 per Hodgdon load data. I worked up from 25.0 to 26.6 grs. .2 increase at a time. My ruger Ultralight really seemed to like 26.0 and 26.2 grs.

Questions:
1. When shooting groups like this what is your guys average group size difference with only a .2 increase in powder?
2. What do you guys think my velocity is with my 20" barrel???

I don't really care about the velocity so much as I will shoot it out to 350 yds or so and see where she prints. I picked up this rifle for coyotes, lynx and fox and my shots should all be less than 200 yds. My smallest 2 groups (3 shots each) where @ 26.0 and where .45" and .42" on my mic. 26.2 came in just over .5" for both groups. On either side of that my groups at 25.8 & 26.4 where .75" to 1.3" 26.6 was well.. ugly (1.5") and anthing below 25.8 looked like shot gun fire! Forgive any dumb Questions as I'm learning. Also if I neck size my brass instead of full length is it safe to assume these loads 26.0-26.2 will still be the most accurate? After that I guess I'll start working on C.O.A.L. But I don't know how crazy I'll let myself get as this is a short range yote' buster with a super light/short barrel!

Thanks, Jake

[skipper]

ultralight

Really there are three key elements I'm looking for when I load develop. Group size alone doesn't tell the whole story.

I'm looking for groups that have less vertical spread than others. Horizontal spread could easily be caused by the conditions changing between shots but, to me, vertical spread is a bad sign. The second thing I'm looking at is Point Of Impact change from load to load. If I can find a small group that is hitting the target at the same spot as the group .2 grains less and .2 grains more then that load will be forgiving if my powder charge is off a little. On the other hand, if the groups .2 grains less and .2 grains more hit the target in different spots then that load will be less forgiving if my powder charges are a little off. The third thing I'm looking for is a load that has a low velocity spread. This will help with consistency since the barrel harmonics should be close each shot. When you find a load that meets these criteria then you should start working on seating depth to fine tune it.

If you're shooting groups in the .4's, you're very close to where you want to be. Try the suggestions above and see if they help you. Remember, you have to be consistent behind the trigger or your load development tests will be useless. I almost overlooked an excellent load because I wasn't shooting very well that particular day. Good luck and post some pictures.

[jo191145]

ultralight

Benchmark is an excellent choice for developing some super accurate loads from a bench gun. Of course it will do very nicely in a walker too.
BM's accuracy nodes are very small. I've found .1 gn variations can give big differences in group size. To reliably weigh charges this fine its almost imperative to use a quality electronic scale.

H-4895 has relatively larger accuracy nodes. Not as accurate as BM in my experience but accurate nonetheless.
No reason not to shoot up your BM but maybe a jug of H-4895 should be on your list.
For whackin yotes you do not need to be shootin .0's .1's and .2's but a load that shoots .5 or better in different weather is nice.
For shooting at paper from a bench I still use BM and find I need to tune my loads slightly for differing weather conditions.
It was a stable higher velocity load with H-4895 that allowed my factory 204 to out score all the custom 6BR guns at a 300yd egg shoot last season. That was a beautiful day

Don't underestimate velocity when hunting yotes. If you experience bullet splash on a furry critter Walt Bergers recommendation is to up the velocity.
I'm not a hunter myself but Walt knows his stuff.

[ultralight]

Thanks for the tips guys,

Do you guys think shooting 3 shot groups is an ok practice for load development with a light weight rifle? I need to get my trigger tweaked than I'll be back at it.

Thanks, Jake

[Lee C.]

Jake, some guy's like 3 shot testing. Alot of guy's like 5 shot testing. I do the 3 shot testing it save's me some powder and bullets. But the very last test i do is a 10 shot test to see if it hold's up to what i'm looking for in the end at 200yds.

[Rambler]

LeeC my thought is three shots test the rifle but a five shot group test the shooter..

[YoteSmoker]

Sometimes if I put 3 bullets in the same hole I stop before I get too proud and screw it up