Thoughts on OCW test

[KSAv8r]

I agree with the comments above. Something is wrong but not enough data to give you much guidance. A Creedmoor usually shoots better than this right out of the box but we did see an AR10 6.5 CM at the range this summer that shot groups like that with several brands of ammo.

Bolt or semi-auto?
Who is the manufacturer and length of barrel?
What is the SD, ES and average fps for each of these groups?
Do you have a way to measure bullet runout?
New brass or shot how many times?
How was the barrel broke in?
How many rounds through the barrel?

I posted a picture a couple weeks ago of my new Ruger Precision Gen 2 with a 5 shot group that could be covered with a nickel at 100 yards. Nosler second firing brass, 40.0 grains of IMR4350, Federal primer, Hornady 140 grain ELD-M with COAL as recommended in the Hornady Reloading Manual. Started at the minimum recommended load and incremented in 0.3 grain increments until I started to feel a slight stiff bolt lift which was at 41.5 grains. It has been too cold to get back out to try some different seating depths but pleased with where it is currently so will probably save my reloading supplies.

Hope everyone had a wonderful Thanksgiving. Even though our nation has some problems, this is still the best place in the World to live and raise a family. Seeing lots of Black Friday ads to spend our money on …..but still lacking primers.

 

[pdshooter2]

This was with Barnes 127 lrx in a creedmoor with H4350. These were shot with a .050 jump. Maybe play with seating depth at 41.0? Peterson's brass has less capacity than most so I was compressed at 42 grains.

where was the wind( the big flaw in this type of shooting) and what distance.
how was gun held, what power scope

 

[Doom2]

That test shows definitely problems based on what you have told us with the rifle/scope or with the shooter, in my opinion. I can say that your powder wt. increment is too large. For a 40 to 45gr charge you should be looking at 0.3 grains. You also started off above Barnes maximum charge weight. You may be above the weight that Barnes felt gave good accuracy.

Some thoughts from just looking at the targets:

If shot round robin you may be experiencing setup issues affecting POI.
Possible scope issues or installation issues.
scope/shooter parallax issues.
Inconsistent brass prep

 

[QuietTexan]

I agree with ^^^ KSAv8r; what rifle/ barrel/ action/ twist/ scope/ mount, etc? All the pedigree info on the setup and loads.

In playing with my new EC tuner I've been able to open groups that far shooting out of a 6.5CM rifle capable of sub-1" , so no jumping to conclusions here, but I do think that a wholistic look is warranted.

Could just be it wasn't really stripped of copper before shooting the LRX, could be way out of tune at that velocity, or just that the gun really hates that mono.

 

[UncleDano]

Maybe the node lies in between the .5 increments? Maybe Trying 41.2 - 41.3 grains and reduce the jump to .020.

 

[6.5saum/300rum]

I would load them at 41 grains and start playing with seating depth. I would try .080 then .10 and .120 jump. That's my experience with Barnes bullets they like lots of jump, I start at .050 like you did and start pushing them back.

 

[jsthntn247]

I shot those at a .050 jump. I took 41 grains and shot .040, .030, .020, and .010 off. This is the result. I also had a few 140 Berger's that I loaded with 40.4 grains (load from a different rifle and it shot 1/2" group, so not the scope or rifle (Tikka Superlight). 20 off was about 3/4" while the others were 2+ inches.

 

[Mikecr]

This is what discredits OCW IMO.
It doesn't account for bullet seating at best CBTO.
There was never a reason for a 50thou pulled out of your butt to be anywhere near the best seating.
And you went through all that testing, trying to pick best out of junk..

But hopefully your brass is fully fire formed and stable, and you can start over with full seating testing, then move to powder either ladder (for best accuracy) or OCW (for most forgiving).

 

[jasonco]

First things first...Let's find where pressure is, for the given case-primer-powder-bullet, with a 10-15 Pressure test, @.010" off the lands if possible or at max magazine length. Get that parameter, before an OCW test is performed, if it hasn't been done.

 

[jsthntn247]

First things first...Let's find where pressure is, for the given case-primer-powder-bullet, with a 10-15 Pressure test, @.010" off the lands if possible or at max magazine length. Get that parameter, before an OCW test is performed, if it hasn't been done.

I'm compressed at 42gr. One thing I don't like about Peterson's brass.

 

[L.Sherm]

Whats your take on your results jsthtn247?

 

[jsthntn247]

I'm going to shoot 40.8-42.1 in .3gr increments at 20 jump. After that I give up.

 

[L.Sherm]

I'm going to shoot 40.8-42.1 in .3gr increments at 20 jump. After that I give up.

After you have determined your best powder charge at .020 jump dont be afraid to try .005 either way you might find it may get better.
Small seating depth changes often dont show up though untill you get to 500

 

[DJ Fergus]

This was with Barnes 127 lrx in a creedmoor with H4350. These were shot with a .050 jump. Maybe play with seating depth at 41.0? Peterson's brass has less capacity than most so I was compressed at 42 grains.

Its been a long time since I developed any loads for Barnes but I thought that somewhere it was recommended to start .050" off and test by seating deeper by .010" for each group. I do know they generally like to be jumped quite a bit.