Adjust charge weight or seating depth based on these groups?

[tominboise]

Background: Rifle is a Savage 110 standard weight OEM barrel. Scope is a Zeiss conquest at 9X and mount is a ded nutz. The rifle is bedded in a plastic Savage stock and is free floated. The bore has been lapped by the Tubb's final finish process. The bullet is the Sierra Matchking over H4350 powder and CCI primer, Win brass.

My question is, would you go after adjusting charge weight or varying the seating depth to close these groups up? I typially get 2 close and one flier with this bullet/powder combo. Sometimes the groups are smaller but still 2+1. This has gone on with a different scope and mount, and also before the rifle was bedded and lapped.

 

[tominboise]

Here is the same rifle, same shooter, same day, but with the 90gr Berger match bullet over IMR4064:

 

[284winner]

Go with your best group by charge then start on the seating depth. All else not being the issue, adjusting the seat depth could shrink groups for you. If you didn't already bed the stock, I'd have thought that was the issue based on the groups

 

[SSL]

Are the flyers on the third shot? If so, possibly barrel heat.
Are the first two shots after a cleaning? I once had a Weatherby .257 that would put three shots on top of each other and then walk any subsequent shots off the paper. Clean it and it would repeat the performance. It would be interesting to see numbered five shot groups to see the progression.

 

[CharlieNC]

Did you develop the load using a ladder / OCW technique to determine the charge weight? If not you may be completely out of a node.

 

[ToddKS]

Shoot a 10 round group. That will give you a much better idea about what that load is doing.

 

[Coyotefurharvester]

Hunting Rifle start seating 0.020 off lands or mag length. Charge minimum to max 3/10 gr between loads, 2/10 for smaller varmint rifles. Shoot low to high charge(stop if pressure issues show up). Look for 2-3 charge weights in sequence that have little or no vertical dispersion. Use middle of that charge sequence for seating depth testing, unless groups meet accuracy requirements, confirm with additional groups/rounds.

 

[NorCalMikie]

Better to do a 5 shot group and only change "one thing at a time"
OR, you'll be chasing your tail.
Leave the OAL where it is and adjust the powder charge. Get your bug hole group and only then, adjust the OAL. If you get bug holes, end of testing.

 

[Ringostar]

More info needed. What cartridge are you shooting that light of bullet, with H4350 powder?

 

[JFrank]

I would want to see a few charge increments on each side of the groups posted before making any assessment.

 

[tominboise]

More info needed. What cartridge are you shooting that light of bullet, with H4350 powder?

Sorry, I thought I had it in the initial post - 243 Winchester

 

[Ringostar]

I haven’t loaded for a 243, but the vertical in your groups usually indicates powder charge. Which matchking bullet are you using?

 

[Jeff Porter]

I have had better luck with H1000 and 4064 than 4350 in 243 with 90-105 weights . As some others have alluded to, read up on the OCW test procedure. Find a set of powder charges that have the same vertical POI and a velocity that will be adequate for the distances you are shooting. Using the middle charge then adjust seating depth for group. If you are just pulling a charge weight And OALfrom a load manual you are rolling the dice and might not be able to reproduce the accuracy and precision in the next trip to the range.