Gunsmithing Rifle groups@ 100 but not at 200??

[NamHunter]

I recently acquired a Sauer 90 Cal 300Wby Mag which made it the 6th Sauer in my hunting rifle collection. All other Sauers I managed to get down to 1/2 Moa with pet loads, even the 375H&H with a light weight barrel.

The 300Wby hovers around the MOA at 100m with some/few hand loads HOWEVER I can not get it to group sub 3-4 MOA at 200m no matter what I do. Re-bedded it twice and used at least 7 different bullets incl. match bullets- no luck, can't get it to shoot.

A friend recently bought a cheap 308 CZ varminter and is experiencing the same problem. Shoots ok at 100 but 3-4 inch at 200?

What could be the problem?

Tension in the barrel/Bad barrel? Why does it shoot okayish at 100m though?

 

[roggom]

Its difficult to say, as the 300 is a hard hitting chambering. Technique can be an issue, or something as scope parallax can cause groups to open up at further distances. My first thought was bullet stability, but you mentioned several bullets. Just make sure you are using the correct bullet for the twist rate of the rifle. Remember its bullet bearing surface not weight.

The easiest option is to choose one bullet that is matched to your twist rate and run a ladder test at 300m

Long-Range Load Development


if that does not work, then look again into the scope, bedding and other mechanical issues.

 

[xringaccuracy]

Rog beat me to it, check the twist rate to begin with. Have seen many factory same model rifles with different twist barrels. Worth looking at before you go bananas

 

[NXS338]

Can you define "okayish" ? Seriously though, what exactly are you getting at 100? Sounds like too heavy/long of bullet for the twist you have. What bullets ? what twist is the barrel?

 

[W8-2112]

NamHunter, can you please provide more specific measurements at each yardline so that I can better understand the size differance of each shot group? Now about your rifle, I second the request for what your twost rate is and also what is your barrel length? What type of sights are you using iron/glass? Now you said you aquired it does that mean it is used, if so how much use has it seen? You bed it twice, what is your pillar contact look like? Is your barrel free floating, if so what is the clearance? Does it have a muzzle break or inlet crown? More information the better the ability to troubleshoot your issue.

 

[JGorski]

I have just the opposite with my 1st 6 Creed, it shoots great at 300 but so so at 100, it's the bullets.

 

[Drifter™]

...used at least 7 different bullets incl. match bullets- no luck, can't get it to shoot.

How many different powders have you tried?

 

[DAVETOOLEY]

What scope are you using?

 

[NamHunter]

Thanks everyone - just sold the gun to a farmer who could not understand why I was unhappy with a 3" grouping at 200m.
Life is to short for bad days at the range