reading groups

[madracer]

are there any ways to pick grouping problems by the shape of the groups?

i have been having problems getting a rifle to group how i was hoping it would.

the rifle is a 6.5-284 barnard with a shilen number 8 contour 30 inch 1-8 twist and its in a McMillian f class stock.

the main group i get is a .75 to 1.25 inch diagonal group

Cheers for any help
Stuart Amos

 

[Eddie Harren]

The 'rounder' the better.

 

[TonyR]

I am trying to work out some of the same issues. I shot an F-Class match last weekend that had a 20 shot diagonal group that would have scored a couple of points better if it had been level. I am fairly certain that I forgot to check the scope level on the four shots that made the group diagonal. I also read somewhere recently, maybe in Nancy Thompkins' book, that inconsistent hold on the stock will create horzontal dispersion, even if the sight picture looks correct. I know that the consistency of my hold has room for improvement. Just a couple of things to consider.

 

[fullersson]

If you are shooting a skinny contour barrel with a hot load you'll get more barrel movement during barrel time,bmbt). You may try adjusting your load. That being said, it could be a number of things like if the mirage is running real heavy which is made worse buy high power optics. I don't know how much case prep. you do but weight sorting your brass, sorting bullets by bearing surface, and trimming your meplats may help in the long run. I do all of these and have found none of them to be the magic answer, but in conjunction with each other my groups have improved drastically.

 

[heikki02003]

Hope this helps:

Stringing