Finding the right seating depth

[Tim Singleton]

Completely out of tune on the left. Very wind sensitive
Slight seating depth and load change in tune on right. Same bullet and half vertical
Same match. Virtually same conditions

Tim, was it only seating depth you changed for this result, or was there some powder tweaking as well.?

I went up half a click as well as coming Off the lands .002 from where I was

 

[brantfredrickson]

I just today tried Tony Boyer's method using a combination of loads and seating depths to find smaller groups. I think it provides a lot more information in a lot less shots. I use to do ten different loads and ten different seating depths, and then the load and seating depth choosen became useless in a 15-20 degree ambient temperature change. A thanks to Tim Singleton for his posts. Also I ordered the Book of Accurate Rifle Shooting. Hope there more stuff like this in it. Below is my first combination of loads and seating depths.
http://i689.photobucket.com/albums/vv253/brantfredrickson/IMG_0003.jpg

 

[Tim Singleton]

I just today tried Tony Boyer's method using a combination of loads and seating depths to find smaller groups. I think it provides a lot more information in a lot less shots. I use to do ten different loads and ten different seating depths, and then the load and seating depth choosen became useless in a 15-20 degree ambient temperature change. A thanks to Tim Singleton for his posts. Also I ordered the Book of Accurate Rifle Shooting. Hope there more stuff like this in it. Below is my first combination of loads and seating depths.
http://i689.photobucket.com/albums/vv253/brantfredrickson/IMG_0003.jpg

I'm not as familiar with your combination. Will you continue testing coming further out of the lands?

 

[Titan700]

Following

 

[kolar55]

These two targets are the same-one may be easier to see than the other. Fired this today. 34 degrees no wind to speak of and very damp. You could see the moisture in the air-making it hard to see. I bought this rifle used with about 1500 rounds through it. Looks like it still wants to shoot though. I had a couple shots that I know I was the problem. I'm thinking that .006 off jam is yhe best seating depth. Not because of the tiny group but because of the most consistent poi in the vertical direction. How about some opinions on that?
Thanks Lonnie

 

[Tim Singleton]

I think so. I would go with .006 off. The tune window is just a little narrow.
When it's in it dotted up tho

 

[kolar55]

I was thinking the same thing that it may be a little fussy. But it was not a good day. The dampness made it feel cold and trying to shoot a light trigger with gloves on doesn't give much feel. Plus it's hard to get the same feel and hold on the rifle. Not trying to make excuses but I don't think it was my best day at the helm. Again this thing is new to me but ya gotta learn how to shoot it sometime.

 

[brantfredrickson]

"I'm not as familiar with your combination. Will you continue testing coming further out of the lands?"


No I don't intend to. A 40.7 grain load is the load that corresponds to the OBT(Chris Long) when calculated in Quickload. Let's say a the outside temperature changes and I need a little more or less velocity to pull the group together; I will increase or decrease the bullet jump. If I need a greater increase or decrease in velocity; I will increase or decrease the charge by a .1 of a grain. Does it make sense?

 

[BartsBullets]

I guess Erik has handed this thread off to the inmates.

This isn't Erik's method. Its what short range benchrest shooters have been doing for years. It's the method Tony Boyer published in a book a few years back. Tim is just helping people understand it.

Bart