What seating depth? Seating depth test

[BlazerBeam]

Here's a pic of a seating depth test I did at 100 yards with a new 7 mag. 67.5 grains H1000 was the powder charge I settled on prior to the seating test. Question I have is where would you seat the bullet for a final load? The 2.695 CBTO is about 25 thou off and the 2.665 is about 55 thou off. I realize the best group is 65 thou off, but would you load at 55 thou off and hopefully stay in that seating mode as the throat migrated?
Or would you seat in between them at about 60 thou off?

 

[Justice1327]

Not sure how many times you have shot this string of seating Depth tests.It's too bad the 2.675 on the one shown in the picture seems to have opened up compared to the other groupings on either side of it. I would clean the barrel shoot one or two fowling shots and reshoot the 2.685,2.675,& 2.665 again to verify. If it remains consistent to the ones shown in the picture I would split the difference.

 

[Plinker147]

I would go with your 95 or 85. I prefer longer with Edlx with the shape of their ogive

 

[Varmint Hunter]

Assuming that it's tight enough; I always prefer a triangular shape group. I'd try 2.660" and if it's repeatable, I'd be done.

 

[LongBomber]

I would shoot 2.665 - 2.660 and see if the groups repeat. Then go as long as possible (2.665) to stay in tune as the throat wears.

 

[Mikecr]

would you load at 55 thou off and hopefully stay in that seating mode as the throat migrated?
Or would you seat in between them at about 60 thou off?

If best is at 55 OTL, then set 55 OTL and powder develop with it.
Throat erosion does not change best CBTO while off the lands (OTL), for the entire accurate barrel life.

I know that doesn't sound right, but you will not have to mess with seating, for that bullet, again.
Trust me

 

[azsugarbear]

What Justice said. One three shot group is not conclusive enough for me. Re-shoot the most likely seating depth lengths and then make your decision.