Seating Depths for .308 win.

[RugerNo1]

I have been reloading for my Kimber 8400 Tactical for a while now and have decided to get a bit more involved than just full sizing, throwing a powder charge, and seating a bullet to 2.8 col. I purchased a Sinclair Seating Depth Tool and a bushing neck sizer.

After following the directions for the depth tool, I discovered that my rifle's chamber must have a very long jump to the rifling because I am getting a touching length of 2.958'' for this particular sample of bullet (from the ogive is 3.196'' using my comparator). At this length the base of the bullet is at or just above the junction from the shoulder to the neck.

I plan on testing just touching the lands, .010'', .015'', and .020'' of jump to see what depth will show the most promise. Then, I will play with tweaking the powder charge for fine tuning.

My main concern is where the base of the bullet is. Am I just being paranoid or what?

Edit: Components: 155 Sierra 2156's, Lapua Brass, CCI BR-2's, IMR 4064 and Varget

[ar15barrels]

The general guideline is to keep at least 1/2 the bullet's diameter worth of neck length in the case.
So, on a 0.308" bullet, try to keep 0.154" worth of straight shank in the case neck.

You probably won't be able to do that with your long chamber though.
Perhaps consider having the gun rebarreled with a better barrel and chamber.

If you MUST hang the bullet out there, keep at least 1/16" in the case or the bullets might start falling off in handling, leaving you with a mess of powder...

[buffybuster]

Is a single-shot going to be any use to you? If it doesn't shoot well enough with rounds loaded to mag length then should look into at least a setback and rechamber or better yet a new barrel.

[RugerNo1]

The general guideline is to keep at least 1/2 the bullet's diameter worth of neck length in the case.
So, on a 0.308" bullet, try to keep 0.154" worth of straight shank in the case neck.

You probably won't be able to do that with your long chamber though.
Perhaps consider having the gun rebarreled with a better barrel and chamber.

If you MUST hang the bullet out there, keep at least 1/16" in the case or the bullets might start falling off in handling, leaving you with a mess of powder...

That is the info I needed Randall, thanks. I need to go back and calculate how much engagement I have and I will follow the numbers you provided. Thank you kindly.

Is a single-shot going to be any use to you? If it doesn't shoot well enough with rounds loaded to mag length then should look into at least a setback and rechamber or better yet a new barrel.

The 8400 gives quite a bit of play with COL. And, The length I have right now still fits in the magazine and cycles.

Accuracy out of this rifle has already suprised me. Second time out I shot a five round group measuring ~0.3 MOA at 100 yards. So I believe there is still untapped potential....