Deer rifles: playing with seating depths?

In most of my rifles, I just try to seat my bullets @ around 10-15 thousandths off of the lands (measured by the ogive) and go from there. I rarely feel the need to 'tweak' this. Until now.

I have a 260 Rem with a fairly short magazine box, and can't seat the bullets close to the lands. I wasn't getting very good accuracy, and after a lot of playing with powders, trigger work, bedding, I'm finally getting around to playing with the seating depth. (Which might be where I should have started first).

How far do you normally seat your bullet from the lands?

I really don't have a normal. Just finding your OAL to the lands means you are thinking about it the right way in my humble opinion. I will start around .020 off the lands but that is a pure guess. For instance my Weatherby in .270 win has a looooong throat and I can't get anywhere near the lands with my SGK 130s. But it is my most accurate rifle and truly shoots bug holes at 100 yards if I do my part. From my experience secant ogive bullets like Bergers or Hornady SST'S are more sensitive to seating depth and may like to be "jammed" into the lands. My Savage .308 is like this with 168 Bergers and the mag is long enough to accommodate the OAL. For hunting though I prefer a projectile that has is not right up on the rifling. I mainly use the Sierras or Nosler partitions. Neither seem too sensitive on the OAL. One advantage to making them a little longer is safely getting a bit more powder in the case. But as you approach the rifling the pressure can spike on you.

I have seen the same gun shoot great with bullets jammed into the lands and I have also seen the same gun shoot great with a lot of jump. It's all a matter of finding and accuracy node and making tiny tweaks from there with seating depth. Most of the 260s I dealt with shot well with just about anything I tried. But some guns are particular. I would let the gun tell you what it likes to do. Berger has a good write up about figuring out seating depth for their bullets. It is applicable to all bullets and just not theirs.


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In my 308 BLR they're seated a bit back from the lands because the magazine on that gun is short, and it doesn't like to chamber anything that's too close to the lands, even dropping them in one at a time. My 30-06 is a different story though. With most ammo it shoots 1.5MOA but if I don't seat the bullet as deep it will shoot under 1 MOA all day long.