308 OAL measurement

[shepheard]

I am loading some 178amax's for my savage 10. After running a bullet in a shell into the chamber and checking that length on my comerator it measured 2.194. oal was 2.821. Seating a bullet to 2.8 as stated in the manuels the ogive measured 2.178. Seemed easy enough but when I compared it to my Sierra match kings I see that at 2.8 oal, the measurement to the ogive is 2.195. It seems that with a amax the bullet is in the lands at 2.194 and a sierra isn't at that same measurement. I would think that the ogive measurement would be the same and the oal would be different when checking distance to the lands.

 

[holstil]

Different bullets have different radius ogives by design. Sort by bearing surface and fine tune the accuracy by seating depth with each individual bullet. However the 308 is typically not finicky, meaning that it will shoot well off or into the lands. Jim

 

[shadowdrak]

Some bullets can be very finicky on seating depth to the lands. My .308 loves VLDs right onto the lands, where the NBT like a jump of .001". That's the part of reloading you have to play around with to find out. Bearing surface is different from manufacture and bullet types. Hornady Amax does have a large bearing surface and on average will seat deeper for ogive length to lands. VLDs on the other hand have a more pointed style and so a shorter bearing surface and will seat out further for ogive to land. The above post is good on sorting bullets for bearing surface as you have already been doing and depending on how accurate your looking to get, and how much time you want to spend at the bench, you can sort bullets to be within .5 of a grain to 1 grain of each other and shoot the groups close to each weight.