firstshot

I'm using a Stoney Point OAL guage and get a different distance to the lands depending on which bullet I'm using.
When I measure using a 140 Grn Sierra Game King, I get 2.265. When I use a 140 Grn Nosler Accubond, I get 2.300.

Seems to me that since you are measuring from the base of the brass to the point where the side of the bullet makes contact with the lands, the distance to the lands should be the same regardless of which bullet you are using to do the measurement. The actual distance to the lands does not change, period. Why am I getting different measurements when using different bullets?

Am I wrong on this? Please elplain.

firstshot
----------------------------
Make your first shot count!

charlie brown

Every bullet has a different curve to it, causing it to touch the lands at different lenghts. If you were to draw a profile of each bullet, you would see the difference in the curve, and how one could go farther into the chamber than another bullet might. I really can't think of any other way to describe it, but I do know that my Nosler Partitions, and Sierra Gameking HPBT, and SPBT touch the lands at three different lenghts. Hope this helps.

mossy33oak

The part where the bullet meets the lands is called the ogive, (pronounced o-jive) it is different on every bullet brand, some bullets (even though they are the same weight) may be longer or shorter. For example, I have Nosler B/T's, Nosler Accubonds, and C/T by Nosler......all 3 are 180 gr (.308) but all 3 are completely different. You need to have a new set of measurements for EVERY different bullet you want to shoot.

bigcountry

You talking jive again mossy. Hate it when you do that. I know dumb joke.

My T-Town friend is right on target here.

Carpmaster

Mossy took the tec terms right out of my mouth!!! Couldnt have said it better!!!!

mossy33oak

hmmmmm I wonder who taught me this????????

Rebel Hog

Hey BC, on a friday night and he is sharp. Proud of you Mossy!

Briman

If you are shooting a 30 caliber, the part of the bullet that is going to make contact with the lands is going to be .300" or larger. If you take measurements on different style bullets such as comparing a RN to a tangent and a secant ogive, you will get different different distances in each bullet before you reach this dimension.

overall lengths of the bullet are a bad indicator too. The spot on the bullet's ogive that meets the contact dimension will be fairly consistant if measured from the base, but comparing several bullets from the same lot will give you several thou difference in lengths. The good news is that with a seating die with the proper seater plug installed, the bullets will be seated so that the ogive to base measurement will be failry consistant although there will be differences in COL which are pretty much meaningless.

bigcountry

Its early, he probably is half liquored up. Hate to shoot his handloads tomorrow.

firstshot

Ok, that makes sense! If I'm understanding you right, even though a 30 caliber bullet is supposed to be .300", it may be a bit larger and hit the lands sooner than a bullet that is exactly .300".

I'm shooting 7mm08, so theoretically, if both the Sierra Game King and the Nosler Accubond were "exactly" .284, then I would get the exact same measurement. So one of these two is larger in diameter than the other.

So, bottom line is, I need to determine distance to the lands for each and every different bullet type that I load in order to be able to seat them a measured distance off the lands.
Correct?

firstshot
--------------------------------
Make your first shot count!