Distance To The Lands.......I don't get it!
 

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!

RE: Distance To The Lands.......I don't get it!
 

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.

RE: Distance To The Lands.......I don't get it!
 

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.

RE: Distance To The Lands.......I don't get it!
 

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

My T-Town friend is right on target here.

RE: Distance To The Lands.......I don't get it!
 

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

RE: Distance To The Lands.......I don't get it!
 

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

RE: Distance To The Lands.......I don't get it!
 

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

RE: Distance To The Lands.......I don't get it!
 

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.

RE: Distance To The Lands.......I don't get it!
 

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

RE: Distance To The Lands.......I don't get it!
 

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!

RE: Distance To The Lands.......I don't get it!
 

No, one bullet is not larger in diameter than the other. They should both have a MAXIMUM diameter of .284, but depending on the ogive of the bullet, one will reach that diameter at a different point from the nose of the bullet, and will be .284" in diameter for a different length of the bullet. A .284" bullet should touch the lands where the bullet is actually .276" (I think, if the lands are .004'' deep). A .308" bullet will touch the lands where the bullet is .300" in diameter, and so on. The reason for the differences is that the deep part of the rifling of a 7mm rifle should be .284", and with .004" deep rifling, you have a total of .008", which makes the distance across the lands .276."

RE: Distance To The Lands.......I don't get it!
 

Ok......so if I want to seat these bullets 10 thousants off the lands, I would seat the Game Kings to 2.255 amd seat the Accubonds to 2.290.......

and I would need to measure a new "distance to the lands" for every type of bullet that I load.

Is this correct?

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

RE: Distance To The Lands.......I don't get it!
 

Yes, if that is how far they are, every rifle is different, and I don't own a 7-08, and I don't have a load book handy, so I don't know what the COAL is of that cartridge. But, I am guessing, then, that your lengths for each bullet were 2.265 and 2.300?

RE: Distance To The Lands.......I don't get it!
 

Yes the lengths for each were 2.265 and 2.300.

Thanks so much to all of you for your help!!!!!!!!

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

RE: Distance To The Lands.......I don't get it!
 

The head to lands distance actually is the same, as it is the dimension of the rifle's chamber. What you are measuring is the length of your cartridge, which as the others have so aptly put it is different for every make of bullet. ;)

RE: Distance To The Lands.......I don't get it!
 

I notice that this is the first place new reloaders get caught up. then after loading for several calibers, they quickly forget about it. If not done right, it can cause you all kinds of issues. I have seen new reloaders seat so far out that only .15" of the bullet is in the case, and the bullet is easily knocked around. I have seen them with severe pressure spikes on occasion due to jamming in the lands. Seen guys on hunting trips that worked hard on reloads to show up in the middle of nowhere that find out they can't put thier bullets in the magazine cause they never did tried it.

I mean its a good question to ask and find out. But I highly suggest you don't sweat it too much. Its the least of the your worries. Just make sure your not in the lands for one, and make sure you can fit your bullets in the mag two.

RE: Distance To The Lands.......I don't get it!
 

Now you have it figured out.:D A guy never stops learning about reloading. When I first started reloading it meant finding another rock for my slingshot. I am still learning;)

RE: Distance To The Lands.......I don't get it!
 

FWIW land depth is not the same on all barrels either so there is really not a math formula you can use. Buy a stoney gauge and a dummy shell for each caliber you load in. You will most likely have different readings for each different type bullet you use.

Like the rest said, most likely they'll all be different and as such just learn to accept and live with it.

BTW just touching is often the worst place you can seat bullets too. A very good rule of thumb to follow is to either stay at least 10th off the rifling or at least 10th engaged(or more in either case). Just touching may well be that with one bullet but the next may jump etc... they are not made perfect and this can play heck with accuracy and pressures.

Jeff