Measure this and measure that.

[4ked Horn]

Thanks for giving this a try Brian. I read you and GG loud and clear. My .308 is all about deer out to 700. Anything beyond this is gravy. Trying to whack chucks out to just over 1k is all about building confidence for that once a season shot at a deer. The fact that I was able to pull off a TRUE one shot clean kill on a chuck at 490 was actually the high point of the whole weekend for me. Not alot of fanfare but extrordinarily satisfying. I will consider anything I can do within my budget to increase this confidence. I am glad however to hear that all of this bullet measuring is not necessary at the distances I am shooting.

 

[Brent]

[ QUOTE ]
This is exactly why I thought the larger or smaller dia would change the BS measurement. If you increased the diameter by .001" the ID of the tools would rest farther apart. If the ogive is tangent to the BS that one thou dia change would be maybe a 10 thou (or more) length increase on the BS.


[/ QUOTE ]

It's kind of hard for "me" to explain but, when a bullet is placed between the inserts to measure BS length, the ID of the insert that the boattail references off of is not touching the OD of the bullet and is away from it by quite a bit, it's up on the ogive and down on the boattail... not where the bullet is full diameter, or .338" in this case.

The fact that these two reference points are both on angles above and below the BS allows the actual bullet diameter to fluctuate (if it does) and not influence the bearing surface length at all.

I hope that makes sense?