Question about ogive

[Itsalongshot]

I may be over thinking this but I have just begun reloading and I am using the Hornady OAL length tool and bullet comparator. I am loading for a 7mm WSM.

My question is universal though. my understanding of ogive is the point on the bullet that it reaches its full diameter and start the bearing surface. Given 3 different bullets in the same caliber in theory when checking the length from bolt face to ogive touching the lands they should all be the same because all the bullets are the same caliber and same diameter at the ogive? Correct me if I am wrong. However because of different bullet designs there over all length from bolt to tip of the bullet will be different?

So I measured 3 bullet types from bolt face to ogive and got 3 different lengths? Is this correct? I checked each one multiple times and the numbers listed are the ones I got consistently.

168 Berger hunting VLD 2.255"
162 Amax 2.237"
175 Sierra matchking 2.293"


Thank you.

 

[barnesuser28]

The reason for varying lengths is the comparator doesnt measure at the exact point where the bullet will touch the lands, it is slightly smaller. And since the nose profiles for the three different bullets you measured are different, you will get a different measurement because it measures off of a different point on each bullet. If the comparator measured exactly where the bullet contacted the rifling then all your measurements would be the same. If that doesnt make sense maybe someone else can explain it better.

 

[Browninglover1]

Ogive refers more to the shape of the nose. The two main types are tangent and secant and the new hybrids that are a combination of the two.

Ogive - Wikipedia, the free encyclopedia

 

[Itsalongshot]

Thank you barnesuser28. That makes perfect sense and answers my question.