Hello,

I'm reloading .223 and doing some measuring with a Hornady OAL gauge and comparator. I know how to measure for the ogive on my rifle and then measure from that to get OAL, but how do I switch that? My Lyman book is calling for a OAL of 2.260" how do I find the ogive measurement with just knowing the OAL when measuring off the tip of the bullet varies so much. I'm asking b/c my .223 is an AR and I can only go to 2.260" b/c of mag length so I wanted to know how far off the rifles ogive I will be off if I seat to 2.260"

Thanks
Mike

Use a ordinary caliper or similar.

the diffrence. measure to the ojive and to the tip. x-y=z

Ogive length will change with every different type of bullet you use.

Measure the depth of the throat. To do this, drop a bullet (not a loaded round but just a bullet) into the chamber and hold it against the rifling with a dowel or pencil. Now take a cleaning rod or a dowel and push it down the barrel from the muzzle until it contacts the bullet and mark it at the muzzle.
Then take the bullet out of the chamber, close the bolt and push the dowel or cleaning rod in until it contacts the bolt and mark it at the muzzle again.
The distance between these two marks on the rod is the longest cartridge overall length that will chamber in your rifle.
The difference between this measurement and 2.26 is the distance your bullet will travel before contacting the lands if you load to a COL of 2.260.
Clear as mud? This is how I do it in bolt rifles, I think it will work in an AR.
As Ted said above, this is for this particular bullet type. If you change weights or styles or brand, you would need to do this again.