Bearing surface measurement tools

[mharpster]

Here is a link to the bullet comparator that Accuracy One sells.
http://www.accuracyone.com/products/bullettipping/
Scroll down to find it.

 

[JohnHoover]

Have the comparator in stock.Give us a call.

Accuracy One Shooting Supplies
1-814-684-5322

John Hoover

 

[newbieshooter]

Does the Accuracy One comparator hold the bullet firmly to be measured? I've seen a few others that look similar - but when you place the bullet in the holder to be measured - it can move/wobble a bit - making it hard to get consistent measurements

 

[jlow]

I don’t have some of these tools being discussed so I won’t say they cannot accurately measure bearing surface length, but I find the idea that a mechanical tool can measure it accurately difficult to comprehend.

The reason is the bearing surface by definition is the thickest area of a bullet. So any tool that can be placed on the bullet either on the ogive or boat tail part can only stay there if it is smaller than the bearing surface in diameter, if it is the same diameter as the bearing surface, it will of course be able to slide freely on the bearing surface.

The problem with this is if the orifice on the tool is ever so slightly smaller than the diameter of the bearing surface, then by definition it is not at the exact juncture of the bearings surface to either the ogive or boat tail which means the number you get is longer than the actual bearing surface.

Now an optical device I can understand, but a mechanical one I have difficulty envisioning.

 

[geo.ulrich]

unless the stem on indicator has lets say a 1.5 per side angle like throat then ogive radius is measured on angle the same as throat would see it.

 

[jlow]

unless the stem on indicator has lets say a 1.5 per side angle like throat then ogive radius is measured on angle the same as throat would see it.

If I read you correctly and I am not sure I have, I think it’s an interesting idea to put an angle on the comparator so that it would catch on the ogive. But that would mean that it would need a different one for the ogive and also the boat tail unless they are the same angle? The other thing is those angles are different for different bullets , how would the tool account for that.

 

[geo.ulrich]

base of bullet would sit in cylinder with base on surface plate bt angle has no bearing on this,probe attached to indicator stem would have basically a throat cut into it.

 

[jlow]

base of bullet would sit in cylinder with base on surface plate bt angle has no bearing on this,probe attached to indicator stem would have basically a throat cut into it.

Sorry but a bit hard to understand what you are trying to say. If you have a manual for the gadget, could you post?

 

[geo.ulrich]

No theres no manual think of checking with calipers and bushing, base against stationary jaw base against surface plate. Moveable jaw on calipers would hold bushing on stand indicator would hold a bushing with leade angle reamed in it. Bushing is nothing more than a way to hold bullet square with .0005 clearance then indicator would drop on ogive to get measurement