Bullet Sorting - or Not

[wkdickinson]

It's not BTO it is measuring higher up on a bullet much closer to the tip
If you squeeze the tip too much it will bulge and deform the jacket
I zero my calipers before pointing and check again after pointing to make sure there's no damage and the calipers is still showing 0.000"
I mostly use it when I'm setting up my pointing die and then I'll check randomly just to make sure everything is good.....hope it makes sense.

BTO = "Base to Ogive". I like you thought that my comparitor was measuring much further up on the bullet. Bullet I deiced to actually measure the diameter of the comparitor insert with pin gauges and found mine to be .236. Given the most cut rifling is about .003 deep, that would result in a .236 dia. on top of the lands. Obviously you need to take the taper in the throat into consideration, but the comparitor is far closer to "touch" than I thought.

 

[DaveTooley]

BTO = "Base to Ogive". I like you thought that my comparitor was measuring much further up on the bullet. Bullet I deiced to actually measure the diameter of the comparitor insert with pin gauges and found mine to be .236. Given the most cut rifling is about .003 deep, that would result in a .236 dia. on top of the lands. Obviously you need to take the taper in the throat into consideration, but the comparitor is far closer to "touch" than I thought.

Being as close to bullet diameter allows you to use a "touch" number that transfers to different bullets. If it didn't you'd have to find a new touch number every time you changed bullets.

 

[wkdickinson]

Being as close to bullet diameter allows you to use a "touch" number that transfers to different bullets. If it didn't you'd have to find a new touch number every time you changed bullets.

I always thought you did have to do a "touch" test whenever you change bullets, because of the difference in ogive shape. I learned something new , thanks!

 

[ridgeway]

So you take a custom hand pulled bullet and custom it some more. The common man doesn't stand a chance.

Yes, but too much can be bad. Gentle touch and attention to detail. There is alot of copper being cold formed and the point is where it terminates and irregular things happen. Lot of good info here. The itty-bitty details show up in aggs...

 

[DaveTooley]

I always thought you did have to do a "touch" test whenever you change bullets, because of the difference in ogive shape. I learned something new , thanks!

It provides a very close starting point, if your comparator is close to bullet diameter or has a tapered hole starting at bullet diameter. That's why I'll never give up my set of Davidson comparators. They have a taper. I have no idea what the angle is but they work.

 

[Rat Rifle]

So you take a custom hand pulled bullet and custom it some more. The common man doesn't stand a chance.

There’s nothing common about Mark

 

[6BRA]

It's not BTO it is measuring higher up on a bullet much closer to the tip
If you squeeze the tip too much it will bulge and deform the jacket
I zero my calipers before pointing and check again after pointing to make sure there's no damage and the calipers is still showing 0.000"
I mostly use it when I'm setting up my pointing die and then I'll check randomly just to make sure everything is good.....hope it makes sense.

Mark,
I just spoke with Dianne Hoover and she clearly stated this is just another BTO tool.
She said the tool that is sold to manually trim meplats, this is the same tool just cut off and slotted to fit calipers and measure BTO.
The manual meplat trimmer not only trimmed but it also measured BTO. I would agree you don't want any jacket distortion or pulling the jacket away from the core. But our conversation just a few minutes ago was without any misunderstanding. It just measures BTO . This caliper tool was made for those running the Lyman Trim X and needing a way to measure BTO.
It does not measure closer to the tip per Dianne.

Edit: Unless you are running a .22 cal tool on 6mm bullets. That may be something to look at. Not sure it would work.

Mike

 

[GetReal]

Standard answer: first determine your accuracy goal. Then once you get your load try sorting versus not sorting and see if you can get your accuracy goal without doing the extra step.

Let laziness be your guide.

 

[True Grit]

There’s nothing common about Mark

For sure, he sold his boat so he can concentrate on shooting instead of fishing.