Comparator tools for measuring at the ogive and the shoulder datum line

This is all new to me have a 4 decimal Mito. To work with. Use the Hornady or Stony point system or the Forster system shown in Midway USA. I have a picture here . Click on it for better look thanks Tribb

If you are asking which to use, I have had good results with the Forster Datum Dial. Thanks, Steve

Been using the Hornady set for years, it's just a comparator each one will measure different from another.

SPitty said:

If you are asking which to use, I have had good results with the Forster Datum Dial. Thanks, Steve

Click to expand...

Thanks

The problem with most of these tools is that the holes are not drilled round, and that the hole size varies between tools, so they have no real value other than as a comparator for your own measurements. Meaning you can't compare results from two different inserts, so always use the SAME insert for subsequent measurements.

I use Short Action Custom (SAC) comparators, which are an update to the Stony Point system, and more like the Sinclair copy than Hornady's aluminum garbage. Better metal, better QC, and more sizes to use.

Do you have an end-goal with these? Or just something new you're using?

I've been using the Hornady comparators for years. I find they work great for my uses. But like Quiet Texan says, the tolerances to which they are held are poor. Understanding that a slight variation in diameter or shape will have a greater variation on the length measurement because you are measuring the diameter on a slope. This can make them useful for your use but if you lose a bushing, you have to start over. You must use the same one at all times, not substituting someone else's, or their numbers.

Other than those stipulations, Forster makes fine tools and it should work fine given the above parameters.

I have the Hornady kit, less than impressed. I've given some thought to making my own insert bushings. The holes would be reamed and then honed to a specific size and the faces would be exactly square to the hole centerline with no edge break unless I can figure out how to precisely and consistently create a .005" radius that is economical to do.
I doubt that I'd make them from aluminum. 17-4 PH or lightly hardened A2 would be my initial choices for metal.

ntsqd said:

I have the Hornady kit, less than impressed. I've given some thought to making my own insert bushings. The holes would be reamed and then honed to a specific size and the faces would be exactly square to the hole centerline with no edge break unless I can figure out how to precisely and consistently create a .005" radius that is economical to do.
I doubt that I'd make them from aluminum. 17-4 PH or lightly hardened A2 would be my initial choices for metal.

Click to expand...

This is the kind of precision needed to make them interchangeable, and most would be unwilling to pay the price for that level of precision, especially for multiple inserts.

Sounds like you've given this some thought. Great ideas!

Tiny Tim said:

This is the kind of precision needed to make them interchangeable, and most would be unwilling to pay the price for that level of precision, especially for multiple inserts.

Sounds like you've given this some thought. Great ideas!

Click to expand...

I use Sinclair for Headspace and Hornady; for Stoney Point style measure of maximum CBTO and to setup seating dies for CBTO. Good points made regarding Hornady aluminum bushings! You must use the same bushing for all CBTO measurements to have meaningful comparisons.

How much pressure does it take on the calipers to deform the aluminum Hornady comparator to make it useless?

Philward said:

How much pressure does it take on the calipers to deform the aluminum Hornady comparator to make it useless?

Click to expand...

Probably enough to destroy the calipers

But there are other ways to deform aluminum not due to normal usage like dropping or nicking/ scratching the edge. And again, the issue is having bushings that would be precise enough so as to be interchangeable between people. But that would also have to include the bushing holder being made to the same precise specifications.

Check out Creedmore Sports. Com.
One gauge does most common calibers.
Been using for a few years.

This is an area where you can over-spend and not get a better ROI. I invested in Redding's Instant Indicator hoping I could get really good (consistent) measurements straight off the press. They're good enough, but for the cost I paid, I have to admit I'm somewhat disappointed.

I am using both the Hornady and the Short Action customs. I found more variance in my selected cartridges' with the Hornady system vs the SAC. It depends upon what your end goals and allowable budget. For many, the Hornady set may meet your needs and it is at a competitive price point. You can get a complete system from Hornady vs 1 insert from SAC. For me, and my goals, I have found the SAC setup to be a better option.