I got a bullet comparator set.

CoalCrackerAl

CoalCrackerAl

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Im going to work on loading .020 from the lands and working out to find best seating for accuracy. . I checked my .223 Axis and 110 with 75 grain RMR bullets. Distance out to the lands is .010 longer on the Axis. Not sure if thats from how it was cut. Or if it's from ware. The Axis has a lot more rounds down the tube. I also have Lee micro seater dies ordered for .223 ,22-250 and 6.5 CM.
 
Comparator is a great tool for serious reloaders. I’ve used mine for a number of years now.

.010” is not much at all. Could absolutely be from wear. Could also be how much pressure you apply on the bullet when seating. What means do you use for checking OAL? Do you have a Hornady C1000 Lock’n Load? Some other method? What about measuring tool? You using Calipers or Micrometer?
 
I use mine for setting shoulder bump and for seating depth, BTO.

Again, because tools are not all the same, I do not report my measurements or compare others measurements to what I achieve. I treat measurements as individual to each gun.
 
CoalCrackerAl said:
Im using this comparator set. And Digital calipers . https://www.hornady.com/reloading/p...s-and-gauges/lock-n-load-bullet-comparator#!/ I got the idea from watching Eric Cortonas video on finding jam.
https://www.hornady.com/reloading/p...s-and-gauges/lock-n-load-bullet-comparator#!/
Click to expand...

Perfect! Yes, ok. Just doing that can account for .010” difference. Probably even .020” difference. Know what I mean? I like Eric Cortonas. He does a good job. However, he is not so concerned with several areas of shooting/reloading, that perhaps some people are more concerned with. One being his view on OAL. But, he’s good. Knows what he’s doing.

By jamming the bullet, allowing the chamber to seat the bullet in the case, you’re not getting an absolute accurate account of where exactly the barrel’s lands/grooves start. The bullet could easily be well into the lands. Different rifles, different cases, all aspects will change from one to the next. The bullets aren’t sticking because he has that stuff. But trust me! Without that, the bullets would be well STUCK into the lands.

It’s still good to do. But don’t sweat a difference of .010” between the rifles. The method simply isn’t precise enough to account for that.
 
Besides my Comparator, I use TWO different COAL gauges.

The Frankford Arsenal OAL gauge.


And the Hornady Lock’n Load OAL gauge. (Although, I actually just made my own out of some Carbon Fiber Tube & rods I had. But the same principle.
 
I have experience with two different comparator sets - one from Stoney Creek (I think that was the name) that had a long comparator and was bought by Hornady around 2008, and one comparator later produced by Hornady that had a physically shorter comparator length.
The longer comparator had a slightly larger bore and measured closer to the ogive.
The shorter comparator has a slightly narrower bore and measured further from the ogive.
The shorter comparator also seemed to be bored less deeply because the long 85.5, 88, and 90 grain match .223 bullets I was using had the tips touch the end of the bore before the bore had reached the slightly shorter 'measured ogive'. The Hornady comparators many have been designed for bullets up to around 80 grains.

In either case, the ogives measured by both comparators were slightly off in their measurements for bullets that fit all the way into the comparator. For the bullets longer the 80 grains, the shorter comparator was not useable.

The cartridge base to tip with the bullet in the lands minus the bullet ogive to tip provided the true cartridge base to ogive for the chamber. I actually use that measure now to determine the chamber depth and measure the chamber erosion. It eliminates the effect of the smaller bores in each comparator.

Because of the slight bore differences, both of which produced measures to a point closer to the tip than the actual ogive, the comparator measures were slightly off providing measures that showed the chambers longer than they actually were.
But both measures were relatively repeatable, although slightly different, for the bullets that fit in the comparators.
If the bullets were being seated off the lands, the jumps were close enough that I couldn't see much difference in the accuracy, especially if the numbers of groups measured with each jump were large enough to eliminate the variations that my shooting skills would generate.
Small samples would easily bias data and result in conclusions that couldn't be replicated over large samples.
 
ONE-TEN said:
Perfect! Yes, ok. Just doing that can account for .010” difference. Probably even .020” difference. Know what I mean? I like Eric Cortonas. He does a good job. However, he is not so concerned with several areas of shooting/reloading, that perhaps some people are more concerned with. One being his view on OAL. But, he’s good. Knows what he’s doing.

By jamming the bullet, allowing the chamber to seat the bullet in the case, you’re not getting an absolute accurate account of where exactly the barrel’s lands/grooves start. The bullet could easily be well into the lands. Different rifles, different cases, all aspects will change from one to the next. The bullets aren’t sticking because he has that stuff. But trust me! Without that, the bullets would be well STUCK into the lands.

It’s still good to do. But don’t sweat a difference of .010” between the rifles. The method simply isn’t precise enough to account for that.
Click to expand...
ERIC CORTINA is who I believe you mean
 
My bushings, that I bought at the same time as the Stoney Creek comparator had the caliber stamped on the inserts, but so lightly that they were almost unreadable.
I had to add a 6.5mm bushing when I bought my 6.5mm CMs, and that also had a more readable stamp on the insert, but it was not a caliber but a number that didn't mean anything to me other than it was the odd one out.
 
ONE-TEN said:
Perfect! Yes, ok. Just doing that can account for .010” difference. Probably even .020” difference. Know what I mean? I like Eric Cortonas. He does a good job. However, he is not so concerned with several areas of shooting/reloading, that perhaps some people are more concerned with. One being his view on OAL. But, he’s good. Knows what he’s doing.

By jamming the bullet, allowing the chamber to seat the bullet in the case, you’re not getting an absolute accurate account of where exactly the barrel’s lands/grooves start. The bullet could easily be well into the lands. Different rifles, different cases, all aspects will change from one to the next. The bullets aren’t sticking because he has that stuff. But trust me! Without that, the bullets would be well STUCK into the lands.

It’s still good to do. But don’t sweat a difference of .010” between the rifles. The method simply isn’t precise enough to account for that.
Click to expand...
Not that it "easily " could be into the lands vs touch. It IS deep in the lands. If you use a normal sized case with about. 003" neck tension and seat long and chamber it you'll end up way deep. I take a fired case and drill out the back. Put a drop of loctite in the neck and carefully insert a bullet. Even more carefully insert the whole thing into the chamber . Take a rod section and push the rim of case till I get shoulder contact. Then insert thru the hole and gently push the bullet forward till I feel "touch".
Put the bolt back in and let it sit 20 minutes. Loctite sets up and I extract it and measure.
 
Oh, I agree! I was t using “easily” meaning it was only slightly in the lands, rather the context was it meant to be”certainly”. I followed with my thought it could be “well into the lands”. In other words, deeply into the lands.
 

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