CBTO measurement

[charlie b]

Know that there is a feel for this, like using a micrometer. You can inadvertently push the bullet more one time than the next. Or, if dropping it, the bullet may go straight through or 'bounce' a bit. When you get to .001" measurements the technique must be consistent. With 'soft' jackets and a worn throat a 'wide' difference can be measured.

[Robinhood]

By using this method, why is the Hornady tool even necessary?


It is not. How can you get accurate numbers if your case headspace dimension is off anyway. Just a resized case fired in that rifle with .002" bump, no primer or powder just seated long. Remove the extractor and ejector if you want. Start moving in .002" until the bolt starts to fall. Then change to .001". Simple and fool proof.


Lets talk about that bullet. I would load it to the manufacturers suggested length. Find a good shooting load(precise charges are important) then seat them .010' deeper and shallower and see if you can tell the difference. If you touch the lands that thing is almost falling out of the neck.

[yobuck]

It is not. How can you get accurate numbers if your case headspace dimension is off anyway. Just a resized case fired in that rifle with .002" bump, no primer or powder just seated long. Remove the extractor and ejector if you want. Start moving in .002" until the bolt starts to fall. Then change to .001". Simple and fool proof.


Lets talk about that bullet. I would load it to the manufacturers suggested length. Find a good shooting load(precise charges are important) then seat them .010' deeper and shallower and see if you can tell the difference. If you touch the lands that thing is almost falling out of the neck.
EXACTLY, no special tools or degrees in a higher education is necessary.
And although i dont personally remove the firing pin and spring as RH does, it is the best way to go about it because you can feel the bullet contact the rifleing.
I simply resize a proper length empty case, seat a bullet long, then chamber it and seat the bullet with the bolt.
I use a match to blacken the bullet for final die adjustments as for seating depth, but RH s way is a better way.
Look, im well aware that the world has changed since i started out, but it dosent mean that it has always changed for the better.
But it does mean that more people are trying to profit by selling things we dont really need, or are any better for our use.

[charlie b]

I do it like RH as well. Erik Cortina has a youtube video on how to do that as well. I also blacken the bullets to see where the engagement is.

I do use the Hornady Comparator with vernier caliper to measure and record the results (as well as marking that case/bullet and keeping it for reference).

[Robinhood]

You should see the way I correct bullet run out.

[yobuck]

You should see the way I correct bullet run out.
Well that could create a whole nuther discussion. lol
What would happen if the run out high point was marked on each case head.
Then each case chambered into the gun with the mark at say 12 oclock?

[yobuck]

I do it like RH as well. Erik Cortina has a youtube video on how to do that as well. I also blacken the bullets to see where the engagement is.

I do use the Hornady Comparator with vernier caliper to measure and record the results (as well as marking that case/bullet and keeping it for reference).
Well can we agree that Cortina can be a bit nuts? lol
For example, does he believe full length resizing is better than neck sizing?
How about Speedy Gonzales, does he believe that also?
And yes, they dont need tools to set the seating depth either.
If were going to be selecting people from the internet for opinions, which ones should we select?

[charlie b]

LOL, yep.

Yes, most of those guys "full length size". But, their version is different that most. They use custom dies. When you see their method of setting the sizing die they are really just neck sizing with the case body supported by the die.

[yobuck]

LOL, yep.

Yes, most of those guys "full length size". But, their version is different that most. They use custom dies. When you see their method of setting the sizing die they are really just neck sizing with the case body supported by the die.
Well i suppose the tolerances of their chambers might be a factor also?

[South Prairie jim]

Nothing complicated about a full length bushing die that matches the chamber well, lots of guys just don’t take the time to measure radial expansion of brass fired in a chamber then after sizing to determine the ideal amount of reduction, doing so extends brass life, eases the entire process of sizing not to mention the fact that I can run a ten shot string without fighting the bolt open on empty rounds keeps me on target during a condition.

[GrenGuy]

Someday I’m going to catch a condition that lasts for 10 rounds :rolleyes:

[Robinhood]

Well that could create a whole nuther discussion. lol
What would happen if the run out high point was marked on each case head.
Then each case chambered into the gun with the mark at say 12 oclock?

I have watched the guys who do that shoot some amazing scores and win TSRA matches. Speedy G was one of them. I can't tell you the amount or location the RO was taken but the mark was on the case head.

[Robinhood]

Well i suppose the tolerances of their chambers might be a factor also?

What I have found is that with many non custom dies require bumping the shoulder or you will increase the RO. Has anyone else noticed that?

[South Prairie jim]

I haven’t shared that experience, I have however tested rounds with run out up to .005 side by side against rounds with very little only to be disappointed in the lack of difference on paper at 550 yards.

[yobuck]

Someday I’m going to catch a condition that lasts for 10 rounds :rolleyes:
It seems that is being overcome to some degree at least by the length of time it takes to get the 10 shots off.
At Williamsport at least everything is 10 shots, and some are getting it done in about 1 minit.
I would venture to say that very soon most of them will be doing that unless there are rule changes affecting the front rest.

[charlie b]

Nothing complicated about a full length bushing die that matches the chamber well, lots of guys just don’t take the time to measure radial expansion of brass fired in a chamber then after sizing to determine the ideal amount of reduction, doing so extends brass life, eases the entire process of sizing not to mention the fact that I can run a ten shot string without fighting the bolt open on empty rounds keeps me on target during a condition.

Exactly.

[NF1E]

I have had excellent results using the Hornady OAL gauges, both the straight and curved ones when used in conjunction with good measuring tools.

[Burr]

I have had excellent results using the Hornady OAL gauges, both the straight and curved ones when used in conjunction with good measuring tools.

Me too. I've used it for so long, it was a Stoney point gauge when I purchased it. I've not encountered inconsistent measurements with it ever. The OP is experiencing something I have not. I would try different bullets, is the variance still wide? Different chambers. With a wide variance, I'd try to narrow down what may be causing it by making some changes. I've always been able to quickly obtain measurements either the same, or .001 very repetitively. Something is not right here.