Case Trimming & Measuring Questions...

[dkhunt14]

How can you see on paper if all I hear you talking about is shooting GONGS and two shot groups. LOL Matt

 

[savagedasher]

Larry, are you talking controlling bump to .001, or just the actual chamber between barrels? I can guarantee you will see sloppy tolerance on bump on paper. As for trim lengths, I think the OP should be able to achieve better with his tools. Unless it's the actual calipers that is wrong.

Tom

Actual chamber bump is critical. I don't even my bump it is al done with feel . Every case when I load for competition. Larry

 

[fguffey]

Copperking81, when reading through your post I can not help but notice you lack for nothing when it comes to tools. I have tools; some of the most accurate tools I have are called ‘case gages’. My case gages came with instructions from L.E. Wilson. The date printed on my Wilson case gage instructions is 1955.


Repeatability; I do not have that problem; then there is the other set of instructions covering repeatability. It says a dial indicator is considered accurate if it is capable of zeroing to .00025+/- every time. Then it goes into pressure as in ‘how much pressure to apply’ when using gages. I do not find a lot of work for it but I do have a micrometer that is designed to be pulled back and released. The pressure applied is set.


F. Guffey

 

[savagedasher]

I just measure with a comparator. Just in case I want to bump them so they don't touch.

Tom

I check each one in the chamber . Just my way . Larry

 

[dmoran]

I just measure with a comparator. Just in case I want to bump them so they don't touch.

Tom

Tom -
It amazes me you have learned to read "jibber jabber".... lol
Did you have to go to a special school ?
Donovan

 

[savagedasher]

How can you see on paper if all I hear you talking about is shooting GONGS and two shot groups. LOL Matt

I test on paper with two shots . Try to win on gongs. This week we tested on gongs and shot the match on on paper . The gongs were better then clay to see where your bullet was hitting . Larry

 

[dkhunt14]

Tom -
It amazes me you have learned to read "jibber jabber".... lol
Did you have to go to a special school ?
Donovan

Tom is just that good.
Matt

 

[Shaggy357]

Depending on the brass case, I have seen variation in the case head from stamped lettering to swelled primer pockets. If I get different reading with same case, I set it on flat surface and give it a "rock" test. If it rocks a little when set on the head, chances are deformation in case head is causing the caliper reading difference. 22 Hornet brass is soft and thin enough to prove out this result.

My Lyman trimmer uses the upper surface of the case head to hold the brass. Variation in rim thickness is visible on the caliper measurements, but total amount of the case in the chamber is the same. Wildcats based on 30-30 cases really show this difference. Quit using the Lee trimmers on these cases and stuck with the Lyman due to way case is held. The Lee trimmer cannot compensate for difference in rim thickness. The Lee trimmers do work great on ammo that gets a roll crimp. OAL case length symmetry and careful die adjustment can lead to near perfect crimps.

Don't know why all this $4it goes thru my head when I am reloading....seems like never ending flow of obvious data that I never really thought about before......just pops in.....