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· Banned
268 Posts
Discussion Starter · #1 ·
Hello from Scotland:

I have recently been playing with my Lyman micrometer and some .444 cases. Im still getting the hang of it but like they say practice makes perfect !

I've have had my first go at evaluating case expansion with some of my home loads. With the benefit of 20/20 hind sight i can see were i went wrong and have learnt a lot !

To start with i took the average of my full length once fired cases 0.4647 also my once fired brass was probably a mix of different loads to start with not good.

I should have measured "each" case and kept them in order though out the test. I should have marked the rim to allow measuring in the same place.

The way things worked out i only tested three of each load instead of a larger amount.

And my measuring could still do with more pratice ! BUT as a learning exercise it was invaluable !

My slightly flawed results are as follows.............

BULLET = Lee 310




Load 1= 41 gn 0.4646 / 0.4648 / 0.4646

Load 2= 43 gn 0.4690 / 0.4657 / 0.4647

Load 3= 44gn 0.4682 / 0.4688 / 0.4674

Load 4= 45 gn 0.4658 / 0.4696 / 0.4692

#There are probably lots of errors that worked there way in ! :rolleyes: But its a start and i have learnt a lot. I can see lots of improvements that i can make.

are there any other .444 shooters who've been playing with there mic's ??


I would love to hear your thoughts and measurements to give me a comparison would be excellant !!

By the way Load 4 is grouping 3" at 100 yards with my Ashly gost rings and shifting at 1840 f.p.s


· Banned
268 Posts
Discussion Starter · #2 ·
Sorry !:rolleyes:

I forgot to mention there was "NO" signs of any changes in the primers, and case extraction was normal.

Load 5 is slightly compressed as is Load 4 if i remember correctly how much further do you think i could go ???


· The Hog Whisperer (Administrator)
39,105 Posts
I've never personally been able to make sense of case head measurements on my loads, and I've used a micrometer for years.

The readings I get are so inconsistent that I can't trust them to estimate pressures.

No doubt some people have figured this out, and can do it, but I can't.

Personally, I rely on the chronograph more than anything else to see if my loads are matching up to the manuals.

Hope someone else can jump in and explain to both of use how it works.....

· Registered
9,796 Posts
It is of questionable value...esp. when used with anything other than new brass. As frass is used, it become harder (less spring back), can anneal the necks...but the HEADS get harder too, and that's what we are measureing.

At best, it can give an aproximation of when a handload is at the same pressure level as a factory load. Need to sacrifice a box of factory shells.

Select 10 rounds and break them down...what we are after are the primed cases. Put the primed cases away for a time.

Mark the LOADED cases 1 -10, measure each of loaded 10 rounds at the is a blade mic. as we want to measure the SOLID head just ahead of the rim. Record the numbers. Fire the rounds and re-measure for expansion. Record the numbers. Find the average case head expansion.

With the 10 cases you broke down, reload with your selected load. Go through the unfired/fired measure again. IF the expansion is higher than the factory load, can assume the pressure is as well. IF the expasnion is less, can assume the pressure is also less.

I gave up trying to eek out the last few FPS and load a bit conservativly. My thninking is that if I have to run a round to the ragged edge of safety, I really need a more powerful rifle.

· Beartooth Regular
1,178 Posts
Hi Guys,

Try the below link for an interesting method using 444 Brass and the Bellm wildcats in a Contender.

I've used the method with the 444 brass based, 358 Bellm and found it to work well.

Don is an extremely thorough and knowledgable fellow.(Scientist) If you show a sincere interest in it, he will usually correspond with an interested party to help as you go through load trials. I did this with him over the course of a few weeks while working up loads for this round and found it an educational experience.

The method at this time is specific to only the Bellm 444 based wildcats with Remington brass. He is currently writing a technical paper on his method.


· Registered
5 Posts
In order to make sense of case head expansion, you need:

1. A micrometer with 1/10,000 inch accuracy (I think the Lyman is only 1/1,000)

2. New, unfired cases

Measure each individual case and either mark the axis you measure it on or note the headstamp orientation.

Measuring a bunch of once/twice-fired cases on random axis with a 1/1K micrometer is just a waste of time.
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