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Topic: Where are the lands? A measurement technique comparison  (Read 838 times) previous topic - next topic

Re: Where are the lands? A measurement technique comparison

Reply #135
Here's a picture of the Mitutoyo I'm think of. It's digital without needing a battery. Less than 1/2 the price of a "real" digital model.



Chris

Re: Where are the lands? A measurement technique comparison

Reply #136
That’s the one I use except no digital read out on the  ten thousands column. It’s good enough for repeatable accuracy.

Re: Where are the lands? A measurement technique comparison

Reply #137
@jvw2008, Is the ten thousands readable from the thimble, if desired?

Never mind, I see in the picture it say it measures to the 4th decimal place.

Snagged an as-new one on FleaBay for $149 plus shipping :)
Chris

Re: Where are the lands? A measurement technique comparison

Reply #138
That's what I'm going to try today.

It's entirely possible I contributed to this by not using the Lee collet die correctly, or with not enough force. The die manual says to apply "at least 25 lbs" which I find confusing. If I had a 25 lb weight where would I put it? On top of the ram? Tied to the end of lever? if so, what length lever does that apply to?

Maybe I'll shoot Lee an email.

Chris your using the lcd right.. necks get thicker.. just a part of it.. your reamer should fix you back up..
Grant

 

Re: Where are the lands? A measurement technique comparison

Reply #139
If I were going to inside ream I would try it before sizing. Then measure and determine if I needed to take more off. I think you will need to but if you can't pass a bullet through a fired neck maybe you can do them all fired once and be close enough to load and fire them then try reaming again.

I think you'll get there but it may take a couple tries.

I would be hesitant to size then ream I would be scared they may get too thin.

Maybe try one and see it could be just right.
Dave

Re: Where are the lands? A measurement technique comparison

Reply #140
Well, half of these I've dinked with trying to figure things out.

What about seating a bullet in each one, pull the bullet, then ream? At least they'd all be the same I.D. to start with, I think.

I pulled the brass on that one round where I'd seated a bullet. I can now insert a bullet by hand; it doesn't drop in or fall out by gravity but it's a long ways from the unseated cases in this regard. I can also manually get the reamer started on the taper.

I'll ream this one and see where I'm at.
Chris

Re: Where are the lands? A measurement technique comparison

Reply #141
This old "Henry Hanson Handy" 1" Mic (1940s?) finally found a new home!...lol...partnered up with some "scrap pail" parts....screen door bracket(2003)..add on cruise control left over bracket (2006)....shower curtain rod bracket (2004)....the ball is a grade 8-8x32 pan head screw...
Zeroed on base line will work good enough for this "Finnlander" to read neck thickness within a half thou.......some Hornady creed brass I checked had almost two thou difference on the same neck!

Total cost:  2 hours of my priceless time...i think I better get a job!
11X Grandfather
Part time Savagesmith

Re: Where are the lands? A measurement technique comparison

Reply #142
That is so cool!  I love that kind of ingenuity!!

Way to go Randy. 👍

Re: Where are the lands? A measurement technique comparison

Reply #143
Chris are all the fired cases too tight to slide a bullet in?   If so your bullet idea for an expander might even them up so the reamer cuts approx the same amount.  Try one measure thickness  you probably  only need to skin a thousandth or a little more from the inside to get you where you want to be.
11X Grandfather
Part time Savagesmith

Re: Where are the lands? A measurement technique comparison

Reply #144
@mnbogboy, yes the fired cases are too tight to slide a bullet in.

I just pulled the bullet from the case I seated, then I reamed the neck. Clearly the bulk, if not all of the material came from the shoulder end of the neck.

Once that was done I could drop a bullet in easily and have it drop out from gravity.

I seated the bullet again and measured 0.293" O.D. on the neck.

I'm thinking if I can repeat that I should be good to process and load these.
Chris

Re: Where are the lands? A measurement technique comparison

Reply #145
The dreaded doughnut.. thats what i suspected
Grant

Re: Where are the lands? A measurement technique comparison

Reply #146
Sounds like donut to me....if the whole batch goes that good then your problem may not come back.
I've inside reamed donuts out a couple different calibers.  Usually once and a few on the next firing they seem to not be a problem after that.  When that brass thickens at that junction I think under pressure after the bullet leaves it causes the forward end of the neck to "curl" inwards.
By habit now I take a bullet and check all fired cases for an easy fit before sizing.  If the bullet stops at the neck shoulder junction it's a donut and needs attention.  Double reaming before sizing with a full caliber reamer and with a smaller reamer after sizing has worked to get rid of the those pesky "breakfast pastries"  also.
Good luck sounds like you have a good handle on it now.
11X Grandfather
Part time Savagesmith

Re: Where are the lands? A measurement technique comparison

Reply #147
Here are the actual Lee instructions for their collet dies, maybe not as confusing as I'd thought, 25 lbs applied to the lever. I have no idea how standardized all the various presses are with respect mechanical advantage and lever force to ram force.

At some point applying more force than needed should not result in any further compression of the neck as long as the die has bottomed out.

 

I cam over with that collet die on my RCBS Primerchucker.  Works just fine. I start with no pressure on cam over and go like 1/16th of a turn until I can feel pressure.  I then measure the neck and turn the die in until I just get my target neck ID. If I do it right, and I hold my finger over the primer hole, I can insert the mandrel and it will bounce back out the case from compressing air inside the case. I can also feel the mandrel machine marks rub the inside of the case neck.  I usually do not get any "lines on the outside of the case neck when I set up this way.

I keep the "fingers" inside the die greased as well.


Re: Where are the lands? A measurement technique comparison

Reply #149
Sounds like your onto something but you still need to check that neck thickness and get some clearance there.

I was wondering if you were going to find thicker necks near the shoulder.
Dave