Oh, my.  That .277 is more consistent with the bullet being .257 on the bands, assuming a case wall thickness of .010. 

Back in the soup!   

Anyway, thanks again!    

I'm done for the night.  Later.

Phil

 

Jerry, you are a prince among men.  Thank you again!

The only question left then is; how are people who are using .251 bullets getting any results at all?    

The only original chamber I have to measure will swallow a letter K drill shank with some to spare, so it's bigger than .281". To get any accuracy at all in original chambers, I'd think that the whole body of the .17 WSM would have to be expanded to at least the .277 you measured, and a .257 bullet used. Even at that, it would hardly be comparable to even "sporting" .22 chambers.

Now, where do I go from here?   With minimal reforming, I can get a case that accepts a .251 bullet, and has an O.D of about .272.  I already ordered a .25 Colt liner, .250 groove diameter.  Have a set of .25 ACP dies around here for some unknown reason.  Reamer will be made or bought - a "D" reamer will be easy-peazy, so I'll probably do that.  Ending up with an undersize .25 RF wildcat, having the advantage over .22 in that it will shoot 60-70 grain bullets from its' 14 twist.  Chambered right, it ought to be reasonably accurate.  It won't work with original ammo, but who cares?  There isn't any around anyway.

Long after I'm dead, some collector will look at this rifle and scratch his head.  And I'll be the gnome. 

waterman wrote on May 19^th, 2017 at 2:21am:


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New guy here that has played with this problem on and off for quite awhile. Came across this post a couple weeks ago searching for other stuff.

Grabbed a box of 17 WSM and went to work.

I did not like the idea of cutting off the case, so pulled the bullets and proceeded to neck up the case. This was a little bit of a problem because the brass is brittle.

What I ended up doing was grabbing a cheap set of numbered drill bits. Started with a #17 (.173") and went to #1(.228") I rounded the back end of the bits.

I also bought a pair of Lee expander pins for .204 and .257 and ground off the decapping pins.

I already had on hand expanding mandrels for neck turning .204 and 6mm.

A separate 3/16 (.187) bit was ground to a long taper.

The neck sizing process was a little time consuming at first, but it's coming together. Because I am using the pins, the drill press is used as an arbor press. 

Starting with the smallest tapered mandrel, I basically belled the neck like you would for seating a cast bullet. I would then take 2-3 drill bits and open the rest of the neck.

This has seemed to be the best method so far. I split a lot of necks before working this out. As long as the drill bit is smaller than the bell, it enlarges the rest of the neck. By only going a few thousandths at a time, bell and repeat, I have been able to work all the way up to the .257 sizing stem.

Refinements to the process are coming and any ideas are greatly appreciated.

Tonight I made a shell holder that is basically a keyhole shape in a piece of shallow channel iron. A .335" hole drilled and slotted to a .270" hole. This clamps to the table of the drill press. Drop the brass in the large hole and slide it to the small.

Next is to trim to size. When these are finished sizing they are 1.165", so having a full size round is possible.

I will load and shoot a few of these this weekend and then decide if it it's worth it to make a mandrel to full length size the case.

First shot will be a pulled original bullet loaded into a new case.

Hope that adds to the project. I am excited about being able to shoot a rifle that I have had for more than forty years, without feeling a little guilty every time I pull the trigger.

WAG ... not even a SWAG.
I wonder if is it possible to clamp them in a collet and spin using a small 
ball to move the material out to nominal dia. Control of heat may be a real 
problem. It just won't do to pop the primer.

If one could re-prime then it would be obvious to anneal and proceed. 

Using the .17 is a great idea. The problem is to make the rework easy.
Still it is much easier than making 25-20SS from 5.56 brass. 

Guess the next problem is to look up the properties of priming material and
see if there is a way to salvage from regular primers. 

craigster wrote on May 20^th, 2017 at 6:47pm:



Craig,

What is the stuff?  DuPont chemists work for 20+ years to produce reliable Kleenbore priming.  These guys have chemicals in 2 bags.  Has anybody tried it and looked at a dozen barrels afterward?

Just a thought - would it be possible to stand them in ice water and anneal the necks?  Or insulate the main part of the body some other way?

Regards, Joe