bought 'nother mauser

Tod, Tod, Tod ! You keep on ( remembering my own habit ) Ah well Ah , Awesome ! Congrats ! Aren't you at least gonna shoot it before it gets assigned a number ? Just a wee quick little test to see if it wants to like cast bullets? It irks me that you may have that much more will power than I ! My regular protocol is #1 take possession, #2 shoot .

C'mon Tod !!! I'll send ya some bullets? Never mind that heavy trigger pull. Just put some rubber bands on it to amount to about 8 pounds and then it should break at about a pound of finger pressure. Perfect!

Thats getting complicated. Buuuuuuut I have done that to get a better neck fit in some rifles. When you shorten the 06 case you end up with thicker than normal necks. Ideally what I like to see is after setting the shoulder back and trimming then seating a bullet the resultant cartridge will not chamber due to too thick necks. Then turn the necks so there is just .001" clearance. That gives a better case alignment in the chamber and only allows the necks to expand .001" on firing so case life is improved. Its a bit of work but a double win for the effort.

""" the neck turn, do you mean outside or inside of the brass? """

The end result is the same either way but with inside reaming you would need an assortment of different diameter reamers because to my knowledge there are no adjustable inside reamers. Outside neck turning on the other hand is far more simple with many different types of adjustable cutters.
The Forster system I use is old and has been in my possession for nearly 40 years but still does the job. It uses a manual rotary trimmer type base with inside neck pilots and adjustable outside cutter. One thing it made obvious to me long ago is the fact that cartridge case necks are far from uniform in wall thickness and usually have a thicker side. That thicker side can push the cartridge out of alignment with the bore center and cause accuracy to degrade.
That is another good reason to start with case necks that are too thick then work them down because you get case neck concentricity which eliminates another variable leading to increased accuracy potential. This is the reason bench rest guns use tight neck chambers so the brass has to be neck turned to fit the chamber.

What your doing by inside reaming is making case necks that are too thick and wont fit the chamber fit by making them thinner. Your dimensions are pre set without specific attention to the specs of either the brass dimensions or your chamber dimensions.
When you outside turn necks you have the opportunity to fit your case neck dimensions to your chamber dimensions with what ever tolerances you build in. Its like going to a tailor for a suit over buying one off a rack.
Some BR shooters even turn necks to a zero clearance fit so that there is zero case neck expansion on firing. This produces a case that never uses a sizer die of any kind only a seater. This extends case life but requires load development with the zero tolerance condition.  It may also limit velocity because without the neck expanding to release the bullet the time/pressure relationship is affected in that the pressure will peak before potential velocity for the cartridge is reached.  
If turning necks you have the choice of anything between a zero clearance up to and exceeding a normal factory condition of on average .002 to .004" clearance. I have encountered mil-surp rifles with as much as .008" clearance but with so much brass working between sized and fired dimensions case life is poor.
At one time I used to prep all new brass to just take off the high spots on the necks to improve concentricity. Now only for a few specific rifles that are nothing if not accurate.
This is why I earlier said for some rifles I like to start out with brass formed from a longer case because with any case the brass gets progressively thicker from mouth to head. Say for instance if I want to build match cases for a 6mm rem the place to start is with a batch of 30-06 cases that have been matched by weight.
Then my process would be first anneal, then form, trim, and then turn necks to the fit that I want. There would still be some work to do on the primer pockets but that is another subject.

That is exactly what I use for neck turning. It is an add on option to the Forster case trimmer. If you are not aware the Forster uses two different base lengths each having two length settings for the trimmer head and collet head. That covers a wide variation in case lengths. I have both bases and have had to use both. There is quite a length change when going from something like a 300 H&H to a 22 Squirrel.

There are others.

The 22 squirrel and the 22 cooper have identical case capacities. I have a model 38 cooper rifle and like its performance but brass is scarce. I have tried but failed to make it.
The 22 squirrel gets the same performance but brass is simple to form. Basically both cartridges slightly out perform the 22 WMR (22 mag) but are reloadable. Shooting cast bullets they are very low cost to reload.
Two loads I use on opposite ends of their performance take .7gn powder on the low end and 7 gn of powder on the high end. The low end load gets 10,000 shots per pound of powder and the high end load gets 1000 shots per pound.
The low end load shoots a 45gn bullet subsonic at about 900 fps while the top end load gets 2000 fps with a 50gn bullet.
In comparison the one 22 mag load from Federal claims 2000 fps with a 50gn bullet but my Ohler model 35P says 1600 fps for that load. The 22 mag will reach 2000 fps with a 40gn load in a rifle.
Just to add a little more ballistic trivia my chronograph testing of the 22 LR and 22 mag showed the 22 mag with 40gn load at 2000 fps from rifle and 1300 fps from revolver. The 22 LR HV 40gn load did 1300 fps from rifle and 900 fps from revolver. I thought it interesting that the 22 LR in a rifle is the ballistic equal to the 22 mag in a revolver.