Is the bushing held tight or is it allowed a small bit of space to float?

I wouldn't full length size as it might correct some things, but create other issues. If your concern is consistency then file a small notch at the same place on every case and chamber them at 12 o'clock every time. Then only neck size and if the chamber is slightly off it will match the case indexed the same way each time. 
If you don't want to file a notch in every rim, just pick a point on the rim rollstamp and index off that each firing.

boho wrote on Dec 22^nd, 2024 at 4:57pm:


Issues like case life. By full length resizing every firing you're going to wear out cases faster. Each firing it forms to the chamber, and then you size it back. By only neck sizing your cases will likely never wear out unless you're a very avid shooter of just one gun.
I have only full length sized new cases, or new to me cases. After that never more than neck size. I've lost so few cases I can't even recall when I last had a case to toss out?

Why do the fired cases have .002-.004” runout at the neck Is that normal ?would they need more than 1 firing to run true?

Boho,

Assuming your .38-55 chamber neck is cylindrical & the main body is tapered, the runout may be a result of non-concentricity in the main body resulting in fired case runout which a neck sizing die will not correct. I understand there is no runout when measuring the middle of the case, but the chamber can still be causing the runout.  If my guess is correct, then full length resizing will remove the runout.  If it were my rifle I'd make a good chamber cast & measure the runout of the cast neck & below the neck.

If you find out the runout is caused by the main chamber body but the neck is cylindrical & uniform, I would not be concerned about it.  If the chamber cast is uniform & concentric then any case runout is most likely due to variations is the case brass thickness & hardness.

Wayne

Variation in runout at the neck can also be a function of wall thickness (depending on how the fixture holds the round being measured).   

Outside neck-turning (holding the brass on a mandrel) will make the wall thickness uniform.

My plan was to get some rounds made up for this rifle get it sighted in and come up with an accurate load and make some notes. I cast 100 bullets a 310 grain PJ creedmoor. I full length sized  the cases and trimmed them all to the same length. I loaded 50 with 17 grains of 4227 and used a large rifle primer.  I used a set of Lee dies. It has an expander that flares it a little and a seater die that nicely seats the bullet and even seems to crimp it some. I took the rifle to my gun club we have 2 side by side 100 yard “tubes” indoors. I had mounted a Flecker 8X scope. I also had a brand new laser bore sight, a $20 Black Friday Amazon special. It looked great came with a lot of neat stuff and built really well. Even came with a screw drive and spare battery. Well it couldn’t be seen at the end of the tunnel there are spot lights that shine on the targets. But I could see it along the dark floor and walls so I tried to line up the crosshairs and the dot as best I could but the elevation ran out of travel. I had blocks on that were for out to 500 meters. So it was shooting about 7” low. My set up was not good and the group was 3-4”. I shot only 25 rounds and left. I changed the rear block to a shorter one and went back the next week. This time my laser failed me and I was on my own. You wouldn’t think a seasoned shooter could get lost in there but I went through my remaining 25 rounds and all I know is it’s shooting 5” high. Windage was fine. I should be happy using the Lee dies but of course I want to compare. I got out the fancy die and I see all this run out. I completely forgot to anneal them could that be the problem? I also tumbled them in ceramic media?