603 Country:
However, your statement that a fellow never has to back off the FL sizing die is not correct. It will depend on the size of the rifle chamber versus the resizing die. Maybe you just haven’t run into the problem yet.
I started handloading in the 1960's and barreling/chambering rifles in the 80's.
Fortunately,between my sense of workmanship and being taught properly,its true I have not run into many problems that were not easily solved.
Perhaps we only slightly misunderstand each other.
I assume maybe you have problems with your 220 Swift.Its a semi rimmed case,designed to headspace on the rim,with shallow shoulder angles and a tapered body. The Swift typically is being loaded with a 4000 fps + mindset.
My point is pressures are not likely to be mild.
It would not be unusual to have case life issues.
So far so good? We on the same page?
I can see no good reason to overly size the brass.I suspect your die is designed to get the case shoulder pushed down enough that the rim is fully responsible for headspacing. Often,the chamber is cut so that does not work out well. The solution,back the die off of the shellholder so the case headspaces on the shoulder. That's what I have done. I'm guessing we agree on that.
I'm thinking the only place we might be doing things differently is with "What is next?"
My understanding of "Partial sizing" is about backing the die off by "turns". One turn,or 1 1/2 turns,etc to just take the case body sizing out of the picture.
That's where we may part procedures. You might get away with using a Lee collet neck sizing die here,rather than backing your sizing die out to "partial size" I can't say for sure,I full length size.
But if I just wanted to headspace on the shoulder,without working the brass,I'd first measure the fireformed case,over the shoulder,by using a bushing. Just a ring to rest on the shoulder and give me something to measure. I'd screw my die down till I got a change of about .002 on my calipers after full length sizing.
Then,to make life easier,I'd try feeler gauges between the shellholder and the die to find one I could just put beteen the shellholder and die body,It might be the .008,I don't care.Whatever works. Next time,I screw the die down on the ,008 feeler gauge. So,yes,I would back the die off .008,but don't forget I sized that case for .002 setback,so my shoulder has been uniformy full length resized.
I use a gauge,not "Turns". Then I'd measure my results,because on tht day,with that brass,I might need a .010 feeler gauge or a .006.
And I am controlling .002 head clearance on a case shoulder that has been restored by the die to at least a degree.
In the handloading language I speak,that is still full length resizing.The shoulder gets sized,just far less. With the repeatable process,we have control,and can tune our outcome.
Calipers,a hardware store bushing,and some feeler gauges. It ain't a NASA project
And I'm happy to share . Good luck!