First of all, I have been reloading safely for 35 years and for the last 5 years have been reloading extensively for several relatives (and myself) that do a fair amount of pd hunting. (over 30 lbs of powder last year) In reloading for all of these different guns I have developed some techniques and observations that I would like to share with you. I have developed a way to keep track of the exact number of times a case has been fired so you can start getting an idea of brass life in each of your rifles. It is quite simple.
I score the case heads with an old sharpened screw driver. Each score mark represents one firing of the case. My reloading regime starts with marking the case heads, then I proceed to the next step. (In this case I removed the primer to make the score marks easier to see)
The first photo shows a case that has been fired 3 times. I drill holes in my bench to hold the cases for marking. The second photo is of the ergonomically designed tool to do the marking and various holes for the cases to fit in upside down for marking.
Using this method you will be able to tell just how many times a case has been fired.
Also some observations. Each rifle (chamber) is a story in and of itself. No one but you can tell what the brass life will be with each of your guns. By keeping track of the firings and watching for splits, cracks, etc., you will eventually get an idea of how many times you can reload a case for THAT chamber.
As others have stated FLR can decrease the life of brass. But I would guess most of the stretch in your cases is coming from when the round is fired. FLR alone does not stretch the case web. This stretching indicates the live round is lose in the chamber for what ever reason, and the solutions for this are listed above.
If you feel you must FLR, I would not buy "high end" brass. The brass you are using is not the problem. A significant outlay of cash will not (in all likelyhood) significantly increase the number of loadings you will get. I use WW brass when ever possible, but have used RP, FC and PMC and have found them servicable as well.
BTW, for all of the 22-250s I load for, I neck size for 4-5 loadings, FLR and then neck size again for a total of 10 firings. After the 10th I discard the case. A lot of experience has told me that after the 11th loading "things" can happen and I don't want them happening on the prairie. (But once again, this has been my experience)