I am reloading 22-250 with 55gr. Vmax bullets with 34.5gr. of IMR4064 powder,CCI stander primers and weight each charge. I also turn the necks. When I cron. there is 64.8 fps diffrence in speed. I belive neck tension is where the trouble is. What can I do?
THANKS
Jerry

There are many variables and neck tension is only one of them that can affect speed. Could be bore fouling, case volume etc.

Neck tension is very important! Not how much in most cases but how even. Every case should have the same tension for accuracy. Don't mix turned brass with unturned.
If you turn brass for a factory rifle, ONLY turn enough to even the thickness which means one side of the neck will have a small spot not touched by the cutter.

Here's a crazy story about neck tension. I'm encouraging a young guy to start reloading. We have great luck with his 300 rum. We now get dies for his 7 wsm browning auto BAR.
For reason (we now have it worked out) they oversize the case mouth in one pass and leave a dimension of about .277" for a grip of .007". We load 4 different bullets in the 150 grain range and most have horrible runnout because of very hard seating into the small case mouth. (alot of it had at least .007" runnout.)
I'm thinking.....well this gun doesn't like factory ammo too much and now I'm really going to show him some "crap" groups.
What happens.....I tell him a bit about the problem.....we'll get it fixed....lets shoot this stuff up and work for better in the future.
WEll......not one of the loadings went over 1.25" at 100yds.....two of them shot 3/4" and all went to the same point of impact. The best groups was the worst runnout as they were 154 grain hornady flat base bullets.....3 were touching. I don't think a round was under .007" runnout.
Was really tight neck tension the "winning favor"???? Hard telling but WOW....it was a eye opening result for me!!

Try not turning the necks,just for the heck of it,bet it will be better! van

quote:

Originally posted by jy:
I also turn the necks. When I cron. there is 64.8 fps diffrence in speed. I belive neck tension is where the trouble is.
Jerry

Do you feel differing tension when you seat your bullets?? What tension are you currently using, how do you establish that, and what means do you have of varying tension??

I agree that differing neck tension can be a problem - for me in terms of accuracy, but I know long range shooters pay a lot of attention to velocity variations. You are already doing a lot to overcome varying neck tension by turning your necks - although if done for a factory chamber, you should probably only turn minimally as noted above by bfrshooter. Still, even with turned necks, brass varies... I have found the following options to try to deal with varying tension - none of which are exactly revolutionary...

1) increase tension. I often found varying tension to be most of a problem when I loaded with very low (.001-.002") tension. These days, I load with .003-.004-.005" depending on caliber and the intended use of the load/gun.

2) attempt to overcome workhardening effects on the brass by annealing every 4-5 loads.

3) make sure your brass is loaded in batches and keep track of how many times it is loaded. Don't mix old and new brass.

Note: if you use Redding (or other manufacturers') bushings to try to control neck tension, I have come to be sceptical about the dimensions stamped on some of these bushings. I have had cases where dimensions of bushing sized brass was completely out of relation (even accounting for brass springback) with the dimension on the bushing. Eventually, you'll find a bushing that works, but it sometimes takes a bit of guesswork - and a lot of expense - to finally get the right one...

- mike