I doubt that sizing a loaded round will set it off but (BIG BUT) it will resize the case and bullet to a smaller diameter that specs. When you size a case - even neck size - you pull the expander through the neck to bring it back out to just under the size it will be after you put the bullet in the case.
Don't do it. shortcuts are always good when you are walking but when you are working with precision tools and things that can go bang - take the long way around. You know that nobody will get hurt that way.

Pull them apart and do it right.

skb2706 wrote:

He still doesn't know why they don't chamber....................

cannot figure it out
have sooted the cases and the projectiles are not reaching the lands, factory chambered Ruger MkII in .223 using american eagle federal 50 grain factory brass- once fired- all in the same rifle.

Yes feeding from the magazine and web doesn't apper to be O/S- actually appears to be less than fired.

All sized the same way, using lanolin as a lube, all sized in the same RCBS FLS die.

When sooting the rounds the soot it almost all rubbed off from the shoulder and it appear to "round" the second shoulder down from the neck a little when I try and force them in with the bolt.

have compared the fired to the resized and the re-sized seem to be fractionally longer to the shoulder than the fired.
Brother has my calipers so I cannot measure other than with my eye ATM.
how can the brass- grow in a FLS die??

thanks

later
P

Yes! Run to your local gun shop and buy a proper bullet puller of some flavor, then break down your rounds and do it all over again, checking all specificatations as you go.
.
It sounds as if you may not have sized your brass enough, or maybe not trimmed them properly. Follow the instructions that come with the dies for proper set up, and measure the case length.

Oh, and the obvious: is your bore obstructed?

NOW! is your firearm a semi-auto? If so, you may need what RCBS calls a set of "small base" dies for proper sizing and function.

Lee makes , or made a "factory sizing die" and at one time, I had a problem with revolver rounds chambering properly. About 25% would not fully chamber, soooo, I tried the Lee solution. about 15% STILL would not chamber. plus there was that feeling of trepidation, like you might be holding a live grenade when using the implement. I haven't used it again.

Good luck, and be safe!

Hey guys, he planned to us a BODY DIE that's not going to touch the neck and can't affect the bullets.