I'm having some issues with my bullets seating correctly after a neck resize in my .270. Here's my issue:

Grab piece of brass that has been neck resized, length check to "Trim to Length" in the manual, chamfered and deburred. I then load the powder, put the bullet in and it just goes straight down to the powder. I checked the neck diameter with my calipers and it says .277. Is my neck resizing die not working properly? Am I over-chamfering my rounds?

I do have mention that some of the brass in this batch were part of a batch that I hit max pressure in. I threw away the brass that had hit max (primers were coming out of the round) - still under book max for the 55.0gr of IMR 5831 that was listed in my Speer Manual.

Thoughts? I know bigfish will say it's because it shoots rainbows...

Sure your not putting a 6.5 bullet in there??

.277 doesn't sound right, seems it should be a bit tighter.

Correct expander button??

Tom - I don't have any 6.5's laying around so I doubt it

1minute - I think so. I used the die a year or so ago and it was working fine then

are you sure it is not the expander, usually, even neck sizing goes undersize then the expander/decapper opens the case back up on the way out, mike it, if it is right on size, polish it down, spin in a drill or lathe chuck and polish off with 320 then 400 wet or dry, if it is carbide it may need a replacement!, I would .0015 under would be good

It must be the neck-resizing die then. I just ran a piece of brass through and the neck measured between .278" and .280" in diameter

Depending on how many times the brass has been fired, it could be "loose necks"? In that case it would require annealing. I ususally toss them if the bullet moves after sizing in the brass.

Try another neck sizing die?

I had that same problem with Hornady NS die and Nosler brass. Agent said dies were in spec, must have been JUST in. Can you borrow another die?

Try neck sizing w/o expander and see what you get.

Check the wall thickness of the case neck.....win brass is usually thinner than other brands. I've seen win as thin as .012.....most other brands are about .014.
Of course a standard 270 die should handle all sizes.

Have you used these dies, cases, and bullets before with success? If so, something has changed to give you the problem.

You should be able to find out what the problem is by changing one variable at a time.
Try different cases to see whether it is the cases.
Try different bullets to see whether it is the bullets.
Try to size the cases with the expanding stem out to see
whether the die is reducing the diameter enough.
If it is not the case, bullet, or die body, then about the only think left if the expander plug. Measure it to make sure it is not too big.

Had this happen with a redding 7X57 die sent it back with resized and unfired brass. They sent me a new die lickity split. Only time it has ever happened.

Figured out the problem.

I recently got my own press (had been using dies at a friends house) and while moving the dies I must have loosened the holder at the top of the die. It had worked for a few dozen pieces and then became too loose to successfully resize the neck. When I sat down to take the die apart the top cap came off quite easily. After putting it all back together and reinstalling it worked perfectly. resizing to .275! Thanks everyone!

I don't suppose you reamed the necks? Reaming needs to be done before the case is resize or exactly what happened to you happens. don't ask how I know!