Problems Resizing

[Texis]

Hi guys,
Dedicated 708 shooter, have been reloading 708, 308, 300WM for years.. but the 708 is my favorite.
I have had excellent success with PPU brass over the years, and I like it. Recently I re-visited making 708 cases from 308 brass for various reason unknown to me. Well there is that Lapua 308 brass is plentiful and commonly $40 less p/100 than Lapua 708 brass.. and I have a bunch of Lapua 308, and continue to buy more.
Here's the issue: my 708 RCBS FL resizing die is creating a small bevel at the neck end of the case? (Ruins the case) It's almost like there is a small, uniform ridge in there that is flaring the 308 brass, but I can't see it or feel it? It does not flare the 708 brass?
The die is set to bump the 708 brass back .003, so I "assumed" I will bump back the same on the 308 case… so it chambers well.
Any ideas what is creating this flare at the bullet insertion orifice??
Btw.. a few of the once fired Lapua 308 cases have come out great, and shoot great. The chamber in this Shilen barrel can handle the extra neck thickness without having to turn the necks.
Thanks in advance, any suggestions are appreciated.

 

[deadidarren]

Have you got a pic .

 

[doverpack12]

Measure the lengths. Might need to trim your 308 brass before sizing to 708

 

[Texis]

Sorry for the delay, here's the results.

 

[Texis]

I thought about trimming, except 308 resized to 708 comes out .015 short already.

 

[Texis]

It's almost like a tubing flare lol

 

[Texis]

Btw the decapping, ID sizing ball is removed.. I used custom mandrels for ID sizing

 

[deadidarren]

Well looks perfectly bell mouthed for seating lead projectiles I am being facetious of course never seen that before

 

[243winxb]

Sizing down to much in 1 step? Seen same 308 to 243.
The excess brass needs to go some where. My guess.

 

[Texis]

I spoke with RCBS, they were familiar with the issue, heard it before. But they have no clue what causes it, or how it can go back through the die and come out this way??

 

[Rosebud]

I've re sized laupa 308 to 708 without issues. Try another die. Or trim off the bevel and load.Went through the 7-08 drought couple of years ago and 308 was there. Bought box of laupa plenty of one shot inside an out. No problem. But the case will be a little short. That will be fixed on next firing.

 

[IllinoisBurt]

If it's just a flare, turn in the seating die to have the crimping ring just kiss it. Should be easy enough to iron it out without actually crimping into the bullet if that's what you wanted.

 

[Texis]

John Whidden was good enough to take a guess, he was right. The brass is snagging at the shoulder to neck transition. He suggested that I could smooth / polish that area in the die. Based on that assessment I beveled the OD of the brass prior to pushing it through and it reduced the flaring effect significantly. Enough that the ID mandrel took out the rest of the flare. I'm in business
He will continue to have my business for any of the precision tooling I need.

 

[Seabeeken]

Btw the decapping, ID sizing ball is removed.. I used custom mandrels for ID sizing

Ive seen this in a few of my dies with the expander ball removed. It usually goes away when i run them over expander mandrel. Saw it also when forming brass for my 250ai. Not certain what causes it. Perhaps annealing will help. You would think it would straighten back out as it is withdrawn out of the die. Maybe springback if the neck is going past the end of the neck sizing area of the die.