Hi

I'm trying to neck 300 WSM brass up to .338. I only have a set of RCBS dies (Forster is working on it) and about every third case the neck folds under on me. I'm lubing the inside of the necks with Imperial case lube and that helps some. Any suggestions???

Speedy,
Try taking a smaller step first. Use a tapered 8mm expander (.323), then go to the .338. That would relieve some of the stress on the shoulder.
Regards,
HockeyPuck

I have a couple of 338 WSM's and do your operation all the time with no problem. Not sure of why your problem except the incorrect configuration on the expander. I've been using the Sinclair expanders used in conjunction with their neck turning tools which have a bullet shaped end. Because they are long I've lubed the inside of the necks very well in order to prevent galling. I'm using RCBS sizing lube applied with a Q tip. You might try lubing with a more conventional sizing lube, and much more than you normally would with Imperial. I don't like Imperial for that type of work.

Not sure if Hornady has come out with a 300 WSM die but if they have, the ideal solution would be to buy their 300 die along with a 338 tapered expander. If you call them direct they are very helpful in configuring your needs. They helped me with their seating dies when I first undertook these WSM projects. I use their short seating body with their 338 guts for bullet seating.

An even better solution is to not even use expanders at all. Fire form your brass using about 20g of Unique, fill the case with cornmeal or Cream O' Wheat, plug with toilet paper and fire away. You would also have the advantage of not having to "straighten" the brass after the expanding, by fire forming. Typically the neck gets offset some in the expanding operation anyway and fire forming is essential for straight brass.

Speedy---

Why bother with a die. Fireform them with a fast powder and inert filler. It's easier and you come out with a better case.

Thanks for the info

I haven't used the inert-filler fire-forming method yet and it would be a little tough right now as I don't have the rifle yet. I'm just trying to work up some dummy rounds to determine what seating depth to use to have the reamer cut to fit. I think I have enough cases ready to finish my little project.