375 tapered expander for case forming

[RobfromME]

Good afternoon,

Im interested in using a forming technique for my 338 Win Mag where a tapered expander 10-15% larger than bullet diameter is used, and then sizing the case until the bolt just closes without excess effort. I read of this technique recently and want to try it, but I'm having difficulties finding the so called tapered expander for case forming.
I'm hoping someone here could point me in the right direction as to where to get one, and which one to buy to avoid getting the wrong type.
Thank you in advance for your time and interest!

All my best,
Rob

 

[thatguyshm]

Look at K&M Shooting, and look for an expander. You'll need the holder also. I would recommend a .358", a .375 might cause neck splits.

Expand Mandrel Selector and Accessories | Reloading

Expand Mandrel | Expand Iron Tool will iron out and slightly expand the case neck. The brass will spring back to the size needed to neck turn your brass.

kmshooting.com

I use a .300 WM neck die to neck up 7mm RM brass when it's new then size for a crush fit in my 7mm die. Just need to get the expander through the neck to open it up

 

[RobfromME]

Thanks so much! Yes, I believe your idea of a 358 expander is much more preferable! I'll ckeck out KM shooting.

Thanks again!

All my best,
Rob

 

[thatguyshm]

Hey no problem. I use a .264 mandral to neck 6mm BR brass up to form a false shoulder for 6mm Dasher rounds. 20 thousandths will be plenty. Good luck from a fellow Mainer.

 

[RobfromME]

Good morning!

Ah, I do see you're from ME! I grew up here and went west after college. I came back for family reasons after 10 years and find I'm homesick for the open skies and dry air! LOL! I never did get re-acclimated to the bitter cold and the rain. It was easy to get used to less than 20" of rain each year!
I intend to get back once the situation here changes. I still enjoy Maine, but it's a very different place from when I left.
Hope you're day is off to a good start, and thanks again!

All my best,
Rob

 

[RobfromME]

Good morning, thatguyshm!

Once again, thanks so much for the info! I purchased one of the 35 cal expanders and holders from KM shooting this morning. Looking forward to using it.

Thanks again for taking the time to share the info with me! Very much appreciated.

All my best,
Rob

 

[thatguyshm]

Awesome! I use imperial sizing wax and q-tip it out after I size back down. When setting up your die you'll want to back it out a touch to get that crush fit. Not heavy resistance, just enough you know the neck shoulder junction is just barely supported.

I usually toss the screw that comes with the expander in my storage box, as I want the entire neck expanded. Just go slow and you'll be fine.