Wildcatting Fun & soft Norma Brass

[Wild Monkey]

View attachment 163466 View attachment 163467 View attachment 163466 View attachment 163467 View attachment 163466 Forming 300 RUM brass down to a lower or shorter Cartridge: For this Example the Wildcat is called the "7mm Win Mag". With a Case is 2.5" long. 1st Trim the Brass to Length. I use a derelict .375 RUM FL Die and Move the shoulder for forming. It's important to establish the shoulder location on the Brass with a die that uses *30 or less shoulder angle. The 7WM uses the 7WSM *35 Shoulder located @ 2.018" high. .375 RUM @ 2.387" subtract the 2.018" = .369" trim off bottom of DIE ( a little more is better).

To step the Neck down I use a Lyman .325 WSM FL Die, then take it to 7mm. It's important to remember once you form the *35 Shoulder Angle, you don't attempt to move the Shoulder Down further, - as this will crush the Soft Norma Brass. Even attempting to move the shoulder after taking the brass down to 7mm can crush or buckle the case. If you attempt to form the shoulder with a Wider Die than the Donor Brass it will Balloon out - & RUM die has a good supporting shoulder for this as the widths are the same before forming. All Brass prep after can use standard WSM Dies & Prep with the longer Neck.

There are negatives to using this Die as a Forming die is better, this particular die is an RCBS Die and will need to be polished out to a larger I.D. towards the center of the Die. The Un-fire formed example starts with a Shoulder that's .530" Wide, which in all practicality duplicates the Dakota & Nosler Shoulder Widths. The Wildcat example has the same Shoulder location as the 33 Nosler Brass to further emphasize how useful this process can be.

To assist Reload'rs having difficulty forming Cases & Crushing Shoulders. I'll bet there are lots of Old Timers that know this trick and probably just got tired of explaining it. This is my Hobby and by No Means can I give examples of Perfect Scientific Data, so please be forthcoming with positive feedback keeping that in mind, thanks. These items listed are only examples and I have no affiliation with any Manufacturers. (Photo for Reference only I make no claim to initial Tradesman who drafted it.)

 

[Mram10us]

I am interested and would like to see a video of the resizing.

 

[can1010]

I did mine back in 2012. while you are using the 2.5 inch length I put my 300 with the neck shoulder in the same place as a 300 win mag and a .338 neck length. I use to shorten the dies and it worked but in the end I used 2 PTG die blanks and a 338 rum reamer and then honed the neck out to .400 on one and left one .338. I push the shoulder back to the body to shoulder location then use a hydro form die to change from 30 degrees to 40 and blow out my taper setting the head space .005 long then use my sizing die to set headspace to .002 in the end I have brass 99% formed without fireforming.

 

[MNbogboy]

Maybe a little related here. Shortening 6.5-284 brass for a small 7mm wildcat.
Had to use several steps to get there using 7 different dies. Read about old timers using STP, had to try (because I am an old timer...lol). The STP was so "slick" I was able to get by with two less step downs. After turning the necks & annealing all 50 in the first batch fireformed up perfect (the reamer here is a 7mm rem mag held short). The final FL die is a shortened 7mm rem mag die.
Hope you can figure it out without crushing any more cases.
Good luck,
Randy

 

[Wild Monkey]

Edd told me about Hornady Custom Form Die Kits available ($120), MNbogboy. That's a whole lotta dies there.

 

[MNbogboy]

Edd told me about Hornady Custom Form Die Kits available ($120), MNbogboy. That's a whole lotta dies there.

The dies were sitting on the shelf for years while this whole project was just a pipe dream and only started it because I wouldn't have to invest much. Bought a $20 used rcbs 7 mag die off eBay and had to buy some brass & bullets. The barrels were Savage take offs that looked ok so I didn't scrap them a long time ago. A quick setback and added a few threads so nothing invested there either. If they don't shoot then I'm only out my time and some reloading components. But I did it just because and have fun doing it.
Now if they shoot good might make a novelty deer rifle for one of my grandkids....certainly so it is a pleasure to shoot because of the lack of recoil....getting about 2900 fps with 120s.