7-300 WSM Q's & Hyperbole

[Wild Monkey]

When Necking down to 7mm how much does the Neck Grow? By simply Necking down the 300 to 284 won't you end up with a very short Neck? I was thinking it would be proper to keep the base of the Neck stationary and lower the Shoulder down roughly to 1.65". Chambering would be easy by simply ordering shorter Gauges? It's easy to trim Dies down to compensate as well. How long would this leave the Neck? Which Dies are you using? Maybe someone could donate a full body die to this experiment? Would 270 WSM be best with the appropriate Neck Bushing?

 

[sable tireur]

We originally started necking down the .300 WSM because we thought the 7 WSM neck was too short for the longer, heavier bullets. This created the wildcat 7mm-300 WSM, 20 some years ago. It was popular for about 10 days until we discovered that the shorter neck created NO such problems. Look at the .300 Win. Mag. neck length or the benchrest cartridge 6mm Wolf Pup.

As to the DIY project you suggest, I think your question was resolved 20+ years ago.

 

[7.62 Gunner]

When Necking down to 7mm how much does the Neck Grow? By simply Necking down the 300 to 284 won't you end up with a very short Neck? I was thinking it would be proper to keep the base of the Neck stationary and lower the Shoulder down roughly to 1.65". Chambering would be easy by simply ordering shorter Gauges? It's easy to trim Dies down to compensate as well. How long would this leave the Neck? Which Dies are you using? Maybe someone could donate a full body die to this experiment? Would 270 WSM be best with the appropriate Neck Bushing?

I recently built a 7-300 wsm with a 45 degree improved shoulder.
Necking down from 30 cal to .284 actually lengthens the neck slightly, while necking up shortens it a tiny bit. You will have to run an expander mandrel into the neck and turn it to remove the thicker material near the shoulder junction

I wouldn't want to shorten the shoulder at all, if you want a simple wildcat keep the parent case specs and simply neck down with a FL 300 wsm bushing die.
Honestly though if you're not improving the shoulder I would stay with a straight 7 wsm, it's fast and extremely accurate as is.