A little background:
I began owning and shooting Thompson Center Contenders around 1983. I've owned several frames and several different barrels over the years but most of them were calibers you could buy in a store. Around 2000 I bought a 357 Maximum and began reloading and casting bullets. Shortly after I sold most my stuff for several reasons but I won't get into that.
So around December 2020 my son wants to get back into shooting and I bought a frame and a couple barrels. This has proven the worst time to try to get into shooting once again especially when you start out with nothing! Due to the shortage of ammo and components we've decided for most our calibers to be based on the 223, or at least be able to make the cartridge from the 223 due to the availability of brass mainly.
Sooooooo, I got the 7mm T/CU and I have to say I really enjoy it. Not a problem to make from 223 but it does have a few drawbacks. Number one being fireforming which ain't a hard task, but you're using a primer you can't get, and powder that's hard to find, but the bullet ain't too big a deal.
And yes I know....... The pre-fireformed ammo shoots as good or almost as a good as the fireformed cartridge.
And therein lies one of my reasons for the 25-45 Sharps.
I like the 10 inch barrel for hunting. My son and I have owned a few 14 inch barrels over the years and currently own two. But I don't like them. If I'm gonna pack something that big I'd as soon buy a carbine.
By the end of the year I'm planning to purchase a 10 inch threaded barrel so I can install a muzzle brake when target shooting and have the convenience of the shorter barrel when hunting. I have neuropathy in my hands so I find my ported 357 magnum barrel much easier to shoot than my son's non ported.
So here's my reasoning:
Both the 25-45 Sharps and 257 T/CU are pretty much wildcat cartridges. Neither is very popular. I've read on multiple different sites where owners of the T/CU constantly drive home the fact that you don't need to do anything special to fireform the cartridge because it shoots just as good before fireforming, so just load it as you would after fireforming and shoot it.
So why? Why even mess with the 257 T/CU if a 25-45 Sharps is gonna be just as good? Because that's whatcha got until you foreform it.
Also, as I stated above, I'll be using a 10 inch barrel. I personally don't think the T/CU will have great gains over the Sharps in the short barrel but I'm unsure.
Like I said, the 7mm T/CU is a fun cartridge. Easy to make. I've found the pre-fireformed cartridges to shoot OK. And I'd suppose the 257 T/CU would be a breeze to make as well. But is it worth the extra steps and would it have a great advantage over the 25-45 Sharps? I just don't know??
What are your thoughts between the two cartridges?