When the barrel on my 7mag was near end of life, I looked at the same question.
Basically, I wanted to launch 180 grain bullets @ 3000 FPS.
Ultimately built a rifle based on Gunwerk's 7mm Long Range Magnum.
I considered 28 Nosler, 7STW and 7 LRM. Wasn't interested in a RUM. Had a 300 RUM Rem 700 that I was going to use as the donor action.
No to the STW because, personally, I don't like belted cases.
The 28 was still new at the time. I like the 404 Jeffrey case / 300 RUM and also use them in my 338 Edge.
Following a board suggestion, read an article about Gunwerks 7mm Long Range Magnum. It holds about 12 grains less powder, and for the same bullet is 200FPS slower. I'm not in a ****ing contest for fastest 7mm slug, and that extra 12 grains of powder makes a world of difference in barrel life. Funny, there has never been a lack of brass available for 375 Ruger, the parent case for the 7LRM. Plus, you can buy already made and headstamped brass from Gunwerks. JMO, advantages to the Gunwerks 7LRM over the 28 Nosler: Longer neck in the finished case, allowing to seat long heavies out farther with confidence; Same magazine space (300 RUM) but allows longer seating; very manageable recoil for the performance offered; some barrel makers will chamber for it; and easy source for my own brass. Disadvantage: it's a wildcat.
While I love what I see in their rifles, I cannot justify a Gunwerks rig. I like a challenge, so started a build. Finished weight, I targeted for 10 lbs. I tried to avoid all the mistakes I made with my 338 Edge build, and though well balanced, it's still too heavy at 12lbs finished. Had I selected a lighter barrel profile and a different chassis I'd be below 10 lbs. With a MB&M brake on it, it recoils like a 308 or lighter. Without, less than a 7Mag, more like an '06.
I run it with a Leupold Mark 4 LRT. It's a joy to shoot. Pick and range a target, adjust the dials, Hit!
The process was a great learning experience. Forming my own brass from 375 Ruger cases taught me a lot. I have both Gunwerks and my own brass. I also discovered my distaste for Hornady dies in the process. They work, they are quality, but I find I do prefer others and will spend more for them.