7mm cartridge choice

I am building a 7mm caliber and looking for the optimum cartridge. I want a belt less cartridge that has a mag bolt face, pushes a 180 in the 3000 fps range and isn't super long. I have a few I like but they have a few downfalls. I like the 7 stw but because it's so long it won't allow long bullets into the magazine. I like the 28 nosler but brass isn't available anywhere. I also like the 7mm lrm but have heard reports of difficultly tuning and getting brass. What other cartridges are similar? Yes I reload. Also this is for my hunting rifle so keep that in mind.

You might look at the 7-300WSM on a long action, throated long enough to seat long range bullets for more powder capacity. You can get 2950 on a short action with 175's without doing much load development, and should be able to hit your 3000 with the right powders. The 7-300 uses the readily available 300 WSM as its parent case, as opposed to the hard to find 7WSM brass.

The straight 7mmWSM will get to 3000 a little easier due to the slightly larger case capacity. You can also make 7mmWSM brass from 270 or 300wsm brass with a simple fireform.

Ruger brass is where I would want to go with it. Whether ya call it a LRM or not. I just don't hunt anywhere a 280ai would be under gunned.

Look at the 7MM Dakota

We dont live in a perfect world so as a rule some compromise is usually necessary.
As for the belted case there are choices. #1 just remove the belt and headspace off the shoulder.
#2 leave the belt and still headspace off the shoulder. That way the belt is there but serves no purpose.
You are complicating the situation with wanting to seat heavy bullets long and still use a factory magazine.
You wont solve that issue quite possibly even with an after market magazine.
The fact is however that guns tend to shoot very well with bullets seated deep.
About 45 years ago the 300 Weatherby case necked down to 7 mm was a very popular long range hunting cartridge.
Reason was Hornady had produced the 162 gr match bt bullet. Later the 7 stw was created using the 8 mm mag case as its parent case.
That cartridge later became and still is a factory chambering. Balisticly, its a duplicate of the 7x300 wby. Both those use belted cases.
Then years later Remington introduced the 7 ultra mag which uses a beltless case. If loaded to full potential it will have about 100 fps advantage
over the other 2 mentioned 7 mms. Ive owned a 7x300 wby for over 40 years. Actually i have 2 of them. One is built on a 40x Rem single shot action
the other on a regular 700 long action with factory magazine. The 40x has a 30" Hart barrel, the other the original 40x 27" factory barrel with some shaved off
the diameter and fluted making it a heavy sporter. Velocity of both guns with the same load is about identicle. Using 7828 powder and the 162 gr hornady, my
velocity is about 3350 fps. Ive done extensive long range testing of various bullets including 180 Bergers and find the 162 the better bullet out to 1200 yds.
I can put 2 rounds in my factory magazine and chamber one for a total of 3. The gun shoots equaly as well as my 40x with bullets seated longer.
Another good option would be to neck down the 300 win mag case to 7mm. That would be a better fit in the factory magazine and would be within about 100 fps
of the stw or 7x300 wby. Its still a belted case however, but my sugestion would be just get over that issue. Its mostly mind over matter and if you dont mind it
wont matter.