C'mon, this is completely off topic and the OP didn't ask for any opinion on suppressors and their validity in apparently every situation. Please delete or modify your post to reflect something useful to his query.
I used a 7mmRm in Africa, I did not see it being to long or to obtrusive for hunting. I think OP Willa get that from my short story. It's my only relevant comment or experience to add.
I agree with this post
Two things you wrote I will refer to. (1.) Silencer is a totally fictional object that was the creation of some Hollywood movie director but do little to mute the sound of a bullet being discharged from a firearm. Suppressors do a similar job to lower the sound of a discharged bullet being fired, however, they only diminish the sound to a level that, sometimes, can keep one from damaging their ears, but usually don't reduce it below 130 decibels. (2.) 7mmRemMag ammo is a lot easier to find.
I think the term "Silencer" or the misnomer that surrounds it is why they are classified as a "Prohibited Weapon" in Australia. It requires a Police permit mostly restricted to Government agencies and law enforcement with few exceptions upon providing a "Genuine Need"
@Gone Ballistic post second point is useful to the OP enquiry
Point 2. 7mmRem Mag ammo is a lot easier to find. Good information from a resident of the same country considering some of the less common chambering mentioned.
Regarding ammo the same may apply in Australia should he wish to travel with the firearm. I expect that Australia and New Zealand offerings are somewhat influenced by the American consumer market and consumer preferences influence on manufacturer production and availability.
@JTH I hope this info is useful.
As for some short cartridges being built on long actions to house longer projectiles . I would say some love the research and the ballistics and happily outlay to pursue their interest. Maybe find a better mousetrap or may feel a new or obscure cartridge is more prestigious than say a 7mmRm.
A .308w is common in Australia, as a Hunting round I don't think it holds the prestige or allure of the .270 but it is readily available. It's "Common" but it works and is available in a variety of platforms.
I don't think there is any disadvantage in using the 7mmRm. Maybe some others will gain a couple of hundred FPS. The rule of thumb is taking an inch off the barrel you lose 50fps and it's. Been tested by chopping a barrel and getting real tested results that's average somewhere close.
So a 22" 7mmRm is maybe starting at a slight disadvantage if velocity matters , and it may at extended ranges.
Maybe try google the various trajectories of a few cartridges or see if someone Run some ballistics software based on a preferred projectile and potential loads.
If you have a specific projectile or weight in mind start by comparing the chamberings against each other with that weight projectile as the benchmark
Google some comparisons, 280ai vs 7mmRm, 7mm WSSM vs 7mmRm, . 7mm SAW vs 7mm SAUM manny variables really
Others I have read about are .284 Shehane and the 7mmSAW both tested by an Aussie Long Range Hunter , ballistician and Engineer who produces Bolly Stocks
My 284 Shehane is my favourite rifle, built as a mountain rifle for hunting further and deeper into the Alpine in the search of elusive Sambar deer, it
precisiondefenceindustries.com
Sounds like. 7mmRm fits the bill but there are options. I built the .280ai based on some recommendations and then research to confirm my belief that it is a good thing, googling comparisons and trajectory tables. I don't have ballistics software or that much knowledge, I didn't address your question properly the first time so I was informed, oh well I like reading these forums and sharing what. I learned.
Basically settle on what you think is right and research enough to support your beliefs unless there is enough to the contrary, then rethink it.
If budget is a consideration then remember your smith might not have the obscure reamer required for chambering, the dies set Willa be dearer and the cases will be dearer so the initial setup. A hot cartridge might be a barrel burner too, that possibly affects the suppressor lifespan.
I built a .280ai, I think it could be rechambered to a 7mmRm if I wanted so starting with a shorter cartridge it could be remed out if the action and bolt face allow. In my case I could have it fitted in the .300wm action I have to make a .7mmRm, that's just thinking outside the box. I expect the .280 ai is what I want in that lightweight build.
I hope some of this gives you a way to consider the options and recommendations and work them back too your requirements and preferences