IIRC it's not possible (or at least very difficult) to obtain an FFL as a nonprofit, as I think the wording of the relevant laws requires that the holder be "in the business" of selling firearms. This is interpreted as selling firearms for profit. Assuming you got around that, I also think you would probably have to incorporate as a 501(c)(4) rather than a 501(c)(3) because of the political criteria behind your firearms distribution; this is how the SRA is incorporated. 501(c)(4) orgs don't get the charitable deduction, meaning you wouldn't be able to write any money you put towards the org off your taxes (if you care about that).

Also, as much as I love the SKS (I own a Chinese one from the 50s myself), it is no longer a very cheap gun to obtain over here, and importation will require significant capital. Others have mentioned ARs, and I think those are the way to go if you're looking to buy some cheap rifles to train others with. People will think I'm memeing but Hipoints are better than nothing and very cheap.

I'm trying to think about how to get clever with this, though, and I might have a way where you can get kind of close to what you want to do. Incorporate as a 501(c)(3) organization with the purpose to educate individuals on how to hunt and defend themselves. Set up courses and materials that provide instruction on how to use an AR, which has use as a hunting platform. Don't charge for the course or the materials. Make admission open to anyone who is interested in hunting and self-defense (but be careful where you advertise so that you really only draw in folks who you want). Buy a couple rifles for yourself to loan to others to use in the classes. Then, if people pass whatever curriculum you impose as a part of your self-defense and hunting training, make them eligible to receive grants from the nonprofit so that they can purchase guns of their own. This would effectively have the same result as if you'd just bought the guns yourself, but with none of the mess of the FFL, and with tax deductibility to boot. However, you'd need to be very careful on who you provided grants to - if you're just providing them to friends and family, then the IRS is going to see the nonprofit as a vehicle for buying cool guns with pre-tax dollars.

If you're serious about this, you should definitely talk to a lawyer before trying to do anything. The IRS and ATF don't fuck around. I'd feel terrible if you ended up in trouble on the basis of my halfcooked advice. Just wanted to float the idea out there .