Just getting started reloading

REGULAR primers ? ? ?

Using standard primers (as opposed to magnum primers) depends on your type of powder. Some powders are harder to ignite and the manuals recommend magnum primers.

If by regular you mean Boxer primers (as opposed to Berdan primers), well, that's a whole 'nuther story. . .

Follow your manual for loading the 7.62x39 and you'll be OK.

A. If you have a strong firing pin spring in your SKS you may have a problem with it piercing the standard commercial primers. You may want to get some Wolf primers. Check the thread on here (this forum) for Wolf primers.

B. Yes, you could reload cases which have Berdan primers, but trust an old man, you wouldn't want to. It's a PIA.

I think what your mean is you might need to use cci #41 mil primers, for use if you think you might get a slam fire. they are harder and will help prevent a slam fire. I have thought of using them in my ar-15 but can`t find any so am going to try winchester small rifle primers, hopefully my ar will not have a slam fire problem with them.