Yes you can, but from what my understanding is that Magnum primers burn a bit hotter and a bit longer to ignite powder in colder temperatures. I also caution you that a large rifle primer may not efficiently burn all of the powder charge, creating lower and inconsistent velocities. This most likely will cause accuracy issues.
I would not up your charge, as you will likely increase the issues that I stated above, and possibly other issues.
I am no expert, I would personally do an extensive search on the web to see what others say, and I am sure others with more experience in reloading will chime in here.
I use Magnum Rifle Primers for loads that contain over 60grs of powder.
I have used Winchester Lg Rifle Primers in loads that were between 60gr and 63gr but it is rare and only after I tried Magnum primers and those were with the faster burn rate slow powders.
The 7mag case holds a lot of powder and it takes a magnum primer to effectively burn all this powder. That's the short answer.
I tried some regular primers years ago and wasn't satisfied so now I only use a magnum primer for all loads.
Less confusion, better results, I would stick with magnum primers.
Leroy if you have plenty of LR primers you may be able to trade out for some Mag primers. As for you question, you can use regular primers but there will be a difference in velocity, do not increase the load.