Here's the deal, OP. You're getting a lot of "oh no, don't dare touch anything, you have to go learn everything first" advice, but the reality is that the core safety tenets of reloading can often be distilled down into "start with the manual data because it's conservative, and work your way up carefully." In your case, your ammo could arguably be called "manual" loads, because factory ammo isn't operating at the raggedy edges for obvious reasons.
So, there's plenty of reason to expect that there's safety margin built into the ammo. Additionally, you've already established that the charge isn't compressed, which would be the primary concern with seating a bullet deeper. Typically, more jump equals lower pressure, since the bullet gets more of a running start at the lands; the limit to this behavior is when you start compressing powder, especially ball powders. This info, combined with the standard reloading approach of "start safe and slowly/carefully work up" would apply to your bullet seating issues too. If you want to be extra conservative, use 0.005" bumps, but I'd feel comfortable in my rifle with 0.010" jumps, especially if you can still hear loose powder. Seat the bullets incrementally deeper and fire them, while watching for pressure signs (stiff bolt lift, cratered/flat primers, ejector swipes, pierced primers are definitely too far).
It's the same incremental process any of us would use to work up a load, you just happen to be starting with a load that was worked up by a factory and deemed "safe" (with plenty of margin, since they know the ammo will go into all sorts of firearms).
