Yes, a longer firing pin if your Mini doesn't have enough protrusion from the factory (some Mini's do, like Corndogs).
No, don't switch to a heavier hammer spring. If your firing pin doesn't have enough protrusion to begin with, smacking the hammer hard will not help, only increase the chances of breaking your too short pin.
Berdan primers are not so hard that a Mini can not set them off, some brands are set deeper. If you see a shallow dent in the primer after the pin strikes it, it doesn't mean it has a harder primer, but the pin isn't going forward far enough.
Guys don't know how much FP protrusion they have, just whether it "works" with steel case or not. Some Mini's come with a FP protrusion of .038"-.039", those will work with nothing else needed. Other Minis leave the factory with only a .032" or .034" protrusion, and those will need a longer pin from firingpins.com fitted.
Ruger doesn't care how long the pins end up, because even the .032" will reliably set off brass case Boxer primed ammo, and that's all they want you to shoot in it.
If you call them and complain that your new Mini-30 won't set off, Tula, Monarch, Wolf, etc, they'll tell you that you shouldn't be shooting that, only domestic (brass, boxer) ammo.
I used to think that all steel case ammo sucked, but then I tried other brands than Tula.
Turns out it's just Tula that sucks. Anything else you choose will be better.
Better ignition, better accuracy, higher velocity and cleaner burning.
With my stock .035" firing pin, about 18 or 20 out of 100 rounds of Tula would fail to go off.
With Red Army Standard, it's 2 rounds out of 100.
With Silver Bear, I've never had one fail to go off, and that is with the factory firing pin.
I do have longer fitted pins on hand in case I ever have to use crap like Tula.
As bonus, Silver Bear shoots like match ammo out of my 3 Mini-30s and my x39 AR.
I buy Silver bear by the case.
One area where a steady diet of steel might be harder on your Mini is the extractor.
Steel doesn't contract as well as brass that millisecond after firing, so your extractor has to work harder. Keep a spare extractor on hand, and know how to change one out.
The plunger and spring that keep the extractor in are small parts, easy to launch them when changing, so get a few spares of those as well. https://rugerforum.net/ruger-semi-au...ctor-mini.html
Some more threads. In this thread I talk about the iron Sight precision aftermarket pin, the company has since changed their name to firingpins.com: https://rugerforum.net/ruger-semi-au...port-ammo.html
Do a search here and on perfectunion's Mini forum for more threads about the Mini-30 and ammo choices/mods.