I asked this same question when I had what I thought was a primer light-strike issue with a T3X Varmint. Short answer:
There aren't any videos or instructions out there because removing/replacing the striker spring is a gold-plated witch.
In my case, I finally got steered to the
Tikka Performance shop at Mountain Tactical. The gentleman I talked to said the T3 spring is extremely powerful; they took one apart
once and had so much trouble that they wouldn't ever do it again.
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So why was I getting light strikes, if the spring is so powerful? Again, short resolution of a 2-month journey: the firing pin tip was completely cylindrical, no radius at all, which distributed the strike impulse over a relatively large area. Cartridges with soft primers like CCI 400s would fire just fine, but rounds with harder primers like CCI 450 or CCI 41 had a 10-20% misfire rate. Once the pin was properly radiused, I never had another problem.
Bottom line is, every
knowledgeable source I contacted said don't even try to remove/replace the spring, and all sources knowledgeable or otherwise said send the bolt back to Tikka for such work. Right. The shop that sold me the rifle sent it back to Tikka for me on their dime; Tikka kept it 5 weeks, sent it back saying it was fine, and the 9th round (with CCI 450) was a misfire. It took a local smith to notice the pin tip had no radius and fix it.