Impressions after running the three side by side:
It's not quite a fair comparison to compare a brand new action to well used ones. I also ran these dry only because the Nucleus is in 6 dasher and I don't have any loaded dasher ammo. That being said, the Nucleus is a damn nice action.
The Nucleus needs to be run with authority. I foresee it having issues if users pull back on the bolt too slowly. In order to activate the ejector, the bolt must be pulled back with some amount of force. Pulling the bolt too lightly or slowly causes it to just stop at the ejector. This may be something that just need to wear in however as I notice it getting better already. There is also some binding when the bolt is all the way back. I have determined this is a result of the extractor making contact with the receiver. This is not very noticeable when running the bolt fast. It is noticeable when running it slow. The extractor seems to be a floating design with no spring pressure on it keeping it in a consistent position. Here is the extractor and the marks from making contact with receiver can be clearly seen:
View attachment 6919826
The bolt lift is certainly heavier than the TL3. That's expected since the TL3 is a 90 degree action and known to have one of the lightest lifts made. I would say the bolt lift is on par with, if not slightly lighter than the RPR. This is actually a pretty close comparison as they are both 70[ish] degree actions and both have dual cocking cams. My RPR has a longer bolt handle than the Nucleus so the fact that the Nucleus may have edged it out is certainly a good thing.
When putting upwards pressure while trying to push the bolt forward, it is difficult and binds, similar to the TL3. I would say it doesn't bind quite as badly from upwards pressure as the TL3 does. With downward pressure, they both run well, with the smoothness going to the TL3. The RPR runs regardless of what direction the bolt is pressed.
As far as the bolt moving forwards and backwards goes, the TL3 is easily the smoothest. The RPR bolt makes contact with a lot points within the receiver. While I wouldn't call it "rough", I would describe it as "bumpy". The Nucleus is similar in that respects but not quite as bad as the RPR. The aforementioned binding with the extractor does not help.
Bolt close is very different between the three. The TL3 closes with smooth even pressure. The RPR has a bit of resistance as soon as I start pressing down. As soon as I break that bump, the bolt snaps complete shut. The Nucleus seems to require me to push forward a bit while pulling down in order to get it to shut. I noticed in a few of hereinAZ's videos, he does not smoothly pull the bolt down and I am experiencing the same if I do not push forward while trying to pull the bolt down. There is a little plunger on a spring at the back of the bolt that is causing this. Not sure what purpose it serves. I think this is a non-issue if cycling the bolt quickly like in a match.
The RPR seems to require less effort to cycle back and forth. I can certainly cycle it faster than I can the Nucleus. The Nucleus is faster than the TL3, but my TL3 is a long action so no quite a fair comparison.
Tilt test. I'm not really a fan on this test, but I've seen come people conduct comparisons with it before. With the bolt fully open, I tilted the rifles downwards to see when the bolt starts sliding forward. I feel that there are a lot of other variables taken into account and that it's not a good test for action smoothness. The TL3's bolt was the first to move, requiring the least angle to do so. This was closely followed by the RPR. The Nucleus required a near 45 degree angle to get the bolt to move. I think this is in most part due to extractor binding.
Overall the cycling of the Nucleus is not bad, especially when running it fast. However it seems that this action NEEDs to be run fast to function. I will continue to cycle it and see if it breaks in more.