Perhaps I'm wrong but it doesn't appear that the Game Warden accepts Tikka actions. At least I just checked and one didn't appear in the action field drop down menu. I'd get the McMillan and here is why. The guy is solid and so is the company. They will fix it for you no questions asked if there is a problem.
I've been looking myself. Picked up a polymer one from another manufacturer with an excellent chassis and it fit the action great. Problem was that the magazine wouldn't stay in the rifle securely and would drop out of battery ever so little upon discharge that the magazine wasn't there any more to pick up another one. So, I examined it because it was a new product from the company and noticed that instead of using a Tikka CTR mag release, they instead had used a Sako. Similar, but not the same. The detent/snatch dimple in the mag that catches the mag release was about 2 mm off due to the wrong mag release being built into the chassis. So when the mag slid by it upon entry, you would hear the positive click because you are not putting the mag in exactly straight, but it was too far from the detent or whatever it catches on to hold and it just slid right back out upon discharge just a little bit so you thought it was still seated but it wasn't.
Luckily, the manufacturer took it back, but not after making me go through all sorts of machinations on my end to see if it wasn't a problem that I had introduced to the process. Move the mag well forward a bit. Didn't work. Toggle the mag release a couple of times when the mag is in already. Nope. More things but not solutions.
Then I explained that at the time I was working for the premiere rifle barrel manufacturer in the world and I think I know something, not a great deal, but something about mechanics and guns and why the fuck are you putting me through all of this plasticland/polymer bullshit (didn't quite say that but it was close)?
What it was really is that they made me one of their initial beta testers without telling me because they had just released the chassis and I found the problem for them. As a result, I wouldn't buy another product from them. Didn't pay me anything for the trouble to take it and put the CTR in it. Drive 35 miles to the range. Pay $20 for the range day. Shoot it and look puzzled when another round wouldn't come up but the mag still looks seated and when you tap the mag, it moves only a very little but makes the clicking noise, run SPORTS (slap pull observe release tap shoot) sort of two or three times on the mag and do that over and over and over. For like an hour wondering WTF was up with this f'ing chassis? Had range officer look at it. Had guy who said he knows everything look at it on the range. Nobody had a clue. I had to take a picture of the mag release and began researching how it was supposed to look and compared it to the one that came on the original rifle. In the images section on Google Search, low and behold, right next to each other there were the pics of the two separate mag releases, the Tikka one and the Sako, two completely differently sized mag releases with one visibly even longer than the other. Clearly not an exact match. That's how I knew it was a Sako mag release because I'd never seen one before.
Don't know if they fixed the problem or not but I see a lot of them up for sale here and that's too bad. It's a nice product but it sounds like a bunch of millenials are running the company and that's a different age group. That kind of corporate behavior is not that unusual from that age group. In my age group, upon driving by the place if it ever happened that you were driving by, you would get out and apologize to the customer or telephone them at least with an apology. Also in my age group, it is acceptable to beat the living daylights out of a millenial or anybody else for that matter for giving you bad kit that could endanger your life or someone else's, or just plain simply aggravate the hell out of you. If someone else saw what they were doing to you, you were allowed some go time.
So, I'm going to follow this thread because I'm looking, too.