So I measured my magazine and came up with 3.374. I checked my loads and I found out that Noslers makes two different Partitions. One is a PT and the other is a PTT. apparently one is longer than the other. Some of my loads with the extended lead tip ended up being 3.430. We'll over max. My other loads fit fine. 

Do a search. I've posted numerous times how to do a Tikka magazine modification that will allow you between .040″ and .080″ extra cartridge length.

I'll look it up, thank you.

If your OAL is at SAMII max then it should fit.

What load did you end up with?  I'm always looking for good 300 WM loads.

So I made it back home and my load is 70 gr of IMR 4350, Federal 210 primers. Gave me right at 2850 fps on my chrony.

I use IMR 4350 and it's book max for the 180 gr Noslers. I can't remember exactly, my memory says it's like 71 gr. Federal Magnum primers, 210's I think, and Winchester brass. I've got it all written down in my load book, I'll check when I get home and post it, if it's different than 71 gr. The load works well and has killed about 6 Moose and a… Read more

I'm out of town working right now so can't confirm. But if memory serves me right they are out pretty close to max. I'm using 180 gr Partitions. The length shoots good in my other rifle and in several hunting partners rifles also, Rugers, Remington's, and a Winchester. I'll have to do some dummy rounds and see what length fits in the mags.…