if l had the kanga l would make a build off a defiance machine custom action
there web site can tell you a lot more than l can
https://defiancemachine.com/actions/deviant/but l will try to give my perspective,
looking at the cartridges you are looking at especially the 300wm you need a magnum length action
to get the most out of it to be able to seat the bullets for a longer oal for more speed with less pressure
defiance machine do this for the 300wm and the features eg.. integral recoil lug and scope mounts are a good thing lMO, these actions are made to benchrest precision quality but will not jam in the field because of a bit of dust like some other benchrest custom actions
this is the one l would pick, a very strong looking action with integral scope mount and recoil lug
the actions l usually use are mauser 98 actions because l can afford them and have a bit of an addiction
they are not really made for the 25-06 or 300wm length cases but can be made to fit
l am still wanting to buy or build a 300wm and looked at the zastava actions in 375 H&H to do a build so l would be able to load long in the mag
apparently these 375 H&H actions are the same mag length as there 300wm mag length, something to check
around 93mm l think
they are still just a commercial mauser 98 with material taken out to fit the bigger cases though
being comercial made they are stronger than the old war actions or should l say you are not living in hope as much
the cost of doing a zastava would be way less than a custom action alone
heres one on used guns
https://www.usedguns.com.au/Product.aspx?p=166389a new barrel, stock a decent scope and jobs done still way under a custom action price
do not believe the hype that a mauser wont shoot because l have a few that do
“If you do not read the newspapers you are uninformed. If you do read the newspapers you are misinformed”. Mark Twain