Just snagged a M77 Mark II in 300 WM and I want to replace the factory boat paddle stock with something else. On some sites it says in the aftermarket stock's description that it will not fit magnum calibers, but I thought the 300 WM was the same length action as all of the non magnum long actions? Are they talking about the slightly larger barrel contour on the magnums for the reason it won't fit, or is there something else going on? I don't want to order a stock and not have it fit.

It could be barrel contour, or the inletting for the recoil shoulder, or it's not strong enough through grip to withstand the recoil of a magnum.

Call them and find out.

Pretty sure it is just a long action. They may be referring to some of the older Ruger big bores in 375 H&H and 416 Rigby. They had a true magnum action, I think they were called the Express Magnum.

You can sell that boat paddle on 24 Hour Campfire. There are a lot of people that love those ugly things.

^^^ he's right...but if you ever plan to sell that gun just put it in a corner because it'll be worth far more with the boat paddle stock than any aftermarket.

No plans to sell it. I got a great deal (I think) on the rifle and since I didn't own a 300 WM, well...

I want to change the stock so I can shoot it off of a bipod. Plus I think those boat paddle stocks are butt ugly.

They are ugly as sin but they are extremely rigid and well made.

Can’t answer the action length question, but my .270 Ruger with the boat paddle stock had more felt recoil than any rifle that caliber should have. I can’t image benching a .300 Win Mag with that stock.

Action lengths are all about screw spacing.

Measure center to center of your action screws. Find that information on the stock maker.

For most actions and stocks there is "long action" and there is "short action". .300 Win Mag obviously fits in the long action category.