There are a couple of options out there if you want to go "permanent".
I hae a WWW mount on my 1894 and it works fine.
Here is a picture w/o a flashlight on it.
A big plus is that is a rail so you have a lot of options.
There is a neat new mount that I use on my shotgun, that enables you to use you light as a weapon light or a flashlight in a couple of seconds. They make one for the AR-15 platform and should work well on a 336. I would not buy their flashlights. There are much better ones out there. I can attest to the fact that recoil does not dislodge it.
BeamLOKR :: Products
There is a good thread in the tactical forum, from a guy who made is own. Take a look. It is a good read.
Bet of luck,
Bob