Call 203-985-3336
They should have it online and free.. http://gunmanuals.net/
marlinfirearms.com
A guy on eBay has a store called Rediscovered Shooting Treasures (RST). He sells reproductions of the Marlin Model 120 manual.
I, too, have been trying to find out about the Marlin 30-30 Model 30AW and I discovered that the Model 30AW is the low priced version of the Model 336. (Very disappointing to pay $400 for a gun to find out it is a "low priced version".) Anyway, here is a link to the owners manual I found: http://www.marlinfirearms.com/pdfs/manuals/MFC_Centerfire.pdf It appears to be the same gun that I purchased.
Read your manual, or request a free catalog from Marlin. Factory load is always what they recommend.
Try the Marlin web site or eBay. Try the Marlin web site or eBay.
The first step should be to read the owner's manual. You can request a paper copy from marlin, or go the the link below that says MARLIN, and it will take you to the owner's manual. Check that the rilfe is unloaded before performing ANY maintenance.
Marlin 336 Owners Manual at Marlin Firearms website: http://www.marlinfirearms.com/pdfs/manuals/MFC_Centerfire.pdf
Try want ads and on line auctions.
The Marlin Model 60 manual may be dowloaded from Marlin's website.
The Marlin Firearm company has owner manuals for the different firearm models that they sell. You can find downloadable versions of the manuals on the company web site.
If you find out, please post. I've been looking for a while now. I even sent a letter to Marlin requesting information and go no response.