Pachmayr just came out with a pre-fit Decelerator for the Marlin 336, be aware that it fits current models only.
I ordered one for my 1981 M336 and it's way too big. After speaking with their tech service I found that the one they list for the 1895 should fit my older 336.
Measure your buttstock and call them to find out which one is closest.
Rob
