35mm film negative would work fine however do some research/reading on scope shimming before you attempt it. Do a search and you will find many posts, some pro and some con, on this forum and others, regarding shimming. Also, I think there was a good Blog posted on the Pyramydair site regarding shimming. You have to be very careful after you install the film shims and begin tightening the scope screws. If you over tighten you could very easily crush the scope tube. If you do decide to use the film shims I would start with one piece and check the results. If you need a second piece add that and re-check the results. The reading I did prior to shimming my scope advised to try not to use more than 2 pieces of film as beyond that the tube crunch issue is increased. I am certainly not advising you to go ahead and shim your scope. I wouldn't do that as I will be the first to admit that I am an airgun beginner and I am not qualified to give such advice. My decision to go ahead and shim my scope was my choice based on my research and my willingness to take a chance with my scope. Your decision of course should be based on your research and your feelings after learning as much as you can about shimming. Anyway, good luck, enjoy your rifle.