Thank you. I started out with a .22 magnum single shot Cricket rifle. I discarded the stock, trigger, sere, bolt handle and cocking handle.
I then machined new parts out of tool steel, following the pictures of the gun in the movie. I had to make a few modifications however. The trigger housing in the movie was a small plate that barely held the sere, and the trigger spring was a thin steel leaf spring in front of the sere. I made mine deep enough to cover the post that holds the Cricket's sere and trigger. I replaced the Cricket's trigger and sere with my own that I made out of tool steel. I also replaced the spring with a softer one, and lapped everything into place. The new trigger is held in place with a sapphire ball detente. and can be removed with a firm pull. The trigger can be hidden inside the butt plate that I made from cherry. I also had to bend the strut to give a more comfortable feel. The stock was made from black walnut, and can be adjusted up to four inches. It also hides six "last ditch" bullets. The strut was made from a bipod I found on EBAY. I decided to use a vintage Weaver K1 sniper scope with a pillar rectical. The one in the movie looked vaguely like a cheap Tasco or Barska scope with some adjustment nuts like nothing I've ever seen. I made the front sight with a marlin hood, then placed a micro green led, switch and 3.4 v. lithium battery inside it. I hope this helps to answer your questions.
If you have any more, please ask and I will try and answer them to the best of my ability. Ed.