I have an old scope from the 70's that my dad bought for his 30-06 back then. Its a Bisle 4x32, I have never heard of them or dont even know if its a good scope. On the occular lens housing it says Bisle 4x32 nitrogen filled. reminds me alot of a tasco. apparently the nitrogen leaked out over the years since in cold weather the scope fogs up from the inside. any help is appreciated thanks