I need a new valve stem for a crosman 400, the stem of the valve that is in it is to short, someone must have put the wrong valve stem in it or have some other wrong parts in it

the crosman parts manual say the 400 takes the 150-60 valve stem, the same stem that is in the 150, but I took a 150 apart and the valve stem in it is the exact same as the one that came out of the 400 that is to short.

I have double checked the stem length needed for the 400, unless they somehow got the wrong main tube on it, it would be imposable for the 150 valve to work in a 400

can someone clear up this as to what valve stem goes in a 400 and where I can get one?

it would seam that a 160 vale stem should work in it, from what I can guess based on what I have looked into.

any help would be greatly appreciated

Thanks
Stan