The first thing to do when looking at such a possibility is first find the case drawings and compare the diameters for the case at rim, just in front of rim and at the neck. If they are the same as the proper ammo then you're good to go. If not then you can't. I'd have to use google to find such information so I'm sure you can as well.
Then you need to see if the jump from the end of the rim to the lip in the chamber where the size is reduced to that of the bullet is short enough that the bullet won't be unsealed and floating in mid air at any point. If the gap is long enough that the bullet will not be sealed by either the casing or the rifled area ahead of this lip at all times during the travel then I would not suggest that you use that ammo.