Looking for old Calvary vs Indian movie.

I saw this when I was a kid around the mid 60's. I believe it was made in the 50's.



At the end the Indians were attacking a fort and the only scene I only scene I recall is that the women and children where put into the power magazine with a soldier. If the fort fell he was to ignite a powder barrel and blow themselves up. I think he was going to do it by shooting it with his pistol.



I'm not positive but the fort might have been adobe and not a log fort.

Thanks.