If you can find them. Fiocchi primers should resolve you problem. If those here can remember how tight the old Alcan primers were. Fiocchi resembles Alcan's to a T. Otherwise maybe a sealer may help. Which is something I don't use myself. Just Fiocchi's only. If my reloads were to leak a little I don't care. Because I reload over current listings and in doing so it is expected but hardly ever seen. So long as my rifle stays accurate fellers. I'm happy.
"Do not follow where the path leads, rather go where there is no path and leave a trail for others to follow."