Guys,
Are the centre-feed magazine boxes for the Stevens 22/250s blocked at the rear?

I've got a 308Win and 223Rem and the width of the 308 is perfect for 7.62x39 other than length, whilst the blocked length of the 223Rem is perfect for length but too narrow. Just wondering whether the 22/250 magazine box may provide the best of both worlds in building a bolt-actioned 7.62x39.
Cheers...
Con