On blind magazine long action mag boxes for short action calobers, did they use a block in the rear of the magazine box or were they full length?

I have 2 long actions, one will end up a 280 Ackley and the other will be a 7mm-08. If they used a block, then I will dedicate one action to the 308 family and the other to the 30'06 fan.

If they were blocked, where do I need to look for a Mag box, spring and follower?

Thanks Darryle