I am pretty new to this building your own rifle thing and I recently obtained a Stevens 200 with 4.4 screw spacing in .223. I am looking to change this to a .308 rifle. I have already ordered and received a PTG bolt head for the .308 and the new barrel. My question relates to a replacement blind magazine. Does anyone know which blind magazine I can buy and finish this build? The .223 magazine is centerfeed and stays in the stock (not attached to the receiver). Can I just buy a detachable magazine and use that as a blind internal magazine? I have been googling this for hours and can't find an answer, as "stevens 200 magazine replacement" doesn't give me any help. Thank you in advance to everyone for their assistance.