I am swapping out the parts on my 223 10FP to 260 Rem. I got the bolt head and baffle along with the ejector, extractor and springs. I bought a 308 bolt head and it seems to have a huge opening at about .535. I stuck a 308 case in and it's swimming around in side. I checked the part number from midway where I got it and it's right. Can someone here tell me if this seems right?