Hi guys. Nice points. Please see my comments below...
helotaxi,
The 300 OSSM is proprietary, expensive and reports show not that much accurate. It is clearly overbored for this platform. Also the WSSM bolts are not the strongest of all.
rcmodel,
It seems to me cutting a .223 bolt face to fit a .308 case would seriously compromise the safety of the bolt lugs.
No need to cut anything. This is the same used in the 6BR and 7BR bolts that are already in circulation. The extensions are very strong.
I'm not even sure there is enough bolt carrier travel to be able to eject a loaded .308 round if you want to unload the rifle without shooting it?
Yes there is enough room. The round is not larger than the magazine overall length. And the travel goes well past that otherwise it would never engage the bolt retain. The trick is how to squeeze the round in there. I am working on this.
That is why the AR-10 bolt and action is bigger.
It makes sense that everything is beefed up for all sort for 308 loads and uses but even a mild load is very reasonable. In the end the RAR and specially the WSSM deal with more powerful loads (ie: WSSM) with bigger bolt face, bigger section and weaker bolts than the 308/BR bolt face.
There are several .30 cal cartridges that will fit an AR-15 action & magazine already out there with rebated rims to fit a .223 bolt face & extractor.
In all, I think it is a very bad idea.
The AR-15 was created to fit the .223 round and not the other way around. We love the AR-15 calibers because we love the ARs but it is hard to find one round that is really popular in the bolt department, with the obvious exceptions of the .223 and 7.62x39 classic, in big part due to its military background.
My thought is to work with a popular round. In the end I will have to modify the loading mechanism once vs special/costly rounds that I have to potentially prepare hundred of times.
Thanks.