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stagpanther · December 15, 2019, 10:54 AM

I did a chamber cast today--and as my luck would have it--this is the first one I blew and got the cast stuck. Had to hammer it out, so it sightly compressed OL and I couldn't get an accurate read on that--no big deal though. Admittedly a conventional mic of a lead cast isn't going to be absolutely precise--but close enough in my experience if something is really off.

As far as I could tell--the chamber on my Faxon 350 legend dimensions match up with SAAMI specs--with the bore of .346 and groove of .355. Except for the difference in twist (16 vs 10)--the 350 legend specs, in terms of the reamed bore, appear to me to be identical to the 9mm Luger (including the groove dimensions). I'm sure there's some sound philosophy behind the slower twist--I just don't know what it is.

Another thing--I was under the impression the case design was derived from the 5.56/.223--I read on Winchester's site that it's a totally new design and manufacture of the case is different--so I assume the case is "strong where it needs to be" considering the (IMO) unusual head dimensions for an AR design.

December 15, 2019, 10:54 AM	#76
stagpanther Senior Member Join Date: March 2, 2014 Posts: 11,771	I did a chamber cast today--and as my luck would have it--this is the first one I blew and got the cast stuck. Had to hammer it out, so it sightly compressed OL and I couldn't get an accurate read on that--no big deal though. Admittedly a conventional mic of a lead cast isn't going to be absolutely precise--but close enough in my experience if something is really off. As far as I could tell--the chamber on my Faxon 350 legend dimensions match up with SAAMI specs--with the bore of .346 and groove of .355. Except for the difference in twist (16 vs 10)--the 350 legend specs, in terms of the reamed bore, appear to me to be identical to the 9mm Luger (including the groove dimensions). I'm sure there's some sound philosophy behind the slower twist--I just don't know what it is. Another thing--I was under the impression the case design was derived from the 5.56/.223--I read on Winchester's site that it's a totally new design and manufacture of the case is different--so I assume the case is "strong where it needs to be" considering the (IMO) unusual head dimensions for an AR design. __________________ "Everyone speaks gun."--Robert O'Neill *I am NOT an expert--I do not have any formal experience or certification in firearms use or testing; use any information I post at your own risk!* Last edited by stagpanther; December 15, 2019 at 11:02 AM.