Originally Posted by Ruger Redhawk
I had this question awhile back. I asked several people and got a couple different answers. I finally wrote Ruger concerning shooting 5.56 in the Mini 14's and in a M-77 chambered for the 223.Ruger's reply was that 5.56 was completely safe to use in their rifles that they are chambered for the 5.56.So shooting either cartridge is acceptable.
Once again I've gotten different answers. A good friend was a rifle builder and Smith. He again told me it was safe to shoot the 5.56 in a 223. I have a Winchester "Coyote" in 223. As stout as it is I wouldn't hesitate using the 5.56 in it.
No disrespect meant; but, I really don't think Ruger should have told you that! I've been told by a police armorer whose department fields Ruger Mini-14's that - short of actually slugging the chamber - there is no other absolutely certain way to tell which chamber is which in a Mini-14?
This armorer told me Ruger has reluctantly admitted to him that a rifle's serial number will not provide this information; and, the factory does NOT have complete manufacturing records to tell, either, when or how a particular Mini-14's rifle chamber was made.
Awhile ago there was a long thread on this subject going on at Glock Talk. Several posters mentioned that, when it comes to the Mini-14, what factory tech support tells you can vary from day to day, and seems to depend as much on who you talk to as what you ask. Personally, I honestly believe that Ruger has definitely manufactured and sold both types of Mini-14 chambers, at different times, and with different rifle variations.
If you're using an older Mini-14, never forget that there's a lot of, 'political history' to Ruger's little, 'assault rifle'. If even one police armorer tells me that his department has Mini-14's with both chambers, then, that's enough for me to carefully checkout any old or used Mini-14 I might be thinking about using.
However it ain't my face or fingers; so, everyone is more than welcome to do whatever they think best. The only thing I'm positive of is that the NEW Ruger Mini-14's are OK to use with 5.56x45mm. However, as far as I'm concerned, the older Mini-14's remain, something of, a crapshoot.
Here, check THIS