BCM vs PRI SPR mk12 mod 0 Build

[Pryde]

Sorry if a dumb question, but I assume all of these SPR builders are cutting 5.56 chambers in these guns? (since that is probably spec'd by the military)

Can you request they be cut with a Wylde chamber instead? Wouldn't you WANT a Wylde chamber?

(again, I am assuming here that Wylde provides better accuracy, since that is what all the High Power shooters seem to buy... )

The military gun is cut with a proprietary chamber.
It is not a 5.56

[FMJBT]

The military gun is cut with a proprietary chamber.
It is not a 5.56

That jives with everything I've read while researching these. The Douglas barrels Crane used were chambered specifically for the 77 grain Mk 262 round. from what I've read, basically a tighter 5.56 "Match" chamber with a slightly longer throat to accomodate the ogive shape of the Sierra 77 grain bullet. As far as I know, the only barrels commercially available running this chamber are the Compass Lake, High Caliber and Centurion barrels. I'm not sure if PRI runs the same chamber or a standard 5.56 on their Douglas barrels.

In terms of practical accuracy, I don't think you'll see much difference between the 5.56 SPR, 5.56 NATO and .223 Wylde chambers unless you are running actual Mk 262 ammunition. I've seen or owned rifles with all of the above chamberings and have seen all three capable of sub MOA performance.