Bore sizes and Stock agd barrels?

[LCDmag1]

Why are the stock agd barrels large bore. With all the tests that agd has done testing paint to barrel fit, why go with a large bore barrel, that no paint that i know of fits properly? Also why does the RT pro barrel have two nubbins, does that help?
Thanks

[MagShooter]

Nitroduck makes large bore paint and it shoots REALLY well through my stock emag barrel (tho I shoot a zero-g)

[HeerophantG]

what is a specifuc number of Emag stock barrel?? is that 0.690??