I've fired the NTW as well as the RT-20. We also did testing on the 20mm (Vektor GA-1) vs. 12.7mm. The 20mm obviously has a lot more punch, esp the SAPHEI, HEI, API & PRAC rounds but again, obviously isn't as accurate as the 12.7mm. Still, the 12.7 just cannot do what the 20mm can. The recoil is a bit of a pain, but all in all, a 10 on the fun factor.