Easy question. The RGG plans work ! Many functioning guns have been built. The D&E plans will NOT result in a functioning gun ! I have built both designs.
Look at the D&E website, the gun they show as functioning has bolts that are NOT to the plans, they are a modification some one came up with in desperation to get their gun to function. Funny how D&E cannot even find a functioning gun built to their plans to show operation. One of the guns displayed on the D&E website never did fire, it was always intended to be a inert model. LOL
Look through this forum, the only working D&E plan guns are those that were highly modified. Even then they don\'t function as well as the RGG design.
The RGG design although good has room for improvements also. Many builders on this forum have taken the good RGG design and made it even better. Along with that they have found better/easier ways to fabricate the various parts. There are a few minor errors on the RGG drawings, they have been pointed out here on the forum.
Oh yea, one last thing, the D&E gun shoots .22 shorts ! Not easy to find shorts, nor inexpensive ! The RGG gun uses standard .22 Long Rifle ammo.