Ors,
This is my 2cents worth....
I have always used this model pellet gun for training disarms.
http://www.amazon.com/Marksman-MARKSMAN-1010-AIR-PISTOL/dp/B00069PQ5YSimmilar to a Colt 1911 style in shape. metal body so it has some weight.
reasons for this live gun use:
1) allows you to know if you got off the line before the trigger was pulled. you will feel the puff of air hit you.
2) allows the disarmer to practice getting to the fingerbreak barter/negotiation position.
3) allows for controling firearm while you access your own weapon, (knife, gun, kubotan/palmstick)
how the gun is set up for training. Place 2 full wraps of tape around the tip-up barrel, preventing it from being loaded with a projectile.
PRIOR TO EVERY TRAINING SESSION PARTENERS CHECK THEIR GUN BY DRY FIRING AT A SAFE TARGET, SHAKING THE GUN TO CONFIRM NO B.B.'S IN THE RESIVOR THEN DRY FIRING AGAIN AT A SAFE TARGET. (Then the partner rechecks the gun in the same way.)
I personally have never used the red or blue training guns,or a funtional firearm in practice.
If you wanted to the air soft guns would probably wook just as well if you could find one with a metal body. Just remember to wear safetyglasses when you train.
Also, I do not know what videos you have or specifically what disarms you are practicing, but work on checking the weapon before it is drawnor drawing it off you opponent. The second one
drawing your opponets weapon first happened during knife vs. empty hand training with me pulling a joke on my partner. It was very funny hearing him tell me he had the knife (live blade) and he was the one defending and I was not supposed to yell freeze! (our command word to notify your parner you were about to open your knife and demonstrate weather or not you could make a valid cut.) As he was telling me to stop he relized he could not find his knife, then asked how I had his knife.
The second time this happened I disarmed an assailent before he tried to pull his knife on a woman.