yes they do funny thing is brasseagle threads are like twice as wide as spyders so like 2 threads of a spyder goes around 1 of eagles. but they fit snuggly and might not go all teh way in. right now im useing a ceramic on a tigershark. and te other q is yes there will be a huge difference in the 14 inch
it takes the same amount of co2 weather you have a crappy 21 inch, or none attached, it is the same burst of co2 for all barrels, your gun doesent know how long of a barrel is on it, so it shoots the same amount of air. but 14 inches maximises the speed and acuracy of the ball.