Hmm, I see you are lego building. 
The barrel is stupidly long, just get a 430 6.03 (pdi has better barrels but they cost more) and do the milk can mod to the silencer (look inthetallgrass's guide on his sig) to make it lot more quiet, I recommend you to get a r-hop from hunterseeker5armory and if everything falls to their places, you should have a laser rifle, but you "need" to do things like shimming the hopup arm, barrel spacers etc.
The barrel is stupidly long, just get a 430 6.03 (pdi has better barrels but they cost more) and do the milk can mod to the silencer (look inthetallgrass's guide on his sig) to make it lot more quiet, I recommend you to get a r-hop from hunterseeker5armory and if everything falls to their places, you should have a laser rifle, but you "need" to do things like shimming the hopup arm, barrel spacers etc.
