Well... If you do not have any modding experience, and don't know what a bolt sled is, I'd recommend that you mod something easier before the Longshot. The Longshot's internals are quite complicated and a beginner may be overwhelmed.
With that aside, the boltsled is the piece that the two priming handles are connected to. The bolt-sled is what actually moves back the spring to compress it. When you add an extra spring, there is a risk that the 90 degree (or commonly referred to as the L joint) joint may break due to the extra power. This is because the stock sled was only designed to push back the stock spring.
There is a great write up on reinforcing your boltsled (link below), or you can buy a replacement that is made by Orange mod works on Amazon.
Reinforcement write up:http://nerfhaven.com...-reinforcement/
Amazon.com link (American):https://www.amazon.c...ds=Longshot kit
Amazon.ca link (Canadian):https://www.amazon.c...ds=Longshot kit
If you do take out the ARs, pad the plunger with something. This can be craft foam, dart foam, or felt. The ultimate plunger head padding is foam rubber, and that can be found on most mouse pads. And yes, NEVER dry-fire a blaster with the restrictors out. If you do once or twice by accident, it is ok with padding. Just avoid dry firing in general as it's harmful to a modded blaster even with padding in the long run.
Edited by Bubba Longshot, 13 April 2017 - 07:00 PM.
"The only thing that sucks about Nerf modification is the anxiety that something will break... That's why we reinforce a whole lot!" -Me