A dick-waving video showing a few hamp guns, including both the VLTS and the BATS, can be found here:
The VLTS (Vacuum Loaded Tagger Shotgun)
The VLTS is the simplest possible HAMP gun, and is basically a barrel attached to a HAMP, with a few minor additions to enhance useability. Well made VLTSs shoot a single tagger about 60’, and blasts of 8 taggers (or 1 tagger and whatever else fit in the barrel) 45-50 feet. Shotgun loading is faster than multi-barrel shotgun attachments, since they are all dropped (not pushed) into the same hole. A weakness is mediocre range, and aiming is a bit trickier, since the dart is fired while the gun is being “pumped”. Also, the gun has no magazine of any sort, so you need to fill your pockets. Ammo goes fast if you use the shotgun feature.
The BATS (Bolt-Action Tagger Shotgun)
This is the staple of my HAMP arsenal.
This gun has all the same firing properties as the muzzle loader, but includes a longitudinal magazine that holds 8+-2 darts, depending on the size of your gun. Reloading is bolt action OR muzzle load. Bolt action loading requires the gun to be tilted back and leveled prior to cycling the bolt. As a result, refire is similar to an RSCB (sp?) clip. Beware, cycling the bolt while the gun is tilted back can cause a jam as 2 darts will stack on top of each other, and get pinched in the breach. Although the bolt-action can be cycled repeatedly for shotgun loading, personally I think it’s easier to just stuff a handful of darts down the barrel.
CAUTION: It is very important to thoroughly deburr the sharp edges that result from cutting these parts, and even more important to clear all of the chips away. For the steel EMT, that means at the very least blowing / pushing some wet toilet paper through the barrel, repeatedly, from both sides. You don’t (or you shouldn’t) want to be shooting metal chips along with your darts.
1. The Elbow: There are lots of ways to do this, the easiest of which uses a 1/2” piece of braided tubing. The method described here is much more difficult, but improves airflow a great deal (1/2” braided tubing has about ¼” ID). Another method, which has good airflow (but not quite as good as below) starts with a ½” hole, and nests PEX in CPVC, and CPVC in PVC. Most hardware stores carry impact coupling tools to achieve this:
The PEX-CPVC-PVC method only requires a 1/2" hole, which is usually easier to make cleanly. The disadvantage is slightly reduced airflow, more gap between the barrel and the HAMP, and lots of quality time with the hammer.
1a. Drill a 5/8” hole in your HAMP, a close to the plugged end as you can put it without damaging the end cap. This is not a terribly easy task, as drills will get often get stuck and stall out frequently, or they might quickly and unexpectedly make a triangular hole.
A drill press and / or a good clamping system is very helpful for getting the hole to start on the curved surface. Beware that a powerful drill may grab the piece and pull it out of your hands or clamp, spinning it until it hits the post of the drill press our your face (WARNING: facial impact may not stop HAMP rotation). With patience and/or frustration, and a wee bit of scissor work at times, it can be done with a hand drill.
1b. Insert a small piece of CPVC and the CPVC elbow into the hole, and put the PVC coupler on the CPVC elbow (the elbow fits loosely inside the coupler).
1c. Affix these parts. Since my hole looks like it was made by a 3rd grader with an icEffeminatek, I used plumbers putty / epoxy putty, which smells bad, takes time to set, and gets on your fingers.
I have no doubt that this could be accomplished as well by some choice or combination, of duct tape, hot glue, e-tape, and/or ticky tack. Ticky tack is the best for making a good seal, but doesn’t provide any useful mechanical bond. This can be fixed by adding duct tape, which is mechanically great, but doesn’t make very good seals. Hot glue is good if you want to make a messy clusterfuck that seals great until you use it on a hot day. Or a cold day. Or you drop it. Just make sure it’s at least sort of airtight and stays on to your satisfaction. Don’t feel like you need to stick with my methods in part 1; I know I haven’t.
2. Cut off 3’ of 1/2” EMT Steel Electrical Conduit for the barrel, and 3’ of ¾” PVC for the magazine.
All my other BATS have used thinwall ½” PVC, but I was running low, and besides the stuff is hard to find for many people. If you’re making a VLTS, you CAN use ½” PVC for the barrel, and in fact get slightly better range, but it will jam occasionally, and require some unpredictable amount of notably obscene finagling to extract the dart.
3. (BATS only) Breeching the barrel: How you make these cuts is entirely up to you—my first BATS breeches were made using only a hacksaw, plus a great deal of blood sweat and tears. I don’t particularly recommend that method, but it can be done. A dremel tool will make these cuts easier, but I should note that the fastest and cleanest way to do this, and the way I did it, is with a mill. But, normal people don’t sacrifice their bedroom to become a machine shop and sleep in the living room of their apartment, so I imagine most of y’all will be dremeling this.
3a. Cut a breech into the barrel, ½ way deep, from 6” to 10.25”
3b. Cut a breech in the magazine, ½ way deep, from 6” to 10”
3c. (optional) Cut slots in the magazine, so that the ammunition is visible. Make sure that whatever slots you cut are large enough that you can get a knife/scissors in to deburr the inside edges.
As you can see from the pic, I didn’t really cut the magazine as described—I got fancy with the mill, hoping to avoid the need for cardboard flanges later (I still needed them). If you want to mimic that, feel free, but make sure the opening allows darts to very easily drop out.
4. (BATS only) Making a breech cover: This is one of the few times where there’s really only one way that I know how to do this. Cut and split 5.5” of thinwall ½” PVC. Remove material such that the profile is a C shape, covering about 270 degrees. Put a hole ½” from the end, and entirely above the middle of the circle the tubing used to make, through both sides. Stick your preferred bolt-pin through it. This needs to be strong, so I recommend 1/8” to 3/16” steel. If the hole is not the same size as the pin, you need to put something on there to seal it. When complete, the breech cover should snap on and off the barrel, with some difficulty, and the pin should not prevent the breech cover from sealing the breech completely.
Also put some duct tape on the pin, both to keep the pin from sliding out, and to make a safer, more comfortable grip. I didn’t do this until much later in the profile.
VERY RARELY thinwall PVC can be found that slides smoothly over EMT tubing—If you find it, buy as much as you can, because its hella useful for things like foregrip breeches. If you have it, you don’t need to cut it into a C shape, and if you have room on the barrel, you might want to make it longer, and cut the pin further from the end, in order to better seal the breech.
5. Attaching the barrel: This step is MUCH easier if you use hose instead of an elbow in part 1, since you don’t have to space out the barrel to compensate for the elbow height.
5a. Use a small piece of thinwall ½” PVC to mate the barrel with to the PVC coupler. Duct tape or E-tape could be used instead if need be. Superglue the thinwall PVC on to the end, to keep the barrel from sliding into the coupler.
5b. Stick the barrel into the coupler, and put something between the HAMP and the barrel to compensate for the elbow height, then tape it down to the HAMP. I used a 1/2” square wooden stick, but a mess of cardboard and duct tape works alright too. Do everything you can to keep the barrel and the HAMP parallel.
If you used a hose in step 1, there’s no gap to space out and you can just tape down the barrel. If you’re making a BATS, you need to make sure that your spacer and whatnot do not interfere with the action of the breech. I didn’t have to worry about this much with the ½” square wood, but with a mess of duct tape, you might be limited to attaching at the front and rear of the HAMP, leaving the middle (where the breech travel lay) open. Also, if you want to try gluing the barrel, that’ll probably work fine, and in fact will better keep the barrel from moving sideways once dry. I’m a duct tape man, and so that’s what I use.
6. (VLTS only) Put a screw in the very rear of the barrel, to prevent darts from being sucked back into the gun. This wouldn’t hurt for a BATS, but normally the bolt-pin takes care of this.
Edited by KaneTheMediocre, 25 February 2010 - 12:59 AM.