I've been messing with this one for a few weeks now and I'm stumped. I bought it at a thrift store, and I was pretty thrilled about it, but later I found that it doesn't hold pressure. You pump it up and it leaks right out of the barrel end of the tank. I opened it up and put it under water, and it leaks from the front of the tank and nowhere else. The check valve is fine, the hole for the firing pin is fine, its just the rubber seal in the tank that leaks. I was really disappointed because the only way to get to the seal was to cut the barrel off. And that means the gun will never be in original condition which is what I wanted, but I'd rather have a working modded gun than a broken stock gun, so I cut the barrel off.

Once I could get to the seal, I used a little oil on it, that didn't do anything. So then I put a little lithium grease on it. That helped a tiny bit, but it still wont hold pressure. Its not an instant leak, I'd say it takes about a second to leak out 2 pumps. When I push the firing pin into the tank and pump it, it makes no difference, so I don't think a stronger spring would fix it. It seems that higher pressure seems to help seal it, so plugging the pump might work, but not only is the pump glued in and I can't get it out, but I hear that plugging the pump on a SM500 can blow the tank, so I really don't know what to do. I would like to be able to soften the glue on the tank and open it up. I don't want to cut it because I've never been able to successfully glue tanks back together, and since this tank is attached to the pump as one big piece, I'm not even going to try.

I've done everything I know how to do to fix this thing, and I haven't gotten very far. Does anyone have any ideas on what I could do?

I'll try it. Thanks, I'm pretty sure you're talking about Q-tips right? Haha. I don't know much about Big Salvo's But I didn't even open it up, I just stuck 10" CPVC barrels down each existing barrel with some e-tape on each and I'm getting about 110'-120' ranges level. Is it supposed to be that awesome?

I'll try it. Thanks, I'm pretty sure you're talking about Q-tips right? Haha. I don't know much about Big Salvo's But I didn't even open it up, I just stuck 10" CPVC barrels down each existing barrel with some e-tape on each and I'm getting about 110'-120' ranges level. Is it supposed to be that awesome?

Without a plugged pump? It seems a little unlikely to me, but who knows? Maybe you have an exceptionally powerful one.

Yeah I think so, I've heard that the OP valve on it kicks in at around 15 pumps, mine does at 22 pumps.

I just picked up a Big Salvo from Goodwill a couple minutes ago. It seems to work but if i pump it slow the air leaks out of all the barrels. The only way to keep air in the chambers is to pump it really hard really fast, then it works. Whats a good way to fix this?

I'm not 100% if it'll work, but the pin that sticks out of the trigger mechanism could possible trimmed down. If not, then cut a notch out of the trigger itself so the trigger goes farther back before it hits the MS trigger.

okay, well how many darts are you looking to fire?

I guess I'm not sure what you mean by shotgun. Like multiple barrels, or multiple darts in a barrel, like pump action?

well i say epoxy it and wrap it in e-tape or duct tape. If you can get a new one or do that, get a large piece of PETG to slide over it to keep it from breaking more.

First of all, where did you get that pump and whats it for?

But I know what your problem is. In most pumps for guns there is a rubber gasket at the end that lets air in to the tank but not out. You don't have the gasket in the new pump so you can't hold the pressure in. What i would've done is take an old pump with the hose still on it, cut most of the pipe off the original pump. Then you wrap e-tape around the stump of pipe until it fits the opening of you new pump. Then take a piece of PVC of your desired size and stick it over the e-tape. (Make sure its very tight). Then blow into the open end to make sure its sealed perfectly. Then create a new pump handle with a new O-ring, make sure its a perfect fit. I use this on my RF20, Magstrike, and a few of my super soaker's. SO MUCH NICER to only have to pump 10 times to shoot 20 darts!

Hope that helped!

-Banshee

Is it the one in the plunger? If so the whole end of the plunger is lubricated and you probably had some grease in the valve when you filled it. The glue wont stick to the grease at all. Take a q-tip and clean it out well, then try again. You could put some tape over the hole afterwards for safe measures.

Oh my gosh, do some searching. If you've been around for 2 months you'd have seen at least 3 topics about copper piping. Copper can NEVER be used in nerf guns unless you find custom darts to fit it. Its just too big. They make it in practically one size and its expensive as well as heavy. It'll never be used as a barrel material as long as we have brass.

How about you don't because concept threads piss everyone off. We want to see REAL mods, not idea's for them. Take a camera, take pictures of a real mod, and post it up. Otherwise you're going to waste everyone's time.