Pump Stop

[Cunha]

I made a pump stop for my new gun and thought I would share the photos so that other people can keep from beating up the lower tube on their guns. You can't see it as much but the same happens on full body guns if you don't have something else stopping the rearward pump stroke. For mid and half blocks the bolt pin impacts the lower tube. For full body guns the hammer lug usually does this in its slot. Neither are ideal.

Pictures are all out of order but they're there at least.

Remove the pump handle via the 2 allen screws. Don't drop the return spring
Find a rod of some kind that fits in the secondary guide rod hole. I had a good piece of brass but it was too wide, so I "turned" it down with a drill press and file.
Then you test fit it in the pump handle. You don't need to re-install the handle to check the fit, just push the handle on to the guide rods.
Grind it away till it lets the gun recock reliably. I wouldn't try to get it RIGHT on the edge or else you won't reliably catch the hammer.

Now the pump stroke is reduced, but more importantly you aren't bottoming out on something as difficult to replace as the slot of the lower tube.

[Flounder]

Looks like a simple and elegant solution. Well done.

[Jonnydread]

Neat little mod. I'll continue to beat the shit out of my lower tube, but I salute your endeavor!

[Flounder]

Now we know why you are in the shower so long

[Jonnydread]

That. And crying.

[Chuck E Ducky]

That Jonny always in the bushes beating his lower tube.

[XEMON]

I like it, smart and simple ...
I May steel the idea for an up-coming pump build ...

[SignOfZeta]

If like this idea and IMO it should always have been part of the standard design.

I have a slab sided Sniper with CCM pump and I’ll probably do this, even though I don’t really need to because since I’m on CO2 the spring force is relatively high which helps one control the pump stroke better. If anything I have issues not pulling back far enough to let the ball drop.

I’d consider a plastic insert though because now the delrin handle is being slammed into brass, which isn’t as nice as it could be.

[Cunha]

I’ve done it with macro in the main guide rod channel and it’s not quite as good but it works. You just want it to hold up.

on the old ones there’s still a lot of post travel to eliminate. Having a positive stop makes them a lot better you don’t have to waste any effort going past the reliable cocking point just push it to the wall and stop.

Also this is definitely not a new thing it’s probably been done as long as pumps have existed but I thought a basic post would be helpful.

it’s really easy for people to see why if they look at a well used half block sniper.


on autocockers you add shims/ bumpers so the ram stops before the lug slams into the body slot and you set the back block so the ram stops the forward travel and not the back block on the gun body.