The trouble with Pump Mags (as I see it)

[GEE TEE]

Interesting concepts but this all falls way outside the KISS principal. Simplicity of operation is the main reason I love the current pump mag design

I know it isn't easy to Auto trigger/ slam fire a pump mag, but increasing ROF at the expense of accuracy defeats (for me) the point of shooting pump in the first place

[Patron God of Pirates]

Interesting concepts but this all falls way outside the KISS principal. Simplicity of operation is the main reason I love the current pump mag design

I know it isn't easy to Auto trigger/ slam fire a pump mag, but increasing ROF at the expense of accuracy defeats (for me) the point of shooting pump in the first place

Agreed. A spring loaded blocking plate/rod in the rail would actually be less complex than the current design. No need for a wave spring, body milling, or cutting down the spring. That latch is already there in the form of the sear. When the marker if fired the sear releases both the bolt and the blocking plate while switching the on off to the off position. The bolt is free to travel all the way back, but we are still not in semi because the plate prevents recharge via the on/off. Pulling the pump arm pushes the blocking plate back, the sear grabs it and the bolt and the on off returns to on.

The whole thing can be contained within the rail. You would have a plug and play "pump rail" much less complex than a pump rail, pump milled body, wave spring, cut spring, and all the tuning that goes along with it.

No violation of KISS.

In the drawing here I have added a second pump rod. The channels for the rods would actually be tunnels in this design. This lets us put o-rings on the pump rods so they can to double duty as stabilizing rods. Does not get much more simple than this.

[need4reebs]

Agreed. A spring loaded blocking plate/rod in the rail would actually be less complex than the current design. No need for a wave spring, body milling, or cutting down the spring. That latch is already there in the form of the sear. When the marker if fired the sear releases both the bolt and the blocking plate while switching the on off to the off position. The bolt is free to travel all the way back, but we are still not in semi because the plate prevents recharge via the on/off. Pulling the pump arm pushes the blocking plate back, the sear grabs it and the bolt and the on off returns to on.

The whole thing can be contained within the rail. You would have a plug and play "pump rail" much less complex than a pump rail, pump milled body, wave spring, cut spring, and all the tuning that goes along with it.

No violation of KISS.

In the drawing here I have added a second pump rod. The channels for the rods would actually be tunnels in this design. This lets us put o-rings on the pump rods so they can to double duty as stabilizing rods. Does not get much more simple than this.

[ATTACH=CONFIG]87705[/ATTACH]

Oh hells yeah! thats Awesome! damn you and goat boy got some great ideas man!

[GoatBoy]

"Everything should be made as simple as possible -- but no simpler."

Agreed. A spring loaded blocking plate/rod in the rail would actually be less complex than the current design. No need for a wave spring, body milling, or cutting down the spring. That latch is already there in the form of the sear. When the marker if fired the sear releases both the bolt and the blocking plate while switching the on off to the off position. The bolt is free to travel all the way back, but we are still not in semi because the plate prevents recharge via the on/off. Pulling the pump arm pushes the blocking plate back, the sear grabs it and the bolt and the on off returns to on.

The whole thing can be contained within the rail. You would have a plug and play "pump rail" much less complex than a pump rail, pump milled body, wave spring, cut spring, and all the tuning that goes along with it.

No violation of KISS.

In the drawing here I have added a second pump rod. The channels for the rods would actually be tunnels in this design. This lets us put o-rings on the pump rods so they can to double duty as stabilizing rods. Does not get much more simple than this.

[ATTACH=CONFIG]87705[/ATTACH]

I'm having difficulty visualizing the states in your picture.

How do you:

1. Guarantee 0.68" pump travel to reset the state?
2. Prevent the user from just holding the pump rod back and having full-time semi-auto?

This is basically a state machine with some required transitions.

[Patron God of Pirates]

1. Guarantee 0.68" pump travel to reset the state?
2. Prevent the user from just holding the pump rod back and having full-time semi-auto?

1. No idea. I have no tools at my disposal to measure that kind of stuff. My off the cuff response would be to make the plate throw.68"

2. Missed that in this concept but easily rectified. Ad a secondary blocking device bridging the two rods. This would obstruct the sear while held back.



Scratch that. That will keep the sear from latching the first blocking plate. Need to think a bit.

[GoatBoy]

1. No idea. I have no tools at my disposal to measure that kind of stuff. My off the cuff response would be to make the plate throw.68"

2. Missed that in this concept but easily rectified. Ad a secondary blocking device bridging the two rods. This would obstruct the sear while held back.

[ATTACH=CONFIG]87706[/ATTACH]

Scratch that. That will keep the sear from latching the first blocking plate. Need to think a bit.

Sit down, draw the state machine and required transitions and make sure you hit them all and that the state can't change outside the defined sequence.

You need some sort of latch mechanism. Your plate version will work if you can get it to latch back at a certain state, and spring out only after firing and stay out until reset by the pump. But there goes all your mechanical simplicity. I'm sure it can be done, but my version tries to use the existing available facilities with as few parts as possible, and without modification to the body.

[Patron God of Pirates]

Solved (?)

I've extended the pump rods and added a sear interrupting rod to the back of them. Again, no measuring or math done, but it works in the mental model.

[BTAutoMag]

simple question. can we put a powerful magnet or a spring in the grip to prevent the sear from comming back forward and then a pump arm that pushed the sear back intoplace by using the esisting slope on the front as a ramp

[Patron God of Pirates]

simple question. can we put a powerful magnet or a spring in the grip to prevent the sear from comming back forward and then a pump arm that pushed the sear back intoplace by using the esisting slope on the front as a ramp

Simple and feasible. This is probably the cleanest idea yet.
Trouble is that same magnet will incline the marker toward firing itself.

[BTAutoMag]

then make a spring loaded do hickey that catches the sear in the grip after it passes it. ever loosen a spring too much in an autoresponse frame?

[GoatBoy]

Solved (?)

I've extended the pump rods and added a sear interrupting rod to the back of them. Again, no measuring or math done, but it works in the mental model.
[ATTACH=CONFIG]87707[/ATTACH]

There's a reason why I rendered 4 different pictures and labeled the states. You have a very long, random road ahead of you if you don't get everything mapped out.

The rod on the back of the pump arms will work if they are spring loaded and retract in and out of the pump rods, which is actually kind of a neat idea. That's actually probably going to be a much simpler mechanism to implement on that back end.

It's just another implementation of what I did with the spring loaded plate. And thinking things through, I think I have some simplifications that can be made.


The magnet idea is interesting by the way.

[BTAutoMag]

someone with an emag magnet, open up their grip and see if a magnet will hold the sear back after fired. maybe 2

if it works then a magnet pump kit would be SOOO easy

[splat15k]

We'll have to test with different input pressures and On/Off assemblies of course.

[BTAutoMag]

true, I have a couple magnets and a ULTed xvalve, I can give my setup a shot

[Spider-TW]

true, I have a couple magnets and a ULTed xvalve, I can give my setup a shot

This should be a possibility. I was looking at different high strength magnets. With the RT on/off rated at about 4 lbs, I think you would have to put a target on the sear to hold it. The ULT should be about a lb and easier to work with. Perhaps using the catch magnet as a sear stop would help with a ULT in classic valve. A G-Force-ish extension would help with the RT on/off, as much as I hate to think it.

Still, the pump stroke will be a small kick to the sear. By the time you make something to stretch that stroke out, I'm thinking you might as well have a mechanical latch.

The magnet thing is where I liked a lever action, since the lever stroke wouldn't really work well with your finger on the trigger and the lever hanging down all the time. With a short pump stroke, you can always ride it in close to the activation point.