cocker ram high pressure/no chop

[PBpunk]

i posted this a while ago in a thread that started out on the subject of spring return rams but got no replys

here is my idea:

take a regular 4-way, ram and hammer and valve springs and everything take the ram put a spring on the front side of the ram piston that way you can set your pressure really low and what the spring does then is it helps cock the gun and then as the gun chambers a ball (the bolt moves forward) the spring kinda counter acts the air pressure on the other side of the ram so it is not pushing forward very hard and will stop on a ball so you don't get any chops

i would really like to try this idea but dont have the resources right now. so if anyone else wants to try it that would be sweet. or if any one has seen anything like this before.

something else i thought about is it would probably have to be a ram with a pretty big barrel (shocktech, STO or something not ANS or anything that size) to fit a big/long/stiff enough spring in it

tell me what you think

[Redkey]

they make them...

assuming you are talking about autocockers...

Almost all air cylinder manufacturers make single acting rams. Single acting meaning air pushs the ram in one direction and when the air is removed a spring pushs the ram back to the starting position.

On the smaller cylinders the return forces of the springs are pretty low. I'm not sure how much force is required to return the bolt to the closed position... I'm sure it varies from gun to gun.

If you did have a spring strong enough to close the bolt you'd have to increase the cocking pressure. The additional cocking pressure is needed because now you have to compress the cylinder spring in addition to compressing the hammer spring and over coming the friction of the bolt.

I think the main problem with this is the forces put on the bolt during the firing process. With a double acting ram you have air pressure keeping the bolt closed. I've never measured the force it takes to open a closed bolt... I'm guessing it is between 5 and 10 lbs. So... your spring would have to be able to apply that amount of force to keep the bolt closed when the gun is fired. Otherwise the pressure in the chamber will cause the bolt to hop back on every shot.

To make a long post even longer.... when the spring has returned the ram to it's starting position it will be almost fully extended... providing only a fraction of it's compressed force. So, you might have to have a extra beefy precompressed spring to keep the bolt shut during the firing process. Which means you'd need even more force to cock the marker.

Of course, I have never tried this... I'm just making a semi-educated guess at how it would work.

[sarpadian]

Redkey, I believe PBpunk is still taling about a double acting ram, just with an spring assist. I like the idea it's just that if you try and put that in a standard length ram the spring would shorten the amount of travel the ram would have. You would probably have to fabricate a special, longer ram in order to get it to work.

The idea has merit. You would be able to use stiffer main and valve springs but still keep the return force on the bolt low.

Although there are at least 2 things I don't like. One your ram would have to be longer to account for the space the spring would take up. The second is that for best performance you would want to match the spring pressure in the ram to that of the mainspring. People using a heavy mainspring would want a heavier spring in the ram. If you are using a lighter spring you wouldn't need the heavier spring in the ram because the heavier spring would just put more force going back on the back block leading to more kick to the gun.

[thei3ug]

Here's what you're proposing as a retrofit:

On the extending exhaust, put a quick exhaust fitting on that end.

On the return exhaust, put a bleed valve. You'll see a not-very noticable speed difference on the open, and be able to control the rate of bolt close.

You will lose cycle time.