Please explain automag efficiency

[charlie hp]

Hi all. I have been looking at getting an automag coming from an electro spyder because it looks to me like the most "open" platform. All you need from AGD is the central valve unit, and after that you can personalize every single part, which is totally my style.

Anyway, the one think I can't get past is the (in)efficiency of the mags. maybe 800-1000 off a 68/45 with a reasonable barrel? I'm definately not trying to start a flame war or anything like that, its just that I've viewed the gun animations for pretty much every action- automag, angel/viking, cocker, matrix, timmy, and mags seems to be by far the most simple- the actuation of a lever closes one valve and opens another, and then releasing the lever does the opposite. I don't understand why its efficiency is so bad in comparison.

From what I gather, it has to do with the spring not returning the bolt to closed position fast enough to prevent the entire pressure of the dump chamber from being equalized with the atmosphere. They people who explain this say that timmys, vikings, cockers, electro matricies, etc, all use rams which close the dump chamber before its has equalized. This explanation doesn't really make sense to me for 2 reasons:
-first off, It seems to me that in ramming the bolt back, those guns actually have to use as much (probably a little more) energy than they are conserving in terms of air still in the dump chamber .
-Secondly, if there is too much energy in the dump chamber, why not just make it smaller/ lower pressure and get exactly as much energy is needed, thereby keeping the same operation while optimizing efficiency?

I don't know. Can somebody please explain this do me in in definate terms?

Also, if there have been any documented attempts of fixing this problem, whatever it might be, if you could please mention those I would appreciate it.

It seems to me that if fixing the efficiency problem was a simple matter of adding a ram, then there would be lots of people running around with "ram-kitted" mags.

And this isn't supposed to be an argument about whether mag efficiency is "good enough". There are just certain circumstances where getting better efficiency is a definate plus, and that fact that some guns have TWICE the effiency as mags means that theres a lot of room for improvement.

Thanks for your time.
Charlie

[the electrician]

there is always a trade off, for everything. this for that.
to understand it you have to understand flow rate and pressure relationships. it really cannot be compared to other guns, except for perhaps other blow forward designs.

number one, you don't want the dump chamber to dump all the way to atmosheric psi, the ball is already gone, and dumping more air would just be a waist. the mag leaves approx. 50 psi in the chmber after it fires the ball. leaving the bolt longer would not help. closing it sooner would definitely not help, as it is not open for very long now.

but like I said everything is a trade off. the simplistic, low maintenance, highly reliable designs trade off, is some efficiency.

the bolt spring that returns the bolt gets stiffer as the bolt moves forward, so that when the bolt gets to the point the piston comes out of the power tube, it barely comes out, releases pressure, and the spring pushes it back in. this I believe causes a bit of a flow restriction. so higher velocity air is needed to get more air through the restricted area. so more pressure is needed to get higher velocity air.

also the air can leak out of the bolt as soon as the bolt piston moves out of the power tube o-ring. it leaks a little here. then when it fires, air can leak out the back of the bolt, between the bolt and the power tube. it also leaks in the breech, being that the bolt is about .680, and most barrels are larger than that. my ULE body is .694" in the breech. that's a big enough difference to cause significant leakage. there is no bolt tip o-ring on the mag bolt, to stop the leakage. the reason is to reduce the maintenance, and increase it's ability to work with any size barrel/breech, without binding, extra friction or other problems that could possible occur.

those three leaks, I believe add up to a significant increase in needed operating pressure. I'm not sure how much but I'm actually getting ready to test a few thing tonight to find out.

the standard bolt needs about 400 psi to get the velosity up to playing level. the lvl10 actually uses about 470 psi to do it. the reason it needs more is because of the added restricions in flow. but the trade off for that is the fact that you can make it chop free. most people like that trade.


I've been studying the mag design for quite some time, and I'm just now starting to understand it more. I plan on doing more tests to see what I can come up with.

[charlie hp]

thanks for the reply.

Geez, if leaking is the problem then I think that it would be a relatively easy fix. I think there are a lot of people who would be willing to deal with a few o-rings if it meant double efficiency. Maybe not all people would, but definately a lot.

Supposing someone were to manufacture a version of the mag modified to use o-rings to prevent leaking- what other problems would there be? I don't understand why you can't just decrease pressure in the dump chamber so there is exactly enough to accelerate the paintball to your desired velocity- could you explain that to me?

Thanks a lot again

[the electrician]

it's not that simple. like I said it's not just about leaking.

you're not going to do some simple mod and get twice as many shots out of a mag, otherwise it would have been done.

like I said, it's the design. it's simplistic, but at a price of some efficiency.
the bolt spring keeps the bolt piston from coming out of the power tube very far, thus causing it to restrict air flow. to make up for it, you need more pressure. higher pressure air can move through a given orfice faster than air at a lower pressure. this gets more air to the ball in the time it can be used.
you don't have all the time you want. 3 msecs and that ball is gone. you've got to get enough air to act on the ball in less than 3 msecs, to get it up to the desired speed.

you can't just put a lighter spring on the bolt either. this will more than likely cause an increase in bolt speed at the beginning of it's movement, causing it to be more prone to chopping. it will also more than likely let the bolt dump air after the ball is gone, wasting air.

you can gain some efficiency by plugging the two main leaks out of the bolt, but it won't be a large gain, probably 100 shots per 68/4500.

read my posts in this thread:

http://www.automags.org/forums/showthread.php?t=120465&page=2

[sabrefanpc]

i dunno if that would work. what I would be worried about is that the "leaks" may not neccesarily be a bad thing. plugging them up may put too much preassure out the bolt and end up shooting hot or shooting soup. but then ive never tried it so what do i know

[Magglerock]

Hi all. I have been looking at getting an automag coming from an electro spyder because it looks to me like the most "open" platform. All you need from AGD is the central valve unit, and after that you can personalize every single part, which is totally my style.

Are you serious? I love my mag, but it is probably the LEAST customizable marker available, due in large part that almost no other company outside of AGD markets products for it. You have two body styles, neither of which are machinable (and one of which - the TAC-ONE - is down-right fugly), and the slug, which no one except Deadlywind mills. You have about two after-market frame choices, and no pnuematic options. There is only one fringe-market Egrip (The Devilmag), which is both expensive and untested. There is in fact little you can do outside of annoing to distinguish one mag from another. If you're looking for a highly-customizable marker, I can't think of one that DOESN'T fit that description more than a mag.

[Magglerock]

[QUOTE=but like I said everything is a trade off. the simplistic, low maintenance, highly reliable designs trade off, is some efficiency.
[/QUOTE]

That's simply not true. There is no inverse correllation between reliability and efficiency. The Viking and Excal are both highly relaible, simple designs, and both are nearly twice as efficient as the Mag. Further, I have heard that the Borg is low maintence as well, and it has, again, nearly double the efficiency. And I would not lable a Lvl10 bolt "highly reliable".

[charlie hp]

This just keeps getting more confusing to me.

I have been watching the spool valve animation, and have noticed that its exactly like a mag except-

-in mags, flow to the dump chamber is controlled by linkage from the trigger, whereas its controlled by where the bolt is positioned in a spool valve.

-In mags, the bolt is moved forward by pressure from air in the dump chamber working against a small surface asre so as not to break paint, and the bolt is moved back by a spring. In a spool valve the air in the dump chamber never moves the bolt, it is moved by a system that dumps air on one side of the bolt and pressurizes the other, and vice versa.

Why is there such a difference in efficiency?

Also, this thinking made me come up for a new idea for a paintgun (well somebody probably already has thought of it) that works like a spool valve/ lvl 10 hybrid that returns the bolt and bounces off paint all without springs, an LPR, or a solenoid. I'll post some more details in deep blue i guess.

[the electrician]

maggerlock- please do not misconstrue, or take out of context what I have stated.

the statement you quoted had NOTHING to do with the excal or viking or any other gun other than the mag. it is a completely different design. as far as the mag goes it's simplistic design has a trade off. and it's trade is some efficiency. nobody said anything about the lvl 10 being simple. nobody said that was the trade off for every paintball gun either.

the excal is more complicated than the mag. it has more parts, it uses a dual solenoid design. but it does not trade off any efficiency. it performs better the a mechanical mag, and is more efficient. it also cost alot more.but it has absolutely NOTHING to do with my statement.

I get upset when people quote me, and then take it out of context. please read carefully.

charlie- spool valve guns work on the basis of what is called a "balanced spool valve" design. the pressure in the chamber pushes on two surfaces of equal surface area that are on opposite ends of the spool. examine the matrix animation and you'll see what I'm talking about. the cyinder that is around the bolt controls the movement of it. it doesn't take that much to move it back and forth because it is balanced.

what makes a matrix inefficient is the absolutely huge expansion area the air fill after it is dischrged and before it reaches the ball. several bolts have been designed for it that improve efficiency, but it could be really efficient if someone designed a bolt that reduced the expansion area.

the new shockers are also a balanced spool valve design, it is very efficient in it use of the dump chamber air when using the new bolt kits (evolve and HE) but it uses alot of air to move the bolt back and forth(much more than the matrix) so this limits it's efficiency capabilities.

these guns designs are not really like the mag. the mag is not a balanced spool design.


I read your post in deep blue. that "contraption" you speak of is a called an air cylinder. there is double acting and single acting. in other words, single acting uses air to push only one direction.

in your idea though, you still need a valve to control the air going into the bolt reset cylinder, you should use lower pressure to do this, other wise you will have a hard time finding a control valve that can handle the higher pressure. you can make one to use higher pressure, but it will have higher o-ring friction, and stiffer action than probably what is necessary. none of this is actually going to automatically make the gun more efficient and it's not really a spool valve. you mention giving a little bit of surface area to help move the bolt forward but you still need to be mindful of cycle speed. little force through the stroke, means low speed, which can affect cycle rate. I think your going in the right direction though.

I have to ask, did you read my posts in the thread I gave the link to? because you are basically trying to describe a version of what I'm working on now. if you did not read my posts, you should.

[toymyster]

As far as 'mags go paint to barrel match is absolutely critical for efficiency!!! I have noticed on my LX E-mag, with a proper match, I get around 1300-1400 shots from my 68/4500 tank. Now, if I switch to a slightly looser (.004") insert on the same barrel, I drop downt to about 1000 shots per tank!!! I'm not calling these result typical, or scientific, it is just what I get out of my gun!!! Hope this helps!!!

[Predator-KMK]

the easy way to solve that is to get 2(two) gas bottles...