Armson Semi - HELP Needed !!!

[Lewisit]

today i got myself a "new" gun: it's an Armson Semi-Auto issued in 1997 :)

the Armson Semi-Auto [...] with a blow forward style bolt licensed by Airgun Designs, Inc.

the gun is in great shape and works like a charm - with one big problem:

i cannot turn up the velocity higher than ca. 250fps - when i try, air leaks out of the velocityadjuster-nut at the back of the gun

i use a 850psi bulldog preset mounted directly to the gun - and there are no leaks or anything...

what can i do?

cut the bolt-spring?

dremel out the velocityadjuster-nut, so the airchamber gets bigger?

anything?

p-l-e-a-s-e help !!!

[ZapTheMad]

Wow, that thing is crazy looking!

If it is like mags, then it is probly the regulator piston. It has a relief valve built in. If it is failing, it will start leaking at lower pressures.

[Lewisit]

from the "armson semi FAQ":

The Armson consists of one chamber which mounts on to the trigger frame. The chamber hosts the valve, bolt spring etc and is very similar in design to the AutoMag except for one main difference. The Armson does not have an integrated Regulator built in to the rear of the valve assembly

btw: a look at the cmplette gun:

[OysterBoy]

Is it any good? I wonder why it didn't take off, seems like a simple but good design..

[RRfireblade]

Stopped production due to a few technical issues.

I have one at the shop, I'll see what I can find out about the velocity adjustment. I haven't really messed with one in a while.

[Lewisit]

@fireblade

that'd be great!

i'm looking forward to your reply :)


ps:
you don't happen to have one of the original 1/2" dummy plugs for the donkey left over (mine is lost and i have one not-so-good-looking substitute)?

[RRfireblade]

OK, Here's the deal.

The valve is a volume based system so if it's leaking out the back,it can really only be the o-ring on the adjuster. So....when and where exactly does it leak? And I'm assuming you know that backing out the screw increases velocity.

There other thing is there are 2 different velocity adjusters....kinda. Pull yours completely out and look at the back. Is it drilled out, as in,is the adjuster hollow? Or solid? If it's solid,you can drill it out to make it basically hollow which will increase the velocity dramatically. An finally,what length barrel is on it? Due to the valve desigh, a long/longer barrel will give more velocity as well.

LMK is any of that helps.

Jay.

P.S. I have one here if you wanna see a pic, they're pretty neat as well as there history.

[Lewisit]

when and where exactly does it leak?

it leaks when i unscrew the adjuster too much i.e. when the o-ring cannot seal anymore because of the thread (this happens at about 250fps)


There other thing is there are 2 different velocity adjusters.... Is it drilled out, as in,is the adjuster hollow? Or solid? If it's solid,you can drill it out to make it basically hollow which will increase the velocity dramatically.

it's solid and today i gave it to a friend of mine to drill it out (i figured out that this should be the solution by myself - but i am glad to hear from you that you give me the same advice)


An finally,what length barrel is on it? Due to the valve desigh, a long/longer barrel will give more velocity as well.

it's an 10" barrel - and probably the only one that i'll ever get hold of (i live in germany...)


LMK is any of that helps.

i get the adjuster back tomorrow - but can test it not until saturday or sunday
i'll keep you informed - thanx a lot 4 now :)


I have one here if you wanna see a pic

sure

[RRfireblade]

Cool, good luck with it.

I have one of the protos that was used for 'non-lethal' weapon testing.With the velocity mod and a 16" barrel and a few other things,it shoot a 12-13g projectile at like 500fps or something. Crazy.

Here's the one I have here.........

[Lewisit]

everything ist fine now !!!

but i have anthoer question:

there is a hole on each side of the body (see star-selection in the pic)

i have seen an automag, where somebody drilled the same holes through the body (and the barrel) - what are the holes in this place good for?

isn't it crazy to have holes in the "ball-chamber"

[RRfireblade]

They are actually just 'pre-chamber' , there to eliminate any blow back up the feed tube. Between that and the powerefeed you'll notice it has next to none.

Glad you got it working, it's a pretty neat little marker. Don't be surprised to see some new developments of it in the future.