From: henryc@panix.com (Henry Chan)
Newsgroups: rec.sport.paintball
Subject: Re: Paintball Gun Question
Date: 8 Sep 92 02:40:25 GMT
Organization: PANIX Public Access Unix & Internet, NYC

In article <18gft1INN4me@usenet.INS.CWRU.Edu> mjc5@po.CWRU.Edu (Michael J. Cavotta) writes:
>
>	I am interested in purchasing a paintball gun, but am not as well
>informed about PB guns as I am firearms.  If you have any experience or
>technical insight you'd be willing to share with me, please drop me a line.
>I'm looking to order one as soon as possible, so if you can respond soon
>please do!
>
The rec.sport.paintball equipment FAQ, maintain and posted by Robert 
Osborne, has reviews on a couple of the popular guns out there.

There are two major varieties of paintguns availible, Pump action and 
Semi-automatic.

Pump Action:
All pump action paintguns on the market are based either on the Sheridan
or Nelson valve design.  Sheridan PGP,PMI, Bud Orr Sniper, Sterling are
based the Sheridan design while guns like the Bushmaster, SL-68, Traccer,
Phantom, Razorback are based on the Nelson design.  Nelson based paintguns
break down into a further division between guns which are Nelson parts
compatible and those that are not (ie, Razorback I is 100% nelson compatble
but Traccer isn't).  Usually this means that the individual manufacturer decided
to use his own tap and die standard.  ie; Razorback powertubes won't take 
standard nelson cup seals because the threads are different.
Nelson based paintguns have lots of advantages.  Parts availibity is never a
problem because so many pump guns are based on nelson parts.  Dissassembly is
a snap, needing only an adjustable wrench to unscrew the valve seat from the
valve body.  Because the nelson design has been proven, there shouln't be any
problem a field owner, experienced friend or an airsmith can't pinpoint and
figure out for your nelson based gun.
I have noticed that nearly all of leakage, burping, low power originate with
the powertube and cup seal failing in one way or another.


The Sheridan design IMHO is more difficult to service than the Nelson.  To
open up the valve body you'll need a special Sheridan dissasembly tool.  
Inside the valve there are up to 3 rubber seals and a delicate lead seal.
Never open up a Sheridan valve unless its necessary.  I found it to be a
pain in the butt and frustrating in comparison to the simpler nelson
design.  On the brighter note, the Sheridan valve is more rugged and doesn't
suffer from fragile power tubes snapping (like the Nelson) under intense
or rapid pumping.  On a side note, Sheridan based guns are gnerally more
accurate than Nelson based guns.  PGPs,PMI-1s, and Snipers are some of the
more accurate guns I have used.

On Semis, it used to be the rage for semi manufacturers to distinguish their
designs as TRUE semis (gas blowback as opposed to double action).  Nearly all
the popular semis availible are gas blowback (ie: F-1 illustrator, PMI-3,
Tippmann, etc).  For semis, closed bolt actions are considered more accurate
than open bolt semis.  I don't know the mechanics or the physic behind this.
For semi autos, there are more basic designs but from hearsay I think patterns
are starting to form along the lines similiar to pump guns; guns being centered
around one design.  I read on the net that the Line SI Pro-Master copies the 
F-1 Illustrator design while the Icon Z-1 is remarkably similiar to Brass
Eagle's design.  I don't have much first hand experience with semi-autos as
I had with pump guns and this is all I can help you with.

All in all, I think pumpguns are simpler to define and categorize than semis.


-- 
" I am from the planet Larson on the far side of the Galaxy" said the
space cow invading St. Canard -Dark Wing Duck

HenryC@Panix.Com