Line-SI Promaster Questions...

[Lenny]

I got some cash for Christmas, and I'm feeling the need for a new semi. I have a 'Mag, and a 'Cocker, and I'm feeling the urge for something old school, and a Promaster is one gun that my hands have never gotten ahold of.

So, I did a little research, and found out that they can be pretty finicky. They had thier fair share of reliability issues. I also found out that the older Spyders were almost exact clones of the Promaster. So this got me thinking.

I was wondering just how well the parts interchange. I was thinking possibly an ACS bolt, and a stock Spyder valve to mess around with (so I don't screw up the stock Promaster). Those are really the only things I want to add. Plus I honestly like blowbacks, these tend to be relatively cheap, and seems like it'd be a fun gun to tinker with and tune just because.

Also, anyone know what barrel threads they take? I wasn't able to find the answer to that.

Thanks!

[[NA]WARLORD]

To my knowledge, the barrel isnt threaded at all, it slides in and is held in place with a set screw, like the Line SI Bushmaster Deluxe pump was.

[Coralis]

try this http://www.pukindogspaintball.com/bg-guns/PROMAST.htm

[hmudd13]

To my knowledge, the barrel isnt threaded at all, it slides in and is held in place with a set screw, like the Line SI Bushmaster Deluxe pump was.

That is correct.
I never had any problems with either of the 2 I have owned.
It's a pain with the velocity adjuster in the asa though.

I love the removable breach.
It's a not bad marker for rec use, just bring a spare.

[robertsr1811]

Most of the "finicky-ness" was due to there being several spring/valve pin combinations available. Basically, the gun was too tunable, and the average Joe didn't have the time, knowledge or patience to fiddle with 4 different factors (main spring, valve spring, size of valve intake port, and recock pressure from valve pin cutout) to get them working reliably. With all the parts for one, they're worse than an old cocker to get working right. There are just too many possible combinations.

I replaced the valve in all 3 of mine with Tornado or turbo valves and they became great shooters. The barrels on them are fantastic with large bore paint. They were always very accurate for me. I used 2 of them in my loaner fleet, and was on the receiving end of paint from them far too often.

I don't believe that bolts or hammers are interchangeable with Spyders, but you might get lucky. The stock bolts on 2 of the 3 I had were center fire delrin already though, so there might not be much to gain from swapping out in any case.

They take a strong mainspring too. I don't think your average spyder spring kit will get you happy with velocity. I got my mainsprings from the local hardware store from the household spring section. I found one the right size/weight and bought a big handful. I sold them all when I sold the various markers, but it was an off the shelf purchase from an ACE hardware, so I don't really think you should have much trouble finding some if you need them.

Here are 2 of my old ones, both heavily customized





Most of the folks I've seen running these regularly were using a reg to bypass needing to fiddle with the in ASA velocity adjustment. The first picture is of one where I bobbed the rear ASA and blocked the air path so you could use the adjuster if you wanted to, but we still just ended up using the reg because it was so much easier to adjust.