12 gram pump mag build

[captian pinky]

so i have slowly but surely been building a pump mag.

the plan:
ule body
classic valve
rt on/off
lvl 10
agd pump kit
agd 6 pak
12 gram efficiency insert




so i have read about people taking hack saws and such to valves trying to open them luckily i have access to a lathe. I knew i wanted to atleast try it for myself


so here is a bit of progress i made on it.

open says me:









from there i decided to make my own insert, figured worst that would happen is i end up with a pile of chips.



here it is:









so i have aired it up no leaks thankfully, however i was testing with hpa and my velocity maxed out is only 230. so i need to go back and open it up some more currently its like the same size as the ID of the powertube.

does anyone know the size of the ID that people were using with the plastic spacers?

[Cyco-Dude]

wait, why test it with hpa if you're going to be using c02? shouldn't you be testing the insert with c02?

[captian pinky]

so that i can have the option to run with 12 grams or hpa

[luke]

I believe you decreased the volume WAY too much, it looks like about a 66% reduction in chamber size, I think you will find that's too much.

[captian pinky]

i was trying to creep in on it. i know the ones that you made are much larger than the one i made. any suggestions luke?

i also haven't finished my check valve yet either for the 6 pak. waiting on a couple parts in the mail.

[need4reebs]

Drill bunch of holes thru it. Swiss cheese! how did it shoot with CO2?

[luke]

Drill it from the bottom with a .75 drill without going through the top, that will get you (real) close.

[captian pinky]

i did not adjust the velocity when airing up. This is with a classic on/off, lvl 10 and a macroline id of .082", 6-pak setup as a bottom line with no check valve, also had wave spring installed.

with reballs

crosman 12 gram.

1 299
2 302
3 -
4 284
5 265
6 301
7 263
8 286
9 282
10 287
11 -
12 292
13 -
14 240
15 -
16 228
17 213
18 -
19 179 began to leak from lvl 10 when reset
20 147

[captian pinky]

luke why do you say to open it up so large?

i thought some people were having success with pretty small dump chambers?

[luke]

Who else has made inserts other than the ones myself and Hill made? I used his design that was tested and proven to be an improvement over the stock chamber size. You can certainly do whatever you want.

[need4reebs]

does anyone know the size of the ID that people were using with the plastic spacers?

3/8" ID nylon washers

[captian pinky]

http://www.automags.org/forums/showthread.php?249391-30-Shots-from-a-classic-valve-w-a-12G

^used 3/8" ID nylon washers

http://automags.org/forums/showthrea...highlight=gram

^used nylon washers as well

i think Hill was designing his to be more efficient with hpa if im not mistaken.

i still think there is room for me to improve my setup. i may switch to a lvl 7 bolt and see how that compares. i also wanted to switch to braided line and devolumize that. anyone else have any more suggestions?

[jolt00]

Has anyone tried to put "fins" on the insert? like a heat sink? I thought about doing that to mine, to help gasifi the C02 and keep the chamber at a more consistent temperature?

How about something like steel wool? anyone try something like that?

[captian pinky]

I heard someone say that the find wouldn't work because it's still contained in the same chamber. Not sure if that's true or not. I know people used to mill fins into the regs but I don't plan ok shooting that much co2 to worry about freezing the gun up.

[athomas]

Has anyone tried to put "fins" on the insert? like a heat sink? I thought about doing that to mine, to help gasifi the C02 and keep the chamber at a more consistent temperature?

Fins give more surface area to collect or dissipate heat, but that heat needs to come from somewhere other than the chamber that its in. So, putting fins on the insert won't help, especially since the wall of the chamber is stainless steel which really doesn't conduct heat nearly as well as the aluminum insert would. The heat would be too slow coming from the outside of the body to the valve and through the steel/aluminum joint to the inner surface to make a difference.