.30 Impact guru's...............C3 go/no go ?

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far_shot

far_shot

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Jan 21, 2018
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Ia, United States
.30 Impact MKII was running 140 bar/860 fps. Suddenly dropped to 600 fps, yet still recharges with out fail to 140 bar with every 600 fps shot. It has factory settings.Defiantly needs a look inside. Found that a good tap on the top plate allen screws with a 5/32nd punch loosens the stuck ones like magic. Absolutely everything inside was OK except C3 has a little ring of degradation where the hammer strikes it. I didn't have a C3 and nothing looked wrong with all other O-rings and port alignments....so put it back together and still is at 600 fps/140 bar. Doesn't leak down,even tho I reused the un removed/un disturbed 0-rings. Can a C3 make THAT MUCH difference? Breach and barrel 0-rings OK. Valve and seat OK. Valve stop at 4th line open.Probe OK at 44.5 mm. Hammer seat OK at 6.2 mm. Power wheel OK at 15 mm and MAX. I did find the front set screw for the valve tube was not tight and could easily rotate the valve tube. Secured it correctly on assembly as well as blowing everything clear and clean and assembled with fresh silicone grease.. Valve rod spring had a weird termination on the end,but both ends were the same so I guess that's how they are wound. Wish I had taken a picture of C3 :( Any clues? I did not dig into the trigger group or regulator because that is all working fine.I guess I can make a Delrin C3 and get a complete 0-ring kit and go from there. Just as well put in the improved valve seat too. I worked with industry pneumatics for 20 years of diagnosis and repair...thought I had this Impact on the run...but found really nothing other than the C3 that pinged my radar.... :( :(

Weird spring termination on the valve rod.....I guess OK/normal
1559536996_12776180215cf4a564cd74a8.69194489_impactsprg .jpg

 
Basically If you add a normal buna 70 oring , you are adding cushion to place that should not have cushion, ergo low fps since the valve doesn't open fully, needs to be duro 90 or hard plastic like acetal or nylon. The purpose is avoid metal to metal hits, without cushion, anything that make that possible and can take the punishment , works. 
 
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Thanks Edosan. After looking at the pictures, I was thinking those would be easy to make with a core bit. Just drill out a chunk, drill out the center and sand it to the right thickness. Might just be easier to buy them if they don't take too long to get here. Thanks bud. Stoti
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My pleasure!, you are right are very easy to make, 1.5 up to 2mm thick is fine. 3mm also work if you do not use a Hammer Weight. 

Here is a link if you want to make it https://www.ebay.com/itm/Delrin-Acetal-Rod-White-3-8-diameter-6-long/123770429125?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

from 5/16 up to 3/8 is fine ( about 8 - 10 mm)
 
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None of you guys have a hand pump or compressor? These small white delrin ring always ship with them. I have cheap $40 hand pump that came with a few. Also have a hatsan lighting compressor that came with some white delrin rings too. I just use those. They usually go before you screw in the hose or gauge to stop leaking. I just used those and they fit nicely and work just fine. You guys making it seem harder than it really is. Lol.
 
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Ok when you use the orings that came with hand pump or lightning did you do anything to it first.i used that sanded it down to make thinner. After about 1000 shots it busted is that normal
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I did not sand it. I just use it as is. Mine still work great. Getting 890-900 fps on 34 gr jsb. Before I replaced with the delrin. The original c3 o ring I was getting max 850-860 with same pellets.
1559627506_9597450255cf606f2e94226.74723042_IMG_20190517_171100.jpg
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None of you guys have a hand pump or compressor? These small white delrin ring always ship with them. I have cheap $40 hand pump that came with a few. Also have a hatsan lighting compressor that came with some white delrin rings too. I just use those. They usually go before you screw in the hose or gauge to stop leaking. I just used those and they fit nicely and work just fine. You guys making it seem harder than it really is. Lol.
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😅 If you check my comments and links https://www.airgunnation.com/topic/30-impact-gurus-c3-go-no-go/#post-508452 you will see that a few post up, is exactly what I post as a good replacement for C3 bumper... sometimes reading is a good thing! jk ..jaja :p btw that dimension will work without a hammer weight, if you add a hammer weight might be too thick

Just search for "Paintball PCP O-Ring Gasket"

edosan

c3 needs to be in perfect condition.

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F173916192266

Those work, you can make it thin if you like
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Hard to believe this C3 was the problem. Super simple to replace.Degas by taking the bottle off. Loosen the barrel set screw and slide out the barrel.Take out the three picatinny rail screws and you are done with screws. Remove the front valve adjuster and grab the hammer rest with a soft (*)vise grip and pull it out far enuf to put a second soft vise grip on the valve pin,inboard of the C3. Unscrew the hammer rest and replace the C3. Screw back on the hammer rest with some soft sealant on the threads to lock them and put it back together.

(*) Soft vise grip= needle nose vice grip with several layers of masking tape wrapped around each jaw.

1559883683_67683305cf9efa3a9f637.70067310_ccc3.jpg




C3 I made out of Delrin. Pretty easy to make.
Took a couple shots at the dirt in the dark tonight and it sounded like it was back up to speed. Tomorrow will tell the tale of success :)

1559883734_19728765665cf9efd6497067.72764348_cc3.jpg

 
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