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View Full Version : Acs Bolt. It Works!


jimbo001
03-27-2008, 05:57 PM
When the bolt is new the internal ACS bolt spring is too stiff to allow the striker to travel far forword enough to engage the valve pin IF the ACS bolt has stopped at the feed port by a ball that has not fully dropped into the breech. If the striker does not engage the valve pin there is no air discharge to blow the bolt back to the cocked position. The ACS bolt spring must compress enough to allow the striker to move forword far enough to hit the valve pin to cycle the bolt back to the cocked position. Breaking in the ACS bolt spring "weakens" the spring allowing it to fully compress when the ACS bolt is suddenly stopped at the feed port by a misfeed. In orher words, the main spring pushing the striker must be able to overcome the ACS springs' "resistence to compress" when the bolt is lodged against a missfeed at the feed port. Therefore, a stronger main spring pushing the striker forword helps the striker to "reach" the valve pin activating a gas discharge which in turn blows the striker and ACS bolt back to the cocked position. That is why "breaking in" the ACS spring (making it weaker, compared to the main spring) greatly reduces and sometimes eliminates the "uncocking" problem.
I have proven this to be true with my MR2. At first I had the same uncocking problem you hear so much about in the forums. I did the bolt breakin procedure by first leaving the ACS spring completly compressed for about 4 days. was not much better. Then, I manually cycled the ACS bolt spring about 2000 times. It would now occasionally recock if I would stop (jam) the bolt at about 2/3eds into the feed port opening. I then installed the TRINITY RED main spring behind the striker, screwed in the velocity screw until the bolt would recock with the ACS bolt stopped (jammed) at the begining of the feed port opening! Bingo! Exactly what you want it to do. If you are wondering about the velocity with this set up because of the heavy main spring, it shoots about 270 -280 fps. Right on the money. That is how I got my MR2 ACS bolt to work as designed. The trick to the proper function of the ACS bolt lies in the relitive spring pressures of the MAIN SPRING compared to that of the ACS bolt spring. SOFTEN UP THE ACS BOLT SPRING.....BEEF UP THE MAIN SPRING. IT WORKS!

KingTutBaller
03-29-2008, 08:30 AM
nice guide :D I've tried explaining this to a few people, but I'm not very wordy and a tad lazy to type it out, so now I can point them here. Sticky in the works, perhaps? Good stuff again.

ViperX
03-29-2008, 09:08 AM
Very nice work!

Now if we can just get people to understand that if they match their Rate Of Fire with the proper feed rate and a forced fed hopper to overcome the blowby up the feed tube, they wouldn't have to worry about ACS....

PipeRain
03-29-2008, 09:42 AM
So far, this has proven true for me as well. Ran down to the local paintball shop, grabbed a stiffer spring, and after breaking in my ACS bolt, it seems to be working. Granted, this is with a rag stuffed into the feedneck, I haven't had a chance to try it with balls yet, but the principle seems to hold.

Thanks so much for posting this!

SpyderMan723
03-29-2008, 12:48 PM
how did you guys break in your ACS with a ziptie? the way i tried doing it wasnt working so i just gave up on it

slim and shady
03-29-2008, 01:56 PM
You just use a zip tie to hold the spring compressed, lots of people say you have to manualy compress and decompress it by hand a few thousand times to finish breaking it in however.

PipeRain
03-29-2008, 03:39 PM
how did you guys break in your ACS with a ziptie? the way i tried doing it wasnt working so i just gave up on it

Well, actually, it took two zipties. :D


Connect the ties together.
Drop a pencil down the opening in the bolt face.
Loop the ziptie over the stud at the opposite end of the bolt (Sorry, I dunno what its called) then over the pencil.
Compress the ACS Spring as much as possible.
Tighten up the zipties to maintian compression.
Over the course of 4 or 5 days, re-tighten the zipties, as they will stretch.


Once thats done, re-assemble the marker, screw the air tank on, stuff a rag down the feedneck and fire the marker 200-500 times.

Replace the mainspring with a stiffer one.

Enjoy your marker!

PipeRain
03-29-2008, 03:46 PM
You just use a zip tie to hold the spring compressed, lots of people say you have to manualy compress and decompress it by hand a few thousand times to finish breaking it in however.

This is true.

Simply compressing a spring (any spring) will not "Break it in". If that were the case, the springs in your car would fail in short order due to fatigue. However, what the compression WILL do is help the spring take its initial "set". Then the continued cycling of the spring will finish the "Setting" process.

slim and shady
03-30-2008, 06:27 AM
Thats what i said.

alter_77
03-30-2008, 02:22 PM
what spring is he referring to? Is the trinity red spring supposed to go in behind the bolt, in front of the velocity adjuster? I'm a little confused...

PipeRain
03-30-2008, 03:08 PM
what spring is he referring to? Is the trinity red spring supposed to go in behind the bolt, in front of the velocity adjuster? I'm a little confused...

Yup, thats the one!