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!
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!