xrider

Thanks for the input all. I took it back apart and I had a small amount of gap with the hop up rubber in the hop up, meaning I didn't seem to have the rubber pushed all the way in the chamber(no pun intended). I also loosened the two grub screws a little more. Now the grub screws just barely touch the outsides of the chamber, but allow the chamber to move back and forth easily. I shot a complete hi-cap with no further issues. Semi shots and full auto. Just to confirm, I guess the two grub screws act as more of a guide for the chamber to move back and forth while assembled in the outer

I have an issue with my VFC SCAR-L that I hope someone can help me resolve. I replaced my inner barrel and bucking with a Prometheus 6.03 tight bore and Prometheus purple soft bucking. The bucking was very tight and when sliding the hop up unit over it caused the bucking to stretch and some of the material protruded where the plastic collar clips on over the inner barrel and hop up unit area. I trimmed it out, snapped on the plastic collar and put it back together. After reassembly it would shoot 2-4 bb's and they would roll out the end of the barrel. I disassembled it again and noticed th

Kossack, The nub may have been damaged when you removed the barrel. Make sure you turn the hop all the way off when removing the barrel so it doesn't catch on something and rip off.

Looks like it cleared customs faster than I thought. It will be a few days before I post some results. I am still waiting for the guarder hop up and air seal nozzle. Curious as to what my rps does also when I install the Systema M120 spring. I picked up a Amp Tactical torque up motor to play with also, after the spring install.

TK4235, I did order up the prommy barrel. It should be here next week. I will do some grouping tests and chrono again after installing the barrel with stock bucking, then install a guarder and retest. I also have the aftermarket air nozzle on the way, http://airsoftpro.cz/eshop/product_info.php?products_id=1522. I will also chrono test after replacing the air nozzle. I'll post a graph style of stock, prommy barrel, bucking, air nozzle, then lastly Systema M120 spring for FPS.

After reading this entire thread I have but a few questions.....for now. I have read that the PDI W Hold bucking or the Guarder 50% clear bucking is the way to go. I had already ordered a Prometheus purple soft bucking before reading that though. My question is there is mention of the Guarder having a built in nub? Does the PDI also have this? Is it really necessary to have it in the bucking? I take it the Prometheus one does not have the built in nub. I had found on Redwolf and Ehobbyasia that Prometheus makes a Magpul PTS ACR specific 6.03 tight bore barrel. Has anyone used these yet