JphtkdFeb 14, 2004 3:22pm
I just got a TM Knights pro silencer, and I want to put a longer inner barrel on my M4 now, what should I get? I know a few people have done this already so if you can please help me out.
TM M4 inner barrel
CAINFeb 14, 2004 5:02pm
With the M16A2 inner barrel, the tip of it is shy 2.5" from the tip of the Knights pro silencer.
JphtkdFeb 14, 2004 7:13pm
thanks
Golfpride31Feb 14, 2004 7:17pm
Hey, if you get the m16 barrel you will also need a new cylinder with no holes.
CAINFeb 15, 2004 1:30am
Hey GP, Why with no holes? Don't know what brand piston head I have, but it has 3 oval holes. And with a tightbore A2 barrel and m120 with .20 bb's it chrono's in at 427fps. .25's brings it in just under 400fps.
Golfpride31Feb 15, 2004 2:35am
just what your supposed to do usually. if you have a stock piston head you will get a vaccume effect because the air in a m4 cylinder cant fill a m16 barrel so before the bb leaves the barrel the piston will already be sucking air back into the cylinder, reducing the bbs speed. if you have a anti-vccume head you should be fine.
CAINFeb 15, 2004 5:30am
Oh, then I must have one of those anti-suck piston heads. I'm glad the wife doesn't :lol:
stevofettFeb 16, 2004 2:44am
On my M4 with the Knights silencer, I've got a 550mm Prometheus 6.03mm inner barrel. It's a long sucker! So long, it sucks . . . . . literally . . . . Like these guys said the bb velocity is reduced because of the vacuum effect. I had mine chronoed today, and to my dissappointment it was shooting only at 270fps with .25gram bbs, tight bore barrel, and a fresh M120 spring. It seems like it shoots hard, but that's not what the chrono said. I'll have to upgrade the cylinder . . . .
Golfpride31Feb 16, 2004 3:44am
yup, perfect example of the vaccume, you might want to pick up a anti-vaccume piston head too.
redears1Feb 18, 2004 4:05pm
stevofett, you may need a bore up cylinder set to supply enough air volume for such a long barrel. Try the type 0 cylinder first (no hole) though since it'll be cheaper. Longest tightbore I tried in my SG1 (type 0 cylinder) was 534mm. So hopefully, 550mm will still be okay. From what I've read in other forums, the theory is the "volume in the cylinder must be the same or more than in the barrel."
Golfpride31Feb 19, 2004 4:12am
If you are going to get a Bore-up cylinder set then you need to get either a PSG-1 length barrel or a m130 + spring for it to be useful.