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Posted: 9/8/2006 12:06:23 PM EDT
| I got one of the imbal kits and I was thinking of cutting the barrel so that it's 16" including the flash suppressor and then permanently attaching the F/S. Anyone see a problem with this idea? |
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Your biggest problem will be getting reliable gas system operation, with the bullet exiting the barrel so close to the gas port, it does'nt offer enough impulse time to cycle the action reliably. To over come this, the gas system should be positioned 3" back, to bring the cycle dwell time up to optimal range. I would not recomend going any shorter than 17" of rifling with a standard gas system. |
If you want it to operate as a semi auto, then you are going to have great difficulty. For the reasons described above. |
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Thanks for saving me from myself. I was set to cut it short. So the consensus is no shorter than 17"? Is that barrel length with out the F/S or 17 total with the F/S. The flash suppressor I got is an open ended 4 prong style so it doesn't look like it would have much back pressure. P/S I love your shorty madhatter what kind of F/S is that? and were did you get it? |
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I just cut and recrowned mine at 18 ". It wouldn't cycle with the gas all the way closed. After looking up some info ,I redrilled the gas port . Increasing it's size from 0.094 to 0.108 inch to compensate for the loss of dwell time. Now it works perfectly on 3 ,and kicks less. I would recommend not going to less than 17 3/8 unless you shorten the gas system. They can be made to work at less lengths without shortening the gas system,but often the gas port whole winds up large enough to snag the bullet and effect accuracy. I've heard that starts at 0.130 inches ,but I don't screw around with any short enough to mess with it. IIRC ,17 3/8 was around the length of barrel calculated for all of the rounds propellant to be used up inside the barrel. Going from a 21 inch barrel to 18 ,you don't loose much velocity .Maybe 15-30 FPS depending on the barrel and ammo. Under 18 you loose signifigantly more FPS per inch lost. I've heard as much as 100 FPS per inch under 17 . I researched it alot before cutting mine,and decided on an 18 inch barrel. |
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Good advice above, but I have a 16.25" on mine. Perfect cycling every time, even at 11,000 ft above sea level in the Rocky Mtns. If you have cycling troubles, drill the gas port hole a little bit and try it again. Gas sleeve numbers really don't mean much, optimal is somewhere in the middle. Gas piston and gas tube condition play a major role as well. Bill |
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Mine's 161/4 WITH the brake. ALthough I had to modify the gas port, it funsctions fine clean or dirty. In fact, after I finished the modifications, it has never jammed in about 1100 rounds. The biggest drawback is to anyone shooting next to me, it’s pretty loud from the side. MV loss is minimal for my needs, I wanted something that was handy, I slapped on an EoTech and most of my shooting is 100y or less. If you want a 16, make a 16, it will function fine. YMMV. |
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Shortest factory barrel in regular military service was 17-3/8. You can get a 16" gun to run...start by making sure there's no slop in the gas system...you definitely want a tight gas tube and piston. You will need to increase the size of the gas port. Easier to get running well with a short gas system, but obviously more $$ and effort. -hanko |
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