wide45 Posted February 13, 2004 Share Posted February 13, 2004 Throw that gas against a wall and it tries to push the wall away. If that wall's attached to the gun, it ends up pulling the gun forward. Think wind. If you stand in a strong wind you feel a force. The momentum of the air molecules hitting your body cause this force. To use this force, the comp just sticks a baffel out in the gas flow. The fast moving gas hits it and creates a force in the same direction of flow - away from the shooter, reducing recoil. I don't buy that. There is no wind in your barrel. Remember, the breach is still sealed. The force of the gas on the baffles, is canceled by the force of the gas against the bottom of the case. The comp works by reducing the flow of gas out the muzzle, and redirecting it upward. Link to comment Share on other sites More sharing options...
shred Posted February 14, 2004 Share Posted February 14, 2004 Throw that gas against a wall and it tries to push the wall away. If that wall's attached to the gun, it ends up pulling the gun forward. Think wind. If you stand in a strong wind you feel a force. The momentum of the air molecules hitting your body cause this force. To use this force, the comp just sticks a baffel out in the gas flow. The fast moving gas hits it and creates a force in the same direction of flow - away from the shooter, reducing recoil. I don't buy that. There is no wind in your barrel. Remember, the breach is still sealed. The force of the gas on the baffles, is canceled by the force of the gas against the bottom of the case. The comp works by reducing the flow of gas out the muzzle, and redirecting it upward. It's mass and momentum. Here's a real-world example. One of the best rifle comps around is the JP, which directs nearly nothing upwards, so it's main source of compensation has to be the gas smacking into the plates. Tank and artillery compensators work the same way. Say you load 10gr of powder. Before ignition, the center of mass of that powder is the center of the case. At the point when the bullet is about to leave the barrel, the center of mass of that powder (now converted to gas) is halfway down the barrel-- so while there's a uniform pressure in the barrel, that 10gr is busy going forwards. Smack that into a plate and some of the momentum transfers to the plate, which pushes it forwards as well. Should that be attached to something, it pulls what it's attached to along for the ride. Barrel "holes" rely entirely on the jet effects. Compensators with plates do not. Link to comment Share on other sites More sharing options...
Gun Geek Posted February 14, 2004 Share Posted February 14, 2004 Uhh, sorry wide - doesn't work that way. Once the gas is moving it is "wind" and it has momentum. It doesn't need to push against the chamber to continue moving The force that got the gas moving is what you feel as recoil. Some comps do redirect gas up, many (especially rifle comps) do not, or redirect in all directions. If a comp ONLY redirects gas up it probably uses the rocket effect to force the muzzle down, and some of the "wind" effect to reduce recoil. Link to comment Share on other sites More sharing options...
shred Posted February 14, 2004 Share Posted February 14, 2004 Hey, no fair posting quick responses while I'm composing a tome that says the same thing Link to comment Share on other sites More sharing options...
wide45 Posted February 14, 2004 Share Posted February 14, 2004 The JP rifle comp works by striping gas from the jet going out the muzzle. There is pressure on the baffles, but it can not "pull" the gun forward, as it is no more than the pressure against the bottom of the case. Link to comment Share on other sites More sharing options...
Little Bill Posted February 14, 2004 Share Posted February 14, 2004 Shred, GunGeek, DogmaDog, etc,....THIS IS A GREAT THREAD. I have been wondering many of the same questions about the effects of gas formed by the burnt powder in connection with the working relationship of a compensator / hybrid. Keep up the fine posting Gentlemen.....Thank you for your efforts. Link to comment Share on other sites More sharing options...
rhino Posted February 17, 2004 Share Posted February 17, 2004 This is making my head hurt. I have an nigh irresistable urge to crack my old text books and try to build a formal mathematical model of how compensators work, starting with the classic Navier-Stokes equations. Fortunately, the urge is waning ... waning ... waning ... gone. Whew! Given that, Shred and Gun Geek have done a pretty good job of 'splainin' it. It's all about momentum transfer from the expanding gases to the various surfaces of the compensator (and the outside air mass, of course). The baffles in a comp work tranferring some of the momentum of the gases to the gun in the direction away from the shooter, thus counteracting some of the momentum pushing the gun toward the shooter due to the aforementioned "jet effect." The ports then allow the same gases to also impart components of the momentum in different directions (usually downward to counteract muzzle flip) by changing the direction of the gas flow. It's kind of like a snow plow. The truck is pushing forward, but the snow pushes backward and the angle of the blade adds another component related to the angle of the blade to the direction of travel. I'm sure my comments above are chock full of conceptual and practical errors, so feel free to correct me if necessary. If God had meant for us all to be experts in fluid mechanics, he'd have made us all late 19th and early 20th Century French & German guys. Link to comment Share on other sites More sharing options...
Mover480 Posted February 17, 2004 Share Posted February 17, 2004 For a good explaination of how the comps/breaks work, see BP-Technology. The effectiveness is mostly from the momentum of the gas impacting the plates and, as can be seen in the videos, overcompensation can be achieved by design. When this happens, the effect is to push the barrel down. I particularly like the video of the guy shooting the S&W 500 with one hand! Link to comment Share on other sites More sharing options...
Braxton1 Posted February 25, 2004 Share Posted February 25, 2004 Well....the "air in FRONT of the bullet" theory explains something: I have always wondered why some of my bullets go low on the targets. That little puff of air hitting the comp must force the nose of the gun down. I feel much better now. My ego can recover. I always thought it was me. One of these days, I will pontificate on my theory of why the coriolis effect hurts my shooting more than most people's.... Bruce Braxton Senior Instructor College Park (GA) Police Dept. "Those who live by the sword....are probably pretty f***ing good at it" - me Link to comment Share on other sites More sharing options...
AlamoShooter Posted February 8, 2006 Share Posted February 8, 2006 (edited) Oh Man... ... my first custom gun from my first gun smith told me and my buddy that it was the air in font of the bullet... and I believed that for 10 years It could have been me or my buddy that told Old shooter that. Dang Dam darn I think it was my buddy... not me but I do remember saying that yep that is what the gun smith said. It was not Tony Kidd that said it though ....it was an Old Guy. Ok this is why I beleaved the guy, other than he was 'The Gun Smith' and what I did not know much of anything at the time ...or now for that mater. What he said was 'the gas behind the bullet hits the comp walls after the bullet has left the barrel,= so the recoil force is over at that point' = thats why we bit on it. It a heck of a thing to see somthing in print that used to beleave. Are you absolutly shurr that world iis not flat? Edited February 8, 2006 by AlamoShooter Link to comment Share on other sites More sharing options...
XRe Posted February 8, 2006 Share Posted February 8, 2006 If the gas behind the bullet had no effect on recoil compensation - and it was only the air column in the barrel before the bullet moves that made a difference, you would feel recoil and see dot movement exactly the same regardless of which powder you used (with a given bullet weight). You'd also see a trend toward *longer* barrells, with fewer ports, in an attempt to increase the size of that air column (and thus make things more effective). It's easy to take what the so-called "experts" say as being correct. Maku Mozo!!! Link to comment Share on other sites More sharing options...
AlamoShooter Posted February 8, 2006 Share Posted February 8, 2006 (edited) If the gas behind the bullet had no effect on recoil compensation - and it was only the air column in the barrel before the bullet moves that made a difference, you would feel recoil and see dot movement exactly the same regardless of which powder you used (with a given bullet weight). You'd also see a trend toward *longer* barrells, with fewer ports, in an attempt to increase the size of that air column (and thus make things more effective). It's easy to take what the so-called "experts" say as being correct. Maku Mozo!!! Hey I was just confessing to repetting what I was told. This may make me question everything, or keep my mouth shut when I am asked a question Edited February 8, 2006 by AlamoShooter Link to comment Share on other sites More sharing options...
XRe Posted February 8, 2006 Share Posted February 8, 2006 Hey I was just confessing to repetting what I was told. This may make me question everything, or keep my mouth shut when I am asked a question Sorry, Jamie This was just the only bit not covered above, so I thought I'd contribute.... slightly at your expense.... Best bet is to question everything!!! Link to comment Share on other sites More sharing options...
Radical Precision Designs Posted February 8, 2006 Share Posted February 8, 2006 Well, well, well... !!! ??? I wish I had been around when this thread started. I definately would have had my two cents to add. During that time I was right in the middle of R&D'ing my "Hyper-Jet Comp", which since then has been discussed to some degree in these forums. I had to address the same issues and "physics" to get the right engineering specs for this design, which is based in mingling both sets of approaches to compensation. Specifically, to find the way for the "jets" to become "hyper" and work the baffles for redirected motion. I hope my posting this "knowledge" here is not viewed or contrued as "advertising". Far from it. It has been a discussion of the effective workings for a compensator's idiosyncracies, and the how and why. There has to be a progress in technology that we all can benefit from. I may be a "pro" in the field, but I am also a shooter, and a user of this equipment and various approaches to technology. Without expressed input/output there can be no forward gain/movement for us all to benefit. Specifically, lately there has been a tremendous demand for "shorties" and "lighties", which now have sent in a new frontier to be conquered by various approaches to the same old dilemma. Only good can come from discussions such as these. More and more "new" open guns are being either made or retro-fitted with "popple-holes" or hybrid barrels than ever before, sometimes even in "ill-advised" applications. Sometimes not. It would behoove for us all to really look at what can help us in our sport rather than just blindly support what we have been using for ages. This is the twenty-first century, ain't it ? Maybe, now that this thread has been resurrected, we can discuss and examine what has transpired since this discussion started "a year ago". I, for one, vote and say that "jet" technology has come a long way to enhance our compensating efforts for "fast/accurate" shooting. What say y'all? Link to comment Share on other sites More sharing options...
Matt Cheely Posted February 8, 2006 Share Posted February 8, 2006 From the looks of the picture in Bseevers new gun topic. I'd say it looks less like a jet and more like a nuclear bomb going off... Has anyone studied how the gases exit from the comp in a slow motion video capture, or using computers to simulate the gas flow? I'd be interested to see how the flow actually propogates from the barrel and it's interaction with the ports. Link to comment Share on other sites More sharing options...
ipscbob Posted February 8, 2006 Share Posted February 8, 2006 I, for one, vote and say that "jet" technology has come a long way to enhance our compensating efforts for "fast/accurate" shooting. What say y'all? OK.....I'll bite Just how does your compensator design differ from others? Pictures might be helpful as well. Link to comment Share on other sites More sharing options...
Radical Precision Designs Posted February 9, 2006 Share Posted February 9, 2006 I, for one, vote and say that "jet" technology has come a long way to enhance our compensating efforts for "fast/accurate" shooting. What say y'all? OK.....I'll bite Just how does your compensator design differ from others? Pictures might be helpful as well. There are a couple of other threads here that have touched in the discussion of my Hyper-Jet Comp to some extent. My main interest is to utilize this technology, which is not really new, but its application and evolvement is. Some of the advantages are indeed obvious. Here is a picture that was used in a prior thread: This particular set-up uses four "hyper-Jet" chambers and just one conventional baffled chamber plus one "torque bleeder" chamber. The Hyper-Jet chambers differ from conventional popple-holes greatly. Popple-holes just vent out high pressure gases and dissipate into the atmosphere creating a downward motion by re-directing a percentage of the normally available rearwards recoil from forward moving gases, but it is still recoil motion nevertheless. In a conventional baffled chamber some of the forward energy is dissipated as gases expand in the chamber by buffeting the baffles creating a somewhat dampening effect in the rearwards recoil impulse. In a coventional baffled chamber the high pressure momentum is mostly lost as the gases expand at "released surroundings" atmosphere pressure, and then get mitigated by buffeting the baffles into a shared blend of recoil softening and recoil/motion redirecting. Not a bad use of the energy available in the hot expanding gases, by the accepted existing standards. In the Hyper-Jet chambers the high presure gases get directed both down, around and upwards by the bottom jets and up and forward against the front baffles by the top jets, with a venturi assist for dispersion and redistribution of pressures against the same baffles. Hyper-Jet chambers control and maintain the high pressures for a more controlled utilization of these high pressures, not just to help control perceived recoil, but also to continue pushing the bullet out of the barrel for an increase in bullet exit speed. The example shown also shows additional popple-holes in the barrel, but that's another story. Different variations, are also possible, of course by either increasing or decreasing the number of Hyper-Jet chambers or frontal conventional chambers, etc. There is also the Schuemann "tribrid" which uses it's own take of direct porting within the rifling and and the use of conventional baffled chambers. More and more of the newly made open guns sport some sort of "porting" in addition of their conventional comps. Why is that? Link to comment Share on other sites More sharing options...
Harmon Posted February 9, 2006 Share Posted February 9, 2006 were the first comps really just barrel weights used to cut down on the amount of recoil spring needed to operate the gun with a major load...then someone cut a port in one of them to vent gasses? neat stuff anyways... Link to comment Share on other sites More sharing options...
tightloop Posted February 9, 2006 Share Posted February 9, 2006 Yes, they were just weights at first... Link to comment Share on other sites More sharing options...
XRe Posted February 9, 2006 Share Posted February 9, 2006 (edited) Popple-holes just vent out high pressure gases .... Now, Venry, Bob's made it clear that it's only a "Popplehole" if he makes it.... :lol: I kid, I kid... That's a very interesting design - I didn't realize there are bottom ports in the hyper-jet chambers, too?? I know you did some modeling on this design - what would happen if you just had a bottom port in the barrel venting into each chamber, or, alternately, side ports?? It's strange how, even though there are holes in the barrel, the bullet continues to accelerate as long as it's inside the rifling. I've got the same phenomenon in my gun - and it was more noticeably in the 6" barrel version of it I used to have... Maybe someday we'll meet up and can compare technologies. My gun has a one chamber, two port comp - little teeny tiny thing - and yet, with appropriate loads, shoots as soft and flat as a big ol' honkin comp on a long gun (seems like N105 is the magic, at current major ... wonder if I can make it with H110... ). The porting makes a huge difference on mine... (and thus the need for *gas* ... gotta feed my gun beans, or something... Edited February 9, 2006 by XRe Link to comment Share on other sites More sharing options...
Radical Precision Designs Posted February 9, 2006 Share Posted February 9, 2006 (edited) Popple-holes just vent out high pressure gases .... Now, Venry, Bob's made it clear that it's only a "Popplehole" if he makes it.... :lol: I kid, I kid... That's a very interesting design - I didn't realize there are bottom ports in the hyper-jet chambers, too?? I know you did some modeling on this design - what would happen if you just had a bottom port in the barrel venting into each chamber, or, alternately, side ports?? It's strange how, even though there are holes in the barrel, the bullet continues to accelerate as long as it's inside the rifling. I've got the same phenomenon in my gun - and it was more noticeably in the 6" barrel version of it I used to have... Maybe someday we'll meet up and can compare technologies. My gun has a one chamber, two port comp - little teeny tiny thing - and yet, with appropriate loads, shoots as soft and flat as a big ol' honkin comp on a long gun (seems like N105 is the magic, at current major ... wonder if I can make it with H110... ). The porting makes a huge difference on mine... (and thus the need for *gas* ... gotta feed my gun beans, or something... Yes, I did quite a bit of R&D with different configurations to find the optimum balance. I will use the analogy of an exhaust system in a internal combustion engine, more specifically a "tuned" exhaust system. In a tuned exhaust system you do not eliminate completely the back pressure from escaping gases as that "backpressure is needed for the specific performance of the engine and "gas economy". Unlike a race engine with an "open exhaust" which gobbles up fuel and sends a lot of it "unburned" without any benefit out of the exhaust pipe, and just like many compensators (with a particular load) with a huge fireball. By restricting the actual exit of the gases they can be managed for a better performance and utilization of the fuel/powder for the common goal. I used the expression "poppleholes" as it is mostly understood here. (Thank you Bob ) Personally I prefer the terms: "vent ports", "pressure relief ports", or "jet ports", but each of these definitions/names can be made to mean quite different functions. Dave- Actually, I would like to hear some more about your set-up. After all, this forum is to exchange ideas and information about our experiences... ??? Edited February 9, 2006 by Radical Precision Designs Link to comment Share on other sites More sharing options...
shred Posted February 9, 2006 Share Posted February 9, 2006 I like it.. I've been toying with some compensator designs that redirect muzzle gases in interesting directions to get more work out of them (think 'sidepipes' or scavenging headers), but really the main problem is the power pulse available from the powder gases is far shorter than the recoil cycle and there's a minimum level of recoil needed to cycle the slide and feed another round off a big stick (not that far below 7 lbs). It is possible to make a 1911 comp that comps so well the gun won't cycle, but what's the point? (as an aside, I've heard that some low-PF Bianchi guns now have gas-assist for the slide coming off the back of the comp because there wasn't enough energy available from the recoil) Check out this video: http://www.sscmagnum.de/Video/008tanf.mpeg It's a Tanfoglio, but I believe they cycle somewhere around 0.06 seconds like a 1911. If you slow-mo through it, notice how little time the comp actually can do anything during that cycle time... it's only a few frames of what's probably 1000 fps video. Link to comment Share on other sites More sharing options...
ipscbob Posted February 9, 2006 Share Posted February 9, 2006 Venry, thanks for the info. I had missed the previous thread. Very nice indeed and thanks for sharing the rationale behind the concept. I have a spare open gun right now that is begging for a new barrel and comp. Ill PM you for details. Link to comment Share on other sites More sharing options...
XRe Posted February 9, 2006 Share Posted February 9, 2006 Check out how much of the gas is going up, too. By the time the gun has unlocked, the bullet is way gone, and so is the gas... and, yeah, you have to have *some* recoil impulse... Here's something to consider, though - a lot of folks run light recoil springs in an effort to get the gun to shoot flatter. A 7# or 8# recoil spring is only going to store 7 or 8 pounds of energy to use to close the gun. How much energy is being dissipated when the slide reaches the end of it's travel and hits the guiderod head or recoil buffer? Seems like you could still make effort to dissipate most of *that* energy, as well, as long as the gun still unlocks and starts to cycle. Link to comment Share on other sites More sharing options...
Radical Precision Designs Posted February 9, 2006 Share Posted February 9, 2006 (edited) I like it.. I've been toying with some compensator designs that redirect muzzle gases in interesting directions to get more work out of them (think 'sidepipes' or scavenging headers), but really the main problem is the power pulse available from the powder gases is far shorter than the recoil cycle and there's a minimum level of recoil needed to cycle the slide and feed another round off a big stick (not that far below 7 lbs). It is possible to make a 1911 comp that comps so well the gun won't cycle, but what's the point?Check out this video: http://www.sscmagnum.de/Video/008tanf.mpeg It's a Tanfoglio, but I believe they cycle somewhere around 0.06 seconds like a 1911. If you slow-mo through it, notice how little time the comp actually can do anything during that cycle time... it's only a few frames of what's probably 1000 fps video. Yes, Roy. A little "side product" of conventional compensators is that the softer (reduced rearwards motion) they shoot the "weaker" the recoil spring needs to be to allow proper cycling. (Hence the recent move towards faster/snappier powders.) As you point out, balancing the bullet trajectory "dwell time" to the gases baffle dampening requirements during the same period can be offset negatively by the (volume of) gases working to make the gun shoot soft, as the "softer" shooting gun (in theory) would be forced to cycle slower. Some might say that this is a desirable goal if maximum compensation is what you seek. BUT, then your "splits" (in theory) might suffer for the same end result. That is if you really have such a fast trigger finger. A "tuneable" compensator might on the other hand provide you with the best of both worlds, by reducing the requirements of the actual volume of gases neeed for the particular level of compensation, since it works in utilized (high) pressure rather (high) volume. You see high pressure "dwells" for a shorter time, while high-expanded (lower pressure) volume dwells longer. I like to use the parallel analogy of a base-ball being catched at 25 mph or at 90 mph. Compensator/barrel "bottom drag" comes into play also when considering recoil spring weight needed for the cycle time. In theory (and in practice too) if you were to eliminate "all" rearward recoil motion by your compensator (or a very heavy spring) your gun wouldn't cycle at all. That's what I call a real "catch 22". There always will be a "need" for rearward effective/perceived recoil, depending on the total mass being displaced for the gun to work/cycle. Indeed, there is always a price to pay/exchange. Edited February 9, 2006 by Radical Precision Designs Link to comment Share on other sites More sharing options...
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