Compensator Question

[Bear1142]

Okay, I've been working on this for quite some time but I'm having some trouble reasoning it out. With respect to compensator design (rifle and pistol), should the chambers on the compensator decrease size or increase in size as they get further away from the muzzle? I understand that with respect to gas flow, there is an inverse relationship between gas volume and gas pressure. As your pressure goes down, you need more gas volume to maintain the same gas flow. How does chamber size affect this? Should your chambers increase or decrease in size to maintain your gas flow?

Erik

[shred]

My guess is that in reality it doesn't matter, but in Theory (that little town where everything works), every port bleeds off gas, so to get the same amount of gas (pressure * volume) in each port (assuming you want that and that it's even achieveable with a bullet in the way), they would need to get larger.

[L9X25]

My guess is that in reality it doesn't matter, but in Theory (that little town where everything works), every port bleeds off gas, so to get the same amount of gas (pressure * volume) in each port (assuming you want that and that it's even achieveable with a bullet in the way), they would need to get larger.

I believe that a large portion of the gasses escape during the first port or two (depending on the acutal port sizes) and most designs attempt to keep the flow velocity up at the subsequent ports. To accomplish this they reduce the size of the ports to keep the flow velocity up despite the decreased pressure/volume of gas they have to work with. Some designs throw in a huge final chamber to get rid of whatever gasses might remain before they exit the muzzle hole.

Edited July 3, 2006 by L9X25

[wsimpso1]

Your description of the physics IS interesting...

The device works by turning the gases. Assuming a brake on a gun with a clean muzzle and then a brake, In sequence, (and risking explaining the obvious) you get:

One momentum change as the gases exit muzzle, and this one pushes back on the barrel;

Another momentum change as expanding gases get turned to the sides by hitting the back side of the first baffle, and this pulls forward on the barrel;

Another momentum change as the remaining gases clear the hole in the second port, and this one pushes back on the brake;

Another momentum change as those gases get turned by hitting the back of the second baffle, which pulls forward on the brake;

And so on.

Now let's get a few things straight here. You are not concerned with maintaining flow velocities. Nope, not at all, you want to change the direction of the flowing gases as much as possible.

So how to do it. Hmmm. First we have to know that the speed of sound in a gas is related to its temperature, and the speed of sound in the gun gases at the muzzle is quite a bit (1.5x to 2.5x) above the muzzle velocity as the bullet uncorks the end of the barrel, after the gases expand without heat exchange with the surroundings, but as they expand the temp drops and so does the speed of sound. And this happens very quickly after the bullet leaves the bore. Next part is that except in very specific circumstances (this IS rocket science) gases will not flow faster than their local speed of sound. So, if the gases are expanding rapidly, it will be cooling rapidly and its speed will drop rapidly.

So, to get those gases to transfer as much momentum as possible, you want the gas up to speed, but no more than that. For high temp gases on the first baffle of both open gun ports and on rifles, a lot of folks think that 1/2 to 1 caliber is about right. Untill the bullet passes through the first baffle, very little gas gets through to the second chamber.

Once the bullet clears the first baffle, much of the gases will flow through the first baffle and enter the second one. The next chamber will get the gases that come out of the first baffle instead of going out the sides, the temperatures (and velocities) will be somewhat lower here, but there will still be a lot of gas coming out. Some folks think that another 1/2 to 1 caliber chamber is about right, while others have demonstrated to themselves that the second baffle should be further out than the first... This make sense, with less pressure available to drive the gases up to speed, they will accelerate up to local sonic more slowly, and local sonic will be lower too, so you might need a bigger chamber. Anyway, the gases keep getting their directionchanged abruptly by the second baffle until the bullet clears it too.

And so on with third (and fourth, and so on) baffles. With lower and lower temps and pressures and sonic velocities available, at some point, you quit seeing benefit and stop adding baffles.

Interestingly, on pistols, several baffles spaced the same distance apart is the norm, while in rifles, some brakes have baffles equally spaced, and some have short distance on the first, longer to the second, and still longer to the third, and we do have max size rules on rifle brakes (for non-Open guns). Alex Wakal's brake is an example of this...

I hope that helped...

Billski.

[tightloop]

Wow...sounds like rocket science to me...

[EricW]

BTW, this isn't a physics question. It's a mechanical engineering question. And the design of most comps on the market is damning evidence that a true mechanical engineer has yet to tackle the problem.

Edited July 4, 2006 by EricW

[Radical Precision Designs]

BTW, this isn't a physics question. It's a mechanical engineering question. And the design of most comps on the market is damning evidence that a true (????) mechanical engineer has yet to tackle the problem.

Maybe you are not looking enough????

Edited to add: ...perhaps handling "all" the gases "after" they exit the barrel is akin to monday morning quarterbacking...

Edited July 4, 2006 by Radical Precision Designs

[gans]

Okay, I've been working on this for quite some time but I'm having some trouble reasoning it out. With respect to compensator design (rifle and pistol), should the chambers on the compensator decrease size or increase in size as they get further away from the muzzle? I understand that with respect to gas flow, there is an inverse relationship between gas volume and gas pressure. As your pressure goes down, you need more gas volume to maintain the same gas flow. How does chamber size affect this? Should your chambers increase or decrease in size to maintain your gas flow?

Erik

WHAT DO YOU WANT? There is a difference between a rifle muzzle brake and a pistol compensator. A brake is usually designed more to reduce recoil and the compensator to reduce the muzzle flip. The pistol comp must be designed so that it doesn't inhibit the cycling of the slide also. I will address the pistol comp. WHAT DO YOU WANT? The standard 1/4" ports work good with all calibers. Bigger ports work better with higher velocity bullets since all the gas doesn't need to make as sharp a turn upwards and there is more room to get rid of more gas. However, there will be fewer baffles since the ports are bigger. Having more baffles will lessen the recoil. You can add big bleeders to the front end to lessen the recoil even more by getting rid of as much gas as possible. WHAT DO YOU WANT? Do you want a small compact comp for carrying or do you want a big comp for competition? The bigger comp will be more efficient. Remember, as it gets bigger it will push down harder on the slide and will slow down the cycling speed. You can only go so big on the comp before the slide will not cycle. You can machine the slide down to reduce the weight so that a large comp can be used. Some comps even have the recommended weight of the slide listed with them. WHAT DO YOU WANT? A big heavy full profile comp and/or bull barrel will add extra weight up front if that is the feel that you want. It will also slow down the cycling speed since the slide must pull all the extra weight back and down out of the way before it can cycle. A lighter comp/barrel will have a lighter feel up front and it will not impede the cycling as much as a heavy setup. WHAT DO YOU WANT? You can come up with an unlimited number of combinations that will work good. It depends a lot on your preferences. You can do your homework and figure out what you like/want and build a custom gun. Or, you can have someone else do it for you and just buy a prebuilt gun. WHAT DO YOU WANT?

[shred]

BTW, this isn't a physics question. It's a mechanical engineering question. And the design of most comps on the market is damning evidence that a true mechanical engineer has yet to tackle the problem.

I think the trick is that it doesn't really matter.

Scoping some high-speed video of comp guns firing, the comp 'action' takes place almost instantly (at 1000 frames per second it's all in one frame), and far before the gun moves in recoil. A pokey 1350 fps bullet goes right through a 3" comp in 0.0002 of a second or so.

The ports need to be big enough that the gas expands enough to hit a useful amount of the baffles and not waste a lot, but that's about it.

[Radical Precision Designs]

BTW, this isn't a physics question. It's a mechanical engineering question. And the design of most comps on the market is damning evidence that a true mechanical engineer has yet to tackle the problem.

I think the trick is that it doesn't really matter.

Scoping some high-speed video of comp guns firing, the comp 'action' takes place almost instantly (at 1000 frames per second it's all in one frame), and far before the gun moves in recoil. A pokey 1350 fps bullet goes right through a 3" comp in 0.0002 of a second or so.

The ports need to be big enough that the gas expands enough to hit a useful amount of the baffles and not waste a lot, but that's about it.

A little bit simplistic... I wish it was that simple, really. Perhaps is that high/low understandin/expectation that has indeed stunted the availability of better working designs. (?)

Actually there is plenty to work with, as there is so much "raw" energy that can be tailored to do, oh, so many little things. Most of the technology used in compensators nowadays is "modular" and borrowed/modified from existing technology in other usable subjects. Quite a few "mechanical engineers" have looked at the subject of compensated competition pistols. But frankly, any well meaning "M.E." would rather look at the whole package instead of just the shooting end, for what the interaction of the components in their totality will accomplish with the task at hand, and not just one component.

Very often the problem (if there is a problem?) is that the customer wants to pay just barely above the cost of a good Limited pistol for a top of the line "newfangled" Open pistol. Or, figures that you only need to hang on a "discount store" readily available "all purpose" comp and a red dot, and, Bingo: you've got yourself an open gun. Yeah, you've got yourself an Open gun ... according to the "rules". But not according to the winning edge needs of the developing/improving/growing game. There has been a lot of technological improvement in this subject, but usually only as far as the "market" can bear to pay for, and is economical/profitable for the pistolsmith to build. As always: Maku Mozo!

If you look closely, there are a few of us, ( some of us actual M.E.'s) that have been busy doing R&D and building some damn good Open shooters, with state of the art compensation systems incorporated into them. Please, do not say or imply, that we've been seating in our "arses"...

Edited July 4, 2006 by Radical Precision Designs

[sfinney]

Max is winning championships with an STI Trubore T-2 comp I believe..... pretty off the shelf stuff.

Not to say that a better comp couldn't/shouldn't be designed.... but is a one off custom $1000 comp really that much better than a $100 one at the end of the day?

Edited July 4, 2006 by sfinney

[EricW]

Shred,

All I'm saying is that a good mechanical engineer would come up with a very good definition of what the relative port volume should be relative to distance from the muzzle (bbl -not the comp). There is a rule to be found.

[Radical Precision Designs]

Max is winning championships with an STI Trubore T-2 comp I believe..... pretty off the shelf stuff.

Not to say that a better comp couldn't/shouldn't be designed.... but is a one off custom $1000 comp really that much better than a $100 one at the end of the day?

Max could very well go out there with the most mediocre design available (which the S-2 is not!) and win hands down every time. He is a "phenom" in this game. So is Todd Jarret, who can have just as great a show with no comp at all. But where does that compare with us "mere mortals"? They both make a living with what they do, and are paid to go and push a product, regardless of their merit. (This is a generality, not necessarily applied to either STI or Para, Ok?) Yes, I know Max shoots for the Army ... etc. Their performance should by no means indicate that most of the designs available off the shelf for $100.00 are on par with those costing $1,000.00. On the hands of a capable, trained competitor they will both do well, but the question is whether the potential of both the competitor and the equipment is on its optimum possible return???? I have seen some competitors with great equipment on the field, having all kinds of problems with malfunctions, etc. including procedurals and the sort. I wouldn't fault the equipment, just the shooter. But some people will say that the equipment did not help them. Well, it wouldn't have mattered whether it was a $100.00 or a $1,000.00 comp at the end in those cases. On the other hand ...

EricW Posted Today, 12:47 PM

Shred,

All I'm saying is that a good mechanical engineer would come up with a very good definition of what the relative port volume should be relative to distance from the muzzle (bbl -not the comp). There is a rule to be found.

... I am still mulling over the relevance of this statement... Preconceived notions do not make much headway here. As they say different strokes for different folks ... or, there are different ways to skin a cat... or, as some of us say: "modified formulas for modified uses/loads"... You still need to look at the whole picture, not just hang a piece of machined exotic metal (with magical properties) on your muzzle, and expect miracles. In lay terms: While there may be a specific formula that if followed to the 'T' would deliver the goods, don't expect it to be dissected here. You will get some explanations, but never enough ingredients unless you "buy the cow".

...I will give you a parallel illustration. A "one" cylinder engine can deliver the same horsepower as a two, three, four, five, six, (seven?) eight, ten, twelve, or even sixteen cylinders if constrained by a horsepower limit. Then you must consider the efficiency, friction, "smoothness" and cost ($$) to realize which one will suit your needs. But if you go further you can see that the larger number of cylinders per horsepower can make for a more predictable, controllable use of the horsepower, and a much nicer enjoyable ride within the available power range. Then again, a whole bunch of "inefficient" cylinders would just ad unnecessary drag to the system, robbing it of performance, while that one solitary cylinder would require well balanced counterweights or self destroy itself. Thought has to be put into any final product design, rather than just innuendo or hype for it to deliver the goods. Again, Maku mozo.

[Bob Hostetter]

While not wanting to start a flame war here............

While the gentleman from Radical Precision Designs is giving us a lot of interesting verbage, and the gentleman from Gans is doing the same thing, I have yet to see anyone offer anything substantial in response to the question.

I had thought that this was both an honest and interesting question, and was hoping for some serious input from anyone wishing to step forward and offer an answer/opinion. Comp design has been stagnet for sometime now and it would have been interesting to hear some serious discussions on current design's and the thinking behind them.

Too bad, all we seem to be getting is reassurances that everyone is smarter then we thought........

[George]

Again, Maku mozo.

"No Delusive Thought - Don't Daydream" is how I perceive the meaning of the words "Maku Mozo". Turning that phrase into a version of the corrupted usage of "Semper Fi" as practiced by most Jarheads is a new one on me.

BTW, billski has hit the nail on the head. The speed of the gas is the "crux of the biscuit" here. The first chamber is where the main event happens as the initial wavefront passes the projectile as though it is standing still. The rest of the chambers are a sideshow compared to the first puff of supersonic gasses slamming into the 1st baffle. Look at the carbon buildup and the erosion rate at the hole in the first baffle as opposed to the second one on a JP tank brake and you will see where the major portion of the work is being performed.

The trick with additional baffles/chambers is to know the distance required for the gas to regain it's maximum velocity for a given temperature. This is the distance the baffles need to be at for additional chambers and as billski noted this distance increases as the temperature of the gas drops.

[Radical Precision Designs]

As some readers that have read some of my previous posts regarding comps and comp designs have noticed, enough to PM me for a more concise exchange, this is not something I have taken on lightly. I have also received a PM to refrain from posting something that could be construed as direct advertising. Although I would like to be more open in regards to my own R&D, I have yet to establish the 'Dealer-Forums' venue required to do so, in so many words. I am working on it.

Still, if someone was to do the search, enough would be found in my posts to "pique" and satisfy your questions. Yet, there are others who have also broken away from the "stagnant" attitude but will not make their research noted, for whatever reasons.

As for my use of the "Maku mozo" expression... I have the utmost respect for our host Brian Enos, and indeed endeavored to relay his/mine concern with folks being deluded, or herded into something not readily obvious. Like the take on Max Michel and his shooting prowess interpretation.

Why haven't we heard from some of the 'expert' folks eavesdropping on this subject, other than try to glean something useful, without contributing?

Frankly, the present day technological advances are there in plain view. While improvements have been made in some otherwise previously 'stagnant' designs with new variations, there have been others completely new. Or a combination. Barrel porting, while not specifically part of the comp "appendage" seems to be universally utilized in most new Open guns, whether as direct port/poppleholes, or hybrid (Schuemann) set-ups. These seem to work very well as part of the "package" I previously referred to, to further improve the performance of an otherwise lacking or innefficient comp being used.

The question as posed was leading 'only' with regards to the "muzzle compensation unit as a complete system" and elicited responses in that area exclusively, putting aside or not including any other possibilities. Instances were used where the comparison was made between heavier comp/barrels and light cone/comps, noticing that the weight of the barrel was instrumental, yet the enphasis was put on the comp only. This one-sided request ignoring other elements of significance is not conducive to good research, or findings.

As Bob noted, it is not a good thing to try and start a "flame war" here, for it would be self defeating, with their protagonist expressing their oppininons while ignoring all other possibilities. This would close more minds than open them . A "loyalty war" also would ensue. Probably nothing new would be learned, for no one would come forth with anything worth discussing for fear of being torn down unnecessarily.

I wish more candid, open discussions were available here from any well meaning protagonist where new technologies or developmets are concerned, for their own merits rather than being told to:"forget about it and just go to _________ and/or buy a _________ for there is nor will ever be anything better..." The subject of how a "conventional muzzle end" comp works or the physics behind it has been discussed here a few times before, with "mumbo-jumbo" included. I am sure some of our more diligent/observant posters could post some links here. But to say that no progress has been made as a blanket statement ...??????? Makes some of us loosen up and take notice, even though we can't post advertising leading posts.

[George]

Hate to be obvious again, but billski answered the original question quite nicely and with enough "hard intel" that anyone who wants to can figure out the rest.

A lot is obvious upon further inspection here, such as the first baffle being just far enough from the barrel exit to allow the gases to get up to their maximum speed, but not so far that a lot of gas flows through the port in the first baffle ahead of the projectile and disturbs it's stability, that's bad accuracy juju. As billski properly pointed out, the gas is moving faster than the projectile at this point and this is the basis for the next baffle wanting to be close to caliber in distance from the bbl exit (as billski also mentioned). The bbl crown used also has a part to play in which direction away from the bore the initial gas wavefront is traveling and therefore what angle it impinges on the first baffle at.

In considering the discrete force applications involved in opposite directions at different points in the projectiles passage of the brake chambers (also as billski described), it should be noted that some AR brakes (like the JP Tank one) have larger hole sizes in the first baffle that don't seal as completely as the final exit one does. My supposition is that John Paul is aware of the reverse force applied as the projectile uncorks the 1st chambers high pressure contents and he is lessening this effect by keeping this port open a bit. This may disturb accuracy some, but probably not enough to matter to most of us.

Regards,

[EricW]

BTW, this isn't a physics question. It's a mechanical engineering question. And the design of most comps on the market is damning evidence that a true (????) mechanical engineer has yet to tackle the problem.

Maybe you are not looking enough????

No. Between all the random variations with what the market has to offer and this thread (billski excluded), I stand by my original statement.

There's a difference between what works, and the optimum solution. One involves hunting and pecking. The other involves understanding the objective and the underlying mechanics and mathematics.

Still waiting...

[Flexmoney]

There was such a comp. It wasn't machined, it was molded (or, machined in two pieces)? And, it was a bit heavy. I don't know how well it works, but I have one of them around here someplace.

Here is the website: http://www.bp-tec.com/info.htm

[gans]

BTW, this isn't a physics question. It's a mechanical engineering question. And the design of most comps on the market is damning evidence that a true (????) mechanical engineer has yet to tackle the problem.

Maybe you are not looking enough????

No. Between all the random variations with what the market has to offer and this thread (billski excluded), I stand by my original statement.

There's a difference between what works, and the optimum solution. One involves hunting and pecking. The other involves understanding the objective and the underlying mechanics and mathematics.

Still waiting...

With all due respect, maybe there isn't one rule or formula that works for all compensators. There are too many variables as I alluded to in my first reply. Remember, the question was about rifle and pistol compensators. Maybe we should narrow down the original question a bit and go from there.

[Radical Precision Designs]

Okay, I've been working on this for quite some time but I'm having some trouble reasoning it out. With respect to compensator design (rifle and pistol), should the chambers on the compensator decrease size or increase in size as they get further away from the muzzle? I understand that with respect to gas flow, there is an inverse relationship between gas volume and gas pressure. As your pressure goes down, you need more gas volume to maintain the same gas flow. How does chamber size affect this? Should your chambers increase or decrease in size to maintain your gas flow?

Erik

Ok. Uncle!!!!!!!!!!

In re-looking at the Erik's question above. With regards to "rifle and pistol" on compensator design, and disregarding the workings of ammo self-feeding, and no other criteria available other than the named muzzle installed contraption ... and not withstanding the former design tendency of multiple equally sized large chambers, and present tendency of larger first and decreasing thereafter... (and I quote the above) "As your pressure goes down, you need more gas volume to maitain the same gas flow. How does chamber size affect this? Should your chambers increase of decrease in size to maintain your gas flow?"

First, let's look at what is happening after powder ignition through to bullet passage and exit in such "compensator. The key word is COMPENSATOR, not muzzle brake. Correct me if I'm wrong, but it is my understanding that a "compensator" is expected to do both acts of controlling muzzle jump/flip and perceived recoil reduction, in one neat package. As such a compensator is expected to divert and manage available energy within these gases to exert downwards and forward leverage to accomplish this. This is the usual goal. The question posed above is related to what SIZE (chambers)is more efficient to "maintain your gas flow". The request here would dictate to look into maintaining this gas flow as a goal.

To give an illustration (in Billski's strain): When the powder ignites and creates ever expanding self heating gases by such combustion it creates pressure which will accelerate the interjected bullet in its escape route (the barrel), pushing it out of the way so that it can reach equilibrium with atmospheric pressure and cease its transitory existence as all available fuel (powder) is consumed. No more, no less. Beginning and end. How do we manage/route/coach those gases with the "assistance" of the bullet is secondary to this life span. (Has anyone shot blanks through a compensator??)

As the bullet reaches the barrel's exit point (crown) both the gases and the bullet are travelling at the same speed, which is controlled/impeded by the friction/fit of the barrel's rifling. Some of the gases have actually "sneaked" through around the bullet and are leading in front of the bullet, but these are minimal, although they do serve a purpose not unlike the nacelle in a jet-plane. These leading gases initially are moving faster than the bullet or the main mass of gases behind it, but will expand rapidly, cool off, and just as rapidly slow down to the "local sound speed" to the point of being pushed by the bullet. But they do blaze a path, through the barrel and then the comp. Now comes the fun part. Both the bullet and the gases are free fom the barrel's confinement/restrictions, and now can behave by their physical make-up. The bullet now still being pushed by the gases will accelerate some more untill the gases start loosing speed and area in which to push. The gases not being cohesive will expand to atmospheric pressure, and the bullet will go in its merry way untill the friction with the air and gravitational pull will bring it down to the ground.

The real "works" start when the bullet base if forward enough of the crown and the gases can expand uninpeded. These gases do have substance and mass, but are maleable to the surroundings. But as "mass" their initial momentum is forward as they reach the crown, at which time they can utilize their malleability to expand, continued-combustion-accelerate, push the bullet, and even push forth around and in front of it some. But the bigger mass is behind the bullet. Normally, even in large chambers the distance travelled from crown to first baffle is short enough for the bullet to occupy both places before the bullet base clears the crown. This effectively seals that path and forces the gases elsewhere untill that path is available again. As Billki noted, this is a diminishing rettuns effort. But for one exception. This exception is created by the powder charge and its rate of burn. A lot of the powder is still burning as it follows the bullet through the baffles. Diminishing progressively, but still there, creating usefull "hot" expanding gases. Usually you will notice a plume of fire emanating from the front of the compensator when a continuing/slower burning powder is used. While some may argue that this "residual" burning powder doesn't do much to affect usefull acceleration pressure, it does indeed do some to maintain the temperature of the gases.

So my answer is that if the correct powder is used it will maintain the gas flow through the compensator. The size of the chambers will be dictated by the expected need of the performance seeked. But to be specific: if the gases are available, and pressure/volume extended further by the powder used, then continuos large chambers would be usefull ... to the point of diminishing returns.

(Edited to ad: This is my answer to the initial questions posed, but in no way reflects my views in optimum performing "compensating systems" which should encompass the whole, rather than just the front unit commonly referred to as a comp. )

Edited July 4, 2006 by Radical Precision Designs

[Jaxshooter]

I have an STI Stinger 38 super Open gun that was mediocre at best from STI. It now has a custom top end( barrel and comp) designed built by Radical Precision. The pistol is very flat shooting with no muzzle flip and is extremely soft recoiling. The barrel and comp are nothing like anything seen on the market today. There is research and developement being done today. You just have to find the smiths that are exploring this area.

[gans]

While not wanting to start a flame war here............

While the gentleman from Radical Precision Designs is giving us a lot of interesting verbage, and the gentleman from Gans is doing the same thing, I have yet to see anyone offer anything substantial in response to the question.

I had thought that this was both an honest and interesting question, and was hoping for some serious input from anyone wishing to step forward and offer an answer/opinion. Comp design has been stagnet for sometime now and it would have been interesting to hear some serious discussions on current design's and the thinking behind them.

Too bad, all we seem to be getting is reassurances that everyone is smarter then we thought........

What do you want to know?

[Bob Hostetter]

What do I want to know? Personally? I want to know the design spec's for a comp that totally eliminates muzzle flip, reduces rearward felt recoil to a level equal to a .22 rimfire while still maintaining a very high slide velocity. It would be nice if it didn't weigh more then a couple of ounces and was less then an inch in length. Then I would patent the design, CNC a couple 1000 of them, and sell them for a small fortune.

Oh, wait a minute, sorry, just kidding, got carried away for a minute...............

I think the orginial question was basically, "given a static amount of gas pressure and volume, does the effiency of the comp increase or decrease as port length relative to the barrel bore centerline increases or decreases".

[gans]

Okay, I've been working on this for quite some time but I'm having some trouble reasoning it out. With respect to compensator design (rifle and pistol), should the chambers on the compensator decrease size or increase in size as they get further away from the muzzle? I understand that with respect to gas flow, there is an inverse relationship between gas volume and gas pressure. As your pressure goes down, you need more gas volume to maintain the same gas flow. How does chamber size affect this? Should your chambers increase or decrease in size to maintain your gas flow?

Erik

I see that the discussion has been narrowed down to pistol compensators. I have not seen any definition, rule or formula on chamber volume though. EricW may be correct so far. I don't have one to offer either. I don't know that one exists because of the variables.------I agree with the basic theory of how a comp works, that R.P. submitted.------That is just the beginning as the design of a comp is different for a pistol used for Pinshooting from that of an open gun or a steel gun.------Also, the design of the ports can be varied to get different results. Bleeders and smaller ports to get more baffles for a decrease in recoil.------Different designs for different calibers and different power factors.------Oh, so much more.