3 port Comp for 9mm Major?

[ExtremeShot]

I recently had a discussion with a buddy that recommended a 3 port comp for a 9mm Major Open gun. If I remember correctly, his reasoning was that the 9mm produced less gas than the 38 Super which typically had a 5 port comp. After doing some searching, I'm not really finding any info to substantiate the 3 ports. ...I did find a couple of threads that talked about cutting a 5 port down to a 3 port to reduce weight.

Has anyone done a comparison of 3 port versus 5 port with 9mm major?

Also, if 3 port is the way to go, why can't I find anyone selling them?

Thanks,

Darren

[Huston in Austin]

I had a Dawson 3 port on a major 9. Took it off and put the normal Dawson comp on ( 4 port w/ side ports on the end chamber ). Liked it much better.

[Flexmoney]

How much gas you have isn't going to be a matter of which brass you use. A bigger factor will be the mass of the powder and the burn rate. Those thing might be limited, somewhat with 9mm.

When I got into this game, the talk about comps was that the last ports weren't doing much work. Guys would test this by puting tape over the last port or two and shooting the gun...to see if there was any gas effect on the tape. (comps were often bigger then)

I've got a KKM barrel and comp on an Open9 Glock. The comp is two up and two to the side, which isn't enough. (Even with a goodly amount of the impossible to find SP2 powder.) I'm not sure I'd go to a shorter comp for weight reduction, regardless.

[jostein jensen]

if the weight of the comp is your game, get one in titanium.

[gans]

You can't find anyone selling 3 port comps??? Interesting.

As Flexmoney alluded to, case capacity and powder burn rate have an influence.

Also to consider are the weights of the slide and comp/barrel and the size/efficiency of the comp.

Some of the current smaller 3 port comps are designed to be used on slides that have not been lighten very much. You can expect a bit more flip from them.

A comp with 3 big vertical ports or a 4 port will be more efficient and shooter flatter, but it will also push down on the slide more. That will slow the slide cycling down more, so the slide should be lightened more to compensate for it.

5 ports??? Some of the comps with 4 big vertical ports are so efficient that they push down on the slide so much that even a lighten slide will barely cycle if it cycles at all.

[mscott]

You can't find anyone selling 3 port comps??? Interesting.

As Flexmoney alluded to, case capacity and powder burn rate have an influence.

Also to consider are the weights of the slide and comp/barrel and the size/efficiency of the comp.

Some of the current smaller 3 port comps are designed to be used on slides that have not been lighten very much. You can expect a bit more flip from them.

A comp with 3 big vertical ports or a 4 port will be more efficient and shooter flatter, but it will also push down on the slide more. That will slow the slide cycling down more, so the slide should be lightened more to compensate for it.

5 ports??? Some of the comps with 4 big vertical ports are so efficient that they push down on the slide so much that even a lighten slide will barely cycle if it cycles at all.

All of that makes perfect sense now. I always wondered why KKM didn't produce a slightly bigger comp for their set-up, but I guess it is probably in the interest of reliability with the stock slide? Interesting.

[Flexmoney]

Yep. You have a tilting barrel, as the gun unlocks. The comp is pushing down on the front of the barrel...bleeding off some of the energy to cycle the gun (which requires the barrel to tilt).

[HSMITH]

8 or 9 grains of ____ is the same, whether burned in a 9mm or a Super. There are some powders like N105 that in a Super will make major and a tremendous amount of gas that you can't use in a 9mm simply because you can't get enough in the case, but for the most part loadings are similar.

[ExtremeShot]

Thanks for all the responses. It sounds like figuring out what works is a trial and error thing. I decided to start by getting a Bedell titanium comp from Shooters Connection (see pix below). It has the 3 vertical and two horizontal ports. I figure if it's too much comp (and I'm not sure how I would tell that it is too much), I could mill off the first and maybe the second horizontal ports.

Thanks,

Darren

[Flexmoney]

I think I just saw a 3-port comp in the classifieds for cheap...fwiw.

[Flatland Shooter]

I think I just saw a 3-port comp in the classifieds for cheap...fwiw.

I don't know if this is the same one you saw Flex, but Philip Dedmon had two STI S1 coned comps for sale. I bought one of them.

The S1 has two ports pointed up and two more (one to the left and one to the right) up near the muzzle. This is the style of comp STI puts on their Trubor and Grandmaster guns chambered for 9 Major.

Bill

[AlamoShooter]

Radical Precision is good at doing technical questions. Send him a note

But with the information on rifle comps and handgun comps the Comp works Not due to the gas going up out of the port. It works with the Gas hitting the {wall} of the baffle the upward part of the gas is minor. the exception to this is the Pop pols that have small openings

You could take a hose clamp and block off the top holes and the comp would still do 95% of what is was supposed to do.

I have only ran a 3 port comp of Steel and now a 3 port with one pop pol =Seams to do OK for me.

Oh hey I don't know nothing

Side note Not to listen any thing I say

I was hammed a few years ago on the forum for repeating what a gunsmith told me about gas / air being pushed ahead of the bullet. In rifle comps as the bullet leaves it {pushes} the air out of the barrel = this air get compressed because it can not leave as fast as the bullet. = just before the the bullet leaves a burst of the compressed air hits the first Baffle and the comp starts to work before the bullet passes.

Apparently this was prov-en in slow motion photos and "they" used that information to develop comps for rifles and tank barrels.

I told a guy that at an event when and I was hammered silly on the forum for saying it. As in Wrong =That could never and never happens. "no magic air" something like "air' does not exits in front of the bullet, And only gas would work on the comp ?Gas? the world is flat

I really don't know, I just delivered the information I collected. and I was not a part of Comp development.

[Jaxshooter]

My custom built 9mm open gun built by Jim Anglin has a 3 port cone comp with 4 side ports. The dot never leaves the glass and it is the flattest shooting open gun I own.

[jjanglin]

EGW will make ya or sell ya all the three port comps ya want.

Jim/PA

Sailors Custom

[Radical Precision Designs]

Radical Precision is good at doing technical questions. Send him a note

But with the information on rifle comps and handgun comps the Comp works Not due to the gas going up out of the port. It works with the Gas hitting the {wall} of the baffle the upward part of the gas is minor. the exception to this is the Pop pols that have small openings

You could take a hose clamp and block off the top holes and the comp would still do 95% of what is was supposed to do.

I have only ran a 3 port comp of Steel and now a 3 port with one pop pol =Seams to do OK for me.

Oh hey I don't know nothing

Side note Not to listen any thing I say

I was hammed a few years ago on the forum for repeating what a gunsmith told me about gas / air being pushed ahead of the bullet. In rifle comps as the bullet leaves it {pushes} the air out of the barrel = this air get compressed because it can not leave as fast as the bullet. = just before the the bullet leaves a burst of the compressed air hits the first Baffle and the comp starts to work before the bullet passes.

Apparently this was prov-en in slow motion photos and "they" used that information to develop comps for rifles and tank barrels.

I told a guy that at an event when and I was hammered silly on the forum for saying it. As in Wrong =That could never and never happens. "no magic air" something like "air' does not exits in front of the bullet, And only gas would work on the comp ?Gas? the world is flat

I really don't know, I just delivered the information I collected. and I was not a part of Comp development.

Thanks for the vote of confidence ...

It is true that compression of the air in front of the bullet will create a front wave that will "lead/pull" ever so slightly into and through the comp. While the influence is slight it exists. But it does not do much for working the comp. Fire a blank through a comp and feel its impact ... Not much, is it. The same way that the bullet creates the varying recoil as it passes through the barrel, it also makes it possible "within its DWELL time inside the compensator's area" for IT to be effective. It is the slower "directional" velocity of the non expanding mass of the bullet as it BLOCKS the space behind it that will cause the " all- directional expanding mass of the burning gas creating charge" to find its (hopefully) controlled expansion and "reacting" chamber/baffle. Everything else will go along the lines of the effectiveness of the design.

As discussed a few times before, the effectiveness of most commonly available handgun compensators seems to be totally irrelevant, as the costs constraints as to what the shooter is willing to pay will determine what the manufacturers will sell over the counter. Kind of a Jack of all trades and Master of none. But ... oh yeah ... you will get acceptable "comping", even if mediocre at best. There is only so much you can stretch a $$ dollar for value received.

As such most of the presently available "over the counter" compensator manufacturers have reached a reasonable consensus as to what seems to be working best for the price charged, and what the customers have learned to accept. I am also in agreement with it. That consensus indeed IS the three chamber comp with a front horizontal bi-baffle as epitomized by STI S-2 design.

My own Hyper-Jet Comp System incorporates a maximized design use of a two baffled chambers with the forward horizontal bi-baffle in front of the hypered-jets, baffled barrel chambers.

As for the the available case capacity for slower/bulkier powders in the Major 9 ?? Most Major 9 users have found that it is mostly irelevant, as the present power factor limits make it possible to have quite a few choices of powder that work readily available. Only a few powders are not viable, and then only if the very light bullets are used.

Edited December 7, 2007 by Radical Precision Designs

[coltgov]

I'm just going to do some hypothesizing and hope it makes sense.

If you fire a blank there is no built up pressure so the jet effect of the expanding gas is minimal.

You cork it with a bullet, and it's like a bomb, and if channeling the high pressue gas to the point of least resistantance

such as pushing the bullet out the barrel and creating the high pressure jet effect as the bullet leaves the barrel.

This is a secondary force after the primary force of accelerating the bullet down the barrel.

The secondary force of the gas can be used to lessen muzzle flip and backward primary recoil.

The gun piviots up since the barrel is above the hand acting like a lever creating torque.

With the comp the gas is redirect to control muzzle flip and all gases should be expelled before the bullet

exists the comp to be effective.

As to the size of the ports in the comp, this will determine how fast the expelled gas is expended. Fast

creates more thrust and more push. This deals with the muzzle flip.

Now to lessen the primary recoil you need surface area to let the gas push against so the barrel/gun is pushed forward.

So the most effective comp would be smaller holes at the top and side surface baffles for the forward push.

There is an article in the current Front Sight magazine testing the effectiveness of different rifle comps.

Interesteresting reading.

[al503]

costs constraints as to what the shooter is willing to pay will determine what the manufacturers will sell over the counter.

I think you underestimate what a shooter is willing to pay if there is an advantage to be had.

If someone/manufacturer designed a comp that performed appreciably better than the other comps on the market, I would wager that we shooters would purchase those comps even if they were much more expensive. How many of us have magazines that are twice as expensive as a stock mag so they can have another round or two available at the beep even though it probably wouldn't make any difference for most stages?

[gans]

costs constraints as to what the shooter is willing to pay will determine what the manufacturers will sell over the counter.

I think you underestimate what a shooter is willing to pay if there is an advantage to be had.

If someone/manufacturer designed a comp that performed appreciably better than the other comps on the market, I would wager that we shooters would purchase those comps even if they were much more expensive. How many of us have magazines that are twice as expensive as a stock mag so they can have another round or two available at the beep even though it probably wouldn't make any difference for most stages?

You might want to clarify what you mean by a better comp. If you are referring to a more efficient/flatter shooting comp, they are out there. The problem is that they require extensive slide lightening which is quite expensive.

Therefore, most shooters are complacent with the average set up.

[Radical Precision Designs]

costs constraints as to what the shooter is willing to pay will determine what the manufacturers will sell over the counter.

I think you underestimate what a shooter is willing to pay if there is an advantage to be had.

If someone/manufacturer designed a comp that performed appreciably better than the other comps on the market, I would wager that we shooters would purchase those comps even if they were much more expensive. How many of us have magazines that are twice as expensive as a stock mag so they can have another round or two available at the beep even though it probably wouldn't make any difference for most stages?

You might want to clarify what you mean by a better comp. If you are referring to a more efficient/flatter shooting comp, they are out there. The problem is that they require extensive slide lightening which is quite expensive. Therefore, most shooters are complacent with the average set up.

Ok. Since I am asked to expand on the subject ... and clarify ....

I do not understimate what a shooter will pay for what he/she wants. I happen to be in a "niche" spot where my average "repeat" customer pays a hell of a lot more than the average buyer for what they want, because they ARE getting what they ASKED for, as opposed of what is usually available with "over the counter parts" jobs, and no one ever felt they were over-paying. That is the difference between "production made" parts versus "custom made" parts. Similar to the difference in price between production or custom made guns. But there is a big number of customers who will price what they want to pay by the actual costs of what is presently available in catalogs or internet re-sellers ... over the counter. Very seldom will you find "real cutting edge technology" available at cut rate prices over the counter. Oh yeah. There are a couple of designer/manufacturers who do have better more efficient designs available, but usually they are built on custom order or as a part of a system or complete gun, and yes they will cost considerable more. And, they are selling very well, both here and abroad. Not every one wants or is willing to pay the higher prices.

As for the need/requirement of the slide to be "extensively lightened" for them to work better ??? To me that would mean that they are not better or more efficient !!!! IMHO. These are different "modules" and should be designed/approached as such. As a balanced system that optimizes the performance of each other. I do not lighten my slides to make the compensators work, or because I would need a thin rubber-band for a recoil spring otherwise. I lighten my slides to optimize the cycling speed and split times, and then make sure that everything else does its part and is balanced. Those problems would/could probably best describe a situation arrived at by haphazardly grabbing/picking parts without previous thought out of over the counter parts bins without thinking ahead. There are good parts and sources out there, reachable, especially in these Forums.

[gans]

Sorry Venry, but I believe that some of the larger 4 port comps can be made to shoot flatter than the standard 3 port ones that are out there. As I said, they will push down on the barrel and slide harder and cause more friction which will slow the slide down more. That is why the slide needs to be lightened up more. It doesn't have anything to do with making the comp work.

I find that an efficient coned 4 port comp works nice with slide weight of around 10oz. Recoil spring runs between 9-12lbs. I don't know if you consider that a rubber band or not.

I agree that it takes a balance of components to build a fast flat shooting gun.

Maybe I just see things a little differently, as most of the customers I receive usually request that type of a gun to be built.

Respectfully,

Gary

[Radical Precision Designs]

costs constraints as to what the shooter is willing to pay will determine what the manufacturers will sell over the counter.

I think you underestimate what a shooter is willing to pay if there is an advantage to be had.

If someone/manufacturer designed a comp that performed appreciably better than the other comps on the market, I would wager that we shooters would purchase those comps even if they were much more expensive. How many of us have magazines that are twice as expensive as a stock mag so they can have another round or two available at the beep even though it probably wouldn't make any difference for most stages?

You might want to clarify what you mean by a better comp. If you are referring to a more efficient/flatter shooting comp, they are out there. The problem is that they require extensive slide lightening which is quite expensive. Therefore, most shooters are complacent with the average set up.

Ok. Since I am asked to expand on the subject ... and clarify ....

I do not understimate what a shooter will pay for what he/she wants. I happen to be in a "niche" spot where my average "repeat" customer pays a hell of a lot more than the average buyer for what they want, because they ARE getting what they ASKED for, as opposed of what is usually available with "over the counter parts" jobs, and no one ever felt they were over-paying. That is the difference between "production made" parts versus "custom made" parts. Similar to the difference in price between production or custom made guns. But there is a big number of customers who will price what they want to pay by the actual costs of what is presently available in catalogs or internet re-sellers ... over the counter. Very seldom will you find "real cutting edge technology" available at cut rate prices over the counter. Oh yeah. There are a couple of designer/manufacturers who do have better more efficient designs available, but usually they are built on custom order or as a part of a system or complete gun, and yes they will cost considerable more. And, they are selling very well, both here and abroad. Not every one wants or is willing to pay the higher prices.

As for the need/requirement of the slide to be "extensively lightened" for them to work better ??? To me that would mean that they are not better or more efficient !!!! IMHO. These are different "modules" and should be designed/approached as such. As a balanced system that optimizes the performance of each other. I do not lighten my slides to make the compensators (guns) work, or because I would need a thin rubber-band for a recoil spring otherwise. I lighten my slides to optimize the cycling speed and split times, and then make sure that everything else does its part and is balanced. Those problems would/could probably best describe a situation arrived at by haphazardly grabbing/picking parts without previous thought out of over the counter parts bins without thinking ahead. There are good parts and sources out there, reachable, especially in these Forums.

Oops !!! Sorry, my bad. I meant to write the word "guns" instead of comps...

Gary-

You are absolutely right about the "four" chambers (or more?) comps that because of the efficient "cartridge load" would exert that much downward pressure. But as this thread is putting the emphasis in "three chambers", as it is most prevalent in commonly available comps, I addressed that issue. My own design comps utilize more than three agregate chambers, even though usually I don't use more than two (instead of three) conventional baffled chambers. Just as you pointed out that there are some more potentially efficient comps beside the "three chambered" variety.

My own guns are set-up to work efficiently at a power factor of 165+ regardless of using recoil springs from 7 to 11 lbs, with final weight to be determined by the customer's second shot positioning and grip hold. That to me means that the gun should work properly with any of those springs without affecting its performance or "binding" due to an unefficient system. If anybody's gun will only work with a superlight or only a heavy spring, leaving no choice of tuning your point of impact, then that overal design is flawed. IMHO and experience. Coned comp systems are indeed very forgiving and do allow for a good margin of use, while keeping overall weight down. Coned comps also make it easier to eliminate a lot of the "drag" present in a bull barrel design, and make the gun work reliably, but coned comps will always have more dot tracking issues as the pathway used is not linear as that in a bull barrel. Coned comps will suffer from that characteristic last moment comp "dip" as the cone reduces/falls the diameter in its cycle ride. This can be construed/perceived as the comp being "too effective" when it actually is not. Many of the cone comps equiped guns very often will have additional "popple-holes" (?) to help balance the compensating impulses, and are more prevalent in "shorty" guns than full sized.

But I digress, my apologies for that. I can get easily swayed on the discussion of this subject, which I enjoy a lot, and I do not want to "hijack" this thread. The point I am trying to bring about is that that there are a few available systems including the three chambered variety which will work for 9mm Major, and that there is not that much of a difference whether they are meant for 9mm Major or any other .355 chamberings.

Edited for spelling, because of quick writing !!

Edited December 8, 2007 by Radical Precision Designs