I want to get a new 460 Rowland barrel for my .45 XDM and am wondering about these differences. Is a ported barrel louder than comp'd, and is there more of a slow down with the comp'd barrel??? Also is there a difference between brands of compensators in effectiveness if they both have the same basic port sizing and number of ports?
I think it might just be semantics?? But, I have always thought of porting as something you cut into a barrel and a comp as an add on to the end of a barrel (or slide).
I'm pretty sure Rich10 is exactly right about the semantics part; they're pretty much always interchangeable it seems. A barrel port, itself, is a specific method of recoil compensation often used when fitment of a secondary device for compensation isn't needed or wanted. To me, as well, the term "comp'd" usually means that there's some sort of muzzle device or other item fitted to the weapon to compensate for the recoil in one way or another. Basically a port is always a port but "comp'd" can mean anything to compensate for recoil, including (but not limited to) porting.
Not what I'm asking...I want to know the difference in noise made and whether they both accomplish the slowing of the slide equally.
They slow the slide and reduce sound??
I think what they do is reduce muzzle rise and maybe reduce muzzle flash.
Well neither of them are going to reduce the sound signature in any way since neither of them is designed for suppression. Perhaps there might be a distinguishable difference in sound signature as far as perception of direction (more from the side with a comp, generally more from the top/front with porting). In general they will both have a very similar report to that of an unmodified weapon, as far as measurable loudness is concerned, unless you're doing close-in manipulation. In that case you will definitely perceive it to be louder as much more of the report is directed up toward/around you instead of away from you. Regarding the reduction in slide velocity during rearward travel: that's mostly a function of the volume of the modification; if you have multiple large ports, or a significant comp, it will reduce the slide velocity much more than fewer, smaller, ports or a relatively small comp. However much of the expanding gas you're able to redirect from the path it normally takes straight out of the barrel (and consequently pushing straight back on the slide) is a function of how much less velocity you can expect. The equation for this probably involves some wacky math that I won't even pretend to understand. That being said, however, it probably won't reduce the velocity of the slide nearly as much as you'd think, unless you're talking about a significant amount of comp or several large ports, enough to allow a sufficiently large volume of gas to escape prior to the slide reaching its extreme rearward travel. As Rich10 mentiond: mostly they're designed to assist with reducing muzzle flip more than anything else.
I had thought that the noise would be greater with a ported barrel, but am unaware of how a comp barrel would sound. Also it seems your saying that there is no appreciable reduction in slide velocity with comp or porting yet the 460 Rowland conversion uses the comp or porting to do that unless I am completely missing the point. It was also inferred that the reduction would be be relative to the number and size of ports in either the comp or ported barrel. This makes sense to me. What I am trying to ascertain is whether to get a threaded barrel and place a comp from Lone Wolf on it or get a ported barrel. If they are both relatively the same I guess the ported barrel would be the way to go for cost and added size/weight to the front of the gun. In this last post it was stated that the reduction would be attributable to bullet velocity which I am hoping is not correct as I don't want to reduce but rather find increased velocity as a result of a slightly longer barrel though much of that is taken up by the porting.
Yes, adding porting or a comp will alter the sound signature of your weapon, but it won't necessarily make it louder or quieter; you will probably perceive it to be louder just because of the redirection of some of the expanding gas from the front of the barrel being channeled either up or to the side (or both) instead of directly out and away from your gun (and your ears). This can be particularly annoying when in close (think weapon retention) and the concussion from the muzzle blast is partially directed into your face because of the porting. It won't be any louder, technically, but it will certainly seem that way just because you're now experiencing it more directly.
As for the reduction in slide velocity: this is a function of the ammunition along with all of the parts of the gun, to include a compensator or porting; Adding a compensator to a 9mm barrel will have little effect on the slide velocity simply because there's not much expanding gas for the compensator to act on. Now when talking about a .460 Rowland or a .50 Action Express you will definitely notice a reduction in slide velocity as the compensator has more expanding gas to work with and can have a proportionally larger effect on the slide velocity (and muzzle flip). However: the recoil spring upgrade in these conversions plays a more significant role in reducing recoil (obviously) and slide velocity and shouldn't be neglected.
Regarding your question about which to get: that's really up to you. All things considered, it really boils down to which you think you'll need more or get the most use out of. This obviously depends on what you're going to be using it for. If you don't mind the extra weight out front and the added length, a compensator is a tried and true method of recoil and muzzle flip reduction. Porting doesn't add weight out front but rather the opposite, especially if you get an internally ported barrel (which can also be more expensive than just adding a compensator) because you'll have to mill out your slide to accommodate this type of porting (versus extended barrels with external porting, which is also an option). This change is obviously irreversible, however, so if that's a concern you should take that into consideration.
If you're looking to keep velocity up but reduce the recoil/slide velocity of the round I would definitely recommend the compensator as it has several advantages over just having porting: added weight out front, greater barrel length (threaded barrels typically have an additional half-inch or so on the ends to accommodate the threads) which should raise velocity a tiny bit, and an appreciable reduction in muzzle flip and felt recoil because of the action of the gas on the compensator (the act of compensation itself).
I didn't mean to get so long-winded but I hope that helps!
Thanks for the detailed response. I was going to buy a ported barrel that was the same length as a threaded barrel and after these responses I see no distinct purpose of the compensator except to be able to remove it. I can swap the barrel back to my original barrel if I want a shorter length system. Thanks...
No problem, glad to help! One more note about the compensators though: they are probably more efficient when given the right media to work with. There's typically much more surface area in the multiple channels of a compensator for the gas to work against than most porting options so if you need the most efficient method possible, especially when using loads that generate lots of gas, it might be more useful than porting alone. Standard loads, for the most part, will tend to see similar levels of improvement with either option so the cheaper/easier/faster option is probably the best bet. Also: compensators could actually affect the function of the weapon when using lower-powered loads so that's something to keep in mind as well, if that's a possibility. Good luck! Let us know what porting option you go with and how well it works for you!
Sounds like your saying a comp has ports that are not seen so the gases don't just travel straight up from the barrel like they would on a ported barrel???
I'm very new at this and have not seen either up close.
It depends on the particular brand/model/style you go for but there are several different variations. Typically porting is directed straight out the top as in normal Glock "C" models seen here: http://www.lonewolfdist.com/itemmedia/10000/10000_747.jpg (http://www.lonewolfdist.com/itemmedia/10000/10000_747.jpg) or as some aftermarket companies do here: http://www.lonewolfdist.com/itemmedia/10000/10000_939.jpg (http://www.lonewolfdist.com/itemmedia/10000/10000_939.jpg) Compensators, however, typically operate mostly out toward the sides, bust some have a combination of both as seen here: http://www.lonewolfdist.com/itemmedia/10000/10000_1070.jpg (http://www.lonewolfdist.com/itemmedia/10000/10000_1070.jpg) Some other comps don't have any ports on top and look more like a "brake" like those found on rifles and so forth but will obviously have less of an effect reducing muzzle flip versus just reducing recoil: http://sgcusa.com/images/supporting_images_large/Barrett_M82A1CQ_Muzzle_Brake_F.jpg (http://sgcusa.com/images/supporting_images_large/Barrett_M82A1CQ_Muzzle_Brake_F.jpg)
Ported barrels just have holes.
A compensator has a cavity that is larger than the bore, and it has a surface at the front for the gasses to bounce off of forcing the compensator and whatever it is attached to forward.
Both reduce recoil to some degree (mathematically), but you may not always feel it like in a 45 ACP or 38 special. The compensator should reduce recoil better than barrel porting.
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Quote from: ram1000 on December 12 2014 11:48:22 PM MST
Not what I'm asking...I want to know the difference in noise made and whether they both accomplish the slowing of the slide equally.
I doubt either will slow the slide to any degree if the compensator is attached to the barrel (Glock). If the compensator is attached to the slide (1911), than it will slow it down. The increased weight of a compensator on the slide will also cause it to slow down. A compensator on a Glock barrel may reduce slide speed by pulling the barrel forward and causing it to wedge against the top of the slide increasing slide-to-barrel friction.
It also depends on when you want to slow down the slide. With either the ports or compensator, the slide speed isn't effected until the bullet passes the ports or exits the muzzle, and by that time the barrel is unlocked from the slide.
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Since the slide and barrel are locked together for the initial phases of the action cycle, mass added to the barrel, eg compensator, will absolutely have in impact on slide velocity.
A 5oz comp will reduce slide velocity on 460 Rowland by about 25% versus a stock barrel just from weight alone. That will depend a bit on the load. For my calculation I used a 230 grain load at Wikipedia spec 1350 fps. The hypothetical gun had a 13 oz slide and a 5 oz barrel. Slide velocity without/with compensator when the bullet leaves the barrel is 39 fps / 30 fps.
I can't find good data on how much a ported barrel weighs. I would guess about .5 to .75 oz more than a stock length. Comparing those to barrels you get 37 fps slide velocity with the ported barrel vs 30 fps with the comp'd barrel.
sqlbullet, can I ask where you go those numbers for weight values? The one I have experience with, the Lonewolf one I cited above, weighs in right around an ounce and a half according to LW. Even their biggest ones, for "major" 9mm, only weigh 2.5 ounces. Also: typical two-slot porting wouldn't reduce barrel weight by 10-15% (given a 5oz barrel weight) unless you're also figuring the weight of the area cut from the slide to allow for the porting. If you're talking about a full-length port job with four to six ports, then certainly the weight might be reduced upwards of 20%, but you also have to account for the huge section of the slide that has to be cut out of the top of the slide to accommodate those ports, thus negating substantial amount of weight from the slide.
Let me address those in reverse order.
.5 to .75 oz difference for a ported barrel.
This is for an extended barrel versus a stock barrel. The difference is increased weight in the ported barrel, as the ported barrel would be a 6" rather than a 4.6". The assumption was starting with a standard Glock 21 non-ported, and adding a ported barrel to it. The weight was estimated based on 5" barrels I have weighed being around 5 oz weight. About half that weight is the chamber area, leaving 2.5 oz over 4" or about 5/8 oz per inch. If we are comparing a stock Glock 21 to a stock Glock 21C to Comp'd Glock 21 then the relative weights would need to be re-evaluated.
Compensator Weight
I googled Glock compensator, found the lone-wolf 460 rowland comp and looked at shipping weight (.317 lbs = 5.072 oz). You are correct in assuming that this was a wag.
Subbing in a 1.5 oz weight increase for the comp, we see a smaller reduction of about 8% in slide velocity (39 to 36 fps slide velocity).
These numbers are in no way "accurate". They are based on a hypothetical model, using mainly slide weights from my para P16-40. They are intended specifically to clarify that a comp will definitely slow down the slide measurably.
If someone wants to post up actual slide and barrel weights on a Glock 21, Glock 21c, 6" LW ported barrel, LW threaded barrel that a comp would attach to I would be happy to run the numbers for a Glock.
Ah, understood, that makes sense. Thank you for the clarification; I was curious about your estimation for the ported barrel as I was assuming you were talking about a Glock OEM barrel with factory porting ("C" models) which I now understand you weren't.
I do agree that an extended, ported, barrel would definitely weigh more, almost certainly by the amount you estimated. In your estimation would an extended ported barrel produce anything different, numbers-wise, from an internally ported barrel knowing that internal ports require a corresponding weight reduction in the slide due to the necessity of opening the top up? It almost seems like they'd balance each other out, really coming down to a choice of personal preference. All in all, again, I think that a compensator will definitely do "more" for reducing muzzle flip and felt recoil/slide velocity than porting alone be it OEM or aftermarket.
Here is how I see it. We are really talking about two measurable impulses, perceived as mechanical recoil. They are barrel flip and slide velocity.
Glock 21 is baseline. values x for muzzle flip and y for slide velocity.
Glock 21c. X will be reduced by the venting of gases upward during firing, but Y will increase as the barrel/slide mass is reduced by material removed.
Glock 21 + 6" ported barrel. X is reduced by venting of gases upward during firing, and Y is decreased overall due to increased barrel/slide mass of the longer barrel. The "overall" part is because the slide does accelerate for some extra time here due to the longer barrel, but not enough to make up for the increased mass.
Glock 21C + 6" ported barrel. Again X is reduced by the venting of gases. I cannot speak to Y as I have no data regarding the mass of a ported slide and mass of the 6" barrel. If the barrel/slide mass is less than stock, Y goes up. Less than stock, Y goes down. I would guess this will be pretty close to neutral for Y.
Glock 21 + comp. Best of both worlds as you are adding a good bit of mass, as well as venting gas. Meaningful reductions in both X and Y.
Excellent breakdown. That's about how I was figuring it as well. All things considered, I would think that the stock setup with the addition of a compensator would produce a statistically significant difference in both slide velocity and muzzle flip, more so than factory or aftermarket porting, while maintaining at least, or more, mass overall. Mass is clearly the most crucial variable in reducing slide velocity.
Is there any kind of "Handgun Pull-Down" available?? Might be cool to actually get some accurate weights and measurements of the different components out there. It would be interesting to see just how much of a difference there really is between all the options so we can better approximate their effects when put into use.
There isn't.
I have long thought it would be cool to put up a good firearms wiki site. It is really a better format for that type of information than a forum. Maybe I will try to get motivated over x-mas.
Edit--
There is this:
http://guns.wikia.com
But it is so commercialized that I can't stand it, and the information is really limited.
Ah yes, the ever-present Wiki! I knew there had to be at least one dedicated to firearms, especially since there's one for just about everything else. The community-editing part would definitely make it much quicker and more efficient, even with a relatively limited moderator involvement. It's a shame that one is so heavily laden with commercial interests, though. Perhaps if you're motivated enough you could start with a 10mm-Wiki! ;)
(http://i1383.photobucket.com/albums/ah290/patsavonbbillly/Photo0935_zps64383eb6.jpg) (http://s1383.photobucket.com/user/patsavonbbillly/media/Photo0935_zps64383eb6.jpg.html)
g24 c ported barrel
Can you weight the slide and barrel, preferably separately, and post their weights?
billyb, very nice looking setup! 8)
sure might take a few to find a scale an its a 40 cal ( short 10 mm )
Am I wrong? I thought either a comp or porting made the darned thing LOUDER!
Quote from: gandog56 on February 26 2015 04:44:20 PM MST
Am I wrong? I thought either a comp or porting made the darned thing LOUDER!
A comp is a ported weight. Both make the gun seem louder to the shooter as they redirect the energy up, rather than forward.
Just to be silly, can I get an extended barrel with ports and a compensater attached to the slide :P
In theory, if you get it timed correctly, and matched the cuts, you would create longer ports with the two.
I just haven't seen anyone do this in a manner that would compliment each other. What I have seen is a ported match barrel with matching slots in the slide and a solid, non-ported compensater attached to the slide of a 1911 in 9mm. This does not mean that someone hasn't done it, just that I have not seen it done yet.
I've seen ported (Or is it comp'ed) bushings you can put on a 1911. Have no idea if they actually do anything, though.
(http://shopwilsoncombat.com/images/397s-001.jpg)
Those are the compensators being discussed above. The biggest thing they add is weight to the slide. As the bore has to be large enough for the barrel to pass through as the slide moves, the gas sealing is not as effective, so less gas is redirected by the ports than say one that is fitted to the barrel and bored just over bullet diameter.
Quote from: gandog56 on March 13 2015 07:02:46 AM MDT
I've seen ported (Or is it comp'ed) bushings you can put on a 1911. Have no idea if they actually do anything, though.
(http://shopwilsoncombat.com/images/397s-001.jpg)
Those are almost useless on a 1911 using standard ammo. It may work better if you used an ultralight bullet (160 grain) and +P+ pressures.
I had a similar one on my Springfield 1911, and I didn't notice anything with standard ammo.
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I tried a different one on my Springer. Noticed no change in recoil, and a loss of accuracy as it was not fitted to the barrel. Gave up that experiment pretty fast.