Porting question

[Garmil]

I know that porting alone is inferior to a compensator or the combination of the two.

With a compensator you want powder on the slow end of burn rate to work the comp.

Without a compensator you want fast powder for less recoil.

With porting alone which is better? With slow powder is enough gas working the ports to make a major difference? Or would fast be better with the small reduction in muzzle rise from the ports?

[Hi-Power Jack]

I don't know, but imagine that iff the ports are to do anything (or else, why are they there?),

you'd get better results from more gas (slower powder) ???

Let's wait and see what the experts have to say, though

[superdude]

I did a muzzle rise test in a Glock G19C with 2 different powders, 231 and A#7. At 125 power factor using a 124 grain bullet, the muzzle rise was virtually identical. The difference in Ransom Rest movement was 0.07 mm. So no difference between a fast powder (231) and a slow powder (A#7) for that gun.

That said, the ports on a G19C are close to the chamber, and the pressure curves of slow and fast powders might be very similar at that point, whereas they could be more different close to the end of the barrel where folks often port their 'open' guns. So, you might get more reduction in muzzle rise with a slower powder if the ports are near the end of the barrel. If I was going to guess, I'd say it would not be much of a difference (though every little bit helps). But I'm guessing.

[Garmil]

Thanks that's useful info. bullet weight wise I'd be interested in a 115 with slow powder vs. a 147 with fast to try to separate them further and see if the ports are working.

[superdude]

I don't have information on different gunpowders for different weights in that gun, but looking at differences in factory ammo with 115, 124 and 147 grain bullets, the recoil reduction with the G19C was about the same ; 30-32% reduction. No meaningful difference with the ammo i tested.

[Hi-Power Jack]

I have no experience with ports, but I've read that they are not very effective, at all ...

[Garmil]

30-32 percent above that sounds substantial

[kneelingatlas]

I agree with Superdude's assessment, I tested a Magnaported SP01 with 115s over WAC from ~100pf all the way up to 170pf and the ports have little effect.

[superdude]

You'll might find this of interest: http://www.shootingtimes.com/gunsmithing/recoil-reduction-ports-vs-compensator/

[BoyGlock]

I had to shoot a bunch say 5,000 rounds in one ported comped set up gun for months then due to a malf in the match, abruptly changed to my back up unported comped gun. Both were STI and same load of ammo. The difference was significant. The ported comped gun had less flip and the dot was slower to rise. And it is even lighter than the unported gun.

[kneelingatlas]

Perhaps the compensator create back pressure in the barrel, forcing gas up through holes in the barrel because they definitely make a difference in a comp'ed gun.

[superdude]

Perhaps the compensator create back pressure in the barrel, forcing gas up through holes in the barrel because they definitely make a difference in a comp'ed gun.

I suspect that the ports simply add to the force directed upward along with the comp's chambers.

[thompsoncustom]

Ive been thinking about getting a cheap 9mm to cut up and do straight port testing on.

I think high pressures would be key but without doing any testing i just dont know.

[BoyGlock]

Perhaps the compensator create back pressure in the barrel, forcing gas up through holes in the barrel because they definitely make a difference in a comp'ed gun.

I suspect that the ports simply add to the force directed upward along with the comp's chambers.

I think it more than simply add. Being closer to the chamber the pressure vented upward is much higher hence more force to counter muzzle flip. I mean, it adds a lot.

[rustybayonet]

I'm running an M&P9 with a storm lake ported barrel. I have noticed less muzzle rise and tighter groups.

[Bkreutz]

I had Magnaport do the barrel and slide on my Core a couple of years ago (pre ported Core era). As much as I would like to say that it made a big difference (if for no other reason than to justify the money spent) in all honesty, I didn't notice much of a difference if any. It didn't hurt anything, but IMO it shot the same before and after. I haven't shot major PF through it (I have a major gun), so maybe that would be different, but at 136PF it shoots the same.

[superdude]

Subjective evaluation of porting and compensators is fraught with error, especially after a significant delay between testing. That's where the Ransom Rest shines. It offers an objective measure of muzzle rise.

[Garmil]

On July 30, 2016 at 10:55 AM, superdude said:

Subjective evaluation of porting and compensators is fraught with error, especially after a significant delay between testing. That's where the Ransom Rest shines. It offers an objective measure of muzzle rise.

I agree with this but doesn't tell the most important a part. How the gun feels and the dot looks to your eye.

[lefty o]

there's ports, and then there are ports. drill some holes in a barrel, and yeah they arent overly effective. stick a rib on a barrel and then drill some holes in it, and it wil work a ton better as the gasses have some surface area to work against.

[Garmil]

23 hours ago, lefty o said:

there's ports, and then there are ports. drill some holes in a barrel, and yeah they arent overly effective. stick a rib on a barrel and then drill some holes in it, and it wil work a ton better as the gasses have some surface area to work against.

Have not heard that theory. The higher end ported guns do seem to have ribs often.

[Hi-Power Jack]

On ‎8‎/‎18‎/‎2016 at 11:32 PM, lefty o said:

 . stick a rib on and drill holes in it, and it wil work a ton better as the gasses have some surface area to work against.

I've never heard that before, either, and it doesn't sound like something I'd automatically agree to.

Any data to support that theory?

[BoyGlock]

On 19 August 2016 at 11:32 AM, lefty o said:

there's ports, and then there are ports. drill some holes in a barrel, and yeah they arent overly effective. stick a rib on a barrel and then drill some holes in it, and it wil work a ton better as the gasses have some surface area to work against.

Maybe also due to the weigt of the rib in the muzzle?

Edited August 20, 2016 by BoyGlock

[thompsoncustom]

Quote

Perhaps the compensator create back pressure in the barrel, forcing gas up through holes in the barrel because they definitely make a difference in a comp'ed gun.

I also assume this is why a gun with barrel ports and a comp works well. If you read about building silencers the spacing of the first baffle plays a big role in back pressure and cycling of semi auto rifles.

[lefty o]

5 hours ago, Hi-Power Jack said:

I've never heard that before, either, and it doesn't sound like something I'd automatically agree to.

Any data to support that theory?

once upona a time my g34 had a ported stormlake barrel in it, and with same ammo my brother g17 with the old aerotek  ported barrel on it(they added a thin rib on top of the barrel), night and day difference, the ribbed barrel had signifigantly less movement.

[Hi-Power Jack]

Were the G34 and G17 the same weight?