Ported Revolvers, Higher Velocity?

[ClickCL]

So, logically, it's hard to explain; but I keep seeing instances where ported revolvers are showing higher velocities compared to their non-ported counterparts.

Has anyone else noticed this?

I understand due to barrel and cylinder fitment, there will be some variation between revolver velocities, but it does seem like there is a consistent trend.

Perhaps porting reduces the pressure needed to push the air out in front of the bullet? It's a stretch, but all I can think of.

Here are some examples:

Bullet by the inch - Notice the velocities of the 4" non-ported mt gun and the 3" ported Mt gun. Even with one inch less, the ported version produces similar and sometimes better velocites compared to the 4" non-ported. (bottom of page) http://www.ballisticsbytheinch.com/44mag.html

Gun-Test.com review - The taurus tracker which has a slightly shorter barrel and porting, matched and occasionally bested the M69 with a non-ported .25" longer barrel. (image either on the right or bottom of page shows velocities) https://www.gun-tests.com/issues/26_...l#.XdGzNkZKhO9

Forum post - Post comparing a 2" ported vs non-ported revolver. The ported had slightly higher velocities on average. https://www.thehighroad.org/index.ph...barrel.352178/

Jerry Miculek comparing 329pd's - Comparing his ported 329 to a stock 329. His ported 329 had higher velocites. (1:50-2:50) https://www.youtube.com/watch?v=v5alzzxnUKs

The argument that all of the ported examples above had tighter fitment between the cylinder and barrel either due to being shot more or luck of the draw from the factory, becomes less likely with more examples. However, this sample size is small, so it doesn't prove anything. I didn't seek the above examples out, just something I noticed today while reading. There may be many examples showing the opposite, I just haven't seen them yet.

What do you guys think?

[Old4eyes]

I have to say that logic compels one to think you are going to lose pressure by the porting and the velocity will be less.

I have one ported revolver (a Taurus, yes we all get to make mistakes) and with the night flash and the gunk kicking up from the port, using this in a self defense situation is not ideal. You might get the muzzle back onto target but the flash in a low light situation may make it difficult to see the target and if you don't have eye protection on, the gunk flying out of the ports may be a problem. But it's one man's opinion - a man who bought a Taurus.

[ar15barrels]

Originally Posted by ClickCL

So, logically, it's hard to explain; but I keep seeing instances where ported revolvers are showing higher velocities compared to their non-ported counterparts.

Has anyone else noticed this?

I understand due to barrel and cylinder fitment, there will be some variation between revolver velocities, but it does seem like there is a consistent trend.

Perhaps porting reduces the pressure needed to push the air out in front of the bullet? It's a stretch, but all I can think of.

Here are some examples:

Bullet by the inch - Notice the velocities of the 4" non-ported mt gun and the 3" ported Mt gun. Even with one inch less, the ported version produces similar and sometimes better velocites compared to the 4" non-ported. (bottom of page) http://www.ballisticsbytheinch.com/44mag.html

Gun-Test.com review - The taurus tracker which has a slightly shorter barrel and porting, matched and occasionally bested the M69 with a non-ported .25" longer barrel. (image either on the right or bottom of page shows velocities) https://www.gun-tests.com/issues/26_...l#.XdGzNkZKhO9

Forum post - Post comparing a 2" ported vs non-ported revolver. The ported had slightly higher velocities on average. https://www.thehighroad.org/index.ph...barrel.352178/

Jerry Miculek comparing 329pd's - Comparing his ported 329 to a stock 329. His ported 329 had higher velocites. (1:50-2:50) https://www.youtube.com/watch?v=v5alzzxnUKs

The argument that all of the ported examples above had tighter fitment between the cylinder and barrel either due to being shot more or luck of the draw from the factory, becomes less likely with more examples. However, this sample size is small, so it doesn't prove anything. I didn't seek the above examples out, just something I noticed today while reading. There may be many examples showing the opposite, I just haven't seen them yet.

What do you guys think?

ALL of your examples rely on comparing two DIFFERENT barrels.
The way to actually test your theory is to test an unported barrel and then port it and test it again in the same conditions.
Simply changing the temperature will make one barrel faster than another and we don't know how well controlled ANY of the tests you are citing were done.

[hermosabeach]

I need to ask... is the ported segment counted to barrel length?

Some guns have a port that is a brake- it’s not threaded so it does not count as barrel length


If they machines holes in the barrel, the results would surprise me.


If it’s like a S&W, where it adds length to the gun but not the barrel, so it still holds pressure behind the round- it makes more sense.



If they are chopping a barrel down, my guess is they would not machine new ports after each 1” chop

[hermosabeach]

[hermosabeach]

Different brakes and how they are measured or not as barrel length should make a difference on velocity.

[ClickCL]

Originally Posted by ar15barrels

ALL of your examples rely on comparing two DIFFERENT barrels.
The way to actually test your theory is to test an unported barrel and then port it and test it again in the same conditions.
Simply changing the temperature will make one barrel faster than another and we don't know how well controlled ANY of the tests you are citing were done.

Absolutely true. Like I said, this proves nothing. Just something I noticed. And none of the examples above are scientific.

[k1dude]

Originally Posted by ar15barrels

ALL of your examples rely on comparing two DIFFERENT barrels.
The way to actually test your theory is to test an unported barrel and then port it and test it again in the same conditions.
Simply changing the temperature will make one barrel faster than another and we don't know how well controlled ANY of the tests you are citing were done.

As an interesting experiment, the next time someone asks you to port a barrel, ask them if it's OK to chrono the before and after with the same ammo, elevation, temp, and humidity. Ideally indoors.

[BigFatGuy]

Originally Posted by k1dude

As an interesting experiment, the next time someone asks you to port a barrel, ask them if it's OK to chrono the before and after with the same ammo, elevation, temp, and humidity. Ideally indoors.

I'm sure you'd do better by asking if you could HIRE him to do these things. He does this for a living, after all.

also, AR15 is very good, but he doesn't control the weather.

[FalconLair]

good question

i purchased a Performance Center S&W Model 19 a couple of weeks ago and it has a ported barrel

unfortunately i haven't been able to try it out yet, during some dry firing i noticed the double action pull was stressing so i disassembled it and found the double action sear spring had popped out of place compromising the whole DA pull - i don't think it was put in correctly because it shouldn't pop out in that manner

S&W is sending me a new one since it got all bent up

funny how ONE little spring can shut the whole revolver down from me getting to play with it

[Carcassonne]

The velocity from a ported barrel should be a little less than from a non-ported barrel of the same length.



.

[JTROKS]

Some barrels are faster. I’ve shot same handloads over a chrono from a 6” Ruger 6” Colt, and 6” S&W. Results sometimes almost 100 FPS difference.

[ClickCL]

Originally Posted by JTROKS

Some barrels are faster. I’ve shot same handloads over a chrono from a 6” Ruger 6” Colt, and 6” S&W. Results sometimes almost 100 FPS difference.

While I am aware of this and completely agree that is normal, of the four instances where I have found comparisons that were done by the same person/ammo, all four ported barrels are shooting faster for their barrel length.

Statistically if porting had zero/no effect I would expect a 50/50 split (sample size, once again, is too small to really draw any conclusions). But common logic dictates that porting would be worse than zero/no effect, it should have a negative effect on velocity and sway the results in favor of non-ported barrels. But it didn't... Just interesting =)

I'm with all of you, I would love some more controlled comparisons but I just wanted to see if anyone else has noticed this from their own revolvers or tests.

[ar15barrels]

Originally Posted by k1dude

As an interesting experiment, the next time someone asks you to port a barrel, ask them if it's OK to chrono the before and after with the same ammo, elevation, temp, and humidity. Ideally indoors.

I can't shoot out of my shop yet so it's not really possible.
Maybe once I move to Carson City, I could do such testing as there is BLM land around 500yds away from my property.
This would allow me to go setup a chrono and test fire, run back to my shop and do the porting and then run back to test fire again before the weather changes enough to matter.