Barrel porting and velocity

[RangerTrace]

Have any of you checked your PF before and after porting a barrel?  I shot a coworkers P today that had DSC V8 porting on the barrel.  It was super flat and probably flatter than my XC.  I'd be interested in porting my CS carry gun to flatten it out a bit if I knew it wouldn't greatly reduce the velocity.  

[RJH]

https://www.thearmorylife.com/ported-barrels/

 

 

According to this article, it depends

[Farmer]

The one flaw in his testing is that he should have tested the velocities of the ported gun before it was ported. Or use just one gun and do a before an after. The differences are subtle but that could also be just because of two different bbl’s. An accuracy test while doing this would have been nice too. 

Edited January 26 by Farmer
Added

[RangerTrace]

8 hours ago, RJH said:

https://www.thearmorylife.com/ported-barrels/

 

 

According to this article, it depends

That's about as close as you can get and I'm impressed/encouraged with the data.  Thank you!!

[zzt]

FWIW, I had two 3/16" poppels put in my main Open gun after testing with the comp alone.  I lost 3 PF after the poppels were put in.  Shot flatter.  Still made major, but I upped the charge anyway.

[Timido]

Friend does cnc slides and barrel cuts at Pew Pew CNC.   I remember him saying that one of his was 70-80 FPS loss. 

[LHshooter]

I received an MPA DS9 about a month ago with ported and non-ported barrels. I chrono'd 11 different rounds (115, 124, 147 grain, factory and reloads) through the non-ported barrel a couple weeks ago. Tomorrow I plan on going to the range and chrono the same ammo through the ported barrel. I will post the results. This should be an apples to apples comparison unlike the article in The Armory Life. Stay Tuned.

[Braxton1]

"Apples to Apples" comparisons when related to barrels are really not a "thing".

 

The "flaw" that Farmer pointed out is valid.  Different barrels, even those from the same manufacturer, will produce different pressures and different velocities.

 

A non-ported Barrel #1 from Manufacturer "A" might have been produced with the newest rifling cutter in the shop, so it runs on the larger side of bore sizes.  Ported Barrel #2 might've used an old cutter, so it runs small and generates higher pressures.  Non-ported Barrel #3 was cut with the same old cutter.  You could almost predict that 1 and 2 will produce velocities that are very close.   #3 will produce higher velocities than the other two just because of being tighter, plus not having ports. 

 

So, comparing an existing ported barrel to an existing non-ported is really not a valid comparison.

 

Other factors such as the powder used in the testing may produce drastic differences (slower powders that are still producing work when the ports are opened) or no difference at all (hyper-fast powders that have expended most of their juice in the first couple of inches of barrel).

Edited February 21 by Braxton1

[shred]

This.  I've had four identical barrels now in my pair of Dawson Open guns.  All from the same maker, same length, same porting, same load, same fit, same chambering reamer, etc.  They vary by more than 100 fps each.

 

At a guess, a 'slower' barrel has more gas blow-by and might lose less with porting than a fast one, but I have no data behind that.  The slow/fast could be bore friction instead of diameter or something else.

 

 

 

[Timido]

The 70-80 fps loss I am talking another it before and after same barrel.   So it is showing 8-9 Power Factor loss from 1150fps 115g

 

 

[Farmer]

12 hours ago, Timido said:

The 70-80 fps loss I am talking another it before and after same barrel.   So it is showing 8-9 Power Factor loss from 1150fps 115g

 

 

Your example is much more valid. 

[RePete]

Looking at some of the numbers, I see people who don't recheck their load over a chrony and who play close to the line will be DQ'd because of the ammo.

 

I'm not into porting but I say fill yer boots.

 

As Farmer said no before velocities prior to porting.  This almost makes the test invalid.

[LHshooter]

I chrono'd the ported barrel for my MPA DS9 this morning using the same 11 types of ammo for when I chrono'd my non-porting barrel. I decided to get both barrels when I ordered the pistol thinking I might use the ported barrel for CO in IDPA and the non-ported for LO in USPSA. Results are in the table below:

 

 

 

Looks like I've got some work to do to find the best load since I had planned on using 115's or 124's in this pistol.

[RJH]

6 minutes ago, LHshooter said:

I chrono'd the ported barrel for my MPA DS9 this morning using the same 11 types of ammo for when I chrono'd my non-porting barrel. I decided to get both barrels when I ordered the pistol thinking I might use the ported barrel for CO in IDPA and the non-ported for LO in USPSA. Results are in the table below:

 

 

 

Looks like I've got some work to do to find the best load since I had planned on using 115's or 124's in this pistol.

 

Thanks for posting that. Interesting how some of them there was almost no change and other ones there's quite a bit.

 

Is IDPA power factor 125 as well? Or is it a little bit lower I can't remember. Good news is it looks like most of it does make at least 125

 

 

I think one other thing this shows real well is that you can't really guess at it, gotta Chrono it to know

[Farmer]

10 minutes ago, LHshooter said:

I chrono'd the ported barrel for my MPA DS9 this morning using the same 11 types of ammo for when I chrono'd my non-porting barrel. I decided to get both barrels when I ordered the pistol thinking I might use the ported barrel for CO in IDPA and the non-ported for LO in USPSA. Results are in the table below:

 

 

 

Looks like I've got some work to do to find the best load since I had planned on using 115's or 124's in this pistol.

That certainly is quite interesting. No real definitive reason. Would be interesting to know what the powders were used in the loads. 

[LHshooter]

Yes, minor in IDPA is 125 PF.

 

Regarding the powders in the loads, they were as follows:

 

Missouri Bullets - 3.1 gr Titegroup

Hoosier Bullets - 3.2 gr Titegroup

Summit City - 4.1 gr N320

Both Berry's used Universal but I don't know how much (they were given to me)

The factory ammo I obviously don't know.

 

NOTE:: I noticed an error for the std. dev. for the Berry 115 gr. should be 39.56 not 24.68. I have uploaded a corrected table in my original post.

Edited February 22 by LHshooter
Let people know I corrected the data table

[Farmer]

1 hour ago, LHshooter said:

Yes, minor in IDPA is 125 PF.

 

Regarding the powders in the loads, they were as follows:

 

Missouri Bullets - 3.1 gr Titegroup

Hoosier Bullets - 3.2 gr Titegroup

Summit City - 4.1 gr N320

Both Berry's used Universal but I don't know how much (they were given to me)

The factory ammo I obviously don't know.

 

NOTE:: I noticed an error for the std. dev. for the Berry 115 gr. should be 39.56 not 24.68. I have uploaded a corrected table in my original post.

It appears that the 147’s get a more complete burn, but whatever North Florida is loading appears to be quite efficient. How do they shoot? 

[LHshooter]

43 minutes ago, Farmer said:

It appears that the 147’s get a more complete burn, but whatever North Florida is loading appears to be quite efficient. How do they shoot? 

I was surprised by the results from the Blazer and North Florida rounds since the change was so little. I want to go back and retest those two rounds to see if I get the same close results.

 

As far as how the ammo shot. I thought the UMC and PMC 115's were the flattest and has the least dot rise. The North Florida 125's were close behind, along with my Summit City 124 reloads. I'm going to bump up my load for the Summit City by another grain or two to 4.2 or 4.3 and see how they shoot through the ported barrel. When I shot the 147's it almost seemed as though the slide was moving in slow motion.

 

Overall, I've got about 650 rounds through this pistol now with no hiccups at all. 

[zzt]

2 hours ago, LHshooter said:

I chrono'd the ported barrel for my MPA DS9 this morning using the same 11 types of ammo for when I chrono'd my non-porting barrel. I decided to get both barrels when I ordered the pistol thinking I might use the ported barrel for CO in IDPA and the non-ported for LO in USPSA. Results are in the table below:

 

 

 

Looks like I've got some work to do to find the best load since I had planned on using 115's or 124's in this pistol.

 

A word of caution on the CCI Blazer:  if it was Aluminum cased ammo, you are fine.  If brass cased you risk leading up the ports.   CCI recommends against using the brass cased in comps or ports.  The copper plating is so thin it can flake off and lead the comp.  I didn't find that out until I talked to a CCI Ballistician.  Unfortunately, I had just bought a case.

 

2 hours ago, RJH said:

I think one other thing this shows real well is that you can't really guess at it, gotta Chrono it to know

 

 

Edited February 22 by zzt

[LHshooter]

5 minutes ago, zzt said:

 

A word of caution on the CCI Blazer:  if it was Aluminum cased ammo, you are fine.  If brass cased you risk leading up the ports.   CCI recommends against using the brass cased in comps or ports.  The copper plating is so thin it can flake off and lead the comp.  I didn't find that out until I talked to a CCI Ballistician.  Unfortunately, I had just bought a case.

 

 

 

I'm aware of that but thanks for pointing it out for others. I thought about adding a side note in my original post to alert people who may not know, I guess I should have. The CCI Blazer box specifically states not to use in comps or ported barrels.  I only shot enough rounds for the chrono comparison. I also bought a case but will use them in my non-ported barrel. Kinda sucks that their so called FMJ is so thin plated.