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Very Hot Topic (More than 25 Replies) Kent's patented barrel venting (Read 1394 times)
BP
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Re: Kent's patented barrel venting
Reply #15 - Mar 13th, 2018 at 4:40pm
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I thought that barrel venting pattern looked familiar...  Frankford Arsenal used it on a number of very special "venting" projects.    Smiley
  

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Re: Kent's patented barrel venting
Reply #16 - Mar 13th, 2018 at 6:41pm
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I have a problem with the alignments of the holes with either the grooves or lands. Review the attached pic and in particular the apparent slope of the holes seems to me that the angle is much greater then the slope angle of the rifling.  The approximate angle of the rifling of a 14" twist on a 32 caliber barrel would be aprox. 4.2 degrees, give or take. A slower twist would be less. I took the attached picture and measured the angle of the holes with reference to the bore. I did this using a CAD software program. The holes have a slope of about 10 degrees. Now these are not exact values for a number of reasons but is accurate enough to show that the holes do not follow a single groove or land.
I see many shooting issues with this method of adding the holes.
  
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Re: Kent's patented barrel venting
Reply #17 - Mar 13th, 2018 at 6:49pm
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BTW the patent number for the Kent's patent is 812140. If you wish to read it you can google the number and download a PDF copy.
  
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Redsetter
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Re: Kent's patented barrel venting
Reply #18 - Mar 13th, 2018 at 7:03pm
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LRF wrote on Mar 13th, 2018 at 6:41pm:
I have a problem with the alignments of the holes with either the grooves or lands.


Where else can they go?  Sawyers's book noted that Kent started out drilling holes perpendicular to the bore, later angled them toward the muzzle. Wonder what he did to remove burrs?  Seems lapping the bore would have driven up the cost beyond what most would pay.
  
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Re: Kent's patented barrel venting
Reply #19 - Mar 13th, 2018 at 7:19pm
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LRF wrote on Mar 13th, 2018 at 6:41pm:
I have a problem with the alignments of the holes with either the grooves or lands. Review the attached pic and in particular the apparent slope of the holes seems to me that the angle is much greater then the slope angle of the rifling.  The approximate angle of the rifling of a 14" twist on a 32 caliber barrel would be aprox. 4.2 degrees, give or take. A slower twist would be less. I took the attached picture and measured the angle of the holes with reference to the bore. I did this using a CAD software program. The holes have a slope of about 10 degrees. Now these are not exact values for a number of reasons but is accurate enough to show that the holes do not follow a single groove or land.
I see many shooting issues with this method of adding the holes.

LRF,
Sounds like you're saying that each set of 5 vent holes wouldn't all be aligned along the centerline of a respective groove? Am I reading you correctly?
  

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marlinguy
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Re: Kent's patented barrel venting
Reply #20 - Mar 13th, 2018 at 8:06pm
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I'm unsure how it might make any differences if the holes were in lands or grooves? Either way the bullet will be passing over the holes, and either place would require the hole to be clean and free of any burrs.
Since the system was likely designed for jacketed bullets, it wouldn't be a case of the holes filling with lead in lands or grooves.
But I doubt this system had much effect on a barrel chambered in .32-40 regardless.
  

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Re: Kent's patented barrel venting
Reply #21 - Mar 13th, 2018 at 8:09pm
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BP wrote on Mar 13th, 2018 at 7:19pm:
LRF wrote on Mar 13th, 2018 at 6:41pm:
I have a problem with the alignments of the holes with either the grooves or lands. Review the attached pic and in particular the apparent slope of the holes seems to me that the angle is much greater then the slope angle of the rifling.  The approximate angle of the rifling of a 14" twist on a 32 caliber barrel would be aprox. 4.2 degrees, give or take. A slower twist would be less. I took the attached picture and measured the angle of the holes with reference to the bore. I did this using a CAD software program. The holes have a slope of about 10 degrees. Now these are not exact values for a number of reasons but is accurate enough to show that the holes do not follow a single groove or land.
I see many shooting issues with this method of adding the holes.

LRF,
Sounds like you're saying that each set of 5 vent holes wouldn't all be aligned along the centerline of a respective groove? Am I reading you correctly?

BP, Yes
Redsetter, I have similar concerns.
I haven't read the patent yet and will later tonight. I would think the holes would need to be drilled first and then rifled. But only guessing. Today's venting  or porting is usually done with an EDM machine which would leave no burr at all. Or at least that is what I am told.
  
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Redsetter
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Re: Kent's patented barrel venting
Reply #22 - Mar 13th, 2018 at 8:35pm
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LRF wrote on Mar 13th, 2018 at 8:09pm:
I would think the holes would need to be drilled first and then rifled.


Ideally, which is how Pope did it; but he wasn't in the brl making business.
  
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Redsetter
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Re: Kent's patented barrel venting
Reply #23 - Mar 13th, 2018 at 8:49pm
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marlinguy wrote on Mar 13th, 2018 at 8:06pm:
Since the system was likely designed for jacketed bullets, it wouldn't be a case of the holes filling with lead in lands or grooves.


No mention of bullet construction or powder in the part of the brochure that was photographed, but that isn't all of it.  Mann's testing was with lead bullets & BP, which is why he complained of the fouling.
  
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Re: Kent's patented barrel venting
Reply #24 - Mar 13th, 2018 at 9:03pm
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The venting work that Frankford Arsenal conducted using a pattern similar to Kent's method was used with 22LR barrels, and for the use of the standard lubed lead 22 LR bullets.
The arsenal was also able to keep the vent holes aligned with the centerlines of the respective barrel grooves.
  

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marlinguy
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Re: Kent's patented barrel venting
Reply #25 - Mar 13th, 2018 at 9:21pm
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Remember the High Standard Olympic with the two factory ports in their .22 barrels? The early version had two large ports in the barrel, and later they made the muzzle brake a removable version.
I always thought the ports could easily affect the lead bullets, but mine never did. The ports sure built up a ton of crud over a season of practice and matches though!
  

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Re: Kent's patented barrel venting
Reply #26 - Mar 13th, 2018 at 9:27pm
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Vall,

Brownell's still sells the High Standard muzzle brake/stabilizer cleaning tool.    Wink
  

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marlinguy
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Re: Kent's patented barrel venting
Reply #27 - Mar 13th, 2018 at 9:41pm
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I just pop the barrel off and put it in the ultrasonic cleaner.
  

Vall
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