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Apr 29th, 2024
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Joined: Jan 2002
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Sidelock
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Sidelock
Joined: Jan 2002
Posts: 13,163 Likes: 1155 |
Late to the party, but am passing along the following reminder. Shot passage/flow through the forcing cone constriction, as with the choke constriction, is an orderly process, not some slam, bam chaos. The leading shot pellets speed up to get out of the way of the following pellets. Since there is no extra energy input available, the velocity increase must come at the expense of pressure. That is, the pressure drops across the forcing cone constriction and across the choke constriction. I know this is counter-intuitive, but it is so. If not, airplanes don't fly.
Post back if you desire further discussion.
DDA What goes wrong then, Don, when barrels are ruined at the choke by HeviShot? Is the fluid flow principle for lead and steel only? One of my best friends is the owner of two of the major aftermarket choke tube companies, and although he makes his chokes out of very good steel for the purpose, he will not warranty his turkey chokes for use with HeviShot. Occasionally someone will send him a burst barrel and try to blame it on the chokes. He knows when he sees it if it had HeviShot used in it and will call the owner and ask what he was shooting. Usually they own up to using HS. Happens a lot more than you would think. Not a rare occurrence at all, and these are new made guns. SRH
May God bless America and those who defend her.
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Sidelock
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Sidelock
Joined: Jan 2002
Posts: 5,954 Likes: 12 |
Hi, Stan. Team Ithaca missed you at Georgetown.
I would surmise that the irregularity in shape of HS pellets makes it much more subject to pellet bridging. Bridging of spherical pellets is a relatively rare occurrence. The pellets must align very precisely and have relatively low surface friction so they can slide/roll and collapse the bridge. The irregularities of HS, IMO, can mechanically interlock, greatly increasing the chances for development of a stable bridge. The bridge, then, becomes an obstruction to the following pellets and wad and sets up a gas hammer situation.
Does this square with your experience?
DDA
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Sidelock
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Sidelock
Joined: May 2010
Posts: 48 |
I have read that polishing the cones as well as increasing the radii of the transitions will do more for the patterns than lengthening the cones, regardless of wad type. True? I have no first hand knowledge of this; it's just theory to me, I'm just seeking knowledge. Recoil should no be effected from what I've read.
Last edited by WagonWillie; 11/07/15 02:33 AM.
Men build too many walls and not enough bridges. -Isaac Newton
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Sidelock
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Sidelock
Joined: Jan 2002
Posts: 5,954 Likes: 12 |
WW, good question.
I doubt very much that polishing or transition radii have effect on patterns of pressures. Transition radii are good for the barrel metal in terms of reducing stress concentration.
Most pattern "data" needs be taken with a full blown crystal of salt. I suggest you read Dr. Andrew Jones's book, "Sporting Shotgun Performance" for some real statistically valid data.
DDA
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Joined: Feb 2004
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Sidelock
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Sidelock
Joined: Feb 2004
Posts: 13,880 Likes: 16 |
Chuck;
All I can tell you is "Do The Math". Any chamber cut with a cone angle of 5° per side is going to be a short one. It will not be a "Modern Long Cone", period. In my 35+ years in the machine shop I have cut enough angles & tapers to know how to calculate them.
I Double & Triple checked my trig, it is correct.
If you take the 1907 drawing Drew posted with the included taper of 1 7/8" per 12˝". Do the trig on this taper & you get 4° 17' & 21 angle" per side. Calculating the length of cone for the .069" difference in chamber & bore diameters gives a length of .460".
Double checking by another means that .069" is 3.68% of 1.875.
3.68% times 12.5 = .460"
With that same .069" difference between chamber & bore a 5° angle per side would give a cone length of .394", certainly not a long cone.
Remember SAAMI is suggested Not Law.
Miller All I can tell you is the Clymer and Manson reamer makers products and the SAAMI drawings match the 5* angle in 12, 20, 28, and 410. Even the "new" 3 1/2" 12ga has a SAAMI spec of 5*. But 1988 could be called ancient now. Call them what you will, modern or not. It's fact. If you order a catalog reamer it comes with a 5* cone unless custom specified at greater cost and longer lead time. I have three examples that I ordered off the shelf in this century and they are still 5*. The gun makers themselves along with ammunition makers developed these standards, a.k.a. "Industry standard". They haven't changed since you said they aren't modern. Perhaps there's another way to marginalize these facts?
Last edited by Chuck H; 11/07/15 06:36 AM.
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Joined: Jan 2002
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Sidelock
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Sidelock
Joined: Jan 2002
Posts: 13,163 Likes: 1155 |
That is my only explanation for it, too, Don. The owner of the choke tube business' standard reply is, "The stuff (HeviShot) is harder than what the barrel and the choke tubes are made of .......... when it bridges as it enters the constriction, what do you think is going to give?". I agree with him, but also that the odd shapes and sizes contribute to the bridging.
SRH
May God bless America and those who defend her.
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Joined: Dec 2001
Posts: 12,743
Sidelock
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Sidelock
Joined: Dec 2001
Posts: 12,743 |
You may want to double check your trig.
This is a modern chamber/cone drawing. It typifies the modern cone considered to be longer than many early 20th century guns. As you can see, it has a 5* angle per side or 10* included angle cone. A 3* cone measured from either the barrel axis or normal to the barrel axis doesn't jive.
Chuck; You were the one who said this drawing was a "modern cone considered to be longer than many early 20th century guns". In fact it is not a long cone at all. As I said I have double, triple now even quadruple checked my Math. Yes a cone having an angle of 3°1' relative to the bore axis does indeed Jive. In fact to get the much vaunted 1˝" long cone the angle will be on the order of 1°20'12". This is based on a chamber .070" larger than the bore. Inv Tan .035/1.5 = 1.336658978° As has been shown L C Smith was using a longer cone than this 5° one in 1907 & longer still by 1935.
Miller/TN
I Didn't Say Everything I Said, Yogi Berra
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Sidelock
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Sidelock
Joined: Jan 2006
Posts: 15,456 Likes: 86 |
That is my only explanation for it, too, Don. The owner of the choke tube business' standard reply is, "The stuff (HeviShot) is harder than what the barrel and the choke tubes are made of .......... when it bridges as it enters the constriction, what do you think is going to give?". I agree with him, but also that the odd shapes and sizes contribute to the bridging.
SRH A lot of the odd shapes and sizes are not near as bad today as they were when Hevi-Shot first came out. Another explanation could be bad choke design causing it.... One reason I say this is because there are Turkey chokes out there that can and will handle heavy shot with no problems.
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Joined: Feb 2004
Posts: 13,880 Likes: 16
Sidelock
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Sidelock
Joined: Feb 2004
Posts: 13,880 Likes: 16 |
You may want to double check your trig.
This is a modern chamber/cone drawing. It typifies the modern cone considered to be longer than many early 20th century guns. As you can see, it has a 5* angle per side or 10* included angle cone. A 3* cone measured from either the barrel axis or normal to the barrel axis doesn't jive.
Chuck; You were the one who said this drawing was a "modern cone considered to be longer than many early 20th century guns". In fact it is not a long cone at all. As I said I have double, triple now even quadruple checked my Math. Yes a cone having an angle of 3°1' relative to the bore axis does indeed Jive. In fact to get the much vaunted 1˝" long cone the angle will be on the order of 1°20'12". This is based on a chamber .070" larger than the bore. Inv Tan .035/1.5 = 1.336658978° As has been shown L C Smith was using a longer cone than this 5° one in 1907 & longer still by 1935. You win. I accept that you believe your version is more real than hardened and ground tool steel.
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Joined: Dec 2001
Posts: 12,743
Sidelock
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Sidelock
Joined: Dec 2001
Posts: 12,743 |
Chuck;
I truly find it extremely hard to believe I am having this conversation with you of alL people. I have a bit of knowledge of your background. Like I have said several times "JUST DO THE MATH". it's simple trig. I am not disputing what Clymer ground there reamers to or what SAAMI specs say. It's just that those figures "DO NOT PRODUCE A LONG FORCING CONE". That's all I am saying. I simply quoted the angles from the shop drawings for L C Smith & You told me they couldn't be right because they were a lesser angle than these "NEW MODERN LONG CONE REAMERS". Well a 5° angle reamer does not cut a long cone, simple as that. I don't currently have an L C Smith to actually measure, but the 3°1' & 3°13' figures came directly off of a shop drawing as published in the PLans & Specifications book by Brophy, I have no reason to dispute them. What Clymer is cutting their reamers to today has no bearing on what Smith was using in 1935.
Miller/TN
I Didn't Say Everything I Said, Yogi Berra
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