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Thread: Slug and Rifled Choke Question

  1. #21
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    Next time you shoot those slugs use a Diamond shaped target and put the edge of the Red Dot against the left point of the target. Your group will shrink dramatically and the center of the group should print just above and to the left of the point of the diamond. That amount will be half of however big your Red Dot is. IE; 3 MOA dot would yield 1.5" to the left.

    Shooting groups with a Red Dot is all about being able to repeatedly index the dot on the target at the exact same place everytime.

    Hope this helps

    Randy
    "It's not how well you do what you know how to do,,,It's how well you do what you DON'T know how to do!"
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  2. #22
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    Randy,
    How is shooting as you described superior to holding center on a conventional black circular target? Do you believe that centering a red dot in a black circle is less precise? I don't want to start an argument here, I'm just curious. As a person with a vision deficit I find that I shoot better groups holding center on a regular black bull.
    "We take a thousand moments for granted thinking there will be a thousand more to come. Each day, each breath, each beat of your heart is a gift. Live with love & joy, tomorrow is not promised to anyone......"

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  3. #23
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    Quote Originally Posted by W.R.Buchanan View Post
    Kent: Your pics were greatly appreciated! Especially the one muzzle on, as it really shows how deep that rifling was. You can see that the Paradox Slugs had ample room for Lead Displacement so deep rifling would certainly bite and spin the slugs. The grooves look like they are a faster twist than the Carlson's Choke Tube..

    So on the Carlson's Rifled tube I have the Grooves measure .729 and the Lands measure .710. so that means the rifling is .010 deep on each side! Which is a lot deeper than I would have guessed. But wait,,, At the entrance to the tube the grooves are .742 and the lands are .738? So this thing is Choked/Tapered, as well as being rifled. So in the end the grooves go from .002 deep to .010 deep! Go figure?, and obviously we don't know what they were thinking when they designed this thing?

    Maybe I'll call them and ask?

    Oh, and that H&H Paradox was L130,000 plus VAT!

    Randy

    I measured my 20 gauge Carlson's rifled choke.

    I can confirm tapered rifling but my lands are only 0.0055" high at the muzzle. Entrance lands height is 0.002" after a 1/4" long smooth freebore.

    So the entrance is 0.629" no rifling freebore for 1/4" length. Then the groove starts at 0.627 and tapers down to 0.619" at the muzzle end. Lands start at 0.623" and taper down to 0.608" at the muzzle.

    There must have been some experienced brains working on the design. It's not just a simple straight rifled tube. At least they have tried to make the transition to spinning a smooth one.


    I can push both my russian fullbore slugs in the entrance for that 1/4".


  4. #24
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    I tried calling Carlson's today but the guy I needed to talk to is at the SHOT Show all this week.

    I'll call back next week and find out the thinking behind the tapered configuration.

    We need answers, and I'm gonna get 'em!

    Randy
    "It's not how well you do what you know how to do,,,It's how well you do what you DON'T know how to do!"
    www.buchananprecisionmachine.com

  5. #25
    Boolit Grand Master

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    In my opinion tapered/choked rifling makes sense to squeeze and grip the slug... as the original Paradox guns were rifled.

    What doesn't make sense to me is Randy's much oversize land and groove diameters at the choke entrance. Groove diameter should start at or very slightly larger than nominal barrel bore diameter of 0.729" ( for 12 ga.) then tighten from there. Lands should have a short taper lead in then taper down with grooves or even more than grooves resulting in increasing rifling depth.

    My thoughts anyway.

    Longbow

  6. #26
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    Kent: The choke tube is tapered both in the lands and grooves, and choked from back to front.

    I did verify that with the Carlson's guy today, He didn't know why, and the guy who does is in Las Vegas. I'll pick his brain when he gets back next week.

    It is not easy to measure this with accuracy and I had to do it several times to get numbers to Repeat.

    Randy
    "It's not how well you do what you know how to do,,,It's how well you do what you DON'T know how to do!"
    www.buchananprecisionmachine.com

  7. #27
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    Yes, both mine and Petander's choke tubes seem to have the same tapered rifling in grooves and on lands. Easy to have tapered lands, not so easy to have tapered grooves!

    That was one of the questions I asked H&H... are the grooves cut straight through a choked muzzle or are the grooves cut with a choked form as well? But no answer there.

    If your rifling is as deep as you say your choke tube is much different than mine. As best I can measure my lands and grooves both taper smaller diameter towards the muzzle but rifling is only about 0.005" deep at the muzzle. That was one of my complaints about modern rifled choke tubes, rifling is shallow. The Paradox guns were apparently rifled from bore of at least 0.735" down to as small as 0.690" land I.D. (not sure about grooves) but that means squeezing a slug or ball from 0.735"+ down to 0.690" which is some squeeze! If grooves are chokes as well that is a really tight squeeze!

    I'll be interested in what you find out for sure!

    Of course none of this is helping the OP!

    Longbow

  8. #28
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    OK; I stand corrected; I measured it again, This time with a light shining thru so I could see where the Caliper ID hooks were placed and got .720 over the lands and .730 in the grooves. So that means that the rifling is .005 on a side at the Muzzle End.

    There is a Forcing cone that is about .250 long and tapers from .750 at the opening to .742 where the lands start. The forcing cone is there so that the choke tube would never be smaller than the bore of the barrel and always avoid shaving lead or blowing the tube completely out of the Barrel.

    The grooves are .742 at that point and lands are .738 so the rifling is .002 deep on a side, which is what I got last time.

    What I got wrong last time was the ID of the lands at teh Muzzle End. Which I thought were .710 instead of .720.

    I have been cogitating on how they would make this thing and the only way I can come up with is to Hammer Forge it over a Mandrel. You could never get the internal finish they have by any cutting method.

    My only other question is how they got the Knurling on after they hammer forged the tube with out collapsing it. The threads are no problem.

    My last question is how they came up with the tapered internals idea? I'll have to wait til next week to get that answer.

    Randy
    "It's not how well you do what you know how to do,,,It's how well you do what you DON'T know how to do!"
    www.buchananprecisionmachine.com

  9. #29
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    Quote Originally Posted by centershot View Post
    Randy,
    How is shooting as you described superior to holding center on a conventional black circular target? Do you believe that centering a red dot in a black circle is less precise? I don't want to start an argument here, I'm just curious. As a person with a vision deficit I find that I shoot better groups holding center on a regular black bull.
    CTRShot" if your dot is the same size as the target spot then it would be fairly easy to index it in the same place for every shot. However if the target spot is much bigger or smaller then it is almost impossible to index the dot on it perfectly everytime. Also Red Dots on the less expensive Red Dot Sights are seldom perfectly round. I have 6 Bushnell TRS 25 and none of them have round dots due to the reflective pattern that the light has travel thru. The lenses are angled to reflect the dot to a given place on the final lens. The fact that they are angled is what distorts the shape of the dot.

    By placing the edge of whatever shape you've got against the point of the diamond you can easily index it the same way every time no matter the shape of the dot. If the Dot is supposed to be 3MOA then the group should be 1.5" off the point of the diamond when everything is aligned. Here's a target I shot with my Mini14. This was re-sighting after taking the optic off the gun and putting it back on.

    The Elevation was close, but the Windage had moved to the left. The single hole to the left was the first shot and then I corrected to move the group to the right and up, but I went about 2 clicks too far but still left it alone. The group should have been about 1" to the left to be dead on. This was shot at 100 yards and was set up for a 200 yard zero.

    This little tidbit was given to me by Brian Pearce of Handloader/Rifle Magazines. Him and his sons shot more in one week than all of us put together will shoot in a lifetime. They get better groups than we do by shooting more and by learning how to index the gun's sights on a given target. With Open or Aperture Sights they index the Front Sight on the bottom point of the target, and they can center that front sight perfectly on the bottom point of a diamond shaped target.

    With Scope Sighted Rifles they use the cross lines on the target to index the cross hairs on both planes. That is fairly easy to get repeat shots on the same POA.

    Randy
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    Last edited by W.R.Buchanan; 01-18-2022 at 10:56 PM.
    "It's not how well you do what you know how to do,,,It's how well you do what you DON'T know how to do!"
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  10. #30
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    Randy:

    The grooves in my choke tube look to be cut to me... whether broached or single hook cutter I don't know but there are longitudinal striations that look like they were left by a cutting tool.

    I hope you get some answers next week.

    I e-mailed Carlson's with questions but no response yet.

    Longbow

  11. #31
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    Quote Originally Posted by W.R.Buchanan View Post
    Next time you shoot those slugs use a Diamond shaped target and put the edge of the Red Dot against the left point of the target. Your group will shrink dramatically and the center of the group should print just above and to the left of the point of the diamond. That amount will be half of however big your Red Dot is. IE; 3 MOA dot would yield 1.5" to the left.

    Shooting groups with a Red Dot is all about being able to repeatedly index the dot on the target at the exact same place everytime.

    Hope this helps

    Randy
    thanks ill try that.This is the first red dot ive owned,The dot looks more like a left leaning line which im sure is my eyes. my red dot is 3MOA

  12. #32
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    The Carson's Choke plot thickens.

    Randy's observations made me go and get my 20 gauge Carlson's choke again, to take a better look and voila',I discovered a separate ,short steep taper right there at the tube entrance. I somehow missed it the last time.

    So my real tube entrance edge is 0.633", then after 0.060" length it has tapered down to 0.628". Then, after about 0.190" it has tapered down to 0.6255" and that's where the lands start.

    So there is a short steep taper,followed by a longer smooth, not so steep taper. Then the lands start and everything keeps getting tighter while the lands also grow higher.


  13. #33
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    Back to your original question...

    something you should check is slug in wad fit to bore. The fit of slug in wad in your smoothbore barrel should be "snug". Ajay (SuperBlazingSabots) said 6lb. to 10 lb. push through force gives best accuracy for smoothbore. You will also want a pretty tight fit of slug/wad through the rifled choke tube to avoid skidding or slug in wad or stripping of plastic wad in rifling... though you have what you have for smooth bore barrel and rifled choke tube.

    The choke tube should be 0.730" groove diameter so if your smoothbore barrel is 0.729"/0.730" things should work reasonably well.

    You may get better results with tighter or looser fitting wads. It is good to try a few.

    Longbow

  14. #34
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    OK: I talked to Scott at Carlson's yesterday and got some info on the Rifled Choke Tubes. During the evolution of the product they did in fact taper the inside of the tube so that they would pattern slugs better.

    They also found that the sweet spot for Velocity was 1600 fps with Factory Ammo. And they only used factory ammo in their tests. They got 2" groups at 100 yards with some ammo, and Brenneke's "Classic Magnums" were the best.

    The Rifled Choke Tubes pattern Bird Shot like an IC tube. But they don't recommend shooting much shot thru one as they will get shot out.

    He wouldn't divulge how they make these tubes, so our speculations will not be confirmed. They may be "Broached" as he did mention that they do that to other tubes.

    Another tid bit is that there is a "strait section" for about 1/2" before the muzzle. This is true for all their Choke Tubes. And all our measurements were confirmed. This comes from the Jug Choke tech from long ago, which we discussed at length here previously.

    I had a good talk with him and I hope he shows up here to participate in the forum..

    Randy
    "It's not how well you do what you know how to do,,,It's how well you do what you DON'T know how to do!"
    www.buchananprecisionmachine.com

  15. #35
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    @Petlander, all choke tubes are chamfered like that right at the mouth. It keeps them from catching the shot/slug.

  16. #36
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    Yes; it works just like a Forcing Cone, but the main purpose is to be smaller than the bore preceding it so nothing hangs up on it.

    The taper in the Rifled Chokes is to slowly,,, (Relatively Speaking?) compress the slug into the shape of the rifling as opposed to abruptly reforming it..

    Randy
    "It's not how well you do what you know how to do,,,It's how well you do what you DON'T know how to do!"
    www.buchananprecisionmachine.com

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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check