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Forums10
Topics38,481
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Most Online1,335
Apr 27th, 2024
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Joined: Mar 2002
Posts: 1,815 Likes: 4
Sidelock
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OP
Sidelock
Joined: Mar 2002
Posts: 1,815 Likes: 4 |
I am often wondering what the relative chokes are in gauges other that 12 ga and found this in my files. THought it would be of interest. [img:left]  [/img]
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Joined: Jun 2003
Posts: 592 Likes: 2
Sidelock
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Sidelock
Joined: Jun 2003
Posts: 592 Likes: 2 |
Thank you Stallones. Very handy to print out and keep at the workbench.
-jmc
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Joined: Jan 2002
Posts: 1,435 Likes: 1
Sidelock
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Sidelock
Joined: Jan 2002
Posts: 1,435 Likes: 1 |
Don't think I'd ever seen the #1 comment under miscellaneous on that chart. I don't think that is true for British guns.
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Joined: Mar 2002
Posts: 1,815 Likes: 4
Sidelock
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OP
Sidelock
Joined: Mar 2002
Posts: 1,815 Likes: 4 |
Bob,I think they are referring to modern European bores.
My Renato Gambas both have .723-.725 bores
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Joined: Jan 2002
Posts: 11,377 Likes: 105
Sidelock
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Sidelock
Joined: Jan 2002
Posts: 11,377 Likes: 105 |
Some Italian guns are underbored. My 40 year old Bernardelli is just a little tighter than Stallones' Gambas.
Although the Brit 12ga standard is .729, their 16ga standard is .662, which is smaller than the figure given.
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Joined: Dec 2001
Posts: 12,743
Sidelock
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Sidelock
Joined: Dec 2001
Posts: 12,743 |
I think the "True Bore Diameter" term here is an attempt to try to define what the makers use.
"True Gauge" by the formula of what a bore size pure lead ball weighs is 10ga = .775", 12ga = .729", 16ga = .662". 20ga = .615", 28ga = .550" & a .67.49ga = .410". These sizes are recorded by the proof houses.
The old full choke reduction of .040 in a 12 gave an 11% reduction of bore size, a more modern one of .030" gives a reduction of 8%. Lesser constrictions of course give lesser %.
Miller/TN
I Didn't Say Everything I Said, Yogi Berra
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Joined: Feb 2002
Posts: 520
Sidelock
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Sidelock
Joined: Feb 2002
Posts: 520 |
They sort of shifted the Full constriction when shot collars and wads started producing tighter patterns with the same constriction. Full choke for a 12 gauge was 0.040" constriction for a loooong time.
Last edited by Virginian; 02/26/13 10:16 PM.
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Joined: Jan 2003
Posts: 1,227
Sidelock
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Sidelock
Joined: Jan 2003
Posts: 1,227 |
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Joined: Oct 2004
Posts: 1,826 Likes: 12
Sidelock
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Sidelock
Joined: Oct 2004
Posts: 1,826 Likes: 12 |
Some old charts I've seen for 12ga the chokes go by .005 -sk/.005 , Ic/.010 , LM/.015 and so forth. Why is it when going from IM/.025 to full it jumps by .010 on some charts ? In one old chart full is .030 - as it should be IMHO. Paul
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Joined: Jan 2003
Posts: 1,227
Sidelock
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Sidelock
Joined: Jan 2003
Posts: 1,227 |
Look at the Briley Chart....they stay with .005 increments.
Check out the Maker's chart. Some use 35 pts, most of them use 40 pts for full and at a glance I don't see anybody claiming Full with 30 pts.
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