Posted October 25, 2024Oct 25 Community Expert comment_4159065 Taken from the "The Yorkshire Gent" website. I'd found it difficult to find the 20 bore figures in 'English'.
October 25, 2024Oct 25 Community Expert comment_4159079 Interesting on the 20 bore. Both Holland and Holland and Purdey put half choke in at .016, 3/4 at .024 and full at .032. And how I bore them today.
October 25, 2024Oct 25 Author Community Expert comment_4159105 1 hour ago, Fil said: Interesting on the 20 bore. Both Holland and Holland and Purdey put half choke in at .016, 3/4 at .024 and full at .032. And how I bore them today. I could not find any two sites that were in total agreement. The above and the Parker Gun Collectors Association came nearest to doing so and were middlest to diddlest to all the rest.
October 25, 2024Oct 25 Community Expert comment_4159116 12 minutes ago, wymberley said: I could not find any two sites that were in total agreement. The above and the Parker Gun Collectors Association came nearest to doing so and were middlest to diddlest to all the rest. LOL. I'm not surprised. All the manufacturers have their own way within a few thou or so. Some are just bizarre. Especially on the cheaper guns. If anyone's interested I can post the chart that Purdey and Holland and Holland use. Even they do differ a bit. H&H followed the standard chart that you posted. Their choke always measured as per the chart but it was all about angle and lead into the choke to alter the spread to get the correct pellet count. Purdey had there own type of choking. Mainly a set amount of restriction to get the desired pellet count for a particular choke. It depended on cartridge used (65mm or 70mm) One was called 3/4 modified. Which was about 1/2 to you and I using a 65mm cartridge. And then there was "choke" this is 3/4 to you and I. Again using a 65mm cartridge. Purdey had their own language practically. The "recipe" helped us to bore the chokes to said restriction knowing that it will shoot roughly that choke with only a bit of tweaking needed on the pattern plate. Speeded things up.
October 25, 2024Oct 25 Community Expert comment_4159144 1 hour ago, Fil said: LOL. I'm not surprised. All the manufacturers have their own way within a few thou or so. Some are just bizarre. Especially on the cheaper guns. If anyone's interested I can post the chart that Purdey and Holland and Holland use. Even they do differ a bit. H&H followed the standard chart that you posted. Their choke always measured as per the chart but it was all about angle and lead into the choke to alter the spread to get the correct pellet count. Purdey had there own type of choking. Mainly a set amount of restriction to get the desired pellet count for a particular choke. It depended on cartridge used (65mm or 70mm) One was called 3/4 modified. Which was about 1/2 to you and I using a 65mm cartridge. And then there was "choke" this is 3/4 to you and I. Again using a 65mm cartridge. Purdey had their own language practically. The "recipe" helped us to bore the chokes to said restriction knowing that it will shoot roughly that choke with only a bit of tweaking needed on the pattern plate. Speeded things up. Hello, The Chart would be of interest ?
October 25, 2024Oct 25 Community Expert comment_4159152 Hello, Interesting Post Wymberley , I remember a Chart going back a few years with Eley cartridges ( Grand Prix ) 6s and Choke sizes at 30 yards in a 30 inch circle , Those Eley were the go to cartridges until those cheapies like Baikal were selling in gun shops and clay shooting grounds, I had my side by side Yeoman/ No 3 and 4 bored out to improved/ half from half/full and made a good difference shooting over decoys, This new to me Lanber 20 i have started with 1/4/3/4 using 6s and 7.5s , Edited October 25, 2024Oct 25 by oldypigeonpopper
October 25, 2024Oct 25 Community Expert comment_4159158 If you treat choke as a reduction in the area of the muzzle (and ignore difference in choke lengthor shape), 40thou in a 12b is equivalent to 32thou in 20b.
October 28, 2024Oct 28 Community Expert comment_4159704 On 25/10/2024 at 20:08, Stonepark said: If you treat choke as a reduction in the area of the muzzle (and ignore difference in choke lengthor shape), 40thou in a 12b is equivalent to 32thou in 20b. I guarantee you two chokes of the same restriction with different lead in and shape will pattern differently. But in laymens terms yes the measurement of restriction is what most people are interested in.
October 28, 2024Oct 28 Community Expert comment_4159723 20 minutes ago, Fil said: I guarantee you two chokes of the same restriction with different lead in and shape will pattern differently. But in laymens terms yes the measurement of restriction is what most people are interested in. Yes indeed and that is why so many of us had our guns regulated to a particular cartridge and choking. Dave Lowrie used to the work for me in Otford in Kent and I was using Winchester Trap 100's for EVERYTHING in those days.
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