auto culto Posted June 11, 2007 Report Share Posted June 11, 2007 Hi i have a multi-choke semi 12g and i have allway been under the impression that full choke etc would be very similar in size to other full choke guns, but the other day i bought a choke gauge (god knows why but i did) and checked out my chokes . My extra full = 1/4, full = sloppy 1/4 , modified = 1 (whatever that is) and my i could nearly drop the whole gauge through the improved cylinder. How can they be so different to the guage ? even though i can really knock the stuffing out of the high birds with full choke. Quote Link to comment Share on other sites More sharing options...
Hodmedod.one Posted June 11, 2007 Report Share Posted June 11, 2007 Hi i have a multi-choke semi 12g and i have allway been under the impression that full choke etc would be very similar in size to other full choke guns, but the other day i bought a choke gauge (god knows why but i did) and checked out my chokes . My extra full = 1/4, full = sloppy 1/4 , modified = 1 (whatever that is) and my i could nearly drop the whole gauge through the improved cylinder. How can they be so different to the guage ? even though i can really knock the stuffing out of the high birds with full choke. The brass "stepped" type choke gauges are notoriously dodgy bits of kit. Don't pay much attention to it...they make good paperweights though Quote Link to comment Share on other sites More sharing options...
auto culto Posted June 12, 2007 Author Report Share Posted June 12, 2007 Ah i see. I allso checked a mates gun that was spot-on with the guage Quote Link to comment Share on other sites More sharing options...
pin Posted June 12, 2007 Report Share Posted June 12, 2007 Its to do with how the gun is bored, I won't try to explain it do a search as it has been explained by far cleverer people than me, save to say that the constriction each choke provides will be the same but the starting bore on the gun will not be. I think the best summary on this was from Martin (the last engineer), I'll see if I can find it. Quote Link to comment Share on other sites More sharing options...
henry d Posted June 12, 2007 Report Share Posted June 12, 2007 Choke is "Generally" to do with the amount of constriction compared to the bore of the gun, so if the gun is overbored, and some 12`s are virtually 10 bores, then the brass gauge will be as you say sloppy. If you want to check what your gun patterns, then take it and pattern it with the cartridges you will be using, a large sheet of paper or similar of over 4 and preferably 5 feet across to a field that you have permission to shoot on, and attach it to a fence. Then measure 30 yards from the paper and fire a shot at the centre and repeat at least 5 times. You then need to assess these by looking for the apparent centre and drawing a 30" circle, you then count the pellets inside and out and from this work out the "choke" for that cartridge/choke combination. .........or you can look at the pattern and if there aint any big holes in it you can say that`ll do !! Quote Link to comment Share on other sites More sharing options...
dunganick Posted June 12, 2007 Report Share Posted June 12, 2007 choke is simply the difference between the bore and the 'choke', as different guns have different dia. bores, no guns are the same. The only way to be sure of choke is to go into a gun shop and get them to use their tool for measuring the internal bore, then the choke. I;m affraid your 'choke' tool is as said, about as useful as a chocolate teapot, unless it was purpose made for your guns bore. I'm sure pin will find the thread with martins better explanation of this area. Quote Link to comment Share on other sites More sharing options...
auto culto Posted June 12, 2007 Author Report Share Posted June 12, 2007 that's explained it enough for my peeps, cheers . I dont have a problem with the way it shoots and its capable stopping power at range depending on the chokes used as i know the guns capability's. It was just that bloody choke gauge that confused me. Now you've said its all related to the internal bore size i understand whats happening now as its a 3 1/2 inch magnum. Quote Link to comment Share on other sites More sharing options...
mry716 Posted June 13, 2007 Report Share Posted June 13, 2007 Sorry to be late in replying. What you have got to remember is that perhaps a full choke in one barrel is only half in another. Choke is the constriction at the muzzle compared to the bore behind it. If a full choke tube is measured as .689" that will give 40 thou of constriction ie full choke in a barrel bored 729 (standard 12 bore size) but only 20 thou (1/2 choke in a barrel bored 709 (Min 12 bore size or 13 bore) but 50 thou in a barrel showing a size of .739" and 60 thou in a barrel with an internal diameter of .749" (Max 12 bore size or 11 bore). Looking minimum size to maximum means theoretically you could have a full choke tube in one barrel showing cylinder in another. In practice,of course, the variation in size is very limited but it really is something that needs considering. You need to know the internal diameter of the barrel and of the choke tube to find the difference in size and so the amount of constriction and therefore your choke rating. Also remember some take 35 thou as full choke not 40 thou http://doublegunshop.com/choke.htm Imperial 12 bore sizes are:- .710"-.718" .719"-.728" .729"-.739" .740"-.749" Providing 10 thousanths of an inch between proof sizes. Whilst Metric 12 bore sizes are:- 18.1mm-18.9mm although the Proof House will reproof a 12 bore up to 19.1mm if there is sufficient barrel wall thickness. The proof is allowed between any two points ie 18.3-18.5mm So even with metrification, that is now used by UK proof, the size of a 12 bore can still vary by the size of a Full Choke tube. (40 thou) Quote Link to comment Share on other sites More sharing options...
auto culto Posted June 16, 2007 Author Report Share Posted June 16, 2007 cheers mry, very helpfull Quote Link to comment Share on other sites More sharing options...
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