Choke
Unless your gun is a dedicated skeet shooter’s tool, you will probably find that the barrel(s) of your gun are choked, which means that the barrel’s inside diameter is smaller at the muzzle end. The idea of this is to constrict the shot string as it leaves the barrel to produce a tighter shot pattern at a greater distance, for instance a 30inch pattern can be brought down to a 12inch circle. A fixed choke gun has the inside of its barrel bored out with a long funnel shape towards the muzzle when it is made, a multi choke gun has several shorter funnel shaped tubes which can be screwed into the muzzle end of the barrel to provide any constriction the shooter thinks necessary.
Choke of any shotgun is calculated by measuring the nominal bore of the barrel, (12g is somewhere around 0.729 of an inch depending on manufacturer), then adding a constriction of up to 40 thousandths of an inch, therefore cylinder is the same as the bore, 1/4 choke is the nominal bore less 10thou, 1/2 choke is the nominal bore less 20thou, 3/4 choke is the nominal bore less 30thou and full choke is the nominal bore less 40thou. There are other systems which include extra full chokes and intermediate chokes, star markings, notch marks and different names, to find out exactly what you have on your gun, go to your friendly, neighbourhood gunsmith or have a look below.
Using chokes
Having said that, I use a multi-choke gun and have come to the conclusion that I wouldn’t buy one again but go for a fixed 1/4 and 1/2. I have tried everything where chokes are concerned and am the proud owner of three sets – Browning, Briley and Teague. I’ve settled on 3/8 and 3/8 and now shoot whatever comes around with just those two tubes. Using this combination on a good day, I have shot long 45 yard high crossers consistently which seems to me to prove that the pattern is there without going any tighter – I am inclined to believe that cartridges are more of a factor in my shooting than the size of the hole in the end of the barrel. Just remember that as lead prices lead to more expensive cartridges, steel becomes an option. Make sure your gun is capable of using steel and whatever you do, don’t use steel through tight chokes – ask you friendly local gunsmith first.
Choke Markings
Since I’ve been writing this stuff on the interweb several of those who look at my scribings are searching for information about choke markings. It seems to me that each manufacturer has his own way of showing the constriction of each tube or in the case of fixed chokes, each barrel. To my mind there needn’t be that much to worry about because all you need is a choke gauge or one of your fingers to get some idea of each choke in relation to the rest, it’s easy to find out which is the tightest and which is the widest so you can use that knowledge to set up the gun for whatever you’re shooting.
I reckon it doesn’t matter if you don’t have total accuracy in choke measurement – some of the top shooters only use 1/2 choke on 50yd targets, I have broken good targets with 3/8 in both barrels. Some fixed choke guns will have a marking system under the chamber similar to the star markings as below otherwise you’ll have to try to measure them with internal calipers to find out what the constriction is.
Each gun maker will have his own chokes purpose made for his guns so there shouldn’t be a problem there, fit the tube marked 1/2 and you will be choked 1/2 – or will you? I did some research on one of my Brownings when I proved that this isn’t necessarily the case – each barrel is bored to a different size so that the tube marked 1/2 was 1/2 choke in one barrel and 3/8 choke in the other barrel. Bear in mind what we already know – choke size is not regulated and written in stone that it shall be so many thousands of an inch for quarter etc. choke is a restriction in relation to the nominal bore of your barrel. For example, if your barrel is 0.737″ then 1/4 choke will be 0.727″ and 3/4 choke will be 0.707″. Therefore, just because a choke fitted to your barrel is marked 1/4 it doesn’t necessarily follow that barrel will have l /4 choke; you need to know the size of the barrel’s insides and work out the restriction. Your friendly, local gunsmith will measure everything for you if you ask nicely.
Most of us will have tried to beat the rest by using after-market choke tubes, I have several sets from different makers; they and the manufacturers have different ways of marking them to denote size. Some will have written descriptions on the tube, for example, cylinder, skeet, improved, modified; others will have notches cut into the edge of the tubes, others still a system of stars and the best quality chokes will also give a size for each as we’ve seen above i.e. 0.706″. As a general guide:-
1 star or notch is Full choke
2 stars or notches is Improved Modified or 3/4 choke
3 stars or notches is Modified or 1/2 choke
4 stars or notches is Improved Cylinder or 1/4 choke
5 stars or notches is Cylinder or no choke, this tube may also have no markings at all. This all pales into insignificance when you look to buying choke tubes from someone such as Teague or Briley whose websites show reference charts which are mindboggling if you don’t understand some of what goes before. The star system is only part of the story, if you really want to go the whole hog there are probably 9 or 10 tubes offered as standard, complete with descriptions based on the American Cyl, Mod, Full sizes. I suppose it’s technically feasible to own a complete set of over 46 chokes from 0 to 45 thou for each barrel but I still don’t see the point, breaking clays depends on barrel direction, cartridge, trajectory, technique – the choke is there to make the shot pattern tighter at longer distances but it doesn’t mean that the pattern you’ve already got won’t break the target at that distance. Don’t get fixated on choke marking and size like someone I knew years ago who couldn’t hit a thing because he was too worried about changing each choke after each target, if you’re reading this you are like me – you aren’t a professional so don’t mess about with them, fit 1/4 and 1/2 and go break targets.
More Choke
Due to the wonders of the web and everything that goes with it, I’ve noticed lots of people searching for choke info. There’s a bit on the previous page which mentions the subject but I have made up the table below showing choke constrictions in thousandths of an inch alongside common names.
Just remember that your gun and choke names or sizes, whether they’re fixed or multi, may not fall exactly into place, the information is here for a guide only. If you want accurate measurements go to your friendly local gunsmith who will be more than happy to tell you what you are shooting with. To complicate matters even further, different countries have various ways of naming chokes, so once again – this table is a guide only, for a definitive answer to your choke questions, ask a gunsmith about your own shotgun and chokes.