Chokes

[dankidd]

I bought a multi choke over and under about a year ago and ive only ever used the two that were in the gun when i bought it because I didnt know the choke codes! I seem to shoot fine with the ones that are in. On the end of each choke there is a number. These are 2, 5, 7 and 11. I shoot with chokes 2 and 7. Can anybody shed any light on what the chokes are?!

[RAMMER BURT]

what make of gun are the chokes fitted in

[RAMMER BURT]

this may help

Choke is a carefully measured constriction of the bore of a shotgun at the muzzle, designed to control the spread of the shot as it leaves the barrel.

 

Hallowell & Co.'s descriptions of choke borings are determined by measuring with a bore micrometer, irrespective of any markings on the barrels. The internal diameter is measured four inches from the muzzle and again just at the muzzle. Subtracting, gives the amount of constriction in thousandths of an inch.

 

In our descriptions of each gun, chokes are listed in the order of the normal sequence of firing and abbreviated as under the following American Designations:

 

12 Gauge 20 Gauge 28 Gauge .410" Bore American English Browning Italian Perazzi Percentage

Constriction Constriction Constriction Constriction Designation Designation Codes Codes Codes Pattern

.000" -.001" .000" - .001" .000" .000" cyl true cylinder *** C**** 0 40%

.002" - .006" .002" - .004" .001" - .004" .001" - .002" skeet impr cylinder **$ S 1 45%

.007" -.013" .005" - .011" .005" - .007" .003" - .006" imp cyl quarter **- **** 3 55%

.014" -.023" .012" - .019" .008" - .014" .007 - .012" mod half ** *** 4 60%

.024" -.031" .020" - .026" .015" - .020" .013" - .017 " imp mod three quarter *- ** 6 65%

.032" -.040" .027" - .033" .021" - .027" .018" - .021" full full * * 9 70%

.040"+ .034"+ .028"+ .022"+ ex. full 10 75%

 

The dimensions used in the above table are rules of thumb. Bore measurements by micrometer are useful to predict the pattern thrown by a shotgun barrel, but they remain merely a prediction. The only way to determine the actual pattern thrown by a shotgun barrel is to shoot it, by convention at 40 yards, count the percentage of pellets falling within a 30" circle placed around the visual center of the pattern (as in the right-hand column of the above chart), then do it a few more times and take an average.

[dankidd]

Its a Sarriugarte - Its a Spanish gun.... Ive seen that info on a website but it didnt seem to help!

[mikee]

just look at the wall thickness of each choke the thinner walls will be the more open chokes, I generally shoot with 1/2 in the bottom and 3/4 in the top, these are tighter with thicker walls, skeet and 1/4 will have thinner walls

 

mikee

[seeker]

FWIW: Long ago I had a Kemen which came from the same part of the world as your gun. It had a set of Briley made numbered chokes. The higher the number the tighter the choke and they were in 0.1mm increments. Since 0.1 mm is a small fraction under 0.004" a #5 was about 20thou or around half choke.

Some German guns used the same system.

So perhaps your gun MAY use this system? But this is the input side .. as said above shoot pattern sheets and count holes for the actual output.

Or be happy with what's there and concentrate of having fun shooting.

[clayman]

The actual pattern any gun throws from the designated chokes will vary with wear of the gun, manufacturing tolerances, shot load and powder types.

 

Any designation on a choke is only a guide.

 

Best way to find out about your chokes is to pattern the gun.

 

Take a box of your favourite loads, and at 20m shoot a couple of shots at flip chart size bits of paper, or find a ground with a pattern plate. The paper record is best as you can take it away and analyse it.

 

This exersize will tell you about gun fit problems, master eye problems, as well as giving you a true insight into how each choke in the gun performs.

 

The ideal pattern is to have about 2/3rds of the pellet count inside a 30" circle at the range you are shooting.

 

Good ranges for shooting each choke will be target/choke combo around the following guideleines:

 

cy up to-20m

1/4 20-25m

1/2 25-30m

3/4 30-40m

Full 40m +

 

When in dought, choke down.

 

A choke tighter than that needed for the range will always have enough pellet density to kill / break - while a choke too open risks spraying the target but failing to break it. If you are overtight, better aim is needed as pattern will be smaller, but the kill is certain if the target is within the pattern.

[wymberley]

Hi,

Noticed the NGO membership and although you don't say so, it may be that you're going to use this gun for live quarry. If so and you decide to pattern it (which always makes sense), it's best to do it properly. For game, a couple of shots at 20 ms is meaningless. For research 10 shots is the usual standard but for field assessment, 6 is deemed satisfactory. There are plenty of references available and the BASC web-site - research dept., information and fact sheets - has some good info.

Cheers

Edited August 17, 2010 by wymberley