Bloody Chokes!

[jon0881]

Why cant there be one standard for chokes........

 

There is 1/2,1/4 etc for english, then improved cyl, mod cyl etc for american then theres the italian */10!

 

http://www.briley.com/index.asp?PageAction=Custom&ID=51

 

All of which can be marked with 'I','II' etc

 

I have a E Rizzini which is marked up with the 'I's and as it was my first shotgun i was told to put III and IIII in and forget about it. The person told me this was 1/4 and 1/2.......im not so sure. Its an Italian, so i wouldnt mind checking i am right here. I seem to do ok with this setup though

 

Ive just ordered a new escort which comes with the cyl, imp cyl chokes. For pigeons and most of my clay work i was going to put the imp cyl.

 

[Markio]

Certainly for my Lanber it is:

 

No Notch = Cylinder = Cylinder

IIII = 1/4 = Improved Cylinder (IC)

III = 1/2 = Modified (M)

II = 3/4 = Improved Modified (IM)

I = Full = Full

 

And yes, 90% on here will agree with sticking in 1/4 & 1/2 and forget about them. Just take them out when you clean the gun to make sure they will come out when you need them too!

 

EDIT: The above is all well and good for sporting clays but for skeet then the aptly named skeet chokes are the way to go (is the constriction somewhere between Cylinder and 1.4?). For DTL then more like 1/4 and 3/4. Again for pigeons then 1/4 & 1/2. So you are spot on with fitting an IC choke to your Escort.

[dazzyboi]

I have 1/2 in the top and 1/4 in the bottom on my lanber, which are as below:

 

IIII = 1/4 = Improved Cylinder (IC)

III = 1/2 = Modified (M)

[Sundodger]

Hi Guys I have been going through the olds posts and thought I would bring this back to the top. I would like a bit more information I have just bought my new gun (second hand) and it is a multi chioke which is a first for me, it is an italian make and the chokes fitted are :

No Notch = Cylinder = Cylinder

IIII = 1/4 = Improved Cylinder

I am going to use the gun for pigeons and clays are the chokes fitted OK or should I change them and why?

[mry716]

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)