Browning Invector + chokes ..............

[the_commoner]

earlier for some reason dropped a choke guage into the top of my semi auto which had a 4 notch Imp Cyl invector plus choke tube in, the guage dropped right the way down to the end and there was still some movement, the 3 notch which i would consider to be 1/2, drops down to cylinder .............. whats the deal ? anyone enlighten me

[Peter De La Mare]

There is a way to work out the constriction after taking into account the actual barrel bore before the chokes. Backboring changes everything, and no, I don't understand how.

[BlaserF3]

The best place for a drop in choke gauge is the bin.

 

The bore of the gun needs to be measured using a dial gauge then the choke area can be measured which will give you the constriction of the choke.

[seeker]

A fixed choke gauge tells you there's a hole .... but it should be spot on for the gun it was made for... also useful for pipe smokers..

A bore micrometer let's you measure the difference between the bore and choke and tells you what it might do...

Try this link for the ratios

http://www.hallowellco.com/choke_chart.htm

BUT have a look at the BASC site for their article on shotgun patterns and what you might actually get?

[BlaserF3]

Here is another http://www.thefield.co.uk/features/433449/...tgun_choke.html

[the_commoner]

i think i have found the answer in so much as the invector chokes are not the same diameter/bore as a fixed choke but they will throw out the same pattern so what appears on the face of it as a measurement of diameter to be cylinder actually throws out a pattern equivelant to a fixed choke of 1/2 ................

[casts_by_fly]

The 'choke' of a gun refers to how much constriction the shot receives from the barrel diameter to the end of the choke diameter, i.e. the difference between the muzzle opening and barrel ID. For the most part, 10 points of constriction (0.010") will give the same pattern whether the bore diameter is small, normal, or overbored.

 

The invector plus barrels are overbored (over normal diameter) so the chokes will be also as you're seeing.

 

Throw away the fixed choke gauge unless it gives the actual diameters, not just IC/Mod, etc AND you're checking the barrels for proof diameter.

 

Thanks

Rick