Clay Target Q&A
With Russell Mark, Olympic gold and silver medallist
Questions: russell@corporateshootingstars.com.au
Q I am totally confused about the choke tubes I have for a secondhand Perazzi 12-gauge MX 8 shotgun that I purchased recently. It has had variable screw-in choke tubes fitted after the first owner purchased the gun. It has four different chokes with numbers and markings stamped on the side of them that mean nothing at all to me. Can you enlighten me as to what each choke tube may be?
Ken Nader, Qld
A Ken, this is not an easy question to answer without knowing the exact internal measurement (nominal bore size) of your barrel and the markings on each choke tube. You need to measure the barrel before I can give you an accurate answer, but I will make some assumptions on typical Perazzi, and most Italian, barrels that I have seen.
If the internal measurement is .725" (sorry to use imperial measurements, but I am guessing the chokes that have been fitted after the factory built the gun may be American ‘Briley’ chokes which will be marked in imperial specifications), then for every 10 thousandths of an inch the barrel is constricted or tightened, you are going up roughly one choke size. Therefore, if you have a choke that is marked .715, then you have a quarter choke, .705 would equal half, .695 is three-quarter and .685 is full. The latter gives a full 40 thousandths constriction for this barrel on the assumption that its nominal bore size is .725. This is generally accepted as the maximum full choke.
No restriction in bore diameter is called true ‘Cylinder’, but please do not shoot the gun without screwing in any choke tube at all, as it may damage the barrel or the thread that the tubes will be screwed into. Five thousandths of constriction above the barrel’s nominal bore size is commonly called a ‘Skeet’ choke. Quarter choke is often referred to as ‘Improved Cylinder’ and is sometimes marked on many screw-in choke tubes with four stars or four lines. Half choke is ‘Modified’ and identified with three stars, three-quarter choke is known as ‘Improved Modified’ with two stars and full choke is simply known as ‘Full’ and is identified often with one star or line on the choke tube.
A quick check as to your barrel’s bore size may be found underneath your fore-end as it is stamped on the barrel on most Italian shotguns as part of their barrel proofing laws. It will be a number such as 18.4, which is the metric version of approximately .725" (it is actually .724" to be exact). Generally, Italian barrels are most commonly made with a bore size of 18.4mm, but it is not uncommon to find barrels of 18.3mm (.720"), 18.5mm (.728") or 18.6mm (.732"). Don’t confuse this with the other numbers stamped on the barrel such as 1.55, 1.58 or 1.62, as this refers to the net barrel weight in kilograms and has nothing to do with bore size or chokes.
As to what chokes you should be using, this is a whole different subject altogether. This will depend on what distance you are shooting at, what shotshells you are using and what you are trying to knock out of the sky with your shotgun. With all of this knowledge don’t forget the words of advice I once received from Mr Les Hendra, one of the oldest members of my local club at Werribee. He said, “Sonny, there has been no choke ever made that will replace accuracy.” And that’s great advice!