Regular cleaning and inspection of your choke tubes are crucial for optimal performance and longevity. Here are the steps to follow: Clean and grease your choke tube at least twice annually using a soft cloth and a light lubricant, such as gun oil. Inspect the choke tube for any signs of wear or damage.Dec 11, 2023 · I can find no other markings on the gun other than a "G" and "35" stamped on the bottom of the barrel where it is covered by the receiver when the gun is assembled, and also a "G" and "35" stamped on the inside of the receiver where it is covered by the barrel when the gun is assembled. There is no other serial number or choke marking on the gun. Mar 9, 2017 · You don’t say whether your gun is the A5 auto or a Superposed O/U. If an A5, the the choke marking should be on the left rear outside of the barrel. If a Superposed, then on the left side barrel’s breech. Browning choke markings are: * designates full choke (F). *- designates improved modified choke (IM). ** designates modified choke (M). Mar 6, 2011 ... Below is a chart that shows the common markings on a shotgun choke tube. The tightest choke being at the top, Full. Choke Designation ...Choke tube markings are a series of lines, notches, letters, ... Skeet diameters differ based on shotgun brand and choke system. Below is a chart showing the diameter of SK chokes by brand. Type: SK Diameter (inch) Beretta/Benelli Mobil: 0.721: Benelli Crio: 0.722: Beretta Optima Plus:To have it lengthened will cost the same as to lengthen a gun of a higher value. Your £100 Baikal will still be a £100 Baikal even after you paid £80 to lengthen that stock. That's your call. But from a …Invector choke tubes are a standard for early model Browning shotguns, but they also fit certain Winchester and Mossbergshotguns. Invector threads are located at the bottom of the choke and are 1.5-inches long. Standard Invector chokes fit the following shotguns: Winchester Invector. Fits Winchester 1200, 1300, 1400, 1500, & Ranger …I can find no other markings on the gun other than a "G" and "35" stamped on the bottom of the barrel where it is covered by the receiver when the gun is assembled, and also a "G" and "35" stamped on the inside of the receiver where it is covered by the barrel when the gun is assembled. There is no other serial number or choke marking on the gun.j the answer to your question is in the third photo. The right choke has 2 notches cut into it and the left choke has 3 notches. According to Stoeger's website the right choke is an IM or Improved Modified and the left choke is a Mod of Modified choke. Here is a link to their website with the answers you're looking for.(RTTNews) - Today's Daily Dose brings you news about FDA's refusal to approve Aradigm's Linhaliq in its present form; Abeona's progress in its cli... (RTTNews) - Today's Daily Dose...I once had a 1941 37R I rember that the choke was marked full on the side but I do not recall where the 4 was stamped in relation to the serial number. The '46 & '49 guns have the choke numbers in line with the machine operations locator mark and the abbreviated choke on the side of the barrel. The '54 has the abbreviation and the …Factory Choke Identification Codes. AMERICAN TACTICAL IMPORTS. BERETTA. BENELLI/FRANCHI/STOEGER. REMINGTON SPARTAN (SPR) NOTCH CODES. BROWNING …Jul 24, 2004 ... The one where the finger goes in the least is full choke. The one that goes in the furthest is something like Cylinder, Skeet or IC. Once you've ... Choke tubes give a single shotgun the flexibility and freedom to become a decent variety of more specialized firearms used for different purposes. With the right choke tube, they can be an essential tool in improving your marksmanship. If a shotgun has an improved-cylinder choke, the constriction in the barrel is 0.010 inches. If a modified choke, 0.020 inches. If an improved-modified choke, 0.030 inches. A full choke, 0.040 …1. Visual Method. The fastest way to identify the “Family” is to take down one choke you are currently using on your shotgun, clean it and cheek the markings on the side of the choke, here an example: In the example image, you see an Optima-Choke HP Choke. Note: Mobile-Choke “Family” could also be marked as “PB” or “ST”.Feb 20, 2024 · Tristar chokes can be identified by the unique markings or engravings on the choke tubes themselves, which often include the brand name or logo, as well as the constriction size or designation. Some Tristar chokes may also have color-coded bands for easy identification. See 3,000+ New Gun Deals HERE. 1. What markings should I look for on ... May 2, 2024 · The constriction of a Benelli choke tube can be determined by the markings or notches on the end, which indicate its level of tightness. Can I use lead shot with all types of Benelli choke tubes? Most Benelli choke tubes are suitable for use with lead shot, but it’s important to verify this information with the specific choke tube in question. Definition of Chokes. A choke is a tapered constriction of a shotgun’s barrel bore at the muzzle end. Chokes are used to shape the spread of the shot in order to gain better range and accuracy. They come in different types, each designed for a specific purpose in shooting. Definition of Skeet Shooting.The chokes on a Beretta BL3 shotgun can be identified by looking at the engravings on the side of the choke tube. The markings typically indicate the type of choke, such as “C” for cylinder, “IC” for improved cylinder, “M” for modified, and “F” for full. 1.Aug 7, 2008 · The chokes in an L.C. Smith run parrallel for 1" and then taper 1 9/16" to bore size of .729-.732 in 12 ga. Also your gun was made in 1908, and after 1913 the 0 grade became Ideal Grade. The markings on the barrels are probably the barrel makers mark as the 0 grade had London Steel barrels or Damascus steel, I think Chain Damascus. It is a 20 gauge with 3-inch chambers. The choke markings appear to be 14.9 stuck over 15.5 on the right and 14.6 struck over 15.5 on the left. Anyone know what this means in terms of IC< Mod, etc? ... and Mossberg shotguns brands. Come join the discussion about optics, hunting, gunsmithing, styles, reviews, accessories, classifieds, …A choke tube wrench can be used to identify Stoeger chokes by removing the choke tube and inspecting the markings on the tube itself. 10. Do all Stoeger shotguns come with choke tubes? Some Stoeger shotguns come with choke tubes included, while others may require the purchase of compatible choke tubes separately. 11.Feb 17, 2024 · ATA shotguns typically use interchangeable chokes with varying degrees of constriction to effectively control the spread of the shot pattern. These chokes include but are not limited to full, improved modified, modified, improved cylinder, and cylinder. Contents [ show] To easily identify Beretta choke tubes, look for the distinctive “PB” or “Steel Proof” markings on the tubes. These markings indicate that the choke tubes are manufactured by Beretta. See 3,000+ New Gun Deals HERE.Markings. Alternative chokes. Compatibility chart. Steel shot and alternatives. See also. References. Choke (firearms) Illustration of the effect that different types of chokes have on the spread ("pattern") of shotgun projectiles. A choke is a tapered constriction of a firearm barrel at its muzzle end.2786 posts · Joined 2014. #2 · Nov 2, 2015. 2 and 4 would be modified and full. They would be the same as Ithaca guns since the Nitro Special is a Lefever in name only, Ithaca made all of them after acquiring Lefever - but I believe that you already knew that.In the 1960s the Belgian Browning choke designations were: Full Choke *. Improved Modified *-. Modified **. Improved Cylinder **-. Skeet **$. Cylinder ***. By the way, this information is from the excellent Belgian Browning. reference book “The Browning Superposed” by Ned Schwing, Krause.70%. 49%. 32%. A choke concentrates the pellets in a shotgun, so they create a tighter pattern. A 30-inch pattern can be accomplished with all four standard chokes, but the difference comes in distance. A cylinder choke has the widest pattern, meaning it will hit within a 30-inch target at 25 to 30 yards. At the other extreme is the full choke ...I once had a 1941 37R I rember that the choke was marked full on the side but I do not recall where the 4 was stamped in relation to the serial number. The '46 & '49 guns have the choke numbers in line with the machine operations locator mark and the abbreviated choke on the side of the barrel. The '54 has the abbreviation and the …Tristar chokes can be identified by the unique markings or engravings on the choke tubes themselves, which often include the brand name or logo, as well as the constriction size or designation. Some Tristar chokes may also have color-coded bands for easy identification. See 3,000+ New Gun Deals HERE. 1. What markings should I …The diameter table above shows the diameters and constrictions you can expect for choke tubes and shotgun barrels of a specific make and type, as well as 12-gauge choke sizes in inches, 10-gauge, 20-gauge, 16-gauge, 28-gaug e, and .410 shotguns. The most popular choke systems are shown, which include Standard …We would like to show you a description here but the site won’t allow us.A choke is the tapered constriction of a shotgun barrel’s bore at the muzzle end. The purpose of a choke is to alter the distribution of the shot as it leaves the firearm. The various size chokes constrict the barrel thus tightening the spread of the shot. Thus, the thicker the choke, the further and tighter the shot will travel.j the answer to your question is in the third photo. The right choke has 2 notches cut into it and the left choke has 3 notches. According to Stoeger's website the right choke is an IM or Improved Modified and the left choke is a Mod of Modified choke. Here is a link to their website with the answers you're looking for.Mark Spencer is a well-known clothing store that has been around for decades. With its wide range of fashionable apparel and accessories, the store has become a go-to destination f...Shotgun choke does as it sounds. Chokes. That is, it constricts or narrows the barrels of a shotgun. This has the effect of reducing the pattern so that the density of the pellets is increased, which gives a stronger result. Visualise shotgun choke in the same way as a camera aperture which opens or reduces to give more or less light.Invector choke tubes are a standard for early model Browning shotguns, but they also fit certain Winchester and Mossbergshotguns. Invector threads are located at the bottom of the choke and are 1.5-inches long. Standard Invector chokes fit the following shotguns: Winchester Invector. Fits Winchester 1200, 1300, 1400, 1500, & Ranger …Weeds can be a nuisance in any garden, but Creeping Charlie is one of the most difficult to get rid of. This fast-growing perennial weed is known for its ability to spread quickly ...The fixed-choke barrel on this old Winchester shotgun is clearly marked as having a Full constriction. Most modern shotguns of all styles now come with what are known as “interchangeable chokes.” These are short tubes of metal tighter in diameter than the shotgun’s barrel.To do this, shoot off a rest at a center mark in a 30-inch circle at 40 yards. Full choke should put 70 percent of the shot in the circle, modified 60 percent, improved cylinder 45 percent. Cylinder, or no choke at all, should shoot from 25 to 35 percent. With interchangeable choke tubes, a hunter can use the.Most double shotguns represented here. Double gun shotguns - Side by Side shotguns, and over under shotguns - Including drillings, double barreled rifles, SxS double rifles, combination guns. Makers - Darne, Merkel, Arrieta, Beretta, Browning, Holland, Purdey, Richards, Bernardelli, Parker, Fox, LC Smith, and most other double barreled shotgun, …Feb 25, 2024 · About 40 percent of a shell’s total pellets will fit in a 30-inch circle at 40 yards without constriction. You will want to keep targets close with an open choke; within 25 yards is ideal. At 25 yards, you will have a 40-inch spread with a cylinder choke. Open or Cylinder Chokes have no constriction at all. How to identify the right Choke Tube for your gun: Identification Methods. 1) Visual Method. 2) Choke Measurement Method. 3) Barrel Markings Method. 4) Serial Number Method. Choke Tube Constrictions chart. How can I identify which screw in choke tubes I should use in my Beretta shotgun: Mobilechoke, Optima-Choke, Optima-Choke Plus, or …The choke tube table above shows the diameters and constrictions you can expect for choke tubes and shotgun barrels for Stoeger 12-gauge shotguns compared to common fixed choke shotgun gauges. Stoeger shotguns have two different choke systems. Some models are compatible with Beretta/Benelli Mobil style threads, while …Feb 20, 2024 · Simply visually inspect the muzzle of your shotgun to determine which type of choke tube you have. 7. Do Stoeger choke tubes come with wrenches for installation? Many Stoeger choke tubes come with a wrench for easy installation and removal, but it’s always good to have a dedicated choke tube wrench for added convenience. 2454 posts · Joined 2006. #3 · Dec 6, 2007. The Franchi is an European made shotgun.Most European shotguns are marked with stars on the barrel as to the choke rather than being marked with the the words. On the barrel of the shotgun there should be a series of stars.One star /full,two stars improved modified,three stars/modified,four stars ...Optima-Choke choke tubes will be marked Optima-Choke. The start of the threaded portion of the Optima-Choke tube is located a nominal 50.78 mm (2.00 inch) from the breech end of the choke tube. The length of the threaded portion is a nominal 15.9 mm (.625 inch). The major diameter of the choke tube thread is 20 mm (.787 inch).1679 posts · Joined 2007. #2 · Jul 9, 2008. I've got a Boito .410 in single shot. It is a fun little gun. I learned to hunt with it. Most of these .410 guns were full choke. A double might be full/modified. The star choke designation may be the same as the Browning markings, I don't know that for shure though.Rizzini USA would be able to help as well. I got it figured out. Briley's site had pics and measurements for the different Rizzini choke styles. The 28 gauge on the left is a Rizzini choke, the the 20 gauge in the middle and the 12 gauge on the right are both Rizzini plus chokes. The 20 gauge has different measurements to the threads than the ...Shotgun choke does as it sounds. Chokes. That is, it constricts or narrows the barrels of a shotgun. This has the effect of reducing the pattern so that the density of the pellets is increased, which gives a stronger result. Visualise shotgun choke in the same way as a camera aperture which opens or reduces to give more or less light. Choke tubes give a single shotgun the flexibility and freedom to become a decent variety of more specialized firearms used for different purposes. With the right choke tube, they can be an essential tool in improving your marksmanship. A choke is the tapered constriction of a shotgun barrel’s bore at the muzzle end. The purpose of a choke is to alter the distribution of the shot as it leaves the firearm. The various size chokes constrict the barrel thus tightening the spread of the shot. Thus, the thicker the choke, the further and tighter the shot will travel.I was thinking that those markings were I/C & Mod. On every Beretta O/U shotgun with fixed chokes I or my brother owned. The tighter choke was ...Shotgun Choke Markings. A shotgun choke is found inside the bore of a shotgun barrel. It basically has a series of markings that helps shape the spread of the shot that is fired as it is coming out of the barrel. The specific choke you use determines the range and accuracy of the shot.What do the markings on chokes mean? Markings on chokes indicate the level of constriction, with designations such as Cylinder, Improved Cylinder, Modified, Improved Modified, and Full. 4. What is Cylinder choke? Cylinder choke has no constriction and provides the widest shot pattern. 5. What is Modified choke?Muller is a choke tube manufacturer that designs premium choke tubes for waterfowl hunting. All choke tubes are made in the USA. Muller offers shotgun chokes in .410 bore, 20 gauge, and 12 gauge. Muller offers a wide range of choke tubes designed for competition shooting as well as waterfowl hunting.Jul 10, 2020 ... I've recently seen that there was some folks interested in learning more about shotguns and what role the choke has in how the shotgun ...Choke markings are used to identify different choke tubes. The marks can be bands of colour, stars or notches. Unfortunately, different manufacturers mark their choke tubes in different ways – Beretta markings will be different to Browning which will be different to Perazzi.What do the markings on chokes mean? Markings on chokes indicate the level of constriction, with designations such as Cylinder, Improved Cylinder, Modified, Improved Modified, and Full. 4. What is Cylinder choke? Cylinder choke has no constriction and provides the widest shot pattern. 5. What is Modified choke?Virginian. 14840 posts · Joined 2008. #2 · Oct 6, 2018. The choke is normally stamped on the left outside of the barrel a short distance in front of the receiver. You used to be able to special order any combination of regular features for very little cost. Of course you can always measure the bore and the constriction as well.A choke is the tapered constriction of a shotgun barrel’s bore at the muzzle end. The purpose of a choke is to alter the distribution of the shot as it leaves the firearm. The various size chokes constrict the barrel thus tightening the spread of the shot. Thus, the thicker the choke, the further and tighter the shot will travel.When you open the gun, turn it sideways and there should be marks where the barrels go into the receiver. The marks should be something to the extent of *- or something like that. There is a thread at the top of this forum about Browning choke codes. Good luck! Open the gun and look on the left side of the Mono Block.That is what the old Charles Daly I used to have was marked and that is what it was. You lie to the Government, it's a Felony, they lie to you, it's Politics! You are right. I have a Daly Miroku and it was choked Imp Mod (+-) and Mod (++) before Mike Orlen added tubes. I suspect that ++- is light modified.Yildiz shotguns typically use Beretta/Benelli Mobil style choke tubes, making it easier to find compatible chokes for your gun. Contents [ show] 1. Can I use other brands’ choke tubes in a Yildiz shotgun? Yes, as long as they are Beretta/Benelli Mobil style, they should be compatible with Yildiz shotguns. 2.The fixed-choke barrel on this old Winchester shotgun is clearly marked as having a Full constriction. Most modern shotguns of all styles now come with what are known as “interchangeable chokes.” These are short tubes of metal tighter in diameter than the shotgun’s barrel.J. jaguarxk120. 2549 posts · Joined 2007. #2 · May 7, 2011. The usual bore diameter of a 20 gauge is .615 inch. With the 0.598 choke diameter, thats 0.017 constriction. The Hallowell & Co. choke chart shows 0.012 to 0.019 as a mod. choke. Your barrel should be marked on the right side just ahead of the reciever.Understanding the Notch System. The notch system used can vary between manufacturers, but most commonly, a single notch indicates a full choke, suitable for long-range shots with a tight shot pattern. Two notches typically represent an improved modified, providing a slightly wider pattern.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 ...May 6, 2012 ... There are generally five choke types that people use in their shotguns: full, improved modified, modified, imp cylinder and cylinder. The ...1108 posts · Joined 2005. #11 · Jul 4, 2007. Fastarget is correct. Merkel chokes tend to run tight. My 1620 is marked VBZ/1/2 (IC/Mod), but the chokes patterned more like Mod/Improved Mod. I opened the IC barrel to skeet and the left barrel remains a tight Mod. It makes for a pretty versatile gun.That is consistent with the GDR marking on the side of the barrels. 12 / 76 is the gauge and chamber length . Here a 12 gauge with 3 inch chambers. The 18.6 is the bore diameter of the barrels expressed in millimeters. 18.6 equals .732 inches or just slightly larger than the "standard" .729 bore of a 12 gauge.To have it lengthened will cost the same as to lengthen a gun of a higher value. Your £100 Baikal will still be a £100 Baikal even after you paid £80 to lengthen that stock. That's your call. But from a …You don’t say whether your gun is the A5 auto or a Superposed O/U. If an A5, the the choke marking should be on the left rear outside of the barrel. If a Superposed, then on the left side barrel’s breech. Browning choke markings are: * designates full choke (F). *- designates improved modified choke (IM). ** designates modified choke (M).Jul 24, 2004 ... The one where the finger goes in the least is full choke. The one that goes in the furthest is something like Cylinder, Skeet or IC. Once you've ...70%. 49%. 32%. A choke concentrates the pellets in a shotgun, so they create a tighter pattern. A 30-inch pattern can be accomplished with all four standard chokes, but the difference comes in distance. A cylinder choke has the widest pattern, meaning it will hit within a 30-inch target at 25 to 30 yards. At the other extreme is the full choke ... Choke tubes give a single shotgun the flexibility and freedom to become a decent variety of more specialized firearms used for different purposes. With the right choke tube, they can be an essential tool in improving your marksmanship. A shotgun barrel’s choke will be located at the muzzle end of the barrel and you will encounter them in two different designs. The oldest way is called a “fixed choke.”. Many side-by-side and older single barrels will have fixed chokes, meaning that their barrels have the choke constriction built-in to the end of the barrel at the muzzle end.There are a variety of choke sizes that restrict a shotgun’s bore to a greater or lesser degree. “Cylinder” chokes don’t constrict the bore diameter at all. “Full” chokes constrict the bore by about .035 inches. Between cylinder and full, “improved cylinder” chokes constrict the bore about .010 inches, “modified” constrict ...In the 1960s the Belgian Browning choke designations were: Full Choke *. Improved Modified *-. Modified **. Improved Cylinder **-. Skeet **$. Cylinder ***. By the way, this information is from the excellent Belgian Browning. reference book “The Browning Superposed” by Ned Schwing, Krause. To do this, you need a large piece of paper or cardboard placed at 40 yards. Draw a central aiming point and shoot at it from that distance. Find the center of the pattern on the target and draw a 30 inch circle. I do this by attaching a 15” string to a sharpie and holding the other end in the center of the pattern. There were no choke markings on A.H. Fox Gun Co. guns. Here are the Sterlingworth pages from a 1919 A.H. Fox Gun Co. catalog. 1919 Sterlingworth picture.jpg.The choke tube table above shows the diameters and constrictions you can expect for choke tubes and shotgun barrels for Blaser 12-gauge shotguns compared to common fixed choke shotgun gauges. Knowing the diameter of a choke tube is important in order to identify choke tube constriction. The tighter the choke tube, the more …If you’re a fan of Christian comedy and music, then you won’t want to miss the opportunity to see Mark Lowry live. With his unique blend of humor, storytelling, and heartfelt songs...
The chokes in an L.C. Smith run parrallel for 1" and then taper 1 9/16" to bore size of .729-.732 in 12 ga. Also your gun was made in 1908, and after 1913 the 0 grade became Ideal Grade. The markings on the barrels are probably the barrel makers mark as the 0 grade had London Steel barrels or Damascus steel, I think Chain Damascus.. Branson flea markets
I can find no other markings on the gun other than a "G" and "35" stamped on the bottom of the barrel where it is covered by the receiver when the gun is assembled, and also a "G" and "35" stamped on the inside of the receiver where it is covered by the barrel when the gun is assembled. There is no other serial number or choke marking on the gun.The choke tube table above shows the diameters and constrictionsyou can expect for choke tubes and shotgun barrels for SKB 12-gaugeshotguns compared to common fixed choke shotgun gauges. Knowing the diameter of a choke tube is important in order to identify choketube constriction. The tighter the choke tube, the more constriction it has and the ...Choke Type: Identification (Notches, Stars, Alpha Code, or Color Band) Extra Full: No notches, no stars, XFULL Turkey, no color band: Full Choke:ATA shotguns typically use interchangeable chokes with varying degrees of constriction to effectively control the spread of the shot pattern. These chokes include but are not limited to full, improved modified, modified, improved cylinder, and cylinder. Contents [ …It has a modified choke, but like all .410's it throws a truly lousy pattern no matter what choke is used. To twenty five yards, a .410 will work. Twenty yards is much, much better. Anything much over thirty yards and a .410 will spray it's pellets all over the place. A .410 is really not a beginnner's gun.Shotgun choke markings can be identified using 5 simple methods. They include referencing a sizing chart to find the correct choke, counting the lines or notches, observing dots or circles on the choke, locating writing on the side wall, and using bore …Degree of choke, in this case 0.7mm constriction CHOKE 17.0 1924-> Liege Choke constriction, together with barrel dimension this can give a brief view of the choke. 1898 - 1924 Liege Mark for optional superior provisional proof. The mark was seldom requested 1892-1924 Liege Chamber dimensions in millimeters shotguns undergoing …Miroku Choke Designation. I am looking at purchasing a used Miroku 20 ga O/U with 26" bbls. It is marked *- and ** for chokes. My Browning chart says this is Improved Mod & Mod but this seems a bit odd for a 26" barreled shotgun. Did Miroku use a diffrent choke marking system?larryvaughn Discussion starter. 3 posts · Joined 2013. #1 · Jan 29, 2013. My new A71 came with 5 chokes and nary a word about how to identify them. Are the notches the same as Beretta; ie, 1notch=Full, 2=Improved modified, 3= Modified, 4=Improved cylinder, and 5= Cylinder? Old dog trying to learn new tricks.May 30, 2023 · The second shotgun choke that worked really well in the field – in that it was effective and forgiving in use – was a standard Beretta Improved Cylinder Mobilchoke tube. This is a conventional shotgun choke with about five thou of constriction. With the duffer’s gun, I once accounted for 18 average pheasants for 17 shots. When you open the gun, turn it sideways and there should be marks where the barrels go into the receiver. The marks should be something to the extent of *- or something like that. There is a thread at the top of this forum about Browning choke codes. Good luck! Open the gun and look on the left side of the Mono Block.70%. 49%. 32%. A choke concentrates the pellets in a shotgun, so they create a tighter pattern. A 30-inch pattern can be accomplished with all four standard chokes, but the difference comes in distance. A cylinder choke has the widest pattern, meaning it will hit within a 30-inch target at 25 to 30 yards. At the other extreme is the full choke ...I have recently obtained an older used CZ BRNO 12 gauge o/u ejector SG, MOD 501.2 manufactured around 1987-8. I’m trying to decipher the choke markings stamped on the base of the barrels. They are 17,4 ( top barrel) and 17,8 on the bottom. Could anyone please tell me how these equate to either UK choke markings, ie, Open, 1/4, 1/2, 3/4 etc.14040 posts · Joined 2009. #3 · Feb 22, 2010. When I figured out the markings, I wrapped the end of each extended tape with masking tape and wrote on the tape with a magic marker the choke size. Works for me, and I don't have to wear my reading glasses in the field. "We pulled the trigger, the safety went forward, both barrels fired almost ...J. jaguarxk120. 2549 posts · Joined 2007. #2 · May 7, 2011. The usual bore diameter of a 20 gauge is .615 inch. With the 0.598 choke diameter, thats 0.017 constriction. The Hallowell & Co. choke chart shows 0.012 to 0.019 as a mod. choke. Your barrel should be marked on the right side just ahead of the reciever..