Shotgun Chokes

Discussion in 'Competition Shooting Forum' started by gunpir8, Aug 21, 2010.

  1. gunpir8

    gunpir8 New Member

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    Earlier, I posted a thread (see best shot for shooting steel targets) about the best type of shot for three gun competitions using a shotgun since I had so much problem making the plates fall of the Texas star with my Mossberg 500 during my first three gun. I found out that my Mossberg 500 has a cylinder bore which according to my Internet research show that the shot percentage is 40% at 40 yards. Is this sufficient for three gun competition or should I change my barrel to have a different choke? And if I should change my barrel to a different choke, which type of choke should I get? Any opinions or suggestions will be greatly appreciated. You are only as good as your equipment and skill level.
  2. grampawmike

    grampawmike New Member

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    *****************************************************************

    First of all, I don't shoot three gun. I shoot trap. That said, the theory and function of shotgun chokes are the same, no matter what game you're shooting. I had my barrel back bored and a fixed choke cut in on my trap gun. I specified a .027 inch choke.....sort of in between an improved modified and a light full. This gives me good breaks at the short ranges (25 to 30 yds or so) out to the longer (for me) of 50+. For you I would think that an improved mod barrel would do you the best. Chokes are designed to throw a uniform pattern of about 30" in diameter at a given range. The tighter the choke, the farther out that 30" circle will be. Also, the ammo used will vary the patterning ability of a particular choke or choked barrel. Size of shot, amount of shot, powder charge, and wad all have an effect on the resulting pattern. Try a few different brands and loads to help determine what you want to shoot in your particular game. (This is why trap shooters are constantly messing with new loads for their trap guns.)
    Another thing is to determine is the actual POI.....the center of your pattern. Remember, shotguns are not designed to be 'aimed'......they are pointed. That front sight is there for reference, not to be focused on as one would do with a rifle sight. If you are trying to 'rifle shoot' your scattergun, the shot column may not be going where you think it is; unless you use a shotgun with rifle sights BUT, those guns are set up for slugs, and shot will not act the same as a slug. Most people fairly new to shotgunning will try to use the shotgun sight as one would a rifle, however, remember that a rifle has two sights to align with your eye, the shotgun has a single bead out there only as a reference point to tell you where the center of the bore is.
    You might try this; get a few large pieces of cardboard, mark a definite aim point in the center of each. Set up one and back off about 15 yards. Focus on the front bead as you would a rifle, center up on your target and touch off using your usual load. Ignore the single hole made by the wad. You will easily be able to see where the center of the shot is going. Now, set up another and focus on your target, NOT the bead. With your head firmly on the stock, bring the muzzle up to the black blotch in the cardboard and when the front bead touches it, (you'll see the bead peripherally) squeeze off. I think you'll see a difference in POI. Again, ignore the single hole made by the wad. You want...and need that POI to be where you are looking......and you SHOULD be looking at the target, not the front bead.

    Just a few points and thoughts from an old man rambling off. Take from my thoughts what you will, after all, you didn't pay anything for them. Mike
    Last edited: Aug 28, 2010
  3. carver

    carver Moderator

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    I agree with the information that Mike has given you. Every load type will pattern differently in any given gun. I once had a Winchester that shot doughnut patterns with a specific load, a big empty space in the middle of the pattern. When I changed loads, the problem went away. POI is also different with different loads, and with different shotguns. Full choke will put more shot on a target at any given range, but that might not be best for some types of targets. If I were to start shooting three gun compition, I think I would purchase a barrel with at least three screw in chokes, and test them all to determine what works best in my gun, with different loads.
  4. grampawmike

    grampawmike New Member

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    YEP.....Gotta agree with Carver. BUT, I had (still do have) a nice Wingmaster 870 the my kids gave me 30 or so years ago. Came with a RemChoke barrel....that I couldn't make hit clay targets worth a darn, no matter which choke I used. Picked up a fixed choke full barrel for it as a backup gun for trap shooting.........works like a dream. One thing to remember also......not all screw-in chokes or choke systems are equal in quality and/or performance. JMHO. Mike
    Last edited: Aug 28, 2010
  5. carver

    carver Moderator

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    +1
  6. gunpir8

    gunpir8 New Member

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    Thanks for the information. When I was in Law enforcement, I took a tactical shotgun course at FLETC (Federal Law Enforcement Training Center in Glynn County, GA.) and we were taught to use the bead but aim just below your intended point of impact. It has always seemed to work for me until recently while shooting in 3 gun. I am going to take your advice and test different brands of shotgun ammo since that may be the problem. The last 3 gun I shot, I used RIO 7 1/2 skeet and trap loads that I had from shooting in a sporting clays match, and they did not seem very effective against the Texas star plates. So that has made me wonder if it was the ammo or the choke. Thanks for the advice. I really appreciate your input!
  7. ghrit

    ghrit New Member

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    Generally speaking, a field (870) gun will shoot a tad "low", at least in my limited trap shooting experience. Putting the bead below the POA is going to fail on the clays range. But as has been stated, all are not the same, and the answer is on the pattern board. Local friendly Ryder rental place carries mover's wrapping paper, and a scrap pallet does the job nicely.

    7-1/2 is probably a bit light for knocking over plates, I'd suggest 6s.
    Last edited: Aug 29, 2010
  8. grampawmike

    grampawmike New Member

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    gunpir8, back when I was a police firearms instructor/armorer (I retired after 35 years in law enforcement) we used only 00 buckshot loads in most training, along with some slug. With slugs and 00, I found most shooters needed to shoot a little low and slightly to the right (right hand shooter) to get good hits, but, we really didn't train very heavily with the old scattergun. I believe that shooting a little low is the result of most shooters mounting the gun a little low in their shoulder and ending up with the gun pointing a bit high. I did find that an awful lot of LEO's jerked the hell out of the trigger on the shotgun as well flinching into it when they shot, untill the TO worked with them for a while. As time went on we also trained with some of the 'less lethal' stuff but overall, law enforcement trained mostly with the handgun. As time went on and I started shooting more and more with the thing, I learned that trying to sight with it was, more or less, counter productive. After learning to 'point' the gun.....to shoot where you are looking, and looking at your target, not the front sight, things picked up greatly. As ghrit says, generally the 870, as well as most general use field guns, seem to shoot rather 'flat'. I find I must cover my target with the muzzle of and 870 to get good solid hits. Also, as he states, #7 1/2 shot is rather light for the game you are playing and #6's (maybe even #4's) would do you much better.
    Remember that a shotshell doesn't act like a solid projectile cartrige.....even within the barrel. Initially it starts out as a solid mass, it then acts as a fluid mass (not liquid) as it passes through the choke section and is reshaped slightly. It then leaves the barrel as a number of individual solid projectiles......each with it's own trajectory. The smaller the shot size, the quicker each pellet looses energy. Damage to the target is created by multiple strikes of individual pellets (bullets) striking in fairly close proximity to one another. Larger pellets will result in fewer strikes BUT with greater mass and energy behind each strike. JMHO Mike
    Last edited: Aug 29, 2010
  9. gunpir8

    gunpir8 New Member

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    Grampawmike, thanks for your advice. I was considering changing to #6 shot but I am still going to try shooting different brands of shotgun shells to see which brand holds the best pattern with my Mossberg 500. I really appreciate your help and everyone else's suggestions. As an LEO, I was a Swat team member so we did train with the shotgun more than the standard patrol officer, hence the tactical Shotgun Course, but we trained much more with our primary sub guns and pistols. The last three gun I shot in I had a really hard time transitioning from Shotgun to pistol but was very comfortable transitioning from the AR to the pistol. I guess I just need more practice with the shotgun.
  10. grampawmike

    grampawmike New Member

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    gunpir8: A couple of other things to remember about the scattergun. You only have the single sight bead, therefore you are not able to align anything but your eye and the bead, that's why aiming doesn't work too well. Shoulder placement of the gun is paramount for consistent shot placement. Example; if you happen to get the stock out of the pocket and out a bit out on your arm (right handed shooter), that shot is sure to go left. And, believe me, it doesn't take much to do that in a quick transition and under the stress of needing speed. The same is true if the gun ends up low or high in your shoulder; low in the shoulder and the shot goes high....and conversely, high in the shoulder, the shot goes low. I used the 870 at work, and for a long time at play. I found that as I mounted the gun, if any of the anti-glare flat top of the receiver was visible, the gun shot high; if I had flat steel with a little ball on top, we were there, and if any of the ball was cut off, the shot went low. A quick reference, as I believe the Mossy has a flat top receiver also.

    Now, just a tale. I was (as well as being assigned as an instructor and armorer) on our high risk warrant detail and our judicial protection unit, way back when. Somewhere along the line we had seized an SKB auto shotgun which used the long recoil system. The old man had gotten it ordered over to us for our use, and had me modify it for use as a short barrel entry gun. We did have some 870's that were modified with barrels cut down to just in front of the the mag cap, but even with a hand guard installed, he worried that someone might slip when pumping the gun and end up being called 'stubby'.
    Well, I shortened the barrel on that SKB, chopped the stock as much as possible, cleaned it up and smoothed the action as much as I could and coated the thing with a baked-on Teflon coating. The old man loved it.......until he shot it. That thing would kill on both ends! BUT it would put 5 rounds of 00 buck, and all nine 00 pellets from each round, into a man sized target at 25 yards, every time, just as fast as you could recover from the preceding shot. It was a nasty beast, it spit fire and flame as well as having the worst muzzle blast of any gun I ever fired. As to recoil, you'd better be hanging on and have a spot weld with your cheek on the stock. OK, enough of the rambling of a grumpy old man. Mike
    Last edited: Aug 30, 2010
  11. gunpir8

    gunpir8 New Member

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    Mike, Thanks once again for the advice. I am going to pay attention to the way I shoot my shotgun and use your advice. Since I began shooting competitively. I have had to change my entire shooting style and it just takes practice.....lots and lots of practice. With all my military and police experience you would think I would be a good shot. I am as long as I am shooting at the silhouette. I will hit center mass, i.e. from waist line to head and from shoulder to shoulder. Now I am forced to shot a little box. All of my instructors in LE strongly stressed to shoot only center mass and not try to be too accurate. They said that if your shoot to good that the "jury of your peers' will question why you didn't shoot the pistol out of the dirt bags hand. Upon reflection, it makes sense in a sue happy world and TV shows were bullets don't go through walls. So now, I have to change everything and unlearn my learning. Thanks for taking the time to give me some of the tricks of the trade. Surely it will help me in my sporting clays shooting.
    On a lighter note, thanks for the story about the shotgun. It is neat to here stories about other guys experiences. Thanks again.
  12. grampawmike

    grampawmike New Member

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    gunpir8: Thanks for the kind words. At this stage of my life, and at my age, about all I have left is some experience, some advice to give...if wanted...and then taken, and a fistful of 'war stories'. I shoot trap (or at it sometimes), make custom holsters, and once a month, get together with some of the other retirees from my old Dept. for breakfast. At these "Geezers With Guns" get-togethers, we chide one another about not telling of our wild weekend activities, but piss and moan about the new meds we are forced to take. (LOL) But making it passed the 'critical' 5 year anniversary of our retirement is a point to be somewhat proud of. Thanks again, enjoy your retirement, and keep busy. Mike
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