Choke Chooser™

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24 Gram Patterning

Dear Technoid,

Since my last attempt to bring rational thought to the shotgun world was so gratefully disregarded I can but feel compelled to jump in again.

I have this gut feeling that wad strippers and deformed shot are pretty much in the holy writ area, but what the hell. I would suggest that high speed loads do not degrade the patterns for much of any reason other than the choke effect increases as the speed climbs. As we all “know” choke functions on the basis of the radial acceleration imparted to the pellet mass by the narrowing of the passage diameter. If we look back to our jr. high math for the time-rate-distance concept it is fairly easy to understand that the faster you push that glob thru the choke the greater the radial acceleration is going to be. Right?

Of course. So, 24gm masses at 1400fs thru an IC choke equals a full choke, or pretty close. My 7/8 ozers with 19.5gr RedDot push 1400 fs real hard. They also print 100% at 35yd in a 20″ circle out of .012 choke in the bottom bbl of my old MX8. And that’s the truth. The top bbl is .020 and I get 90%+ at 50yd. Figure target speeds out of the bunker or a cranking wobble and you see that second bbl breaks are a LONG ways out. And second bbl hits are not unusual for lots of people. The patterns out of my MX8 are so dense that I can puff half of a target from the 27 with the bottom bbl. I also loaded up some hot 1 ozers and the results were more of the same, so I went back to 7/8.

So I miss a few with the little patterns; well, ok I can live with that. The pump of the inkdot with them is worth it cause I know I’m doing it right. And then when I drop in the 1 1/4 x 3 1/4 for the flyers I feel much better. Now if I could just shift my focus from where the bird was to where it’s going…..

Been a pleasure to help you out again.


Dear Major,

I certainly need all the help that I can get and very much appreciate your erudite analysis. However, that is not what I came up with. I like the radial acceleration bit because it sounds so reasonable, but I have not found it to be the case in the experimentation that I have done.

Being a believer in the adage “Speed Kills”, I managed to get a chronographed 1430 fps out of a pot full of Super Field and 1 1/8 oz of #7 1/2s. At the moment my patented horizontally stratified floor level filing system refuses to yield the notebook containing the exact results, but I distinctly remembered that the hot load patterned considerably more open than that choke produced with that dose of shot at a less punishing 1200 fps. Lacking your imagination, I chalked it up to shot deformation due to setback.

When I was shooting International Skeet in the ’70s and ’80s (when you could use 32 grams), a great deal of load development work was done in an attempt to enlarge effective patterns by increasing velocity. Both Winchester and Federal introduced special IntSk loads with fiber wads and dram equivalencies in the 3 1/2 to 4 dram range in order to spread the shot out. I remember that about half of the AA hulls would split on their initial firing if the day was hot.

In our skeet chokes (ranging from the negative constriction MU-8 Baikal Tulas to the cylinder bore Berettas to the +.005″ Remingtons) the faster you pushed the load, the more open the pattern became. Perhaps it was the fact that our skeet chokes imparted little radial acceleration to overcome the shot deformation that caused the increased pattern size. Perhaps not. I always thought it was shot deformation.

Most of the guys that I know who shoot bunker use Full in the second barrel with those 24 gram loads. When I was in Colombia, we trained on a new LaPorte equipped bunker and used European 24 gram bunker loads in unaltered Mod (maybe Imp Mod?)/Full choked 682s and Mirages. Breaks were normal on those hard targets- definitely not smoke balls. AND we were shooting at 2200 meters altitude, which tightens patterns.

I used to fool around with some of the Victory brand 24 gram Strykers. I chronographed them at a bit over 1400 fps and have to say that they did a very nice job on the long birds when I pointed my gun right. I feel that the answer was in the pointing, not the shell. A load of #9s out of a skeet choked gun will absolutely crush a 40 yard crosser if you can dead-center it. You can just about woof anything with anything if you can center it.

I am not sure where that leaves the “radial acceleration vs pellet deformation” situation though. It is a good theory and when I get backed into a corner, I am sure that I will find it of more use.

Bruce Buck
Shotgun Report’s Technoid

Posted in Shotgun related | 2 Comments

Dragging Firing Pins

Dear Technoid:

I have a Winchester 101 made in about 1969. The gun is in very good to excellent condition. I have owned the gun about 5 years and now am starting to use it more often for trap shooting. The problem is that after firing the gun is difficult to break open. I have thoroughly cleaned it several times but have never attempted to take the action apart. The gun will break easily if simply opened and closed but if dry fired it is difficult to open and even more so when a round is fired.

I know this may have something to do with the cocking mechanism but the gun appears to have had very few rounds through it. Needless to say this is an aggravating condition on the trap field. I consider myself capable of disassembling the gun myself.

Your thoughts would be greatly appreciated.


Dear David,

Well, this is only a guess, but the price is right.

After you have fired both barrels, examine the primer from each fired hull. Does it have a little scratch running from the firing pin dent to the edge of the primer? If so, you have a dragging firing pin and it should be replaced with one that fits properly. The situation is not uncommon, especially on the lower barrel of mass produced Over and Unders.

When the firing pin is struck by the hammer, the pin is pushed forward out through the face of the standing breech and onto the face of the primer. The pin is then supposed to go back into the face of the breech after having done its job. If it doesn’t return and stays stuck in the primer, it will catch on the edge of the primer when the gun is opened. This makes the gun hard to open after firing. If you fire with a live shell or even an empty shell, this dragging can occur. If you dry fire with the chambers empty, the gun should open normally if I have guessed right and dragging pins are the problem. Of course, I could be wrong, but if I am we aren’t going to tell anyone, now are we.

Personally, I would have a gunsmith perform the work as there could be several reasons why the pin is failing to retract fully. He can tell at a glance. The repair is relatively simple if you know what you are doing.

There it is. Hope you got your money’s worth.

Best regards,

Bruce Buck
Shotgun Report’s Technoid

Posted in Shotgun related, Shotguns | 2 Comments

Protecting Gun Wood

Dear Mr. Gun,

I’ve read with some interest your tracks on soaked autoloaders. What worries does the two-holer have? It seem to me the firearm industry does a great job on finishing the outside/visible parts of wood, but really spare the gue when it comes to the inside of the forearm and other places where the wood meets the metal. My older guns show evidence of soaking through the end grain either by moisture or cleaning liquids. Lately I’ve had my gunsmith apply his witches brew to both ends of the stock when he installs recoil pads. What about the forend, etc.?

Many thanks,


Dear Trent,

You mention soaking through at the stock due to moisture or cleaning liquids. It is probably not water as that evaporates quite quickly (though water causes other obvious problems). Normal cleaning liquids of the spray on Gun Scrubber type seldom cause that soaking that you describe. They may eat plastic parts and plastic finishes though. What you have sounds like good old gun oil. Half the oil soaking problem can be solved by trying to keep the oil out of the wood in the first place.

When I get a new O/U, I always take the stock and forend off and apply several coats of Hoppe’s (different company) tung oil or Birchwood Casey’s Tru-Oil to the inside of the forend and the end grains of the stock, paying particular attention to the head of the stock where it mates with the receiver and inside that area.

When I store my shotguns in the safe, I always store them muzzle DOWN. This keep any errant oil out of the head of the stock where it does the most damage.

When I clean my guns, I try never to get too much oil on the metal so as to prevent its running down and soaking into things. Oil is always best applied sparingly.

As you have found, if you do oil soak some wood, gunsmiths can use an absorbent powder marketed by Brownells to leech the oil out. Still, it is better to avoid soaking in the first place by applying some Tru-Oil..

Best regards,

Bruce Buck
Shotgun Report’s Technoid

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Bunch Of Questions

Dear Technoid,

Perhaps this frisky little question is worthy of the Volcano of Knowledge? Actually, a couple of questions:

1) Will smaller size shot, say #8 or 7-1/2, deform more or less than #4 shot, in example, affecting patterning adversely?

2) Will a 1 oz. lead charge deform more in a smaller gauge, 16 or 20, due to the longer “stack height” of the pellets?

3) Is height of the pellet stack a minus re: 3″ and 3-!/2″ magnum loads?

4) Has the Technoid found any evidence that buffered loads do any good?

5) The Omnipotent Technoid has stated that copper-plated shot seems to slide its way through game, proving less effective than lead. Does the copper do much re: reduction in pellet deformation?

6) And finally (are you glad!), can the Technoid speculate as to the rise and fall of the popularity of the 16 gauge? Just picked up an A-5 Sweet Sixteen, and really enjoy popping clays with it . . .

7) Oops, one more – can the Technoid recall approximate shot cloud sizes at forty yards for 1 oz. launched through 12, 16, and 20 ga., assuming “modified” choke performance?

Thanks Bruce, for all your help!


Dear Randy,

Wow! I could make a living off of your questions (that is, if SR ever provided a living- send money and we will see). Answers to questions 1-5 are “YES”. Ta dah! Ok, Vanna, let’s show our guest what he has won.

1) I don’t really know if small shot deforms more easily than big shot or whether deformation affects the small shot more than the large shot due to its smaller mass, but the result is the same. Bottom line is that shot hardness is not as important as the pellet grows in size.

Traditionally, when the shot makers like Lawrence make their “Magnum” (high antimony) offerings they put their highest antimonal contents in the #8 and #7 1/2 sizes. #9s and #6 get a bit less and then it falls off rapidly. In the BB sizes, the difference between “magnum” and “chilled” shot is only 2% vs 1%. My point is that they would not be able to get away with doing this if larger shot didn’t inherently resist deformation (or its effects) better than small shot. Maybe you engineers out there who really know what you are talking about can give me the mechanical why-fors. I am just a practical user who flunked Algebra Two.

2) and 3) These are really both the same “shot column length” questions. The longer the shot column (the height of the stack of shot when it is in the shell awaiting launch time), the more the pellets at the rear get squashed at lift off. The more squashed pellets there are, the more that they fly out of the pattern. It is that simple. The total shot payload really isn’t the question. It is a matter of shot column height.

Example: put one ounce of shot in a ten gauge shell. (I am cribbing from the Alliant Reloader’s Guide here- they have done all the work already). Due to the width of the 10 gauge bore, the shot column is only .610″ high. This means that the shot “passengers” riding at the rear (bottom) of the launch vehicle only get squashed by a .610″ inch high column of lead.

Now look at the miserable skinny idiot stick .410 bore. One ounce of shot jammed in there is almost like putting it down a McDonald’s soda straw. The shot column would be a monstrous 2.175″ long for that same one ounce. This means that at ignition, the pellets in the back would have 3 1/2 times as much weight on top of them and would thus suffer MUCH more damage and deformation. In fact, this is exactly what happens and is one of the reasons why it is so hard to get the .410 to pattern well.

The bore size/ shot column length is also one of the reasons why the manufacturers are touting “backboring” (actually factory enlarged bores) as a pattern enhancer. They may be right in theory, but the difference between the old .729″ and the new .740″ is so slight that it is really just marketing hype.

4) Yes, buffered loads help lead shot. Brister’s book covers a lot of that. The buffered concept has fallen out of favor because it was really only worth buffering large lead shot loads, the type used in waterfowl. Now that non toxic is required and lead is out for waterfowl, there is no point in buffering, except maybe for buck shot. Buffering for steel is not necessary as steel does not deform at ignition.

5) I have never really liked copper coated pellets on game because I do think that they “grease” through birds and don’t shock them as much on impact. Copper is popular with many people because manufacturers usually only bother to plate their hardest shot, so when you buy copper coated shot, you know that you are getting the hardest shot that the manufacturer can make. At least that is the theory. That was why the old Lubaloy shot was so popular. Not so much for the copper coating, but for the hardness.

Copper and nickel coatings do provide the shot with a lubricity that helps is slide around within the shot column as it goes down the barrel and into the choke. This ability to slide a bit helps plated shot avoid some deformation that lead gets when it sort of stick together as it gets jammed into the forcing cone and bore. This is the main reason that plated shot patterns a bit better than unplated shot. There may be some advantage to plated shot also in having less aerodynamic friction, but I can’t prove that. I have seen some awful shiny fresh pure lead pellets. Of course, the plated shot doesn’t oxidize as badly or as quickly either. The US Army Shotgun Team uses copper plated Federal loads exclusively at trench. That ought to tell you something.

6) As to the 16- it remains popular in Europe, as it always has been. Here it has been virtually supplanted by the 3″ 20 gauge and the light 12. There is nothing wrong with the 16, but it is a hassle getting shells. Life is much simpler with the very slightly ballistically inferior 20.

7) That question is really a lot more complicated than it looks and I am going to save it for another time.

Best regards,

Bruce Buck
Shotgun Report’s Technoid
(Often in error, never in doubt.)

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Skeet Patterns Down Under

Dear Technoid,

You will be pleased to hear that I have finally got around to patterning my skeet gun. As usual this exercise raised more questions than it answered. Being somewhat stubborn however I am pressing on and hope you can help me with one of those pesky questions.

I found that my 12 gauge Rem 3200 with 3 to 4 thou of choke printed on average 62 percent patterns at 20 meters. (21point something yards??) This seemed a bit low to me and the effective pattern seemed not much more than around 20 – 21 inches diameter.

I am loading some lower velocity shells to try to bring a few of the fliers back into the pattern but I was wondering if you could tell me the optimum theoretical percentage for 20 meters/yards to give me the biggest effective pattern so I have something to work towards. ( I guess it should be more like at least 70 or even 80 percent). Oh, this was with 24 gram (7/8oz) loads. I am a little shy of recoil and I can’t use my gas gun anymore(sob sob!). I realize it will be different for 1oz loads (maximum legal in Aussi competition). Perhaps you could tell us the optimum for 1oz as well?

Best regards,


Dear Andrew,

You are going to have to do some interpolating because US information uses feet instead of meters and the standard US clay pigeon at 108 mm is slightly higher than the standard ISU clay. I don’t know which one you use. I don’t think that it will matter too much as what you want to do is to compare loads. Here is what I would do:

Warren Johnson’s most excellent Choke Chooser slide card (see our SR ad section. The device is REALLY helpful in this analysis.) shows that a 1 1/8 oz load of #9s at 20 yards has an effective killing pattern of 21″ from a Skeet choke. A 1 oz load of the same has 20″. It would be reasonable to assume that a 24 gram load (about 7/8 oz) would be around 19″. Warren defines the edge of the killing pattern as having an 80% chance of a two pellet strike or 95% chance of a single pellet strike. I have found that this is a very practical definition in the real world.

Now comes the good part. Warren’s work is statistically as accurate as a computer can make it and very useful as a starting point in analysis. Warren has made certain assumptions (as he must) in setting up his Choke Chooser. A Skeet rated choke is considered to throw a 40% pattern into a 30″ circle at 40 yards. If your Skeet choke actually does perform that way (depends on your barrel, choke and shell), then the rest of the mathematical analysis follows.

Here is what I would do. Your 3200 barrels of .003″ to .004″ are close enough to the nominal skeet choke constriction of .005″ so that you have the right to expect “skeet” patterns. This means that you should be looking for ABOUT a 20″ effective pattern at 20 yards. This certainly bears out your initial analysis.

To fine tune and compare loads, I would simply get a yard stick and, using it as a compass, scribe a 19″ circle and a 21″ circle around the visual center of the shot cloud (not around the aiming mark) of a pattern you have just fired on paper. Count ONLY the pellets in that 19″-21″ ring. Do at least three of each and every shell that you want to compare. I use red resin flooring paper, 36″ wide and in large rolls, for patterning. The shell that puts the most pellets into that 19″-21″ circle will be your best skeet load. It is labor intensive, but simple. It will allow very accurate comparison among shells and guns.

If you don’t think that your gun is performing up to standard , compare it to a gun of known performance using the same shell. Counting only the pellets in the annular ring will save sometime. Just remember to find the center of the shot cloud on paper by eyeball, not by using the aiming mark. Aiming marks are seldom the correct center if you wobble around as much as I do.

If it is helpful, most of the US International Skeet shooters are using 24 gram loads of #8 1/2s and IC (.010″) choke. International clays are physically much harder than the standard soft 108s. ISU skeet also requires doubles on most stations, so they have to choke for that second bird.

Best regards,

Bruce Buck
Shotgun Report’s Technoid

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