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.

Major

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

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4 Responses to 24 Gram Patterning

  1. Gerald Elwood says:

    That was not the best use of my time!!

    Like

    • stanley m. wren says:

      All you would ever want to know on shotgun ballistics but bottom line, not a SIGNIFICANT difference. The recognized Bible on Shotgun Ballistics:

      Sporting Shotgun Performance
      Measurement, Analysis, Optimization
      by DR. A.C. Jones

      Seven years in the making, 2500 test patterns, clay pigeon impact tests, computational fluid dynamics analysis: There is no other book on shotgun performance quite like this!

      Like

  2. Jan Nielsen says:

    Just to add to the confusion; Here’s a link to a post I made a while ago in another forum. If anyone can come up with a better explanation for “How Chokes Work” I’m all ears (or eyes):

    https://castboolits.gunloads.com/showthread.php?427710-Buckshot-Choke&p=5222356&viewfull=1#post5222356

    Like

  3. stanley m. wren says:

    A interesting discussion but Red Dot won’t push a 7/8 oz. load in a AA hull to 1400 fps. Most of the data is 18.5-19.5 grs. all coming in around 1300 fps. Possibly a Fed 209A would get you to about 1315 fps. but 1400 fps?

    Like

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