12 Gauge Payload Substitutions and Pressure

Discussion in 'Handloading and Reloading' started by twofewscrews, Jun 13, 2021.

  1. twofewscrews

    twofewscrews Member

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    Hi,

    So I was looking into turning some factory produced birdshot rounds, either Federal target or Remington gun club, into slugs. In researching whether this was possible, safe, effective, and/or practical I found many different answers. Some people said it was unsafe and I would lose a finger or worse, some people said they had been doing it for years and it was pretty safe to do. Putting aside the dangers involved, as well as the tools, recipes, and components required to properly do so, I have a couple of physics/pressure related questions.

    1a. If I reduced the payload (but use the same type of shot, ie swapped out #8 shot for #2 shot) what effect would it have?
    1b. Would reducing the payload increase the speed at which the payload travels?
    1c. Would reducing the payload increase or decrease the pressure?
    1d. Is there any danger in reducing the payload of a factory produced shotshell while keeping everything else unchanged?

    2a. If I swapped out one payload for a payload of a different type (keeping the payload weight the same or less) what effect would this have? (ie bird shot to buck shot or slug, buckshot to bird shot or slug, or slug to bird shot or buck shot)
    2b. I've read that if I put a slug in place of birdshot I would increase the pressure on the round/in the barrel, is this true?
    2c. If true, why? Is this due to the fact that the slug generates more friction as it travels through the bore, is this due to the density of the payload, is this due to the powder burn rate for slugs, bird shot, and buckshot being different, or is there something else I am missing?

    I have a couple more questions but for the moment I am unable to clearly articulate them.
    Any answers would help, answers from those who have done this before more then from those who haven't. I'm looking for something more then, "your should be ok" but less then "the internal pressure will increase 2.5 times based on the . . . just divide the density of the payload by the weight of the powder and you will be ok". The first I've heard already and the second will only cause headaches. My level of technical understanding is limited, but honestly, any answer, be it overly complicated or simplified to the point of absurdity will be appreciated.

    Thanks for your time, and remember, the only time a firearm should be considered safe is when it is directly under your control.
     
  2. George P

    George P member

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    1A just changing shot size while keeping the weight the same changes nothing as the shotgun doesn't know what size shot is being fired.
    1B yes
    1C decrease
    1D if you reduce it too much you won't get good crimps

    I have no experience with slugs in place of birdshot

    I know a few folks who have opened the crimp and then poured wax onto the shot trying to make it act like a slug (didn't work very well)
    Then there is making a cut shotgun shell:
    https://americanshootingjournal.com/survival-hack-cut-shotgun-shells/
     
  3. mcb

    mcb Member

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    1a. This question is not clear, you say reduce payload but then talk about swapping shot size. Reducing payload weight see 1b & 1c If you keeping the payload the same but swapping shot sizes there will be minimal if any change in pressure, it might increase slightly as you move up in shot size as the payload is slightly "stiffer" since the larger pellets tend to bridge more.

    1b. It would likely increase in most cases but it could decrease depending on how much and what powder was being used. ie if you decreased payload a lot and the original load was using a slow burning powder you might actually see a decrease in velocity.

    1c Reducing payload almost always reduced peak pressure.

    1d IMHO no real danger assuming you simply reduce the original shot amount

    2a see 1a though once you step up to buckshot and slugs you could start to see pressure increases depending on wadding and other factors. Many slugs need specialized wads. Though there are several slugs designed to go in standard shot cups. If your set on doing this swap I would seek out slugs designed for standard shot cups.

    2b could go either way depending on the slug and wadding. Most slugs (in their proper wadding) produce less force outward on the barrel since they are one big junk of lead and thus have less barrel friction. Shot payload tend to try to spread out under the setback of the propellent gas creating force pushing out on the barrel increase wad friction. This is nearly impossible to answer definitively without being more specific on original loads and the particular substitute slug.

    2c see 2b

    I applaud the effort to learn and get more information and intuition on this topic but I would ask why? There is lots of commercial slug ammunition available even in the current market I have seen slugs pop up more than some other type of ammo. If you are a reloader and have the equipment then you will get much much better performance if you actually load slugs from the ground up using the proper components. Ballistics Products (and I am sure others but BP is my favorite) sell lots of components for loading shotgun slugs and has a fair amount of load data they will share too.
     
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  4. entropy

    entropy Member

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    If you have to ask these questions, you should not be deviating from published data.
     
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  5. George P

    George P member

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    True, and there companies that will do the pressure testing if your loads for a fee.
     
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  6. mcb

    mcb Member

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    Agree. (devil's advocate->) but how else are you to get the knowledge to deviate from publish loads if you don't ask?

    The engineer: There are books and software available to the common man that has this information too if you willing to put the effort forward to study and understand it. (some understanding of dynamics including fluid and thermo, along with basic chemistry helps, alot)
     
  7. entropy

    entropy Member

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    TIme in grade, as they say in the military. Working with and becoming familiar with the properties of different powders, primers, wads, and shot payloads within published parameters enough to know we don't substitute the same charge weight of 700-X for Green Dot, or Federal 209A primers for Win. 209 on a load that is already at or near max. Doing such things can lead to barrels that look like banana peels. Or worse, all that overpressure coming out the back, adding a little iron to your diet.
    I've been reloading shotgun shells since I was nine years old. ( A LONG time...) and I only will move up or down a MEC bushing or two from a published load, and that only on my middle of the pressure curve Trap loads.

    Twoferscrews, if you want to load slugs, I suggest you start here;

    https://www.ballisticproducts.com/

    They have all the data you need to load slugs, and (usually) have the components also.
     
  8. forrest r

    forrest r Member

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    Never did slugs but I've have used dimes in the past.

    Used to take the 1 1/8oz birdshot loads and put 20 dimes in them and re-crimp them. yes I know 20 dimes weigh 1.6oz. But when I used 15 dimes (1.2oz) the loads were a mousefart load.

    Used to used the 20 dime load on the bowling pin table. Used to do 3 man fun shoots, the 3 shooters could use pistols/revolvers/shotguns. All 3 would line up & when the buzzer sounded all hell broke loose:evil::evil::evil:

    I'd use a double barreled sawed off shotgun (savage 511) leveling it and pulling both triggers. All's you'd hear is zzzziiiiiiinnnnnngggggggg!!!! Some would go sideways sticking into the pins, others stayed flat & you could make out the details enough to see if it was heads or tails that hit the pin.
     
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  9. mokin

    mokin Member

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    I think mcb pretty well covered it - and a little more.

    One thing I've noticed after shooting slugs, the bore tends to have lead in it. Sometimes I can see it peeling off near the muzzle. Some slugs can be put inside a shot cup similar to bird or buck shot that will help mitigate leading. If you are using a rifled barrel, you can use a sabot. Either way, there are a lot of moving parts that all have to coordinate. Ballistic Products is a great place to start.
     
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  10. mokin

    mokin Member

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    I made a box worth of dummy shells to practice reloading/dry firing with for three gun. I bought a box of ammunition with pink hulls - the only color I don't have live ammo and loaded them with ( think) fifteen pennies. At the cost of lead, I figured I saved a couple cents on each shell.
     
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  11. twofewscrews

    twofewscrews Member

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    A mix of general curiosity regarding the physics involved and a specific curiosity as to the safety of doing so. I've heard and found a lot of conflicting information. People either tell me its completely safe so long as you don't exceed the original payloads weight or that its the most unsafe thing in the world. I'm more interested in why it would or would not work then I am in actually replacing the bird shot with a slug in a factory produced round.

    Your right, I wasn't. I was asking a question without actually asking it and butchering the question I was trying to ask, but you figured out what I meant. Part of the confusion here is I neglected a piece of information that I was told, which was that the pressure would increase if you switched the size of the shot. For example if you went from bird shot to buckshot there would be a slight increase in pressure but if you went from bird shot to a slug there would a be a large, possibly dangerous, increase in pressure.
     
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  12. twofewscrews

    twofewscrews Member

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    The wax slug thing has always sounded dubious to me. A wax being propelled down a hot barrel or even sitting inside a hot chamber sounds like a sure fire way create a barrel obstruction and destroy your firearm and possibly yourself.
    Cut shells seem like they would work fine out of an over-under or a double barrel but I would hesitate to load a pump or auto loader with em. Not sure why I feel like they would work in an over-under or double barrel and not a pump or auto loader.
     
  13. twofewscrews

    twofewscrews Member

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    I am referring specifically modifying a factory target load. Specifically emptying the shot and modifying the shot cup, replacing the shot with a slug, and leaving the rest (powder, primer, etc) untouched.
     
  14. milsurpguy

    milsurpguy member

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    When I load shotgun shells I'll use the exact same primer, shell, powder, amount of powder, wad and I'll load number 9, 6, 4, 2 and lead BB, can't tell the difference when shooting them until I see the target.
    I could load slugs in those shells, I could drop in a Lee key slug into an unmodified shot cup with a stack of wads so the crimp folds correctly. But the slugs have their own load, fifty some grains of bluedot, full 3 inch magnum power.
    I tried doing 00 buckshot, but the crimp is funky. I haven't tried #4 buck.
     
    Last edited: Jun 13, 2021
  15. entropy

    entropy Member

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    And not always then, with what you are suggesting.

    If you have the eqipment to do this, you have the equipment to load purpose-made slugs to proven data. Just sayin.....
     
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  16. George P

    George P member

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    Because you would be loading them directly into the chamber without exertion or forces trying to pull them from a magazine. Personally, either buy the proper components or tools or buy factory. You could always melt the shot and use a mold to make slugs you have a recipe for.
     
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  17. mokin

    mokin Member

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    Shotguns are amazingly versatile. Being able to make your own ammunition only increases their usefulness.
     
  18. mcb

    mcb Member

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    I am not necessarily condoning this but if your going to go off into uncharted waters with weird projectiles and the like a 12 gauge is probably far more forgiving than a high pressure rifle or pistol cartridge.

    The early days of Demolition Ranch and nearly all Taofledermaus YouTube videos make great use of the 12 ga cartridges and the inherent forgiveness of the low pressure and big bore. Now they probably have done more behind the scenes research than they let on in the videos since the both still have all their fingers and toes but they also have gotten away with somethings for sure due to the forgiveness of the cartridge. Taofledermaus has the motto, "you make it, we shoot it". With some experience you can safely load and shoot a bewildering array of strange stuff into a 12 ga. That is sort of Taofledermaus' bread and butter.
     
    Last edited: Jun 13, 2021
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  19. Bcwitt

    Bcwitt Member

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    I once saw a guy cut 3/4 the way around the shell. You fire it just like that & the whole mass goes down the bore, front part of case & all. It seemed to be reasonably accurate.
     
  20. entropy

    entropy Member

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    Yes, that is a 'cut shell' as mentioned in post #2......
     
  21. mokin

    mokin Member

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    I spent a morning and the better part of a box of shells trying that. The results were decidedly mixed enough that I would not count on cutting shells. I set up a B-27 target 50 yards away and started shooting. Some of the shells worked as advertised with the hull separating at the cut and making only a single hole in the target. Others worked very much like regular shot shells, peppering the target with shot and possibly hitting it with the wad. The hull extracted in a single piece. Then there were those that appeared to work like a regular shot shell, but when I opened the gun, only half the shell came out with the ejector. The remainder of the hull was in the barrel.

    If you have the space, time, ammunition, and are inclined to extreme safety, I encourage anyone out there to try it. Your results may be different and you might just find a new way to deploy your shotgun. For me, cutting a shell is an extreme last resort. There are plenty of better options out there.
     
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