Shot shell “only use recipe”

We don't have the hi-tech tools needed to test/measure pressure. Plus, it's fairly complicated to get get powder, wads and crimps matched up.

I shoot sporting clays and skeet, and I hunt ducks, doves, quail, and pheasant. Everything from 3/4 oz of shot up to 1 3/8. 1100 fps to 1500.

I've never felt the need to try to use my own formulas - there's a lot of load info available that covers a very wide variety of needs. Buckshot can be frustrating during these times if you don't have everything you need on hand. I will admit to being tempted a time or two there, but then I've seen a superimposed barrel come apart a couple of stations away so that temptation leaves fast. We were finding pieces for weeks.

Because the powder level is calibrated to the components used in a shotgun recipe and the difference between straight wall and taper hulls, for example, can be quite significant in terms of pressure. 12 ga SAAMI MAP is 11,500 psi and 20ga is 12,000 psi. Therefore, a component change that yields only a 2,000 psi increase in pressure can be quite significant.

WestKentucky said:

Why do people say to only use a published recipe for shot shells? Is it that the plastic hull doesn’t provide much structural support to contain the load? Is it more a question of the large bore and thin wall of a shotgun barrel? Combination thereof? I have loaded shotshells and have stuck to published loads simply because I don’t have a whole lot of experience with it... maybe 500 rounds over the last couple years. I’m soon to dig into .410 pretty heavily so a better understanding would be greatly appreciated.

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Unlike measuring devices for metallic loading, shotshell powder is measured by volume. Consequently, there is less wiggle room in powder charges. The wad factors in also. Too much height presses the wad down with more pressure. (Fiber wads require pressure, plastic wads don't) Too little makes for bad crimps, and variable pressures. And as with metallic loading, different primers have differing properties, including more (or less) velocity, and more (or less pressure.)
Hulls come in two major types, and switching wad types around can cause velocity and pressure variations also, and you don't get warning signs like you can with rifle ammo.
If you are familiar with metallic reloading, you know an excess or too little of either property can be disastrous. Shotgun shells have more components, and substituting on any of them can cause problems, because as DocRock says above, you have a very narrow window of pressure to work with.

When loading for .410 watch for shot bridging in the drop tube.

Perhaps reading something like the Lyman's book can help you. Shotgun shells are NOT metallic; while there are some substitutions that experienced folks know about; we discourage new reloaders from doing so as the margin for error is slight - similar to some handgun loads where .2 grains can be the difference between min and max

The biggest issue is the variability in capacities of different hulls and wads. This is where the recipe comes into play, telling you which components fit with which hull.

Gaining experience, one can draw parallels. The old Lee load data used to (maybe still does), only break it down into plastic base hull vs paper/composite based hull, simply giving you a powder charge per shot weight for each. The rest was up to you to figure out! As I started loading shotgun before the internet was a thing, and a proper loading manual was not in my budget, this was all I had to go on and it did work without blowing up my gun.

Everyone already pretty much covered the whys, components. Changing the hull, primer or wad(s) can change the pressures drastically.
The only thing I could add is that in some recipes there is a higher powder charge and a lower charge. In that case, it is ok to vary your powder charge within the published high and low to tune the load to your gun. But only for those specific recipes. All other components in that recipe remain the same.

As said, it is best to stick with the published recipes for shot shell loading. The hull design and wad design for a recipe is important and dictates powder and shot charges.

Since .410 uses powders like W296 and 2400, I made sure I had an infinitely adjustable charge bar on my loader so that I could accurately dial in the powder and shot charge to match the recipe.

With the larger gauges, there is a bit of flexibilty on powder charges that make the use of bushings acceptable in the charge bars. Select the bushing as close as possible to the desired powder charge.

As a side note, the charge bars for my MEC600jr have a fixed cavity for the shot. For different size shot, the charge weight will vary a little from the nominal weight the charge bar is supposed to throw. MEC had special charge bars for folks loading ammunition for registered targets that threw shot charge weights at or a bit below the maximum allowable shot charge for the gauge.

When I was shooting competitve skeet, I’d shoot new factory ammunition in the tournaments so that I did not have to worry that my shot charge was over weight. I never had my ammunition inspected at a tournament but they reserved the right to do so.

cfullgraf said:

Select the bushing as close as possible to the desired powder charge.

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The next lowest one, even if it is closer to a higher one Drop deviations go both ways. And while were on the subject, ALWAYS test your drops! I weigh 10 drops to get a decent average, then decide if that bushing is acceptable. If it is not, I go down one.

It is good to check your drops during a run also, particularly with an adjustable, so I'm told. I've never used one.

entropy said:

The next lowest one, even if it is closer to a higher one Drop deviations go both ways. And while were on the subject, ALWAYS test your drops! I weigh 10 drops to get a decent average, then decide if that bushing is acceptable. If it is not, I go down one.

It is good to check your drops during a run also, particularly with an adjustable, so I'm told. I've never used one.

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Yes, it is good to periodically check the powder drops.

.410 is the only gauge I load with an adjustable charge bar.

Well, that is not totally true. I have four MEC600jr's, one for each gauge for skeet competition. My MEC600jr's for 12, 20 and 28 gauges have charge bars that use bushings for powder charges. But, two years ago, I bought a Dillon SL900. Both the shot and powder charging systems are infinitely adjustable charging systems. But, the SL900 only loads 12, 20 and 28 gauge.

I think .410 was available for the SL900 at sometime in the past but no longer. That is ok. I still have half a case of .410-2-1/2" skeet loads left over from the 1990s. I don't shoot much .410 at present.

I tend to load .410 at a slower rate than the larger gauges but then, I do not shoot as much .410 as the larger gauges.

entropy said:

The next lowest one, even if it is closer to a higher one Drop deviations go both ways. And while were on the subject, ALWAYS test your drops! I weigh 10 drops to get a decent average, then decide if that bushing is acceptable. If it is not, I go down one.

It is good to check your drops during a run also, particularly with an adjustable, so I'm told. I've never used one.

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I actually has to go up 2 bushing sizes on my MEC for ExtraLite from what I was dropping. I started getting some soft loads and checking the weight on my scale showed it to be a full 1 grain off @ 15 in lieu of the 16.3 I was wanting. Even though I loaded thousands with that, weather changes, humidity (or lack of) can vary powder drops so it pays to check every time you set up to load and adjust accordingly.

I can remember my father and grandfather reloading paper hulls and cursing felt and paper cards trying to get a load column right. This would have been back in the late '50s. I remember scoops for powder, but I don't remember manuals and have no idea what they used for starting data, but both were lifelong serious shotgunners. I shot a buncha ducks with their loads.

So, yea, there was a time when folks had to dabble a bit, but there's really no need today.

What little shotshell reloading I did the main reason for using a specific combination of components was to get a good fit in the shell. A bit too much shot, a missing card, or mismatched wads and the crimp would either be dished down or wouldn't close. Shot could leak pout with either poor crimp. Only tried a few roll crimps and they seemed more particular for components heights...

But I only have one shotgun and I figgered out a good 00 buckshot load and stopped experimenting...