Why no shot shell scale loads?

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julesr

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Hi all,
Been reloading rifle and pistol forever, decided to start loading shotshells as well. I loaded a few dozen slugs and buckshot rounds with adequate success.
But... started wondering why I'm not doing scale loads to find the sweet spot for the charge. I get shot shells deal with a lot of pressure, but why can't I load light, and scale up .5 gr until I see signs of pressure. Why do the reloading manuals only give a light load and heavy load?
thoughts?
 
Lyman's shotshell reloading book only provides 1 charge, I assume it's maximum. I usually start 10% lower than stated and work around it either up or done depending desired oomph and accuracy. I have actually found more accuracy gains from changing hulls, powders, wads, and using different spacer cards such as cork or nitro cards. However I mostly load slugs with some buck so target loads may react differently.
 
julesr said:
Ok thanks.
By pressure signs, I mean difficulty to extract the don't shell, flattened primers, ripped case etc.
Click to expand...

You may get ripped cases earlier but difficulty extracting and flattened primers wouldn't happen until well above max pressure. Shotshell reloading is totally different from metallic case reloading. You have no way of knowing what the pressure is like until it's significantly into the danger zone.

I do the same as others have mentioned. Treat the book value as a max and subtract 10% to work up.
 
Lyman Shotshell manual has pressures and velocities for each load listed.
Working up is not necessary, or desirable. You will find that sub-pressure loads are not reliable in colder weather. Bloopers, extremely low pressure loads, can leave a wad lodged in the bore.
Choose a load indicating modest pressures if that is what you want. Use the exact components listed in a trusted shotshell manual or website. Changing components will lead you into unknown excess pressure.
Read the introductory instructions in the Lyman No. 5 Shotshell Reloading Handbook.
 
You take entirely the wrong message from this article.
Testing to destruction has nothing to do with safe working loads. You need to read Tom Roster on the effects of substituting primers, for example.
Unless you have access to pressure testing, going into uncharted territory is foolish.
Advising the inexperienced to do so is irresponsible.
 
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Developing shotshell loads is totally different than developing metallic cartridge loads.
You are offering advice by implying otherwise.
 
ok thanks.
i get that the loads in the lyman book are the max loads, but it still doesn't explain why I couldn't load them down from that... in one example, there is a load for 17.5 and another with the same components but with 20 grains as the charge. so am I to understand that anything in between there is not safe?
 
Some manuals give a range of loads for a given selection of components, some don't. In your case, you can load anywhere in between the listed values - just stick to the listed components. In shotgun reloading, just changing primers can increase pressure substantially.
Whether your experiment of changing powder charges to fine tune slug accuracy will bear fruit, is questionable. I suspect there are other variables that govern over a fast powder deflagration. Let us know how it works out.
 
Not at all unsafe to be between listed loads in the manual or on the powder mfg. website.
Going lower than published loads "may" lead you into poor performance, particularly in cold weather. Also, going lower in powder may give inadequate stack height, making for poor crimps. Poor crimps make less consistent pressure loads.

Shotshells perform best around 10K PSI with most powders. A few powders allow reliable loads at lower pressure.

You should also be aware that there are poor combinations listed, safe but a poor choice. Winchester and Remington hulls have tapered walls. Federal, Cheddite and Fiocchi hulls are straight walled. There are two types of wads optimised for straight walled or taper walled hulls.
 
Got it.
In the lyman manuals, there isn't any loads using Cheddite 209 primers. Is thwre a listed primer that they are a substitute for?
 
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