Shotshell reloading tolerances?

[Mk1_Trebuchet]

I've been reloading rifle ammunition for a number of years, and am just getting started doing shotshells. When it comes to powder, what is considered an acceptable tolerance on the measure?

I've got a recipe for a load that I'm trying to put together and one bushing drops a bit light and the next drops a bit heavy. Completely unacceptable for a precision rifle load, but is a few tenths up or down ok for a shotshell? (Should I err light or heavy?)

 

[Sparkey]

Either way you will be fine I have been reloading shotshell for 20 years. You can stay on the light side but as long as you are not pushing the limits you will be fine.
What load are you using ?

 

[IPSC_DRL]

Sparkey pretty much nailed it. A few 10ths won't make a noticeable difference. if it will feed and chamber, you should be OK.

 

[mac1911]

as noted unless your starting to push the upper limits of your powder choice for anything but sabot from a rifled barrel you wont see a difference...or really feel it for that matter.

 

[gerrycaruso]

Shotgun shells seem to vary so much in length that they can be measured with a tape measure as opposed to a caliper. If you're dropping powder with something more precise than a kitchen spoon, you should be alright.

 

[Mk1_Trebuchet]

Thanks everyone, I feel better now. I selected a light skeet load from a Ballistic Products load book as my first attempt. So far, so good....

 

[icyclefar]

Lets get rid of the picky stuff first.

What gauge, what pressure, what are you shooting them in?

I ask this because if you were to answer something like "20GA, in Briley insert tubes in my 12GA Browning", then you need to be absolutely concerned that no matter the powder drop you stay well below 10,000 psi or risk damaging the tubes.

Or, if your recipe is already at MAX for the components, then you need to approach it as XX.X grains minus 2-3 tenths, plus ZERO.

Most published recipes give you several drop weight variations so pick the speed you like and if there are faster recipes using another 1/2 or whole grain above what your doing you are more than safe. It is not uncommon for shotshell drops to run as much as +/- 3 tenths although mine are usually +/- 2 tenths.

* Don't forget to weigh your shot drops too. If your making a shell thats at max pressure for a 1oz load, and your machine is actually dropping heavier, your resulting pressures will be higher too.

 

[Mk1_Trebuchet]

12GA, 7/8 shot, Lists 9100 psi @ 1400 fps (22gn Clays) Getting one dropping 21.7 avg next one up averages 22.2

They list the same load at 23gn (up a full grain) - so it sounds like its safe to try both -.3 and +.2 to see if there is a material performance difference between them.

How much variance in shot weight should I be concerned about?

 

[icyclefar]

For skeet targets I’d load that to 1200 FPS max

My go to load is:

12 ga Remington STS hull or Gun Club
Claybuster CB0178-12 wad
Winchester 209 primer
17.1 grains of clays (actual drop 17.5)
8900 psi
1200 FPS

I loaded and shot thousands of these, they pattern beautifully and crush birds with little recoil.



With regard to shot drop, don’t worry about small variations, just make sure it right.