Home Forums Hunting & Shooting Hunter's Campfire Reloading - shotgun shell vs rifle/handgun

Why does the seemingly universal edict "Start 10% low and work up" not apply to shotgun shell reloading where we are warned not to deviate AT ALL from the published 'recipe'? Is it due to the speed of shotgun powders being so much faster and the relatively heavy payloads (ounces vs 150 grains or so)?

Interesting question, I don’t know the answer.
Shotgun pressures are roughly 20% of high pressure rifle loads, maybe that’s the issue.

I always used the recipe in the book and never looked any further.

I have friends that actually “worked up” by shooting over a chronograph to match what the recipe stated

I only load per the manufactures data. Never had a problem, because they already done the work for us. Stick to published data and save time and headaches.

Shotgun loads are pressure tested with the exact components listed. Substitution of any components could give excess pressure. Also of note is that increasing velocity can cause patterns to blow out. Rifle data is listed with a max load with warnings that it may not be safe in all rifles.

Hard to say... I load both shot gun and rifle loads.

I tend to shop for my desired result on loading my shot gun.... like... shot load size and speed of shot and then I load that specific load to get those results. And I use the recipe accordingly...

For instance... I want a 1 1/8oz of #7 copper plated shot load moving at 1225 fps in my 12 gauge and 1oz of #6 moving at 1185 in my 20.

But in my 300wsm I want a 150gr ttsx with holes touching at 100 yards and speed is not as relevent... a little hotter powder or a little slower burn at different grains may get me accuracy or not.

Just seems weird to me that just using the available wad instead of the specified one, at low psi, is such a no-no.

That’s what im sayin brother man

This.

Including hulls.

I haven't always followed this concerning hulls, but one certainly should.

With SG's the pressure builder is mostly in the payload, hull, & wad. Something the ballistician can test & control in house, ans once that payload leaves the hull the pressure build curtails.

With rifle/HC there are additional pressure builders(throat, bore dia, & surface finish) that fluctuate from gun to gun. These are variables that the ballistician cannot control or predict, therefor, the warning to back off 10% & try in your own gun before proceeding.

Which is because different wads can result in WIDELY varying pressures.

Might also mention that I have chronographed many handloads in shotguns over the past 25 years, and despite somewhat different barrel lengths and even chamber lengths (such as 3" vs. 2-3/4" in both 20 and 12-gauge) the velocities have almost always been close to what's published. This is no doubt due to the higher interior volume of shotgun barrels, and lower pressures, as opposed to the much higher ratio of powder to volume in rifle barrels.

One major factor in shotshells is also primers, which as with rifle primers can also affect pressures considerably. But with the much faster-burning shotshell powders it can vary even more. Here are the results of a major ammunition factory's tests of various shotshell primers in 12-gauge loads from a few years ago, all using the same wads, cases, powder charge and shot:

Federal 209A—10,860 PSI
CCI 209M—10,460
Winchester 209, 1st lot—10,200
Winchester 209, 2nd lot—10,240
Remington 209 STS—9,740
Fiocchi 616—9,690
CCI 209—9,650
Cheddite 209—9,270
Federal 209—9,070

The difference may not seem like much, but the highest pressure is 20% higher than the lowest--which in typical modern rifle loads is equivalent to 65,000 PSI (the highest average pressure allowed by SAAMI) and 78,000 PSI--which usually blows primers.

Hm. Thanks for that. I guess I just need to make damn sure my components match the recipe. Haven't started yet but my press and hulls and wads are under my bench waiting for a rainy day

Also operating pressure zones. Underpressure loads will burn inconsistent and dirty. I look for a load that is least 9000 psi and closer to 10,000 if possible, with components I have.

Kent

I haven't reloaded any shotgun shells in several years in part because it's kind of a pain to line up all the components needed to match load data when components are hard to source.

I have loaded shotgun shells, but I was loading for trap only, trying to save money, so I never experimented much.
I did find that without some multistage expensive setup, it’s really hard to save any money, because trap eats up ammo.
Rifles, OTOH, I love loading for because,
A. I can do a helluva lot more shooting than I would buying factory ammo.
I know I’m not saving money, truth is I’m spending probably a lot more.
B. The extra money I’m spending over buying factory loads allows me to do way more shooting, both my hunting and target rifles than a normal person person would buying factory ammunition.
And recreational Gunfire helps me keep the stress away!
C. Some people find handloading tedious. I do not.
As a matter of fact I find it relaxing. I listen to my favorite music, and I feel a little better after loading 50 shells.
D. I know what I’m feeding my rifles, and I know the ammo I’m shooting is the very best, because it’s tailored for each rifle! (Even different Rifles in the same caliber!)
If I didn’t enjoy doing it, I wouldn’t, but like I said, I find both the process and the end result more fun than watching tv or running around. I don’t push the limits though, I’m very careful about my guns, and if I see signs something may be wrong, I stop that and try something else.
Even the process of working up a load for a new rifle is great for me, because I enjoy both sides of doing it.
I’ve never gotten into handguns or pistols enough to try doing it. So I have nothing further to add.
7mm

Explain the variation over the years. We used to load 37 grains of blue dot with an 1 3/8 of shot in a peters blue magic case with a wwra red12 wad in the 70's from Hercules. One duck killing load. They kept dropping the charge weight then changed the wad by 1982. Wtf

I used book recipes for shotgun, but I did weigh charges on a scale for grins. I used Lyman powder bushing chart.

Important Information About Shotshell Pressures

Written by Tom Roster

https://www.shotgunlife.com/shotguns/tom-roster/important-information-about-shotshell-pressures.html

Leon pretty well hit it.

What John said with a couple of additions.

!. Shotguns have thinner barrels than rifles. SOME, much thinner than others. The loads are still developed to be safe in those thin barrels.

2. Target shooting loads have max velocities that aren't supposed to be exceeded for competition.

3. There is no work up a load to pressure with shotguns because pressure is never all that far from BOOM because of the much faster burning powders used.

4. Shotgun barrels while perfectly capable of being a PITA about patterning with a new load are more rarely finicky about small variances in bore diameter. Some shoot well with dents/bends in them that would hurt you in a rifle barrel.