Regarding BP, what does "forgiving" mean?

[2ndAllin]

In trying to educate myself on BP cartridge reloading, I keep hearing variations of "black powder is pretty forgiving stuff". I'm not sure if people are just trying to ease my fear of blowing myself up, or if BP is somehow safer to use than smokeless. My take so far is that the pressures generated are more manageable, but that BP requires much more care in handling. What else am I missing?

[Kelley O. Roos]

"What else I'm I missing"

Depends?

Kelley O.

[martinibelgian]

There he goes again!

[montana_charlie]

When you load a round with smokeless powder you need to pay close attention to the weight of the charge. More powder can raise pressure, of course, but the variation in internal case volume caused by changing the volume of powder also can affect the pressure curve.
You may be able to predict the amount of pressure increase caused by a heavier charge.
But, the changes in the 'rate of pressure rise' created by the volume variation may be harder to figure...and therefore 'unsafe'.

Black powder, by comparison, is 'more forgiving'.
You can't expect gilt-edged accuracy if your individual charges vary by a half-grain...or more...but they won't blow up the gun, and they might shoot better than you would expect.

CM

[NickSS]

By forgiving I think people mean that you can not get enough of the stuff in a cartridge to cause you any worry about pressure and blowing yourself up. This is due to the fact that all original black powder shells are loaded with no air space. To get more power in the days of black powder they either enlarged the bullet diameter and weight or lengthened the shell to fit more powder. The big thing I have found is not so much as how much powder you put in the case but how much compression of the powder charge you are using. Some powders/rifles I own like very little compression as long as there is no air space its OK but others require more compression to get good accuracy and burning consistency.

[2ndAllin]

Some powders/rifles I own like very little compression as long as there is no air space its OK but others require more compression to get good accuracy and burning consistency.

Thanks NickSS and Montana Charlie. Regarding the above quote, which powder(s) have you found benefit from more compression? How about BP Substitutes?

[montana_charlie]

In general, Goex powder is considered to benefit from compression.
I can't comment on any of the BP substitutes.

CM

[John Boy]

Some powders/rifles I own like very little compression as long as there is no air space its OK but others require more compression to get good accuracy and burning consistency.

the Black Powder Cartridge News -2009 Fall - "Some Black Powder Compression Data" article by Bob Woodfill:
Caliber - 45-70
Lyman 457124
Constant volume of FFg powder used
Compression tested: 0" - 1/8" - 1/4" - 3/8" and 1/2"
Best 3 Shot Groups 100yds ... 5 shot groups were tested also, with the same compression values except for Goex (1/4") and Schuetzen (1/2")
Goex - 0.62" with 1/8" compression
Goex Express - 0.26" with 1/4" compression
Schuetzen - 0.61" with 1/4" compression
Swiss - 0.56" with 1/2" compression
KIK - 0.65" with 0" compression

Comments such as these from "Internet Experts" don't know shit from Shinola and are too lazy to do the testing themselves!
Compressing the powder little will make it burn cleaner
Goex likes to be compressed but Swiss doesn't
Compress the powder about 1/16" to 1/14"
PS: It pays in spades to buy a subscription of BPC News magazine to find loading data tests like this and much more!

[montana_charlie]

That experiment sure leaves a lot to wonder about, doesn't it John?
CM

[Kelley O. Roos]

Which comment are you talking about? The one by Nick or the ones at the end of the page?

Kelley O.

[Kurt]

There are a lot more variables involved with a accurate load then powder compression.
I read a lot of this so called testing and I have posted a lot of it but I stopped because it don't mean smitt from person to person the way they go about loading and there ability to handle the rifle.
As far as compressing Swiss or not, I compress swiss .400 and it shoots as good as it does not compressing.
Goex is the same and it also makes a big difference in the caliber.
All of these powders listed will shoot cleaner with a lot of compression. I have my preference using Goex because I find the fouling softer but I can make any of the other powders shoot just as good.

Kurt

[John Boy]

or the ones at the end of the page?

Kelley, copied from the article at the end of the page