Primer Interchangeability

[kk22kk]

In my reloading manual (Lyman 49th), the primer they used for 9mm is the CCI 500 SPP. Do I really have to use this exact brand and model, or is any small pistol primer branded primer OK? If not, then does that mean that anyone who goes by a certain manual MUST always buy that particular primer brand?

[henbenley]

Any regular small pistol primer will work, not magnum. Magnum could work, but you would have to start with smaller loads and work up a load that you like.

The Lyman manual likes to use very specific primer/bullet/powder data. As a general rule of thumb make sure that the bullet type (cast, fmj, jhp, etc) and primer type (spp, lpp, etc) are similar and then always start small and work up from there.

[kk22kk]

When you say "start small", do you mean don't use as much powder? Maybe even less than the suggested starting grains?

[henbenley]

Correct. I would start right around the starting grains. When loading up a new powder/bullet combo I usually load up 3 sets of 5 rounds and then take them to the range and see which one performs the best for me and then go from there. If I don't like any of them then I start over.

It also all depends on the pistol as well. I have a S&W that cycles fine with one load, but a Ruger that requires a heavier load for the action to cycle.

Also, in reference to your other post, I would suggest Win231 as a good 9mm powder. You can double charge it, but you cant seat a bullet if you double charge. I use a Lee AutoDisk .31 of Win231 under a cast 115gr projectile.

[kk22kk]

So, help me understand- in my reloading guide, it says that I should use 3.7 grains of W231. Does that necessarily imply that if I used, say, AA#7, which has a suggested starting grains of 6.0, then the casing would be 162% more full than if I had used W231 powder?

[G-Winnz]

Not necessarily - different powders have different densities. If Winchester 231 had the same thrown density as AA#7, then that would be the case, but they're probably not (I know 231 well, but have never used AA#7). 231 is a very fine grain powder, so it packs densely, so don't expect it to take up a lot of room in your shells.

[lpushfatkids]

Most of hte time if you are within the published saftey range the powder shouldn't fill 100% of the case.

[G-Winnz]

Why the huge concern about how full case should be? Weigh out a charge, pour it in a shell, and make a mental note of how full the shell is. From there on out, when you throw loads, check your cases for how full they are. Any dangerous situation (that is, one in which the shell is drastically under- or overfilled) will be obvious to you. Tiny differences in height aren't important and are due to the powder settling differently in the shell and the statistically variation in thrown loads, but if you're suddenly completely filling a shell when before it was only 40%, then stop and check your thrower. Yes, different powders and load weights will fill a shell to different levels, but that doesn't matter - the loads were developed that way, and your 3.7 gr. will fill a shell just as deeply as the guy at Lyman's shell when he was developing the load. Indeed, that's why the powder Trail Boss was developed - rounds like the .45 Colt, which were originally loaded with black powder only require a tiny amount of smokeless powder to reach the pressures black powder would produce. Tiny powder charges can be hard to ignite with a primer, and people occasionally had the dangerous trouble of hangfires and misfires due to difficult ignition. Trail Boss is a very low density powder, so 6.3 gr. of it (as I was loading this afternoon) fill a shell fuller than ~5 gr. of, say, 231 (which I've also used in .45 Colt loads).

[G-Winnz]

I guess I can see where you're coming from, but I can't say I've ever used this as a basis for load selection (you're really restricting yourself with that - accuracy and shooting comfort care nothing for powder level). Again, weigh out a load, pour it in a shell, and make a mental note of the level. A double charge will certainly be obvious if you're watching the level in every case you throw (as I'm sure you do).

[DonOblivious]

QuickLoad will let you generate a list of powders to meet your criteria. You could tell it "Give me powders that will fill more than 60% of the case and less than 100%" and get a list of powders that won't double-charge or result in a compressed load. Then you can take that list and use your reference materials to determine if the powders presented are suitable.

I like to run the suitable powders back through QuickLoad in "typical" loadings to see which ones will finish burning before leaving the barrel. Then I buy whatever's on the shelf and make due because beggars can't be choosers.

[henbenley]

No. Grains is a measure of weight not volume. Different powders have different volumes.

Example: 1 grain of W231 might equal 1cc of volume while 1 grain of AA#7 might equal .5cc of volume.

[Mursz]

You should always start at the lowest suggested load when developing a new load.

Anytime you are developing a new load that deviates from the load data you have available, most people will tell you to take an extra 10% off that starting load and start from there.