New to reloading...couple of questions

[mcdaniel52761]

First question is....all other things being equal, would the load data change if the bullet was flat based vs. hollow based?

Secondly...I'm trying to understand *why to use* different powders. I know they all have different burn rates, shapes, and maybe a couple of other characteristics..but say you have powder "A" and powder "B" and you're reloading .40 S&W. You have a given pressure range and a given velocity range. Powder A might be in the range of 3.5gr-4.5gr. and powder B might be 5.0gr.-5.7gr. Obviously, both powders will get you to a given pressure to achieve the velocity allowed. So why would (or should) I use one powder instead of the other one?

 

[dab102999]

First question...yes.....changing bullet shape changes air cavity in caseing among other things.

Second question is a lot to do with personal choice. If I have 5 calibers that work with one powder it would be a benifit to me if the 6 th caliber would use the same powder. And then their are reloaders that want absolutely the cleanest, or most accurate, or whatever it might be. So therefore multiple powders on their shelf works..

I don't reload enough to have 8lbs of 12 different powders on my shelf...a 8 lbs keg is cheaper per pound....so one 8 lbs keg will get me roughly 15,000 handgun bullets depending on which caliber I shoot most...may not be the most accurate...or cleanest burning...but I am only shooting under 15 yards and it gives me cheap practice.

 

[mdi]

Different bullet base shapes react to powder burning pressure differently. A hollow based bullet is generally a target style bullet ment for low pressure/velocity shooting and needs to be loaded much lower than a bullet of the same weight but with a plain base. Gas checks and jackets add another variable (along with alloy of jacket and friction differences).

As for your second question, I'll try. I would think that basically, if you load a round to a specific pressure, it won't make much difference which powder is used, but there are more differences to consider. The volume of the powder charge makes a difference with the air space in the loaded round. I believe the powder that will give a closer to 100% load density will be more consistant burning than a load of say 25% (even at the same pressure. I know, how do you justify that with Bullseye extra accurate loads?). The speed of the burn is another variable. When the pressure curve is at it's peak can effect bullet preformance. A slower powder will have more of a "push" on the bullet and a faster powder will "hit" the bullet. Now all this takes place in micro-seconds.

This is is the way I understand what goes on inside a cartridge when it's fired, and not being a ballistics expert I could be way off....

 

[mdi]

way off....

 

[mcdaniel52761]

So since most load data will just say "FMJ", what if you have a fmj with a flat base vs. one with a hollow base?

Regarding the different powders....I should assume, then, that it is better to use a powder that will fill up the shell or case more than one that will leave more empty space?

As far as accuracy in different powders, if you have 10 rounds loaded with 10 different powders, adjusted to give you the same velocity and pressure.....wouldn't they all shoot the same?

Bear with me......just trying to understand

 

[David E]

As mentioned, hollow base bullets are meant for low velocities. A double ended wadcutter vs a hollow base wadcutter are usually fired at slow speeds, so any change in airspace won't mean much, if anything. If Berrys fmj bullets, don't worry about the hollow base at all.

What caliber(s) are you reloading?

Powders have different burn rates resulting in different pressures at a given time. Don't be like my BIL and think that since you have room left over in the case, you can double your charge of Bullseye.

If you're asking why would you use 8 grains of this powder to reach X velocity when 5 grains of that powder will reach the same speed, then there are other things to consider.

Such as: Consistency. Accuracy, Cleanliness, Recoil Impulse and Convenience being some of them.

Recently, a thread asked "if only one powder..." Many people picked Unique. Not because it was ideal for every caliber and load, but because it was pretty good for quite a few. It wasn't the best powder for .38 bullseye competition, nor did it allow a full house .357 magnum load. But it allows pretty good "all-around" loads for both.

10 loads, 10 powders, same velocity will NOT necessarily shoot the same. Your gun, bullet and load may combine to show a preference as to which load is most accurate. Further, there's recoil impulse. The faster powders (fewer grains of powder required) have more of a jolt, while the slower powders (more grains) are more of a push. You may prefer one over the other.

 

[wraith56]

For safety, choosing a powder that fills the cartridge is good to prevent an overcharge accident is a good thing when possible. However, I don't usually do that in 38 spec because the case is so big compared to the powder for I got for practice loads. That shouldn't be an issue with most auto pistol cartridges.

 

[jb27]

My advice on your 2nd question is to just accept that different powders will provide different results. Unless you plan on using a software program such as Quick Load to estimate pressures given all of the variables in your shooting equation, you will not know what pressure you are at. You could estimate based on the values shown in your reloading manual, but there are a lot of variable at play, that will be different for you and your gun/rounds than the test gun the manual used. You won't know for certain.

My approach has been to research on this forum and in my manuals to see what powders are providing the best result for a lot of people, and starting there for my own load development. One of my major goals with reloading is to produce the most accurate rounds I can.

You didn't state what your intentions are, so it is hard to know if/why you should use different powders. If you are trying to achieve the utmost accuracy, then experimenting with different powder/primer/bullets/brass will certainly be in order for each gun you plan to load for. If you are trying to just make rounds for plinking or shooting 1" groups, you probably don't need to experiment with various components. Just do some homework here and find a powder that most people use and go with it, working up your own load within the parameters of your reloading manual.

Good luck, It is a great hobby.

 

[oldpapps]

I think 'David E' hit it on the head.

I would like to add, the 'hollow base' bullets are for light loads. Back when... the 'Minie' bullet (I don't know how to put a comma over the 'e' to make it sound like a long 'a'.) was developed, the hollow base was to expand under pressure and seal the barrel, the word is obturate. This provided greater accuracy. The concept was utilized in target ammunition, most notable being the .38 Special target loadings. The bullet is low pressure. (They do make a nasty very short range extreme hollow point if loaded backwards. The powder charge is completely different and they lead a lot.)

Now my view of powders.
For 95% of my loading I can get by with only 3 powders, 231/HP38 and 748 and 1 other that is no longer produced
The 231/HP38 does most all pistol rounds.
748 does the same for rifle rounds.
The third is a magnum pistol powder.

All three of these powders have very different characteristics in volume, burn rates and some others. Could 231/HP38 be used in a 30.06? Yes but, a big but. It would be far from ideal and then with poor results. No, I would not even start working out a loading. Could 748 be used in a 40 S&W? Probably but only as a single shot and then a poor one. Case volume and the volume of the given powder must be matched. Look at it this way. Put 'coal oil' in your car. Will it burn, yes. Will your car run, maybe but not well. Switch to JP4 Jet fuel. How long before your engine is toast?

Chemical engineers work hard to come up with the best and most versatile smokeless powders and they haven't came up with the 'one' do all powder.

 

[rfwobbly]

1) Yes, but....
You can use a listed recipe if your caliber, bullet weight and construction all match. So if you find a listing for 9mm 124gr JHP, then you can use it to load 9mm 124gr plated RN. Jacketed data for jacketed or plated; lead data for lead.

But, the minor difference in bullet length is made up by beginning at the "starting load" and working up slowly in small increments. So 'Yes' you can use the same recipe, but different shape bullets may take a slightly different load.

2) My personal take on this is that you want all powders to burn cleanly, which means they are burning efficiently. If I want my bullet to move at (say for instance) 1100 fps, then I'd choose a powder with a Max Load speed of 1150-1170 fps. That means to achieve 1100 fps, I'm burning an approx 90% load, which is still high enough to burn efficiently, but well under max chamber pressure in my gun. Follow?

 

[mcdaniel52761]

Thanks for the replies guys. I can tell I have much more reading and studying to do.

 

[David E]

Thanks for the replies guys. I can tell I have much more reading and studying to do.

Not really. Follow what the reloading manuals say and you're golden.

 

[mdi]

Just to add to the confusion there is a FMJ, and a TMJ. FMJ (full metal jacket) usually is the one with exposed lead on the base and TMJ (total metal jacket) is the one with the enclosed base. But folks usually use these terms very loosly...

Plated bullets should not be loaded to the same velocitiesas jacketed bullets (as per the manufacturers). Plaring is thinner than jackets and will not tollerate higher velocities. Check the manufacturer's web site for instructions on loading plated bullets (Berrys says up up mid jacketed bullet loads).

 

[Hondo 60]

Faster burning powders work best in lighter loads
Tite Group is a fast burner - works GREAT in 38 Spl, 9mm, 45 acp

2400 is a slower powder - works great in 32 H&R Magnum, 357 magnum & 44 magnum.

Slower powders = heavier recoil = higher velocity
Faster Powders = lighter recoil = lower velocities.