Stupid mistake

[mosin]

what makes a powder specific to a pistol vs a rifle?

Excellent question and this "stupid error" was the vehicle by which a member can clarify some misunderstanding. See? This thread did some good already!

The powder burn rate is the biggest factor in powder selection (but not the ONLY one). I'll edit this post and link a burn rate chart after the post is done.

As the primer lights the powder, it burns, not explodes. It's a fast burn but it's still a controlled, predictable burn.

As the bullet proceeds up the barrel, it relieves/reduces pressure as the volume of the gas behind it increases. With the bullet moving, the cavity containing the gas is getting larger so pressure is dropping. Meanwhile, the powder is still burning, which increases the same pressure in that cavity. Ideally, the powder burn rate will exactly equal the loss of pressure and length of the barrel determines how long that burn will be.

Using a very slow powder in a long barrel will result in unburned powder when the bullet exits the muzzle and a fireball results. Using a very fast powder in a long barrel will result in extreme pressure spikes as the balance mentioned previously is upset.

When you load for a 2" barrel, it requires a very fast powder like Bullseye, Red Dot or WW231 so it is consumed before the bullet exits the barrel. Otherwise, we get that fireball. In a 4" or 6" pistol barrel, a slightly slower powder like Unique will be better. The classic load for a 44 magnum is 2400, which is pretty slow powder. Elmer Keith developed that 2400 load.

The best plan is to follow your loading manual data. Some of the best sources are from the powder companies. They spend millions of Dollars to research this data.

The worst case in reloading is to take a super fast pistol powder like Bullseye or 231, fill a rifle case with it and the result will be our KB or KABOOM! I doubt if any rifle could withstand that. The reverse, like old Vet did is less dangerous. He substituted a slower rifle powder in a short barrel. No doubt there will be a fireball of unburned powder but this is less dangerous. Not good....just not as bad.

I'll snag that powder burn chart.............

Powder Burn Rates

There are other factors in powder selection, too. Bullseye requires a tiny amount of powder for a 9mm or .45acp. It's easy to double charge with Bullseye because there's plenty of room in the cartridge case. A loader may choose 231 or Red Dot because the volume of powder for each round is greater and a double charge will overfill the case and make it noticeable.

A slower powder will accelerate the projectile less quickly and reduce felt recoil to the shooter.

In rifle, I use IMR (Improved Military Rifle) 4895 for most cartridges. That is a powder made of tiny tubes of powder. Recently, I changed to 748 in .223 because the IMR 4895 clogged ("Bridged") in the tiny neck of the .223. 748 is a ball shaped powder which flows through the case neck better when loading it.

Hope that helps! Excellent question!


Flash

Thank you I'm trying to soak up everything I can before getting into it.

 

[robertc1024]

I was considering asking the same thing. It seemed at least two of us learned something today.

"Speak softly and carry a big stick!" ~ Theodore Roosevelt

That'd make three of us.

 

[ROGER4314]

That post got pretty long and I apologize for that. My shooting hobby is different than most folks. I love the technical aspect and physics of the shooting and reloading. The actual range shooting is simply a natural detour from that.

May I clarify something in my previous post? There is a set of three gas laws that describe the behavior of confined gasses. One of those laws applies perfectly here. Imagine a bicycle tire pump. As you push downward, the volume of the gas confined in the pump is made smaller, causing a pressure increase. The bullet/barrel travel analogy is the same law but viewed in reverse. As the bullet moves, confined space of the gas (combustion gas) is increased, so pressure drops. The trick to getting the right powder is to keep that pressure stabilized and/or constant.

The tire pump also shows another one of the gas laws. As the volume of the air trapped in the pump is squeezed, its temperature increases. That's not real relevant here, though.

A too fast powder burn will raise the pressure unnecessarily high. A slow powder choice will not maintain the gas pressure and will spit out as a fireball outside of the muzzle.

Have you fired a Mosin M44 short barrel rifle? Russian/Bulgarian 7,62x54R ammo is designed for the extra long 91/30 rifle barrel. Shooting the ammo in a short M44 makes a legendary size fireball!

Since I'm a retired teacher, I'll assign some homework.....snicker.

Look at the powder burn chart and locate Bullseye, 231, Unique, 2400 (44 mag) and Red Dot. Those are all classic pistol powders. Then locate 748 powder that OldVet substituted in error in the .45 acp rounds in question. Can you see where he went wrong? Would that have a prayer of working right?

Also, please note that 2400 is a slow powder for the famous .44 magnum Elmer Keith load. It is a compressed load....lots of powder squeezed into the case by the bullet seating. Magnum loads don't use fast powders. They tend to be slower and stable burning powders (unless it's for a very short barrel magnum handgun).

Later...

Flash

 

[boisestatebronco]

Roger4314 have you ever thought of teaching a reloading class or something if the sort?

As somebody that is looking at getting into reloading, I for one, would sign up and travel to take part.

 

[caleb7]

I agree. For someone with your qualifications and knowledge on the issue, you could probably make a good deal of money on the side teaching such a class.

"Speak softly and carry a big stick!" ~ Theodore Roosevelt

 

[ROGER4314]

Thanks guys,

I do some of that for free and one of my former HS students is now married with a daughter so I'm coaching him into the field. I view it as my responsibility to a sport that has treated me well for over 50 years.

You guys are the future of this sport and are the greatest resource that any Second Amendment group has. It would be an honor to help you learn. I'm WAY east of Houston and miles from anywhere. Logistically, it doesn't work well at all.

In the interim, please don't hesitate to ask questions.

Flash

 

[ROGER4314]

OK....more homework............

Go back to the powder burn chart and locate:

IMR 4895 (THE classic M1 Garand rifle powder)
IMR 3031 (A strong favorite as a Substitute for .30 caliber rifles)
H4895 (another favorite .30 rifle powder)
748 (a ball powder especially favored by AR-15 shooters)

What does their grouping on the burn chart suggest as far as their application goes? Is there a TON of difference in burn rate?

A similar grouping exists in Bullseye, 231, Unique, Red Dot and on the far end 2400 of the application. Which would be better for a short barrel? Which is better for a longer (6-7") barrel?

And the final exam.........How do you select which one is the best for your shooting and how much will you use in your load?

Here's some hints:
http://www.alliantpowder.com/reloaders/recipedetail.aspx?gtypeid=1&weight=185&shellid=35&bulletid=59

http://www.alliantpowder.com/reloaders/recipedetail.aspx?gtypeid=1&weight=230&shellid=35&bulletid=65

http://www.alliantpowder.com/reloaders/recipedetail.aspx?gtypeid=2&weight=55&shellid=46&bulletid=269

I tossed some other powders in the mix. See if they run approx the same burn rates as the classics.

Flash

 

[alaska1996]

I've yet to complete a round with the wrong powder, but there been one to many with no powder. It's pretty embarrassing when your showing off your new load, when you have a squib. I only reload when I'm sure I won't be bothered, no since in being stressed with my favorite past time.

 

[mosin]

In rifle, I use IMR (Improved Military Rifle) 4895 for most cartridges. That is a powder made of tiny tubes of powder. Recently, I changed to 748 in .223 because the IMR 4895 clogged ("Bridged") in the tiny neck of the .223. 748 is a ball shaped powder which flows through the case neck better when loading it.

Hope that helps! Excellent question!


Flash

Starting "my homework"

So the reason for going to 748 vs another ball type was it was close to 4895 in its burn rate characteristics as to not mess with previously established recipes correct?

Any particular reason you chose not to go with the h335 which would be a spherical between those two and closer to 4895?

 

[mosin]

OK....more homework............

Go back to the powder burn chart and locate:

IMR 4895 (THE classic M1 Garand rifle powder)
IMR 3031 (A strong favorite as a Substitute for .30 caliber rifles)
H4895 (another favorite .30 rifle powder)
748 (a ball powder especially favored by AR-15 shooters)

What does their grouping on the burn chart suggest as far as their application goes? Is there a TON of difference in burn rate?

A similar grouping exists in Bullseye, 231, Unique, Red Dot and on the far end 2400 of the application. Which would be better for a short barrel? Which is better for a longer (6-7") barrel?

And the final exam.........How do you select which one is the best for your shooting and how much will you use in your load?

Here's some hints:
Alliant Powder - Reloader's Guide

Alliant Powder - Reloader's Guide

Alliant Powder - Reloader's Guide

I tossed some other powders in the mix. See if they run approx the same burn rates as the classics.

Flash

The 4895-748 best for mid length barrels being in the middle of the chart.

So the idea isn't a spike to a pressure but to hit and maintain a certain pressure as it travels down the barrel.

Is this why a heavier and I'm assuming slower bullet in a given caliber requires less powder? The slower bullet would have more burned powder behind it for a given distance and thus a higher pressure compared to the same charge behind a smaller bullet.

 

[ROGER4314]

Any particular reason you chose not to go with the h335 which would be a spherical between those two and closer to 4895?

I chose the 748 primarily because it was a ball powder and easy to flow into the case neck. The 748 was the winner because it is so common and easy to find as compared to some other powders. In the case of 748, I went with what was easy to find and it had a good reputation with match shooters.

Is this why a heavier and I'm assuming slower bullet in a given caliber requires less powder? The slower bullet would have more burned powder behind it and thus a higher pressure compared to the same charge behind a smaller bullet.

If you check the loading data, it's common to use a slower powder for a heavy bullet. That keeps recoil minimized as the slug accelerates and keeps pressure from spiking. Again, it's more common for a magnum load to be a slower and more stable burning powder.

So the idea isn't a spike to a pressure but to hit and maintain a certain pressure as it travels down the barrel.
Yes, SAAMI sets the standard for allowable pressure in each caliber and load. The pressure resulting from combustion must not exceed SAAMI specs. A slow powder can get a heavy bullet moving without unauthorized pressure spikes. (I know you'll research SAAMI....snicker)

There is a huge revision underway to change SAAMI spec pressure readings from "CUP" to PSI. CUP is "copper units of pressure". It uses a crusher gun that smashes a copper disk. Dimension of that disk after firing, tells the maximum pressure. They don't read real time pressure....only maximum pressure. Some of the standards have been changed over to PSI (pounds/square inch) and some have not so data may show one or the other.

A powder that is too fast will cause a spike that exceeds SAAMI specs and will result in being rejected. It must stay below SAAMI.

With advances in technology, it's reasonable to assume that pressure curves of loads are coming next. Real time pressure measurement as the bullet travels. Pretty impressive!

Richard Lees' loading manual is crammed with data. It's also not conservative. When he says "don't exceed" a loading, he's serious! Lyman 49 is the most conservative of any that I have.

You guys are doing great! We sort of Hijacked Old Vet's thread but it started out on subject.

Flash

 

[OLDVET]

It's cool. I have learned some new things from the diversion.
All the technical stuff aside, I prefer Win. 231 for my .45ACP loads and Win. 748 for most of my rifle loads. I am just starting to load .38 spl.
I have Win. 231 and AutoComp on hand, and I have loaded a few test rounds using each powder. I hear H38 is a good powder too. Seems to me Win. 231 and H38 are very similar. What is the general opinion on .38 spl powders?

 

[mosin]

If you check the loading data, it's common to use a slower powder for a heavy bullet. That keeps recoil minimized as the slug accelerates and keeps pressure from spiking. Again, it's more common for a magnum load to be a slower and more stable burning powder.

I was more referring to the charts I'm looking over that show less of a given powder as the bullet weight goes up for a given bullet in the same cartridge rather than altering powders for a bullet size. It just seems counter intuitive. I kind of get it though as long as I dont think about it to much. Been to long since I played with physics/gas laws

223 Winchester; Hogdon reloading data center Cartridge Loads - Hodgdon Reloading Data Center - data.hodgdon.com

35 GR. NOS BT LF

Hodgdon

H335

.224"

2.280"

27.9 3885 53,200 PSI

45 GR. SFIRE Hodgdon H335 .224" 2.220" 25.3 3428 50,700 PSI

55 GR. SFIRE

Hodgdon

H335

.224"

2.220"

22.8 3099 51,800 PSI

77 GR. SIE HPBT

Hodgdon

H335

.224"

2.260"

22.6

2738

51,700 CUP

There is a huge revision underway to change SAAMI spec pressure readings from "CUP" to PSI. CUP is "copper units of pressure". It uses a crusher gun that smashes a copper disk. Dimension of that disk after firing, tells the maximum pressure. They don't read real time pressure....only maximum pressure.

Well that explains my next question about why some are listed a CUP. These are interchangeable units as far a reloading chart is concerned right?


With advances in technology, it's reasonable to assume that pressure curves of loads are coming next. Real time pressure measurement as the bullet travels. Pretty impressive!

Would be some very interesting stuff.

Richard Lees' loading manual is crammed with data. It's also not conservative. When he says "don't exceed" a loading, he's serious!

I'll keep that in mind if I get a kit with their book

 

[ROGER4314]

I've used Bullseye and Red Dot in handgun cartridges for decades. For magnums, I use Unique. These days, much of your decision will be based upon what you can get. Stores stock what sells well. All of the powders that we have kicked around are very popular and more likely to be available.

My eyes are trashed and I couldn't read the above chart. I load ONLY published loads because those who publish the loads guarantee their accuracy. If a powder works with lighter bullets then drops off the chart for heavier bullets, there is a reason based upon actual research. I trust that.

Guys, reloading data manuals give some of the cheapest insurance for safety and success in reloading. Get several and rely on them. If they don't print a load, I won't load it. The best ones come from the powder companies. Lyman and Lee are exceptional values. I trusted my Speer manuals for many years.

Flash

 

[ROGER4314]

Well that explains my next question about why some are listed a CUP. These are interchangeable units as far a reloading chart is concerned right?

I'm not sure that interchangeable is the correct term. Remember that SAAMI is dedicated to standardizing specs in many aspects of firearms and cartridges. I think of it as a work in progress. Some data has been changed over to PSI and some hasn't been changed yet. For the time being, we get a little of both pressure readings. Either way, pressure must not exceed SAAMI at any point in the cartridge firing process.

Flash

 

[mosin]

I've used Bullseye and Red Dot in handgun cartridges for decades. For magnums, I use Unique. These days, much of your decision will be based upon what you can get. Stores stock what sells well. All of the powders that we have kicked around are very popular and more likely to be available.

My eyes are trashed and I couldn't read the above chart. I load ONLY published loads because those who publish the loads guarantee their accuracy. If a powder works with lighter bullets then drops off the chart for heavier bullets, there is a reason based upon actual research. I trust that.

Guys, reloading data manuals give some of the cheapest insurance for safety and success in reloading. Get several and rely on them. If they don't print a load, I won't load it. The best ones come from the powder companies. Lyman and Lee are exceptional values. I trusted my Speer manuals for many years.

Flash

How exact do you need to follow the loads. If my bullet selection isn't on there for a particular powder is it safe to use a bullet of the same weight and use its powder load? For example if the chart is reading 22gr of 748 for a 55gr barnes tsx, can i use that charge behind a 55gr nosler, which is not listed, safely?

 

[TexMex247]

How exact do you need to follow the loads. If my bullet selection isn't on there for a particular powder is it safe to use a bullet of the same weight and use its powder load? For example if the chart is reading 22gr of 748 for a 55gr barnes tsx, can i use that charge behind a 55gr nosler, which is not listed, safely?

It's usually ok to use the same powder charge for different projectiles of the same wt./cal. However, there are a few exceptions like the Barnes TSX(which is solid copper) and gold dot bullets which do have unique loads developed for them. Usually though, you can safely load a hp, bt or fmj bullet of similar weight in grains with the same powder charges without any danger. You probably picked one of the few exceptions to that rule with the TSX. It is simply not constructed the same as lead core jacketed bullets which are the most common out there.

 

[ROGER4314]

It's usually ok to use the same powder charge for different projectiles of the same wt./cal.

True. Most of the time that works just fine except the bullet BC may not be identical so the ballistics may differ. Don't substitute Jacketed for lead or the reverse.

Lets talk BC....Ballistic co-efficient. Regardless what you've heard, the MODEL for BC is based upon a German Artillery shell. It is a pointy rascal and it was accepted as the model or standard for Ballistic Coeffcient. There's a lot of calculation involved but the bottom line is that your bullet is compared to that ideal round or model. The coefficient will be expressed as less that 1.0. A 1.0 is identical to the German round.

That bullet shape is a Spitzer with translates to (I think) "pointy bullet" . Gringos say "spit zer". Germans say "SPY ZER" Any time you see ballistic coefficient listed, the shape of that bullet is compared to that German model. The closer it is to that model, the more efficient it is in traveling through the air. If you use some of the ballistic calculators online, they will ask the BC, weight, velocity and altitude as i remember and calculate the trajectory of the round. Round and flat nose bullets have lousy BC. Pointy bullets have good BC. Increased air resistance in round or flat projectiles makes a more curved trajectory as speed is scrubbed off more quickly.

Tomorrow........AR-15 barrel twist and optimum bullet weights.

Flash

 

[ROGER4314]

Bullet weights and barrel twist rates.

There are some classic bullet/barrel combinations. In 30-06/.308, 148 to 160 grain projectiles, the classic twist rate is 1 rifling twist in 10 inches. That's expressed 1:10 or 1 in 10. In .22 LR, the classic is 1:16. That's what shoots best and unless you have a special application, it's wise to stick with those combinations. Each caliber and bullet weight has a favorite rifling twist rate. There is no place in our sport where this s more pronounced that in .223 and especially AR-15.

I'm going to take flack for posting this but these are my actual experiences and observations. I didn't read this crap on the 'Net and spread it as gospel afterwards!

Typical AR barrel twist rates are
1:7
1:8
1:9

In my experience, the 1:9 twist is the best overall selection. !:7 is a fast twist that stabilizes heavier bullets well. Match shooters who use 77 grain and similar heavy bullets like the 1:7 twist. Those heavy bullets do not feed well in the AR-15 so they are single loaded by using a modified magazine called a "sled". In my profile picture, I am poised with an AR in prone. The magazine is identified with a red tape indicating that it's a modified "sled" magazine. The follower is removed and a tray shaped follower is substituted for single loading.

1:7 barrels stabilize the heavy bullets but at a cost. Throat wear is higher in the 1:7 barrels.

1:8 twist uses 68/69 grain bullets to good advantage. The best match scores I ever shot in AR-15 were with a 1:8 Bushmaster using 69 grain Sierra Match Kings at 200 and 600 yards. Those scores were with iron sights at 200 and 600. My best scores were with the 69 grain MK's. The WORST scores at 600 yards were with the same gun shooting 55 grain bullets. I fired many 600 yard matches with the 55 grain bullets from a 1:9 twist Colt. For some reason, I thought that could work well in a 1:8 twist. That match was an embarrassment! 55 grain bullets worked fairly well through that 1:8 twist rifle at 200 but crashed at 600. I may as well have used a slingshot at 600 than to try 55 grain in a 1:8 twist!

1:9 twist rate is, in my opinion, the best overall twist. It handles the 55 grain el cheapos beautifully and the 69 grain slugs work great, too. It is my favorite of the three twist rates.

A word, here about bullet weights. The weight of the bullet is NOT the determining factor on whether a rifle twist rate will work well. A bullet cannot be made larger in diameter as it needs to travel down the bore. The only way to make a bullet heavier, is to make it LONGER. The weight of the bullet is immaterial. Because the heavier bullet is longer, the twist rate must be adapted to stabilize it. The length if the bullet is the critical factor! Heavier bullet is longer. What's the difference? So what?

A member at our range was cussing his rifle at high volume. He was trying out Barnes solid copper bullets, chose the same bullet weight that he always used. He couldn't get them to stabilize. Copper is less dense than lead. To get a copper bullet of the same weight in grains, meant that he got LONGER bullets for the same weight. That lack of understanding bit him in the butt! The longer/heavier copper bullets would not stabilize with his barrel twist.

It's not the weight of the bullet that's important in stabilizing it. LENGTH of the projectile is crucial!

Gotta grocery shop. Later...........

Flash

 

[OLDVET]

Been away awhile. Damn, this has sure changed direction since I originally posted it.