Powders and Loads

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Zeroed

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Hey guys/gals, I'm new to the forum and also a beginner reloader. Actually, I haven't even turned the first round out yet. Got about 60% of the stuff I need and hunting for the rest.
Anyway, I'm interested in some of your knowledge in reloading.
If using 3 different powders (to find what your rifle likes), subsequently you'll most likely have 3 different powder measurements. Is this because of the powders burn rate, or maybe because of being either grain, flake or cylinder type powders, or Both? Any other reasons?
And if, as I suspect, it's the burn rate. A fast burn should get a higher fps, right? And a slow burn rate should get a slower fps (dependent on the barrel length) right?
So for a short barrel you'd need a fast burn powder, and a long barrel such as a 28", maybe a slow burn powder, right? But then if this is true, wouldn't the slow burn powder produce a higher fps due to the long barrel length than a fast burn powder would in the same barrel?
And to keep this in a bit easier, let's say it's a Bolt, 139g 7mm-08 Rem, 26" barrel.
Any thoughts would be appreciated.
 
I think you are heading down the right road. A powder has a certain burn rate that is variable by temp, pressure, etc. Kernel shape impacts surface area which is key in this design.

Powder burn rate can be matched to barrel length somewhat, but it is hard to get the specific data to do this.
 
In 40 years of reloading I’ve not seen any reference to choosing a powder based on a comparison with barrel length.
I’d suggest you’d do yourself a huge favor by searching for “The Complete Book of Practical Handloading” by John Wooters. Wooters passed away, but his book is where I started and it discusses everything you need to know.
Powder burn rate lists are just a guide to see where all the powders stand relative to each other. I have one that lists 149 available powders, so I numbered the first, and “fastest,” as #1 to the last, “slowest,” #149 and I have all my inventory labeled that way, just so, at a glance, I can tell where they stand relative to each other, in burn rate.
A longer barrel will provide a higher velocity regardless of the powder you use because there is more time for the pressure to act on the bullet before it leaves the barrel.
Here’s some comparisons from my Hodgdon’s Relaoding manual as an example of burning rate and velocity:
Using a 117gr bullet in 25-06, we see the max velocity achieved with these powder choices, and I have listed the relative powder burning rates as described above:
H1000 – 3046fps -140/149
H4831 – 2937 -128
H4350 – 2923 -117
Varget – 2838 -101
H4895 - 2797 - 71

Notice the “slowest” powders provide higher velocities than the “faster” powders below them. But the amount of powder used is a factor as well- I didn’t list them but H1000 needed 58.5gr and all those under them had lower powder charges until you get to H4895 which needed 40.0gr. This points out that generally, “slow” powders can use a higher charge weight, which explains their tendency to deliver higher velocity.

Now this is not universal. If we look at the 25-06 using a 75gr bullet, the chart looks like this:

H1000 – 62gr – 3339 – 140/149
H4831 – 62gr – 3599 – 128
H4350 – 58.5- 3700 – 117
H414 - 55gr - 3626 – 112
Varget - 49.7gr-3660 – 101



Here the “faster” H4831 gave a higher velocity than the “slower” H1000 but they were at the same powder volume of 62gr.

The technique I use to get past all this stuff is to start by looking at a list of powders for a given bullet, and search for the powders that will deliver the highest velocity at the LOWEST pressure.

For the 117gr bullet in 25-06, for example, that list shows the following pressures:
H1000- 51,000 CUP
H4831- 50,900 CUP
H4350- 50,800 CUP
Varget- 50,100 CUP
H4895 - 50,600 CUP

So I would start with H1000 to get 3046fps (AT MAX LOAD) at 51,000 CUP. H4831 is only 100 CUP lower, not enough advantage to have me settle for 2937 fps. Now, realistically, here is no major advantage to the 3046 fps vs 2937, but you need to start somewhere.

A better example in that list is Varget vs H4895:

Varget – 37 gr -2838 fps -50,100 CUP
H4895 – 37gr -2797 fps -50,600 CUP

Here, at the same powder weight, H4895 gives less velocity but higher pressure. I would start with Varget.

When you review pressure lists be aware there may be values of CUP mixed with PSI. You’re stuck in this case as they are not comparable.

There’s a lot to learn when you begin handloading but it’s not rocket science; you just need to keep it slow until you are comfortable with your learning curve and what experience it has produced at the range.
 
Zeroed,

Please do yourself a favor and buy and read a good reloading manual such as the one Lyman sells. Several of the assumptions you listed in your post are just plain wrong.

Don
 
Check out the "ABC's of Reloading" at http://tinyurl.com/y9cwdhxk for all the info (and more) you can use. Great book and covers reloading and powders with recommendations for use of them.

One tip: Fast powders are not useful in long barrels and slower ones are. I know, seems the opposite but that's where the books come in. Good Luck!
 
USSR, the questions I posted was things I've read on-line (gotta believe only half of what you read), so I wanted to hear from responsible handloaders. That's the main reason I joined this forum, to get the most experienced advice that isn't in a handbook.
I looked thru a friends reloader book (not a manual), it basically just gives the load amounts, etc., and to start at a lower amount of powder and work up, and not to exceed the max load recommendations. Good advise, but I think it's a quick guide book for someone already reloading.
So with cdoc's advice, I'll try and locate that book he suggested.
 
cdoc42, that's very informative and I appreciate you taking the time to list that info. I'll try and find J. Wooters book. Wish I had that list of powder burn rates you made. I have a # of H4895, but I'm nowhere ready to actually start reloading. I've got a lot of reading and studying until I feel ready, and then I plan on having a reloader friend to oversee my 1st loads, so I don't mess up. Things that go "boom" are dangerous, that's why I want to get it right the 1st time around.
Thanks again for that info you posted.
 
Zeroed said:
I looked thru a friends reloader book (not a manual), it basically just gives the load amounts, etc., and to start at a lower amount of powder and work up, and not to exceed the max load recommendations. Good advise, but I think it's a quick guide book for someone already reloading.
So with cdoc's advice, I'll try and locate that book he suggested.
Click to expand...

I'd be willing to bet that the first couple chapters in your friends book included the basics on reloading. There are pamphlets out there that only include load data, but any "book" I've ever seen also covers the basics. 90% of the book might be load data, but usually the beginning of the book has the requisite reading material.

I know the Lyman manual has a chart of powders listed from fastest to slowest, but honestly you could spend years reloading and never even look at it. Follow the load recipes and you'll be fine. There a numerous variables that go into determining why different powders use different amounts. But again it's not really something to worry about other than knowing that any load should be based upon published data.
 
Zeroed,

I've looked at bullet position data, and, in general, the powder that gives a long barrel the highest velocity will also give a short barrel the highest velocity until you get down to 10" or so, at which point too small a percent the slower powder burns completely. So best velocity in short barrel rifles (SBR; special federal license required below 16") or for single-shot handguns chambered in rifle calibers.

Otherwise, slower burn rate gives higher velocity by allowing you to put enough charge weight in the case to give you the same peak pressure your fast powder is limited to, but maintaining higher post-peak pressure as the bullet goes down the bore, thereby giving it more additional acceleration later in the barrel to add speed to the bullet. But this only works up the point that you select a powder so slow you can't fit enough into the case to reach adequate peak pressure, so there is a maximum slowness that will work in any given chambering and bullet combination (bullet weight affects this because a heavier bullet offers more inertia for the pressure to build against, allowing maximum slowness to be slower than it is for a light bullet). The load data will give you this information.

I'll add that the mass of the powder charge is expelled with the bullet, plus higher pressure maintained to the muzzle increases what is variously called "rocket effect" or "after-effect" in which the expanding gasses push the gun back like a pulse rocket engine after the bullet clears the muzzle. These two factors mean, for a given bullet and a given muzzle velocity, slower powders produce more recoil.
 
A fast burn should get a higher fps, right? And a slow burn rate should get a slower fps (dependent on the barrel length) right?
Click to expand...

It's not quite that simple. There are several constraints that you have to deal with. One is pressure, and the other is case capacity.

So for a short barrel you'd need a fast burn powder, and a long barrel such as a 28", maybe a slow burn powder, right? But then if this is true, wouldn't the slow burn powder produce a higher fps due to the long barrel length than a fast burn powder would in the same barrel?
Click to expand...

You don't need a faster burn rate powder just because you have a short barrel. A slower burn rate powder will provide a higher velocity even in a short barrel, providing you can get enough of the powder in the case to have it operate in a suitable pressure range. Instead of looking at this from the perspective of barrel length, you would be much better served looking at it from bullet weight perspective. If you intend to use a light for caliber bullet weight, a faster burn rate powder will operate in a better pressure range than a slower burn rate powder. If you intend to use a heavy for caliber bullet weight, a faster burn rate powder will reach maximum pressure at a lower velocity than a slower burn rate powder will.

Don
 
yup, I need the books. I've had about a foot or so of fire come out the end of my 26" rifle barrel before with factory ammo (varmint hunting @ night). Just figured it was a really slow burning powder? Don't remember what make it was, but it wasn't for night shooting I can tell you that. lol
I primarily shoot .204 ruger and 7-08 rem. for varmints. The 7-08 I use for deer as well. I also shoot the .223, 6.5cm and .308 win. While the cost of .223 is going down in price, the 6.5cm hasn't. So this is why I want to reload, that and to achieve a more accurate round.
I really do appreciate all the feedback and recommendations y'all have given me. And if there's any other things you think I need or could use, please let me know.
I will look into getting the abc's book you mentioned too, robhic. Thanks again everyone.
 
Oh, USSR, I've been reading and studying the cup pressures too. I'll start low on powder and work up to a desired accuracy. But I want to use different powders to try myself to find what works best. Seems everyone has their own recipe with different powders than someone else's. But I figure it's mostly out of preference, and what their barrel likes.
And then I got to learn the differences in Primers. Geez, there's alot to learn, no doubt. Thanks again all.
 
hey, fella, you haven't heard this yet as far as I could see.

The key is acceleration, acceleration is provided by ongoing high pressure. A chamber pressure doesn't mean squat for velocity. Your sustained pressure as the bullet goes down the bore is what matters. In fact, some really extremely weird loads will actually slow down in the trip down the bore because of friction and extreme pressure drop.

When you use a slow burning powder such as 4831, your pressure is sustained all throughout the run down the barrel, and yes, a lot of that fire is wasted outside of the barrel. You use a slow powder to generate sustained high pressures all the way down the barrel. It generates thrust. It increases the rate of speed buildup or acceleration.

A faster burning powder will fizzle out, so to speak, and the pressure peaks early and fails to provide further acceleration.your velocity is limited because your pressure peaks early and it kills acceleration.

There are so many factors involved. Resistance of the bullet because of the weight is important. so many others, like case capacity. All of this change the way a charge ignites and burns, how acceleration builds.

For example, a .30-30 is a tiny case that must use a relatively quick burning powder to get up to speed because there is no room in the case for a slow burning powder, and a slow burning powder in a small case cant really generate the needed thrust and pressure.

A 30-06 is a larger case. it can support a larger charge. Since there is more room, we can pack in more, and slower powder, and that entire charge will be effectively used to move the bullet. just that one thing, bigger case, larger, slower charge will cause a longer high pressure period.

A .300 ultra magnum is going to have so much capacity that it is hard to actually find a proper load. using a fast powder, a small charge of something that will fizzle out halfway down the barrel with an extremely high chamber pressure is a waste. it will not generate even a fraction of the power and velocity that the full load of extremely slow powder will.

There are many, dozens and more, factors that decide what powder will be effective in any given case. Generally speaking, choose the load data that gives the higher velocity range and test them. The slowest powders will generally give the greatest velocities but what does that mean? it means that MAYBE your loads will shoot faster. Does it mean that it will work well? No. High velocity may be a poor decision in your individul rifle. Accuracy may be terrible.

It used to be that when you looked for load data you had over a dozen, sometimes every possible powder offered. Many if not most of them were just useless, written only to put words on the paper. Now, the makers have gotten smarter, they have limited the suggested loads to the ones that are most appropriate, and best capable of generating safe, accurate, powerful loads.

The perfect situation would be that a cartridge maintains the same pressure from chamber to bore, accelerating every MM of the way. A powder that allows that to work will generate the highest possible velocity from any given cartridge.

This exact effect is why we have coatings on powders to slow ignition a bit. We have powders in larger granules to slow down the buildup of pressure. we have powders that are pierced, since under high pressure that also ignites them and they burn from the inside out. granule shape and size, ranging from small ball powder to sticks all have different amounts of surface exposed to the flame.

Have you noticed that certain "ball" powders are actually flakes? "ball" powder is the description of how it is made, not the shape. Many ball powders are rolled flat, this exposes more surface area, accelerating the burn.

Nobody but an engineer or a very well educated person can fully understand or predict what a powder will do. What this means to you is that you should never deviate from the professionally generated data.

Keep in mind that if you are crazy enough to load something like nitroglycerin into a cartridge, count on the rifle to explode, but in all honesty, you may not be able to find actual acceptable signs of "overpressure".
 
With the slowest burning powders all is burned within about 12" or less. With faster burning powder all is burned in a few inches less. The powder that is fastest in a 28" barrel will also be the fastest in a 16" barrel. As long as your barrel is long enough to be legal this isn't a consideration.

Even though all of it burns very quickly, the pressure continues to accelerate the bullet in the barrel so the longer barrel will always be faster. At least up to a point. In theory the bullet could start to slow down if the barrel is too long. This can actually happen with 22's, but I don't think any common center fire barrel is so long to do this.

There is a reason standard barrels are the length they are. The ratio of powder to bore diameter determines the optimum barrel length. Lots of powder being burned in a smaller bore size needs a longer barrel to get optimum performance. A 7mm magnum with 70 gr of powder being burned in a 7mm diameter barrel needs a longer barrel than a 308 with 45 gr of powder in a 30 caliber barrel.

A 7mm magnum needs about 24" of barrel and 26" or more helps. Going shorter than 24" and you give up lots of speed. A 308 gives about all the speed it is capable of in 22". You have to go up to 28" or 30" just to see very small gains in speed. Going as short as 16"-18" in a 308 just doesn't hurt it all that much.
 
Thanks for the info briandg. Do you know why/how it's possible that a lower load can give you a higher fps than a higher load of the same powder? I've seen where people say while finding the highest fps and accuracy, they use x-amount of grains less than the max. Sometimes it's a lot less. Something similar to this, 40gr 2760fps, 41gr 2800fps, 42gr 2780fps, etc (not actual data but as an example). I used to contribute this to barrel length which is usually omitted from their loads and results, but not sure now with jmr40' post. They usually just post pwdr make, grains, bullet weight and fps. Now I'm thinking can it be the powder? Maybe the chronograph?
 
jmr40, I certainly did not know that about the .308 barrel lengths. my .308 is 26" long, only because I couldn't find a 28" length one, and didn't want to wait for one. Makes me feel better about it now. Thanks
 
Zeroed, reducing a powder charge but keeping everything else equal should never, in normal conditions, increase velocity. Add more powder to identical rounds in the same rifle will result in higher pressure, and that should result in higher velocity.

There could be certain examples in which this isn't the actual fact, but it is, nonetheless, a physical rule.

Firing my load in my rifle should give me 3,000 fps, with maybe 30 fps either way. Your rifle may get 2,900 with the same load, and if you press the load a little higher, you may get 3,100.

The thing that you must keep in mind is that there are no unyielding constants, there are minute variations all across the board. Even changing the brand of primer alters your performance a bit. Buying a new can of powder after eight years, there may be slight variations in it.

Since all of these variations exist, load data, as well as loaded ammunition, are set lower than necessary. One rifle can take fifty grains of a powder and another only forty. The forty is the only safe load to sell. The only safe data to provide.

Something that you need to always remember, these rules are not made to be broken.
 
All the posts have been a good read , the only add an very small one is stick powders like Varget , RL 15 & IMR 4064 will fill the case better on low & medium loads . After the OP loads his first round I'm sure the the other questions will come . For now follow the basics an see what your rifle likes . Welcome to the family. Chris
 
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