Powder Burn Rate Question

CalCoyote

CalCoyote

Member
I have always had the impression that as a general rule, powders with a faster burn rate will give a lighter bullet more velocity and in the same caliber powders with slower burn rates will give a heavy bullet greater velocity.

Well, if I look at the 243 load data on the Hodgdon website I find that H414 is one of the top velocity performers spinning a 55g Nosler BT down the barrel. But then the load data also says that it is the top velocity producer for the 95g Nosler Partition. How can H414 be a top velocity performer for both light and heavy weight bullets?

I don't own a chronograph (need to buy one) so I can't verify Hodgdon's velocity data.
 
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"As a general rule" , exactly that. Always the exception to that. Some powders will cover a certain niche perfectly, while others work nearly as well over a broader range and in multiple combinations. Not always will it be the best for all, but acceptable for a "one powder fits all" approach. Bear in mind that velocity and accuracy do not walk the path hand in hand. Once again, acceptable compromise.
 
Originally Posted By: CalCoyoteI have always had the impression that as a general rule, powders with a faster burn rate will give a lighter bullet more velocity and in the same caliber powders with slower burn rates will give a heavy bullet greater velocity.

Well, if I look at the 243 load data on the Hodgdon website I find that H414 is one of the top velocity performers spinning a 55g Nosler BT down the barrel. But then the load data also says that it is the top velocity producer for the 95g Nosler Partition. How can H414 be a top velocity performer for both light and heavy weight bullets?

I don't own a chronograph (need to buy one) so I can't verify Hodgdon's velocity data.

You will NEVER be able to verify Hodgdon's (or anyone else's) data, no matter what instruments you buy.

Like Women, each gun is different, and like men looking at women, each loader sees pressure signs differently.

Your interpretation of 414 being a "top performer" is not an accurate reading of the data chart.

H-414 is too slow for optimum velocity of the 55gr bullet - it requires 50 grains to get 3950 fps at 51,600 psi, whereas H-4895 (a faster powder) requires 44.5 (5.5 gr LESS) powder to get 4058 fps, at 49,300 psi, 108 fps faster with 5.5 gr less powder, and a lower peak pressure... H-414 is NOT a good choice for "spinning a 55g Nosler BT down the barrel", it is too slow... it reaches it's peak pressure too late in the process to produce the higher velocities.

H-414 is a proper match to the 95 gr Nosler - it requires 42 grains to get 3138 fps at 50,700 psi, whereas H-4895 (a faster powder) uses 35.0 (5.5 gr LESS) powder to get 2990 fps, at 50,700 - at the same pressure of 50,700, H-4895 peaks too fast to reach the velocity achieved by H-414... 148 fps slower at the same pressure.
H-4895 is NOT a good choice, it is too fast.... it reaches it's peak pressure too early
in the process to produce the higher velocities.

The above is exactly what is to be expected for the two powders and two bullets. Lighter bullets require faster powders to achieve top velocity...and heavier bullets require slower powders to achieve top velocities.

Neither one has anything to do with accuracy.


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Originally Posted By: CalCoyoteI have always had the impression that as a general rule, powders with a faster burn rate will give a lighter bullet more velocity and in the same caliber powders with slower burn rates will give a heavy bullet greater velocity.

Originally Posted By: CatShooter
The above is exactly what is to be expected for the two powders and two bullets. Lighter bullets require faster powders to achieve top velocity...and heavier bullets require slower powders to achieve top velocities.

I think the general rule is, slower powders for heavier bullets, faster for smaller.

Good, glad we agreed on that.
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Originally Posted By: SShooterZOriginally Posted By: CalCoyoteI have always had the impression that as a general rule, powders with a faster burn rate will give a lighter bullet more velocity and in the same caliber powders with slower burn rates will give a heavy bullet greater velocity.

Originally Posted By: CatShooter
The above is exactly what is to be expected for the two powders and two bullets. Lighter bullets require faster powders to achieve top velocity...and heavier bullets require slower powders to achieve top velocities.

I think the general rule is, slower powders for heavier bullets, faster for smaller.

Good, glad we agreed on that.
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While I agree with the "Lighter/Faster Burn" and "Heavier/Slower Burn" concept, for the last couple of years I've been trying to match powder burn rates with the length of barrel in an attempt to maximize the efficiency of the burn considering that if the burn rate is exhausted prior to the bullet leaving the barrel, you don't get full benefit and if there is excessive burn, powder/energy is being wasted after the bullet leaves the muzzle...

It's just one of those questions that tends to bother us old guys in the middle of the night sometimes...
 
i use to think the same way. i have a 223 with 20 in. barrel i ran h-4198 a grn. hotter, ibought a chrony and was getting 3100 out of it with 55 grn. blitz kings 1/2 inch group i switch to slower h- 4895 and now im getting 3400 with a little titer group, my charge 26.9 grns. little warm acording seirra book. my barrel has around 1200 rounds thru it still going strong. joel
 
Originally Posted By: jotroti use to think the same way. i have a 223 with 20 in. barrel i ran h-4198 a grn. hotter, ibought a chrony and was getting 3100 out of it with 55 grn. blitz kings 1/2 inch group i switch to slower h- 4895 and now im getting 3400 with a little titer group, my charge 26.9 grns. little warm acording seirra book. my barrel has around 1200 rounds thru it still going strong. joel

The optimum powder for a given bullet weight will be the same, no matter what the barrel length is. 4895 has always been a top choice for the 222 family and 50/55 grain bullets.
 
I will deviate from Cat a tad on the 414/760 arguement.
I agree 100% that EVERY rifle is different, I agree 100% that a faster burning powder is generally a "better" choice than a slower one.

That said, I have fantastic luck, and velocity with Win 760 and 55-58gr bullets in my Hawkeye.
Don't have my notes handy, but in MY gun, something like 49gr gives me 4000fps with the 55gr.
 
Originally Posted By: DarkkerI will deviate from Cat a tad on the 414/760 arguement.
I agree 100% that EVERY rifle is different, I agree 100% that a faster burning powder is generally a "better" choice than a slower one.

That said, I have fantastic luck, and velocity with Win 760 and 55-58gr bullets in my Hawkeye.
Don't have my notes handy, but in MY gun, something like 49gr gives me 4000fps with the 55gr.


I can imagine the muzzle blast.

I would go with a bit faster burn rate myself.
 
I shoot H414 in my 220 swift (55gr) and my 6mm Rem (90 gr)and it gives me top velocity and accuaracy. I would suggest the you spend $100 and buy a chronograph. You will be anazed at what it will show you. Just because a book shows X velocity doesn't mean your rifle will produce it. It also makes it more fun. Good luck.
 
From where I stand, I deal with the recoil, not the muzzle blast
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Believe it or not, it really isn't any different than when stoked with CFE 223. But in my weather, I've also never had an issue lighting 760/414. Those old formula ball powders have a "reputation" for needing a mag primer to light. For me, going to the 20's to teens in the winter, still don't have issues.

YMMV
 
Catshooter,

I would have thought with your vast experience, you would have known that Hodgdon measures the pressure of their powders in a given load by the older method of Copper Units of Pressure, (CUP) not Pounds per square inch. (PSI) Typo perhaps.?

JD
 
Smokeless,
Don't know that I have anything against them per se, Just don't see any shining perk for them OVER a ball powder. But one thing that I tend to gravitate to. The only powders left that are being made in the U.S.(smokeless rifle) are General Dynamics ball powders. What we know as Hodgdon/Win ball powders. GD also now owns the old Alliant extruded plant in Canada. Otherwise the builders are French State owned, French defense contractors, or a German defense contractor.

Call me a sucker for supporting an American Defense contractor instead of foriegn.
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Bigdog,
That actually is not the case across the board.
A couple things about that. Ohlin(winny) and Hodgy are having a bit of a contract dispute at the moment. Hodgy's view is that Ohlin was to provide the testing and pressure data, while Hodgy promotes and sells the brand. They haven't been, So Hodgy only posted what was last given to them. They will quickly point out that it is so old, they don't know when it was last done.
Their extruded powders are all Thales(ADI), depending upon how "old" the powder is, some of the data is still being shown in CUP. Newer powders like SMP-842...I mean CFE223, are shown in PSI; as that is only 10 years old.

Remember that there is no reliable way to "translate" CUP to PSI. Given the fact that SAAMI has been almost none-existant(in terms of involvement, and updates)for the past couple of years. Unless all parties involved agree what PSI an old CUP standard should be, they aren't going to change. Also remember that unlike CIP, SAAMI is a voluntary deal.
No one HAS to follow their rules.
 
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Originally Posted By: DarkkerSmokeless,
Don't know that I have anything against them per se, Just don't see any shining perk for them OVER a ball powder. But one thing that I tend to gravitate to. The only powders left that are being made in the U.S.(smokeless rifle) are General Dynamics ball powders. What we know as Hodgdon/Win ball powders. GD also now owns the old Alliant extruded plant in Canada. Otherwise the builders are French State owned, French defense contractors, or a German defense contractor.

Call me a sucker for supporting an American Defense contractor instead of foriegn.
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Bigdog,
That actually is not the case across the board.
A couple things about that. Ohlin(winny) and Hodgy are having a bit of a contract dispute at the moment. Hodgy's view is that Ohlin was to provide the testing and pressure data, while Hodgy promotes and sells the brand. They haven't been, So Hodgy only posted what was last given to them. They will quickly point out that it is so old, they don't know when it was last done.
Their extruded powders are all Thales(ADI), depending upon how "old" the powder is, some of the data is still being shown in CUP. Newer powders like SMP-842...I mean CFE223, are shown in PSI; as that is only 10 years old.

Remember that there is no reliable way to "translate" CUP to PSI. Given the fact that SAAMI has been almost none-existant(in terms of involvement, and updates)for the past couple of years. Unless all parties involved agree what PSI an old CUP standard should be, they aren't going to change. Also remember that unlike CIP, SAAMI is a voluntary deal.
No one HAS to follow their rules.


Well I suppose I now like Canadians more [I use Alliant Powders], and it is nice to see the French finally doing something productive. How do the Australians fit in to this, or do they any more?
 


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