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Powder Flame Temp Test: An Experiment
- Thread starter DoneNOut
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MagnumManiac
Well-Known Member
No, the extra gas does not coincide with extra pressure in the sense of more pressure for a given amount of gas, it just means it expels that gas for a longer time against the base of the bullet.
The other thing that hasn't even been discussed in these threads is the fact that the type of powder, progressive, digressive and a few others all play a role not only in heat, but gas output. A lot of experimentation has taken place in the last 20 years and recently there are even more ways to control burn rate, heat and flash than ever before.
It is becoming far more complex studying internal ballistics and propellant types. Some is trickling into reloading, but most are being developed for military applications and ADI is at the forefront for this.
Cheers.
The other thing that hasn't even been discussed in these threads is the fact that the type of powder, progressive, digressive and a few others all play a role not only in heat, but gas output. A lot of experimentation has taken place in the last 20 years and recently there are even more ways to control burn rate, heat and flash than ever before.
It is becoming far more complex studying internal ballistics and propellant types. Some is trickling into reloading, but most are being developed for military applications and ADI is at the forefront for this.
Cheers.
What i'm wondering is...........what was each of the powder charges? If both have the same charge I know the velocities will be more spread. What would be the temp if both were near max? The throat would be a better place of gauging as the lands/grooves would have extra heat due to friction cause by speed. This is still a relevant test you're doing regardless of the negative posting.
Dang! I don't know whether I'm more informed now, or if I'm more confused. I was commenting on Gingerman's test in my post. I should have known better than posting in a ballistics testing thread. Logical conclusions carry very little weight in science it seems. Carry on…..
DoneNOut
Well-Known Member
H100V - 45.5gr
RL17 - 45gr
I had both these loads running 2810-15. I goofed and shot the 10rnds of H100V in once fired brass, and all else in virgin brass. I think this is why that string ave was 2780. More volume in the once fired case.
Powder filled to the base of bullet on H100V and RL17 slightly compressed.
DoneNOut
Well-Known Member
I was thinking about the cumulative effect of the 5 degree difference, if that what it truly turns out to be. I questioned this temp difference, especially at 5 degree difference, would even be detectible in the decision to retire the barrel at end of use. For me that decision would be if the barrel no loner shot MOA. (10 shot strings)
When I thermal scanned the barrel from back to front, I could see a definite rise and fall of the temp reading just before and after the throat area of the barrel. I thought this the best place to take the highest readings.
My experimenter bias, and looking at the flame temp chart had me thinking the RL17 string was going to be like 160F and the H100V 100F. Or some greater amount of difference. So, you can imagine me sitting in the grass with my clipboard, like, "Hmm!"
Carey Farmer
Well-Known Member
The "flame temperature" chart is actually a "heat of combustion" chart... the amount of heat (in Joules) released when 1 gram of powder is burned. But the ratio of the burning powder temperature rise should be about the same as the heat-of-combustion ratio.
Per the heat of combustion chart, RL17 releases 13% more heat than H100V. The ratio of temperature rise (from ambient) of the barrels is 15%. That is really close to what one would expect!
Per the heat of combustion chart, RL17 releases 13% more heat than H100V. The ratio of temperature rise (from ambient) of the barrels is 15%. That is really close to what one would expect!
DoneNOut
Well-Known Member
There is only 4% difference between the two powders though. In regards to temp readings.
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Carey Farmer
Well-Known Member
3990 / 3545 = 1.126 right?
DoneNOut
Well-Known Member
In regards to the temp readings
Doom2
Well-Known Member
Those numbers in the chart are NOT temperatures. They are heat of explosion numbers with is energy release/mass. In this case kilojoules/kilogram. While temperature is a function od heat release it is also a function of caliber/chamber and load density.
The barrel is hot for both which re-enforces cool down after 3 shots. KISS
Gingerman, you read the data on the Heat Index chart, then do your own testing over time in barrels you shoot keeping some good records.
A. leade growth per 100 rounds or even 50 rounds. Get ready for a shock if you are using Hot burning powders on the heat index chart such as N500 series.
B. Velocity drops as your throat grows in both length and diameter. You can measure the dia in throat growth with a Grizzley Rod from PTG and an oversize set of reamer pilots. As a baseline, in high-quality barrels, the bore dia is uniform to 0.0001 from end to end. As your velocity drops, add a tad more powder, maintain the distance from the lands that the bullet liked when the barrel was new, or re-barrel.
C. shots 4-10 in a string increase throat wear exponentially if done on a hot barrel, this is an expensive lesson to learn, measuring throat length wear range trip to range trip where you may fire 35-50 rounds per trip.
I have my own rifle range, shoot and reload at the range. With just a tad bit of record keeping, it seems that the manufacturers made certain powders just to eat barrels up. I could give examples, but it would just bore the heck out of you. Some things you just have to have "hands-on experience" to learn, and in the end, gained performance from really hot burning powders may be a good trade-off. We all have varying amounts of disposable income to invest in new barrels, some more than others.
Often, if you start off with enough Shank or "straight" on the back end of the barrel, you can set the barrel back. I found that with the hot burning powders, often 4-9" had to be cut off to get back to where the bore dia would be the same at the muzzle and throat.
IN my 7/08 AI, I will use AA2700 and HV100 first, as they burn extremely cool. I have shot cases of AA2700 with CCI 250s in my 243 AI over the years with very hard use on varmints, like dumping out a box of 50 and firing as fast as I can single load and pull the trigger. Barrel setbacks are around 1800 rounds with .070 freebore growth. Setbacks run 3/4" on the first, 2" on the second and third, then 4-6" on the fourth, barrel starting at a 30", Hart barrels, with a barrel ending up a 6 BR on the 4th chamber, 12 twist.
The first powder I used was IMR 4064 which wiped out 6" of the barrel in 2000 rounds, then IMR 4350, about the same as 4064. Winchester 760 was the first real change in seeing much less throat wear, then switched to AA2700(cooler burning yet). CCI 250's got the SD down below 9 fps. This is just one example as we found the same thing in the 22/250 AI with 12T with 55s at 4150 fps, 223 and 223 AI with 748 and H335 get incredible barrel life, but when we had other barrels we shot H322, AA2015, Benchmark, LT35, the leade just walked out much faster, not to mention the carbon in the barrel was cooked on to a greater degree.
The fastest barrels I ever shot out were with R#15 in a 22 BR, 220 Swift with N550, 22/250s with IMR 4064 & Varget, 243 Win with IMR 4064 and Varget, and 6 Remington with IMR 4064.
For guys that work up loads for a new rifle(big game hunting), verify zero from year to year, it would take a lifetime to fire 500 rounds, so you have to keep things in perspective.
A. leade growth per 100 rounds or even 50 rounds. Get ready for a shock if you are using Hot burning powders on the heat index chart such as N500 series.
B. Velocity drops as your throat grows in both length and diameter. You can measure the dia in throat growth with a Grizzley Rod from PTG and an oversize set of reamer pilots. As a baseline, in high-quality barrels, the bore dia is uniform to 0.0001 from end to end. As your velocity drops, add a tad more powder, maintain the distance from the lands that the bullet liked when the barrel was new, or re-barrel.
C. shots 4-10 in a string increase throat wear exponentially if done on a hot barrel, this is an expensive lesson to learn, measuring throat length wear range trip to range trip where you may fire 35-50 rounds per trip.
I have my own rifle range, shoot and reload at the range. With just a tad bit of record keeping, it seems that the manufacturers made certain powders just to eat barrels up. I could give examples, but it would just bore the heck out of you. Some things you just have to have "hands-on experience" to learn, and in the end, gained performance from really hot burning powders may be a good trade-off. We all have varying amounts of disposable income to invest in new barrels, some more than others.
Often, if you start off with enough Shank or "straight" on the back end of the barrel, you can set the barrel back. I found that with the hot burning powders, often 4-9" had to be cut off to get back to where the bore dia would be the same at the muzzle and throat.
IN my 7/08 AI, I will use AA2700 and HV100 first, as they burn extremely cool. I have shot cases of AA2700 with CCI 250s in my 243 AI over the years with very hard use on varmints, like dumping out a box of 50 and firing as fast as I can single load and pull the trigger. Barrel setbacks are around 1800 rounds with .070 freebore growth. Setbacks run 3/4" on the first, 2" on the second and third, then 4-6" on the fourth, barrel starting at a 30", Hart barrels, with a barrel ending up a 6 BR on the 4th chamber, 12 twist.
The first powder I used was IMR 4064 which wiped out 6" of the barrel in 2000 rounds, then IMR 4350, about the same as 4064. Winchester 760 was the first real change in seeing much less throat wear, then switched to AA2700(cooler burning yet). CCI 250's got the SD down below 9 fps. This is just one example as we found the same thing in the 22/250 AI with 12T with 55s at 4150 fps, 223 and 223 AI with 748 and H335 get incredible barrel life, but when we had other barrels we shot H322, AA2015, Benchmark, LT35, the leade just walked out much faster, not to mention the carbon in the barrel was cooked on to a greater degree.
The fastest barrels I ever shot out were with R#15 in a 22 BR, 220 Swift with N550, 22/250s with IMR 4064 & Varget, 243 Win with IMR 4064 and Varget, and 6 Remington with IMR 4064.
For guys that work up loads for a new rifle(big game hunting), verify zero from year to year, it would take a lifetime to fire 500 rounds, so you have to keep things in perspective.
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Carey Farmer
Well-Known Member
(123 - 85) / (118 - 85) = 1.15 right?
