Read some where that Re#17 is harder on bbls then various other 4350 burn rate powders ?
Re#17 vs Barrel life
- Thread starter Ironworker
- Start date
WyleWD
Silver $$ Contributor
If you can find or remember where you read that, please post it. I'm curious (and would be skeptical) of the supporting data to prove or disprove that statement. :-\
IMHO there are a lot more keyboard wizards than there are solid scientific fact wizards posting on these subjects. A lot like the "temperature sensitive" concerns that are posted, again IMHO. :
If you are shooting really nice groups with it, winning matches, hitting all the critters you're aiming for or what ever, then short barrel life is some of the price you pay for having an overbore rifle.
WD
IMHO there are a lot more keyboard wizards than there are solid scientific fact wizards posting on these subjects. A lot like the "temperature sensitive" concerns that are posted, again IMHO. :
If you are shooting really nice groups with it, winning matches, hitting all the critters you're aiming for or what ever, then short barrel life is some of the price you pay for having an overbore rifle.
WDAckleymanII
Gold $$ Contributor
Iornworker, back during the great p. dog wars from 1978-1993, we found that ball powders extended the barrel life greatly over stick powders that were available back then, specifically IMR 4064 and IMR 4350. At that time, we shot from 18,000-26,000 rounds a year, and setting back barrels along with barrels on order at all times were normal.
Powders with 20% DNT eat barrels.
Powders with 20% DNT eat barrels.
AckleymanII
Gold $$ Contributor
Boyd, specifically, we used Win 748, WC844, AA2230-s, Win 760, and AA2700.
We kept strict records on rounds fired and leade growth. Anytime IMR 4064 or IMR 4350 were used, leade growth picked up substantially.
AA2015 left chalky substance in the barrel in 223's at the 125 round mark.
I do not remember the results of H322 or T 32 in 223 meant more frequent cleanings, but we switched to 748 due to the fact that leade growth was minor.
I shot AA2230S in a 6 PPC with 60g Bullets and shot no less than 300 rounds inbetween cleanings. The Hart barrel was still shooting groups in the low 3's at 10,000 rounds.
We kept strict records on rounds fired and leade growth. Anytime IMR 4064 or IMR 4350 were used, leade growth picked up substantially.
AA2015 left chalky substance in the barrel in 223's at the 125 round mark.
I do not remember the results of H322 or T 32 in 223 meant more frequent cleanings, but we switched to 748 due to the fact that leade growth was minor.
I shot AA2230S in a 6 PPC with 60g Bullets and shot no less than 300 rounds inbetween cleanings. The Hart barrel was still shooting groups in the low 3's at 10,000 rounds.
bigedp51
Normally the higher the Nitroglycerin content the hotter the peak flame temperature will be "BUT" the shape and size of the powder and deterrent coatings controls the burning rate and peak flame temperature. In the majority of cases ball powder will burn cooler than stick powder when the right powder is used.
NOTE: The military doesn't use double base ball powders because they burn out barrels quicker, it uses ball powders selected to give "LONGER" barrel life.
1. At 43,000 cup the peak flame temperature is just starting to reach the melting point of modern barrel steel.
2. The larger the diameter of the bullet the easier it is to be pushed down the barrel with less bore erosion.
3. Ball powder has a comparatively small surface-area-to-volume ratio, so it burns comparatively slowly, and as it burns, its surface area decreases. This means as the powder burns, the burn rate slows down. To some degree, this can be offset by the use of a retardant coating on the surface of the powder, which slows the initial burn rate and flattens out the rate of change. Ball powders are generally formulated as slow pistol powders, or fast rifle powders.
In "Everything you always wanted to know about R-17" by Germán A. Salazar
How does RL17 produce so much added speed? There are two main reasons--unique burn properties and high load density. In its chemical properties, RL17 is like no other powder available in the U.S. market. Made in Switzerland by Nitrochemie, RL17 has a unique burn-rate controlling chemical that penetrates all the way through the kernels. Other common extruded powders have only a surface coating. Reloader 17's unique penetrating burn-rate regulator smooths out the pressure curve, allowing RL17 to maintain high energy for a longer period of time.
This means RL17 releases pressure and heat at a lower and slower rate than stick powder with less bore erosion.
Material Safety Data Sheet
Smokeless powder - Reloder 17
Nitrocellulose 80%
Nitroglycerin 13%
Smokeless powder - Reloder 15
Nitrocellulose 80%
Nitroglycerin 8%
Smokeless powder - Reloder 7
Nitrocellulose 90%
Nitroglycerin 5%
British double base Cordite powder used in the Enfield rifle WWI-WWII
Nitrocellulose 37%
Nitroglycerin 58%
NOTE: The hotter burning Cordite powder did cause throat and bore erosion to a higher degree than "ANY" double base powder presently made. Cordite powder contained more Nitroglycerin than the fastest burning pistols in use today.
NOTE: The military doesn't use double base ball powders because they burn out barrels quicker, it uses ball powders selected to give "LONGER" barrel life.
1. At 43,000 cup the peak flame temperature is just starting to reach the melting point of modern barrel steel.
2. The larger the diameter of the bullet the easier it is to be pushed down the barrel with less bore erosion.
3. Ball powder has a comparatively small surface-area-to-volume ratio, so it burns comparatively slowly, and as it burns, its surface area decreases. This means as the powder burns, the burn rate slows down. To some degree, this can be offset by the use of a retardant coating on the surface of the powder, which slows the initial burn rate and flattens out the rate of change. Ball powders are generally formulated as slow pistol powders, or fast rifle powders.
In "Everything you always wanted to know about R-17" by Germán A. Salazar
How does RL17 produce so much added speed? There are two main reasons--unique burn properties and high load density. In its chemical properties, RL17 is like no other powder available in the U.S. market. Made in Switzerland by Nitrochemie, RL17 has a unique burn-rate controlling chemical that penetrates all the way through the kernels. Other common extruded powders have only a surface coating. Reloader 17's unique penetrating burn-rate regulator smooths out the pressure curve, allowing RL17 to maintain high energy for a longer period of time.
This means RL17 releases pressure and heat at a lower and slower rate than stick powder with less bore erosion.
Material Safety Data Sheet
Smokeless powder - Reloder 17
Nitrocellulose 80%
Nitroglycerin 13%
Smokeless powder - Reloder 15
Nitrocellulose 80%
Nitroglycerin 8%
Smokeless powder - Reloder 7
Nitrocellulose 90%
Nitroglycerin 5%
British double base Cordite powder used in the Enfield rifle WWI-WWII
Nitrocellulose 37%
Nitroglycerin 58%
NOTE: The hotter burning Cordite powder did cause throat and bore erosion to a higher degree than "ANY" double base powder presently made. Cordite powder contained more Nitroglycerin than the fastest burning pistols in use today.
All good stuff, but I would challenge most of #3. If you divide the surface area of a smaller particle by its volume, you get a larger number, than a relatively larger particle would give. If you take the total surface area of a given weight (or volume for that matter) of fine grained powder, and compare it to the surface area of the same weight of a coarser powder, the former will have substantially more total surface area, and since burning takes place at the surface, smaller grained powders are more dependent on their deterrent coatings for regulation of burn speed. Even within the same ball powder, screening experiments have shown that when the particles are sorted, that the smaller ones burn faster than the larger ones. You might ask Dick Wright about that one.
270 loads:
130 gr VLD moly 3.34" 57.7 gr Re17 , 22" barrel 3228 fps over chronograph
55 Re17 150VLD 3.38571kpsi
..1) M70 22" barrel, 7X scope, 3023, 2996, 2969, 3003, 3009, 3003, 3009, 3037
..2) Ruger #1, 26" barrel, 25X Mk IV scope, 3037, 3058, 3044, 3072 fps,
I got those velocities with long brass life.
I would have bet a lot of money at long odds that no powder could do that.
Then I ran into the Re17 velocity vs temperature graphs in April 09.
Kombayotch at Snipers hide and Canadian gun nutz took a cooler and an oven to the range and tested over a chrono with Varget as the control.
If you look over the entire possible temp range, Re17 is no bargain. Low velocities and pressures at low temp and very high pressures at high temp.
If Re17 and Varget loads are safe at high temp, then with those same loads, Varget can beat Re17 for velocity at low temp.
I have not shot Re17 since, and in 2011 I concentrated on H4350.
130 gr VLD moly 3.34" 57.7 gr Re17 , 22" barrel 3228 fps over chronograph
55 Re17 150VLD 3.38571kpsi
..1) M70 22" barrel, 7X scope, 3023, 2996, 2969, 3003, 3009, 3003, 3009, 3037
..2) Ruger #1, 26" barrel, 25X Mk IV scope, 3037, 3058, 3044, 3072 fps,
I got those velocities with long brass life.
I would have bet a lot of money at long odds that no powder could do that.
Then I ran into the Re17 velocity vs temperature graphs in April 09.
Kombayotch at Snipers hide and Canadian gun nutz took a cooler and an oven to the range and tested over a chrono with Varget as the control.
If you look over the entire possible temp range, Re17 is no bargain. Low velocities and pressures at low temp and very high pressures at high temp.
If Re17 and Varget loads are safe at high temp, then with those same loads, Varget can beat Re17 for velocity at low temp.
I have not shot Re17 since, and in 2011 I concentrated on H4350.
When I used RL17 in the .284 I had to reduce the load twice. At the high point of summer my final reduction was from 51.6 grs to 49.0 grs and was still getting the same node. Yes RL17 does have a temp sensitivity factor to it.
If my info is correct.. RL17 has been used in the ammo for K31's and the 7.5 Swede for many years. And that combo shoots pretty darn well. Also known as GP11.
I have seen 3 308 Winchester barrels go south in a all of a sudden bad way with less than 4k rounds, 1 Rock, 1 Bartlein, and 1 Krieger, all were shooting 208 Amax's at around 2600, thumping big heavies out of a 308 Win gives 260 Rem wind holds, and slightly better 260 Rem barrel life, not an increased life in my experience.
My understanding is that all ball powders are double-base - never heard of one that wasn't. I've always believed than any double-base powder will be more subject to temp. changes than most single-base powders, but that the newer spherical propellants from Belgium & the St. Marks plant in Florida were a big improvement in that respect. eg - I used a lot of TAC in 223 loads for NRA HP matches in the late '90s, and never had problems with temp sensitivity like I did when shooting older powders like BL-C2, W748, & AA2520.
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