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May 17th, 2018
A couple seasons back, PrecisionRifleBlog.com (PRB) published a significant field test of powder temperature stability. The test was designed to quantify the temperature stability of Hodgdon H4350 and Varget powders compared to IMR’s Enduron line of powders, specifically IMR 4166 and 4451. The results were very interesting, to say the least…
Hodgdon Extreme Series powders have attracted quite a fan base, with over 90% of the top shooters in the Precision Rifle Series choosing to run one of those powders. IMR offers a modern line of powders “with Enduron Technology” — which is also marketed to have “extreme temperature stability”. Sounds familiar! These new powders should compete directly with the Hodgdon Extreme Series, which gives shooters more temp-stable powder options to consider.
CLICK HERE to Read Full Powder Temperature Stability Test on Precision RifleBlog.com.
The top shooters in the PRS and veteran long-range shooters in other disciplines have learned to value a temperature-stable powder. That’s because a change in temperature can affect the trajectory or “flight path” of the bullet in two well-known ways:
1. Assuming all other environmental conditions remain the same, an increase in air temperature will cause a flatter trajectory due to a lower air density (easier for the bullet to cut through the air).
2. The same increase in temperature also causes the nitrocellulose-based powder inside the cartridge to burn at a higher rate, producing approximately four times the Point of Impact (POI) shift than just air temperature alone. (SEE: Temperature Effects On Zero on KestrelMeters.com.)
“The initial heat condition of your powder will affect the burn rate,” Bryan Litz explained at a recent Applied Ballistics Seminar. That means swings in ambient outside temperature can affect your internal ballistics, which will directly affect your muzzle velocity, which will change your bullet’s trajectory. Some powders are more affected by changes in temperature than others. So if your goal is first-shot hits and you may shoot in a variety of conditions — you should care about temperature stable powders.
The folks at PrecisionRifleBlog.com meticulously loaded 6.5×47 Lapua ammo with each powder using some of the best equipment available. This included the top-of-the-line Prometheus Gen II Powder Scale, which is capable of loading to the nearest kernel of powder. This ensured the powder charges were identical for each round of ammo. PRB’s testers explain the full set of equipment and steps in their loading process in the Full Test Report.
Once they had a couple dozen rounds loaded with each powder, they went and shot them with each powder at 25° F, 65° F, and 140° F. The muzzle velocity of each shot was recorded using BOTH a LabRadar Doppler Radar and a MagnetoSpeed Chronograph. That provided two sets of velocity numbers. When placed and configured optimally, the LabRadar can measure muzzle velocity with +/- 0.1% accuracy, according to the manufacturer.
Here are the results from the PRB Powder Temp Stability Tests:
You can see Hodgdon H4350 had the least variance in muzzle velocity, with just 25 fps over the 115° swing in temperature! That is very, very low. Hodgdon Varget was the second least temperature sensitive powder in this test, with 46 fps of variance in muzzle velocity between temperatures of 25° F and 140° F. IMR 4166 performed very similar to Varget, and proved to be fairly insensitive to large swings in temperature. IMR 4451 had the largest swing in muzzle velocity of the powders tested, but keep in mind just 68 fps over 115° F swing is still a good performance.
Most powders aren’t specially formulated to be temperature stable. So they would likely show much larger swings than what these four top-performing powders showed. However, Alliant’s relatively new Reloder 16 is an extremely temp-stable powder, with a burn rate that is a close match to H4350. Many F-Open competitors are now using Reloder 16 with considerable success.
PRB’s test team also noticed other interesting trends in the data. For example, variation in velocity does NOT appear to be linear across the full range of temperatures. By that, they mean the change per degree from 20° to 65° might be smaller or larger than the change per degree from 65° to 140°.
PRB’s testers talk about those things, provide a few other insightful views of the data, and discuss tools that can help you manage temp/muzzle velocity in the field in their full post. You can find that here: http://precisionrifleblog.com/2016/06/19/powder-temp-stability-hodgdon-extreme-vs-imr-enduron/
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August 19th, 2016
Here’s an important announcement for anyone who uses a powder in the 4350 range. Alliant is now shipping the all-new Reloder 16 powder. The burn rate is slightly faster than Reloder 17, and a bit slower than Varget or Reloder 15. Notably, this new Reloder 16 powder is very temp stable. AccurateShooter.com was shown “top secret” test results comparing Reloder 16 with other popular propellants, including Hodgdon Extreme series powders. The results for Reloder 16 were remarkable. Reloder 16 showed extremely constant velocities even with very high ambient temps — so this is a powder you can shoot even on hot Arizona summer days.
CLICK HERE for Reloder 16 Suggested Load Recipes
This is NOT just a slower version of Alliant’s double-based Reloder 15 (which words great in the 6mmBR and Dasher cartridges). Reloder 16 is a completely new formulation, produced in Sweden by Bofors for Alliant. Reloder 16 utilizes TZ technology, which manipulates the response of the propellant and resists the natural tendency to generate more pressure at higher temperatures and less pressure at lower temperatures.
As a result, Reloder 16 offers outstanding temperature stability. Based on the test results we’ve seen, if you are using H4350 or IMR 4451 currently, you should definitely give Reloder 16 a try. The powder also boasts excellent lot-to-lot consistency and contains a proprietary de-coppering additive.
Match and Hunting Cartridge Applications:
Alliant tells us that Reloader 16 “is ideal for traditional hunting cartridges, such as .30-06 Springfield and .270 Winchester, as well as 6.5mm target loads and tactical applications wherein temperature stability is required.” We also think the powder may work very well in these popular match cartridges: 6XC, .243 Win, 6.5×47 Lapua, 6.5 Creedmoor, .260 Rem, .284 Win, and .300 WSM. For example, Alliant’s Load Data Sheet shows a 2772 FPS load with 142gr SMKs in the .260 Rem.
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July 19th, 2016
PrecisionRifleBlog.com (PRB) recently published results from a field test PRB conducted to quantify the temperature stability of the popular Hodgdon H4350 and Varget powders and compare those to IMR’s new Enduron line of powders, specifically IMR 4166 and 4451.
Hodgdon Extreme Series powders have attracted quite a fan base, with over 90% of the top shooters in the Precision Rifle Series choosing to run one of those powders. IMR recently released a new line of powders “with Enduron Technology” — which is also marketed to have “extreme temperature stability”. Sounds familiar! These new powders should compete directly with the Hodgdon Extreme Series, which gives shooters more temp-stable powder options to consider.
CLICK HERE to Read Full Powder Temperature Stability Test on Precision RifleBlog.com.
The top shooters in the PRS and veteran long-range shooters in other disciplines have learned to value a temperature-stable powder. That’s because a change in temperature can affect the trajectory or “flight path” of the bullet in two well-known ways:
1. Assuming all other environmental conditions remain the same, an increase in air temperature will cause a flatter trajectory due to a lower air density (easier for the bullet to cut through the air).
2. The same increase in temperature also causes the nitrocellulose-based powder inside the cartridge to burn at a higher rate, producing approximately four times the Point of Impact (POI) shift than just air temperature alone. (SEE: Temperature Effects On Zero on KestrelMeters.com.)
“The initial heat condition of your powder will affect the burn rate,” Bryan Litz explained at a recent Applied Ballistics Seminar. That means swings in ambient outside temperature can affect your internal ballistics, which will directly affect your muzzle velocity, which will change your bullet’s trajectory. Some powders are more affected by changes in temperature than others. So if your goal is first-shot hits and you may shoot in a variety of conditions — you should care about temperature stable powders.
The folks at PrecisionRifleBlog.com meticulously loaded 6.5×47 Lapua ammo with each powder using some of the best equipment available. This included the top-of-the-line Prometheus Gen II Powder Scale, which is capable of loading to the nearest kernel of powder. This ensured the powder charges were identical for each round of ammo. PRB’s testers explain the full set of equipment and steps in their loading process in the Full Test Report.
Once they had a couple dozen rounds loaded with each powder, they went and shot them with each powder at 25° F, 65° F, and 140° F. The muzzle velocity of each shot was recorded using both a LabRadar Doppler Radar and a MagnetoSpeed Chronograph. The LabRadar is a new type of device that allows you to measure muzzle velocity within at least +/- 0.1% of the reading.
Here are the results from the PRB Powder Temp Stability Tests:
You can see Hodgdon H4350 had the least variance in muzzle velocity, with just 25 fps over the 115° swing in temperature! That is very, very low. Hodgdon Varget was the second least temperature sensitive powder in this test, with 46 fps of variance in muzzle velocity between temperatures of 25° F and 140° F. IMR 4166 performed very similar to Varget, and proved to be fairly insensitive to large swings in temperature. IMR 4451 had the largest swing in muzzle velocity of the powders tested, but keep in mind just 68 fps over 115° F swing is still a good performance.
Most powders aren’t specially formulated to be temperature stable. So they would likely show much larger swings than what these four top-performing powders showed.
PRB’s test team also noticed other interesting trends in the data. For example, variation in velocity does NOT appear to be linear across the full range of temperatures. By that, they mean the change per degree from 20° to 65° might be smaller or larger than the change per degree from 65° to 140°.
PRB’s testers talk about those things, provide a few other insightful views of the data, and discuss tools that can help you manage temp/muzzle velocity in the field in their full post. You can find that here: http://precisionrifleblog.com/2016/06/19/powder-temp-stability-hodgdon-extreme-vs-imr-enduron/
Share the post "Powder Temp Stability: IMR Enduron vs. Hodgdon Extreme"
July 10th, 2016
Many Forum members have been looking for a good substitute for Hodgdon H4350 powder, which remains hard-to-find in many parts of the country. One of the best alternatives is IMR 4451, part of IMR’s new Enduron line of powders. Last year, top F-Class shooter Rick Jensen did a comparison between H4350 and IMR 4451, shooting the two powder in a wide range of temperatures. His data suggests that both powders show good temp stability.
Powder Comparison Test: H4350 vs. IMR 4451
Rick Jensen, Captain of the U.S. F-Open Rifle Team, has tested some of the new IMR 4451 powder. Rick and other team members were looking for a good powder that could replace Hodgdon 4350 which is difficult to obtain currently. The makers of IMR 4451 claim that it is not sensitive to temperature and that it delivers competitive accuracy. So far, Rick’s tests, done with a .284 Winchester and 180gr Berger Hybrids, appear to confirm those claims. Rick posts:
 “I did a little informal powder comparison of H4350 versus the new IMR 4451. Rifle used was a Kelbly Panda with a 30″, 1:8.75″ twist 5R Bartlein barrel [chambered in .284 Win]. All charge weights were 50.0 grains using CCI BR2 primers. I was very impressed with this new powder and I believe it to be equal to H4350 as far as temperature sensitivity.
I did not test for accuracy but I will tell you my groups were pretty much equal between the two and all were in the .2-.3 MOA range. I will defiantly be shooting more of this powder in the weeks to come, assuming the supply chain will allow. It looks very encouraging to finally have a alternative to H4350 that we might actually be able to buy.”
Chronograph Results with Temps from 23° F to 101°
Here are chronograph results of a comparison test between IMR 4451 and H4350. Rick’s rifle was cleaned and allowed to cool between each test. Five fouling shots were fired before each test. Important: Note that for both Test #1 and Test #2, the powder order is reversed in the mid-temp fields (IMR 4451 first, then H4350). For the low and high temp entries, H4350 is listed first.
Here are the IMR 4451 fired cases, displayed Left to right, coldest to the hottest (in terms of case temp when fired). All charge weights were the same: 50.0 grains.
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June 10th, 2016
IMR® Legendary Powders now offers four (4) Enduron powders: IMR 4166, IMR 4451, IMR 4955, and IMR 7977. Shooters looking for readily-available alternatives to hard-to-find extruded powders should definitely check out the Enduron line-up. Precision shooters will find an Enduron option well-suited to most of the popular precision cartridge types. For example, IMR 4166 is a good replacement for Hodgdon Varget (commonly used in the .223 Rem, 6mmBR and .308 Win), while IMR 4955 is a fine substitute for H4831 (favored by F-Open shooters for the .284 Win and 7mm WSM cartridges).
Modern Powder Technology for Enhanced Performance
The technology in IMR’s Enduron line of powders provides four very important qualities that enhance both in-gun and downrange performance.
Copper fouling reduction – these powders contain an additive that drastically reduces copper fouling in the gun barrel. Copper fouling should be minimal, allowing shooters to spend more time shooting and less time cleaning a rifle to retain accuracy.
Temperature change stability – the Enduron line is insensitive to temperature changes. Whether a rifle is sighted in during the heat of summer, hunted in a November snowstorm or hunting multiple locations with drastic temperature swings, point of impact with ammunition loaded with Enduron technology will be very consistent.
Optimal load density - Enduron powders provide optimal load density, assisting in maintaining low standard deviations in velocity and pressure, a key feature for top accuracy.
Environmentally friendly - Enduron technology is environmentally friendly, crafted using raw materials that are not harmful to the environment.
The Enduron Line-Up of Four Powders
IMR now offers four Enduron powders that cover a broad range of burn rates. They are suitable for a wide variety of cartridges, from small varmint cartridges all the way up to the .338 Lapua Magnum.
IMR 4166 possesses the fastest burn rate in the Enduron lineup. It is the perfect burn speed for cartridges such as .308 Win, 7.62mm NATO, 22-250 Rem and 257 Roberts. A versatile, match-grade propellant, IMR 4166 is comparable to Hodgdon® Varget.
IMR 4451 is a mid-range burn speed powder, ideally suited for cartridges such as .270 Winchester, .30-06 and 300 Winchester Short Magnum. This powder is comparable to Hodgdon H4350.
IMR 4955 is a medium burn speed powder, falling in between IMR 4451 and IMR 7977 in burn speed. It provides top performance in big game cartridges such as 25-06, 280 Remington and 300 Winchester Magnum. This powder is comparable to Hodgdon H4831.
IMR 7977 has the slowest burn rate among the Enduron Technology powders. Its loading density is perfect for magnum cartridges and contributes to superb uniformity, yielding outstanding performance in 300 Winchester Magnum, 7MM Remington Magnum and .338 Lapua Magnum. IMR 7977 is comparable to Hodgdon H1000.
The Enduron Technology powders are available in one-pound (1 lb) and eight-pound (8-lb) containers from quality reloading retailers. Learn more about Enduron powders at www.enduronimr.com. For info on other IMR powders, visit www.imrpowder.com.
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February 21st, 2015
Rick Jensen, Captain of the U.S. F-Open Rifle Team, recently tested some of the new IMR 4451 powder. Rick and other team members were looking for a good powder that could replace Hodgdon 4350 which is difficult to obtain currently. The makers of IMR 4451 claim that it is not sensitive to temperature and that it delivers competitive accuracy. So far, Rick’s tests, done with a .284 Winchester and 180gr Berger Hybrids, appear to confirm those claims. Rick posts:
“I did a little informal powder comparison of H4350 versus the new IMR 4451. Rifle used was a Kelbly Panda with a 30″, 1:8.75″ twist 5R Bartlein barrel [chambered in .284 Win]. All charge weights were 50.0 grains using CCI BR2 primers. I was very impressed with this new powder and I believe it to be equal to H4350 as far as temperature sensitivity.
I did not test for accuracy but I will tell you my groups were pretty much equal between the two and all were in the .2-.3 MOA range. I will defiantly be shooting more of this powder in the weeks to come, assuming the supply chain will allow. It looks very encouraging to finally have a alternative to H4350 that we might actually be able to buy.”
Chronograph Results with Temps from 23° F to 101°
Here are chronograph results of a comparison test between IMR 4451 and H4350. Rick’s rifle was cleaned and allowed to cool between each test. Five fouling shots were fired before each test. Important: Note that for both Test #1 and Test #2, the powder order is reversed in the mid-temp fields (IMR 4451 first, then H4350). For the low and high temp entries, H4350 is listed first.
Here are the IMR 4451 fired cases, displayed Left to right, coldest to the hottest (in terms of case temp when fired). All charge weights were the same: 50.0 grains.
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