Enduron powders

Stopped by a gunstore today and grabbed some Enduron powders , 4166, 4451 and 7977 by the pound. I have never tried them, I hear the 4166 is great for the .308 and the 4451 is for the 6.5 Creedmoor and the 7977 for the 7mm and 300 magnums. Burn rate of the 4166 is similar to Varget, 4451 is to H4350 and 7977 is between RL-25 and H1000. The great thing is these powders are insensitive to temp changes.

How have you folks experienced with these new powders and results on the range?

So far IMR 4451 has worked well in the 260 Remington with 130 gr Sierra HPBT bullets. I usually use H 4350 and IMR 7828 ssc but limited testing so far 4451 seems as good. Tried it in a 7mm Rem Mag with 154 gr Hornady spire points, didn't chronograph but it was accurate.

Have tried IMR 4955 with 140's in 6.5x55 and 150's in 270 Win. Accurate in both although published data seems a bit hot in the 270 Win.

IMR 7977 works well with the 150 gr Ballistic Tip and 160 gr Partition, somewhat compressed loads but not overly so. Good speed and accuracy. Tried this as well in 7mm Rem Mag with the 154 gr Hornady, it also was accurate.

Haven't tried IMR 4166 but it is supposed to be very similar to Varget so should be quite useful.

So far I like them a lot. As a bonus they are Canadian made so are much easier to get than Alliant powders, at least in my home town.

IMR 4451 has been excellent in my 30-06 with 180gr Noslers. Added benefit is less copper but more carbon in the barrel. H4350 became non existent in my area.

I've been working up some loads in my .30-06 and .243 with 4166. Good so far.

I've been playing with IMR 4451 and 4955 in two 30-06 and a 280 Remington with 180 grain and 175 grain Nosler Partitions respectfully. So it won't necessarily correlate to your 6.5, 7 and 300 mags.

Have you read the Precision Rifle Blog on the temperature stability of IMR 4166 and 4451 vs H4350 and Varget? if not I would recommend a quick skim though the article and I can send you the link through a PM. They use a 6.5x47 Lapua which I think is roughly comparable to your 6.5 Creedmoor. One of their conclusions is that the IMR powders might be primer sensitive, and as such the powders might significantly benefit from a hotter or otherwise temperature insensitive primer.

On a personal note, I've been having mixed success. The IMR 4451 seemed to give a large ES and accuracy wasn't repeatable in the 30-06 I tested it in. Testing was done in 30-40 degrees; so I'm thinking that the powder might be temperature sensitive in my application, the primers were also acting funny and the rifle had a couple of cracks in the stock... So I don't know if it was a rifle, primer or powder issue.

IMR 4955 is giving great velocity and good groups out to 175 yards in both the 30-06 and 280, but it seems really touchy in the 30-06. 0.2 grains will cause the groups to open up by several inches at 100 yards. The 280 though is happy as a clam at high tide and doesn't seem finicky in the least and I've gone over Hogdgon's max listing by a hair without any issues.

With the 30-06 the velocities don't match at all and it is picky! It is grouping at 57.8-58 grains and the chronograph is showing a consistent 2800-2810 fps at 58 grains, velocity is level from 58-58.5 grains and I'm getting shot gun groups and pressure signs at 58.2 and 58.5 grains. Hogdgon's starting load for a 180 grain Sierra boat tail is 56.7 with a velocity of 2635 grains and tops off at 61 grains at 2828 fps - so I'm way out in left field. My guess is that the Nosler Partition is compressing the powder and the burn rate changed or the primer is mismatched - but that is just a wild guess and I really need to see how it responds this summer at hotter temps.

My point on the IMR 4955 is that these are newer powders and I've heard a few stories about guys blowing primers a grain or two below Hodgdon's max in 270 Win - so I would recommend starting low! I'm not noticing any less copper fouling, and carbon fouling is pretty bad. I will be using them though this year and will make a final decision on them this winter when it gets down into the 10's-20's degrees F.

Thanks folks for the feedback, I'll try the 300 win Mag with the IMR 7977 and hopefully shoots well. By the way, where are most of the data for charge weights for those listed powders?

I do not see much data online except some data from the Hodgdon website which isn't much. I guess I need to start low and work up to find my own data while observing signs of pressure.

Hodgdon online and their yearly publication are the main source for load data. Quickload is probably 2nd.

Hornady 10th edition has a few listings with IMR 4451 and 7977... I haven’t seen 4166 or 4955 in the manual.
7mm Rem mag has 4451 listed for 120-162 grainers.
6.5 Creedmoor has a 140 grain bullet with 4451.
300 Win mag has 130-180 grainers with 4451 and their 190 grain bullet with 7977 and 4451.

Nimrod84":3muhhtp1 said:

Hodgdon online and their yearly publication are the main source for load data. Quickload is probably 2nd.

Hornady 10th edition has a few listings with IMR 4451 and 7977... I haven’t seen 4166 or 4955 in the manual.
7mm Rem mag has 4451 listed for 120-162 grainers.
6.5 Creedmoor has a 140 grain bullet with 4451.
300 Win mag has 130-180 grainers with 4451 and their 190 grain bullet with 7977 and 4451.

Click to expand...

Thanks Nimrod.

I have gotten loads over the phone from Hornady tech support especially on new bullets where there is little data available.


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I've had good luck with 4955 in a modern 6.5x55 swede. 140 gr bullets around 2950 fps. And accurate too!