IMR Enduron® 4955
$49.99 - $357.99
IMR Enduron® 4955
IMR Enduron® 4955
IMR Enduron® 4955
IMR Enduron® 4955
IMR Enduron® 4955
IMR Enduron® 4955

IMR Enduron 4955 is a versatile, match-grade propellant with a mid-range burn speed that is in between IMR4451 and IMR7977. It is an extruded powder and provides top performance for big game cartridges like 25-06, 270 Winchester, 280 Remington and 300 Win Mag, among other cartridges.

The main features of the Enduron series are copper fouling eliminator, insensitivity to temperature changes, ideal loading density and being environmentally friendly.

This propellant performs comparably to Hodgdon H4831 but charge weights are materially different.

IMR recommends always consulting for the most accurate, up-to-date data.

Available in 1-LB and 8-LB containers.


Warnings for California Residents

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WARNING: This product contains chemicals known to the State of California to cause cancer and birth defects or other reproductive harm.

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Reviews and Ratings

Alan R. Williams
IMR 4955

I have had problems with the powder at mid to the high end of charge
table, it developies too high pressure.. I am having the poweder gas blow back through the primers. I have used in both my 25-06 and .270. I had the most problems using WinchesterPprimers. ICC Primers worked better.

John Pfligler

All around great powder for my .25-06, meters nice, good velocities and does seem to leave barrel cleaner.

vergal williams
4955 powder

work very well 270 win

Tom Baker
IMR 4955

I went to the store looking for anything I could use and there was a can of IMR 4955 I did some tests and bought 9 more lbs Its great in 243, 25-06 and 300 win mag

Don Baldwin

Great powder for 270 and 280 Rem

Larry Broomfield
IMR 4955

Excellent powder that delivers as promissed. Best MOA that I have ever achieved.

Good choice for the 300 Win Mag

This powder is Sierra's pick for accuracy under their 200 grain bullets. I have a very picky eater (Bergara B-14 HMR) and I've had very poor results with the factory ammo I've had to feed it just to get some brass on hand to load. Right out of the gate, this powder got me under ½ MOA and just over ¼ MOA on a 2nd try at the same load. I'm equally impressed and pleased with this powder.

Kyle Hendren
Imr 4955

Great powder as with all of the enduron line

Just starting out with load development

This is the first of the newer enduron powders I’ve worked with. I bought it because I couldn’t find the powder I prefer for 3006 rounds there are recipes listed for 3006 and am interested in the temperature insensitivity and anti fouling properties. It is a short fat cylindrical shape, rather than the long skinny cylindrical extruded powder I’m used to seeing. From what I can tell so far, you will end up with a full to compressed load. The powder compressed easier than the longer skinnier shaped powders. Metered uniformly, threw well and trickled well. I’ve a batch loaded up to test for velocity, accuracy, and pressure signs, but haven’t shot them yet. Which is the reason for 4 stars as I haven’t shot it yet, but if my loads come close to published results, I expect to be pleased.

IMR 4955

So far it is working as advertised. I worked up some 6.5x55mm loads. No signs of pressure, the velocity was what I was hoping for, accuracy is good. Very happy.

Dustin H Leonard
Amazing Accuracy

Getting .3 moa groups out of my 300 win mag with 168 grain barnes bullets@72 grains. Not sure on the range for safe loads anything over 72 and I start getting pressure signs. Like around 72.5 I see obvious primer flattening.

Roger Lehrer

IMR4955 is a great find. Not well known but I suspect more people will use it with more reporting. As stated by A. Williams, it can blow out primers at higher loads so build up carefully as always. Additionally, I use it in my .243 and pressures are not the same for all equal bullet weights. Ex: Nosler E-Tip 90's blew out the primers while Berger 90's shot fine: same 45 grains of 4955 out of Winchester brass. I'm getting 1/2 MOA with my 80 & 90 Berger's.

Odd pressure problems

Like Alan I experienced failure on the case head right where the edge of the primer meets the edge of the primer pocket. .260 remington (custom with perfect headspace). Charge weight was 44 grains in Resized FGGM cases, primer was WIN LR and WIN LR Magnum. I got a blast of gas to the face and smoking around the bolt shroud on a remmy 700. 2 out of 5 cases had a pinhole in the mentioned location. Charge is 1.1 grains under max with a 142 SMK, and velocity averag was 2711 out of a 25 inch SS Krieger. For reference .260 FGGM factory ammo shoots the 142 SMK at 2742 average and has no issues.

IMR 4955

I just finished firing three loads in the 25 06 using a 117 gr. Hornady btsp. Starting with 51.5 grains of IMR 4955 then 52.5 and 53.5. Not max load but the faster I pushed it the more accurate it got! Also no signs of high pressure at all.

Frank Adamek
300 win nag

Got good velocity and accuracy. Stopped 1 1/2 grains short of max for 300 win mag with 180 grain. Very satisfied

Bob Aguiar
IMR 4955 issue

I loaded a few 270 Win shells with Nosler 165gr 56 gr of IMR 4955. Should be 1gr below max. Blew the primer and ruptured the case. Guess I should have started 5 gr below max but with bullets, primers and powder shortages I cut corners. Mistake

Philip Richardson
Imr 4955 enduron

This Is the worst powder I’ve tried to develop a load for, in the .284 win, ladder speed test was up and down so much it was hard to believe it was the same powder in each case! It developed serious signs of pressure within .5 g! I couldn’t get the velocity i wanted without excessive pressure in my custom rig! Es poor too.

Zac Ferguson

If you are doing a load build up, make sure you have a chronograph. What the powder chart shows on here is not what I saw in practice. They were MUCH higher in my Remington 700 Sendero, it could be that it has 26" barrel. Shot well, with good groups. Over all, I'm pleased! Just watch your speed.

IMR 4955 powder

Loaded 6.5 CM with this powder and Hornady ELD Match 120 gr and Hornady Match 140 gr. BTHP. I shoot at 100 yds. or less for white tail. At 100 yds. my pattern was no greater than 1/2 inch and velocity was very constant. I don't feel the need to max out a load because the deer are always close. I used a mid range powder load and get mid 2400s on the 140 gr. and mid 2600s on the 120 gr. I'm very pleased

Jay Wright

this is a great powder for 300 win mag . I get great es and tight groups. it stomps the metal targets at 1000 yards to glad i got 36 pounds of this stuff

Rene Sarasin
300 Win Mag

4955 works well in my 300 Win Mag. I'm shooting 1/4 moa groups at 100yds with 165 gr Nosler ballistic tips. I killed my mule deer at 525 yds this past season. Extremely happy with this powder.