any info on IMR 4451?

[bryan s]

Just seeing if anyone has tried IMR 4451 as a replacement for H 4350? If so what kind of results did you find?

[XC700116]

getting ready to test a lb of it soon.

[spqrzilla]

Article about it in the recent Handloading magazine.

[Zombie Steve]

Wish I could help out... tagged for XC's results... particularly interested in temp sensitivity...

[XC700116]

Well so far I'm finding at least in my 260 (26" barrel that has seen a lot of rounds already and is almost toast) that it's on the slow side when it comes to Velocity as compared to H4350, however I haven't hit any pressure signs yet so it's hard to tell and I'm going very slowly since I'm FAR beyond anything that's published data on it. To illustrate here's Hodgdon's data on 260 Rem with 142 SMK's (which is as close as it gets to the 139gr Lapua I'm testing with)

H4350 - Max 44.5 gr - 2735 fps
I4451 - Max 41.5 gr - 2717 fps

My pet load in this rifle is 42.0 gr of H4350 and it produces 2815 fps

Now I'm up to 43.0 grs of 4451 in the same rifle with the same brass, primer and bullet and I'm seeing about 2795. So far the nodes are nice and wide with LOW SD/ES but as I mentioned I'm proceeding very slowly as 1. I don't care to blow my face off and I'm a long ways passed published data vs my standard load finding pressure well inside published data with H4350. and 2. I REALLY hate pulling down loads so I don't like to load up too broad of a group when I'm getting to the higher limits.

As far as the temp sensitivity goes, everything I've seen so far is that it is every bit as stable as H4350. So if I can get a load to perform with accuracy and the velocity I'm wanting out of it, I'll be buying as much of it as I can afford.

I'll also be testing it in a 6X47L as soon as the rifle is completed, side by side with H4350, H4831sc and probably Varget. I'm obviously really hoping it works well in at least one of them or both as I'm running dangerously low on H4350 and Varget, and H4831sc isn't exactly overflowing the shelves.

[Zombie Steve]

Go fast, take chances. Report back if you can.

[Coffee]

Seriously, thanks for posting. More data is more gooder. I am sort of curious why you'd try Varget in the new rifle against much slower powders and a heavy for caliber bullet.

???

[XC700116]

Basically because a lot of other guys are having good luck with it, and the new rifle is going to be a relatively short barrel, so it may work better than the slower powders, but it's pretty much at the bottom of my hope list since it as hard or harder to find than H4350.

[XC700116]

Well, a dog shines on a dogs ass every once in a while and it was shining today. [rockon]

So I went to the range to test the latest run of test loads with 4451 in my 260 and the results were gratifying enough that I just ordered 16 lbs of it from Powder Valley. I was able to up my MV to 2840 fps, about 25 fps faster than my current H4350 load and was rewarded with single digit SD's on the best group, and it produced a sub 1/2" 5 round group. This was with a charge of 43.3gr of 4451 I was able to push it up to the low 2900 range but it wasn't quite as consistent, producing SD's in the lower half of the teens, and started to give some signs of being up against the pressure limits.

It does take about 1.3 gr more of the 4451 to do that, and it's in a higher pressure node than with H4350 (ie my H4350 load could go a lot hotter before pressure started to show up, but shot so well I wasn't going to mess with it) I start to see pressure with H4350 about 1.5 gr higher than my current load of 42.0 gr, but with 4451, I'm seeing it about .5 gr higher than the node that produced the accuracy and low SD while still moving slightly faster than my pet H4350 load. So overall I'm quite pleased with it, and am ready to jump to it as an alternative to H4350 for this rifle.

Now I can only hope that it will be similar in my 6X47L , but I do have 1 8lb jug of H4350 if 4451 doesn't cut the mustard in that cartridge, time and testing will tell, but I'm hopeful.

[XC700116]

As an aside, I also tested some of the new 4166 which is REALLY close to 4064, and is basically supposed to be a CFE and Temp stable version of 4064, I was halfheartedly hoping for a good alternative to Varget for my 73gr 223 load, but it was about 200 fps slow when I started hitting pressure as compared to Varget. Since I have never used 4064 I can't really comment on the comparison there, but I will say 4166 did provide a very accurate load with really low SD's as well. I was seeing SD's that are right in line with what this rifle produces with Varget (low teens). Keep in mind this is an AR15 too so the ultra low SD's you see with a bolt gun just aren't typical in an AR.

While you don't get the speed from 223 heavies that you do with Varget, it is a definite performer for accuracy and consistency.