I've been doing some load development these past few weeks with two of my 338 Win Mags and working up a load for a co-worker's 338 Win Mag. In the past, I have had excellent accuracy with the following load in four 338 Win Mags. 225 grain Barnes X/TTSX bullets fueled by 67.5 grains IMR 4350, Winchester cases and CCI 250 or Federal 215M primers. Ironically, the best seating depth in three of these 338s turned out to be the same. I can't recall the seating depth on the fourth one and I sold it several years ago. At any rate, I wanted to try H4350 (because my three 30-06s love it with a 168 TTSX) and the new IMR 4451 to see how they worked.

The rifles I used were a Browning XBolt with 26 inch barrel and a Weatherby Vanguard with a 24 inch barrel. Here's how the velocity stacked between the three powders using Norma cases instead of Winchester and Fed 215M primers: (I had to increase the IMR 4350 charge weight one full grain to get comparable velocities when switching from Winchester to Norma cases)

68.5 grains IMR 4350 average velocity
XBolt 2825 fps
Vanguard 2764 fps

66.5 grains H4350 average velocity
XBolt 2808 fps
Vanguard 2744

68.5 grains IMR 4451 average velocity
XBolt 2786 fps
Vanguard 2739 fps

So, it would appear the new IMR 4451 is slower than IMR 4350 and definitely slower than H4350. H4350 didn't produce decent groups in either rifle but IMR 4451 did in both rifles. I loaded a few rounds up to 69.0 grains using IMR 4451 and didn't see any pressure signs in either rifle. I may bump the charge weight up and shoot a few more til I see pressure signs then back off accordingly.

I emailed Barnes to see if they had any load data for IMR 4451 for the 338 Win Mag and Ty responded saying they don't right now but they are working on a new reloading manual. He suggested I use Hodgdon's load data from their web site as a rough baseline.

IMR 4350 has been very good to me over the years but I'm gonna see what I can get out of this new IMR 4451. Allegedly it's a little more temperature stable than IMR 4350. We'll see...

quote:

Originally posted by sep:
I've been doing some load development these past few weeks with two of my 338 Win Mags and working up a load for a co-worker's 338 Win Mag. In the past, I have had excellent accuracy with the following load in four 338 Win Mags. 225 grain Barnes X/TTSX bullets fueled by 67.5 grains IMR 4350, Winchester cases and CCI 250 or Federal 215M primers. Ironically, the best seating depth in three of these 338s turned out to be the same. I can't recall the seating depth on the fourth one and I sold it several years ago. At any rate, I wanted to try H4350 (because my three 30-06s love it with a 168 TTSX) and the new IMR 4451 to see how they worked.

The rifles I used were a Browning XBolt with 26 inch barrel and a Weatherby Vanguard with a 24 inch barrel. Here's how the velocity stacked between the three powders using Norma cases instead of Winchester and Fed 215M primers: (I had to increase the IMR 4350 charge weight one full grain to get comparable velocities when switching from Winchester to Norma cases)

68.5 grains IMR 4350 average velocity
XBolt 2825 fps
Vanguard 2764 fps

66.5 grains H4350 average velocity
XBolt 2808 fps
Vanguard 2744

68.5 grains IMR 4451 average velocity
XBolt 2786 fps
Vanguard 2739 fps

So, it would appear the new IMR 4451 is slower than IMR 4350 and definitely slower than H4350. H4350 didn't produce decent groups in either rifle but IMR 4451 did in both rifles. I loaded a few rounds up to 69.0 grains using IMR 4451 and didn't see any pressure signs in either rifle. I may bump the charge weight up and shoot a few more til I see pressure signs then back off accordingly.

I emailed Barnes to see if they had any load data for IMR 4451 for the 338 Win Mag and Ty responded saying they don't right now but they are working on a new reloading manual. He suggested I use Hodgdon's load data from their web site as a rough baseline.

IMR 4350 has been very good to me over the years but I'm gonna see what I can get out of this new IMR 4451. Allegedly it's a little more temperature stable than IMR 4350. We'll see...

If it helps, with the 225TTSX
I get 2835fps with 71 grains Reloder 17 and Fed 215Match in a 24.4" barrel
and also 2810fps with 69 grains R-17, Fed215M, in a different 24.4" barrel.

One of the rifles seems to have a slightly larger chamber and needed an extra 1.5 grains for a similar velocity. I would expect 4451 to produce slightly lower velocities (-25fps) for similar pressure and charge. But those are within variances of different batches of powder so you're on your own, as always.

Thanks 416Tanzan...appreciate it.

I expected 4451 to be a bit slower but Hodgdon's powder burn rate chart listed them in order of fastest to slowest as IMR 4350, IMR 4451 and H4350. My results don't jive with that burn rate for H4350. Maybe I've got a fast lot of H4350? I'll continue development with 4451 and if it continues to perform accurately I'll stick with it.

You're welcome.

With these new powders, it seems that there are some more complicated dynamics involved than simply a linear burn rate.

Rel-17 seems to have some kind of extended peak, which means some kind of complex interaction at higher pressures. I am guessing that 4451 is similarly complex, though it may not have quite as much 'second gear' as R-17. What I have noticed in loading for my wife's 375 Ruger is that similar charges of 4451 produce less velocity than R-17. Also, similar weights of 4451 are bulkier than R-17, so there will be some combinations where R-17 is needed for a max velocity.

One other important consideration seems to affect these new powders--primers.

When using IMR-4166 at less than max loads in a 375Ruger the Rem 9.5Mag primers produced tighter groups than the same charges/bullets and WLRM primers. So is there something going on with initial combustion and 4166, or were the loads a statistical fluke? I don't have the time or availability to follow up for the next few months, but I have plenty of both primers so I going with the Rem9.5M for the 4166 loads (375Ruger, 200 grain GSC, Rem9.5M, 73.0 IMR4166, for 2825 in a 20" barrel. I'll be loading those up for ferrying to East Africa. As for 4451 and Rel-17, the primers haven't seemed to affect the groups. So I use the Rem 9.5M for "medium" charges (70-85 grains) and save my WLRM primers for heavier charges (90-105 grains in 500AccRel and 416 Rigby). I've run out of Fed215M's and am saving those on hand for occasional 'legacy' loads when loading something up to ferry overseas.

Pictures follow, 100 yards:

Rem9.5M with 73.0 4166 for 2828fps in 375Ruger with 200grain GSC

The 0.83" group is good for hunting and beats the 1.25"-1.5" that were obtained with WLRM.

Rem9.5M with 81.0 4451 for 2683 in 375Ruger with 250grain TTSX

The group was excellent but the velocity was too slow for a final load choice. Fortunately, I had a couple of cans of R-17 available. See below.

Rem9.5M with 84.0 grains Rel-17 for 2826fps in 375Ruger with 250grain TTSX

On a different day this had only produced 0.8" groups, but either way is good to go for hunting in Africa.

And my wife's final two-shot test:

The impact those primers were having on the loads is interesting. Definitely, more than I expected. Either way, your wife's got a very accurate rifle and load to use in Africa.

Just curious, how did you determine your maximum charge weight for the IMR 4451 loads? I'm asking because we don't have load data from Barnes and this powder yet and I recently watched a video by Gunwerks where they showed how they develop loads for their rifles. They increase powder charge weight til they start seeing ejector marks on the case head and then back off 1/2 grain. They consider that a max load for that rifle with those particular components.

That approach seems a little hot to me. Although, I have no idea when brass will actually flow causing ejector marks. I've read 70,000 psi but not all cartridge cases are the same and if that number is true, I doubt backing off 1/2 a grain will lower peak pressure to within SAAMI specs. I usually don't exceed max loads in the appropriate bullet manufacturer's data but in this case, I have no established data to use.

I don't mind a slight reduction in velocity as would seem appropriate for this powder based on Hodgdon's data and Hornady bullets but if safe pressures make it perform similar to H4831 then I'm movin back to "the old brown mule"...IMR 4350. I used RL19 with this caliber when I first started using the 338 Win Mag back in the mid 1990s but it just didn't perform consistently. So, I tried IMR 4350 and my first two groups with it were around .5 I've been using it ever since.

Part of my safety method involves overall energy. Most calibers have enough data so that we know approximately what a particular caliber can safely achieve with appropriate powders.

For example, I consider the 338 Win Mag to rate approximately 3800 to 4100 ftlbs. as the expected muzzle energy with appropriate powders. IMR4451 is certainly to be considered an appropriate powder, along with the 4350's, R17, IMR4831, and H4831 with heavier bullets.

Of course, I check primers and for extractor bright spots, as well as casehead expansion. Sometimes my loads tend toward a max load where primers just start to lose some of their roundness, though definitely not flattening, especially in 270Win. The 375Ruger loads above were all tame, as their muzzle energies of 3600-4500 would attest. The 375H&H is a 4300-4600 ft# caliber and the Ruger capacity goes beyond that, though the 20" barrel of the Alaskan brings it back to H&H levels. My 416 Rigby loads go way over anemic book rates but leave primers looking pristine (e.g. 101.5 R-17 350TTSX for 2820fps and 6180 ft#) and cases just slide out.

On 4451 and R17 in the 375Ruger, I noticed that the 81-grain 4451 was starting to fill up and might not handle testing at 84-85-86 grains. Hence the switch to R-17. Noting that RealGuns had tested quite a few 375 Ruger loads to over 5000 ft#, I wasn't too concerned until my loads would have approached 3000fps (=5000ftlbs with 250 TTSX). I've stopped at 84 grains since the accuracy was outstanding and 85 grains with 250 TTSX was not an improvement. 2825 fps is plenty fast.

So I guess common sense stopped me with the 250TTSX before I ever got close to finding a true max load. I would agree that 1/2 grain is too little margin is you see bright ejector marks. I would probably want to back off two grains.

Great! Thank you for the info and it sounds like your approach to load development is both safe and practical.

I get such good performance from H4831, I have never seen a need to look at other powders.

quote:

Originally posted by buckeyeshooter:
I get such good performance from H4831, I have never seen a need to look at other powders.

That might work for 275-300 and 250 grain bullets, but as one tries out lighter and monolithic bullets slightly faster powders come into the optimum picture for the 338WinMag.

quote:

Originally posted by sep
So, I tried IMR 4350 and my first two groups with it were around .5 I've been using it ever since.

Sep this was my experience as well. I was going to start with IMR 4350 then try other powders but my groups with 4350 were excellent and the velocity was great. My .338 Win Mag has a 20" barrel and I still get over 2800 fps with a 225 grain Sierra.
Below I'll post a picture. I now use Federal brass and am getting 2840 fps with the Sierra 225 grain bullet.

Snellstrom,

I don't blame you...no need to look any further than IMR 4350 with the groups you're getting with those 225 Sierras. That's good shootin too!

quote:

Originally posted by 416Tanzan:

quote:

Originally posted by buckeyeshooter:
I get such good performance from H4831, I have never seen a need to look at other powders.

That might work for 275-300 and 250 grain bullets, but as one tries out lighter and monolithic bullets slightly faster powders come into the optimum picture for the 338WinMag.

Yep, never shoot anything lighter than a 250 grain in .338.