I just finished a quick check of the velocity of a 300 WSM load using IMR 4350 at -5 degrees Fahrenheit with very good results.

Load Details:
65.5 grains IMR4350
180 grain Barnes TTSX
Fed 215M
Norma Brass
COL: 2.900"
The load is listed as max in the Barnes #4 manual with the only changes being the brass and COL.

The gun is a Winchester M70 with a 24" barrel.

At 75 degrees velocities were 2996, 3009, and 3037 fps.

At -5 degrees velocities were 3003, 2996, and 3003 fps.

In both cases the gun and ammo was allowed to acclimate for a couple hours before shooting. I used a cheap ProChrono set 15 feet from the muzzle on overcast days.

I'm not able to check accuracy/POI at the same time as velocity, but the load has seemed consistent (around and inch at 100 yds) in a variety of conditions.

I'm just sharing since I was a little surprised how well it did.

Thanks. I tried RL16 in 11-14deg temps and it did well

Thanks for the write up.

handy info! thanks for testing and sharing!!

Nice 1st post FallGuy - welcome aboard.

It would be interesting to see a comparison of IMR-4350, H-4350 and IMR-4451. I just picked up a 300 WSM and will start working with H4350.

what bullet?

I have some 165 TSX and TTSX's to try.

Actually, I think I'll start with some 155 Skinners - just to see if the used, but like new, Kimber Montana is a shooter. IIRC, it seemed like Tanner killed some good stuff with the Skinners.

I have worked up a nice load using H4350 and the 165 grain TTSX. Barnes' latest online load data lists a maximum of 69.6 grains of H4350 at 3181fps. That is a few grains more than several other sources I looked at, but I didn't have any issues working up that far. My velocities also tracked right with their data.

I found my sweet spot with this:

68.5 grains H4350
165 grain Barnes TTSX
Fed 215
Winchester brass
COL: 2.860"

They shot a little over 3100 fps and grouped under an inch at 100 yds.

Ironically, I worked up this load partially with the idea that it would be better than the IMR4350 load across a wide temperature range. I should have tested first. I guess I'll try to find a good load with 180 grain Partitions next so that I can play a proper game of Eenie, Meenie, Miney, Moe.

FallGuy,

H4350 is normally better across wide temperature ranges than IMR4350, but any powder's temperature resistance is to some degree application specific. I've tested IMR4350 in various cartridges in cold weather and in some it's very good, as you discovered. In my .375 H&H with 300-grain bullets, for instance, it's also good.

But in my .30-06 with 165-grain bullets it's not as good. It doesn't lose all that much velocity from 70 to zero, about 75 fps, but point of impact at 100 yards shifts a couple inches. This obviously wouldn't normally make any difference on big game at 100 yards, but very well might at 300.

But I've also tested H4350 considerably at zero, along with several other Hodgdon Extreme powders, and have yet to find any signficant difference in velocity or point of impact in a wide variety of cartridges and loads. The only problem with H4350, of course, is these days it's often hard to find!

Thanks Mule Deer. I have three of your books, and love them. Your work is what led me to actually test my specific loads rather than guess.

I am beginning to think that capacity has a affect on temp stability.
For instance, in my 6.5 Creedmoor velocity dropped about 70 fps when going from 80 degrees to 30 degrees with IMR 4350

In my 7mm rem mag using IMR 4350, my velocity went unchanged and ES fell within acceptable parameters of 7 fps over 10 shots..

So it seems the higher capacity cartridges help with stability mainly I think, because once you get so much of it in a case, it burns so hot it eliminates the temp problem..

I also noticed this with RL 17, the 6.5 Creedmoor showed some erratic velocity changes. But my 30-06 showed no extreme changes, to where I had a problem with velocity.

FallGuy,

Thanks! Yep, checking sure beats guessing.... :-)

logdog,

Maybe so, but the least amount of velocity change in any cold-test I've done was a .223 Remington with Ramshot TAC. The string fired at zero averaged EXACTLY the same as it did at 70. That had to be pure chance, as chronographing two strings of the same ammo within minutes of each other normally results in a few fps difference--but it still indicated the cold-weather velocity was very close to warm-weather velocity.

20 years ago, whenn I checked IMR4350, IMR4831, H4350 and H4831, in a 30-06AI, the IMR powders showed a fair bit of velcocity loss and increased ES. Maybe Hodgdon has addressed that in more recent times.

I'm always a little leery of chrono velocity operating exposed in cold temps--the crystal is supposedly temp sensitive too!

Casey

I will definetly remember Ramshot TAC, when looking for 223 powders.. Good info!!

When I said "unchanged" I should have specified a little more.
I really meant that it didn't change enough to take me out of my node...

That's almost exactly what I found with 30-06 and 165gr. pills with IMR4350. I'm very surprised about the OPS findings. However, we know the 300WSM is said to be extremely efficient. I'm wondering if this is one of the reasons? I'd expect H4350 to get the results the OP posted, not IMR4350...

Casey,

Yep, you have to make sure the chronograph is reasonably warm. But it's not difficult, especially with a vehicle nearby.

logdog,

That's exactly what I normally mean, too. I check both velocity and accuracy to see how closely the load performs to its "warm" standards.

Have been doing this kind of testing since the early 1990's, and the .223/TAC load was the only time the velocity was exactly the same!

bsa,

The "efficiency" of the .300 WSM was an advertising line Winchester came up with when it was first introduced, implying it got more velocity out of a given amount of powder room than "conventional" cases. This wasn';t true, but it does burn powder more consistently, resulting in smaller variations in pressure and velocity, which may be why it worked so well in this instance.

But it also may simply be a coincidence. As I noted above, many powders are more temperature-consistent in specific applications, which aren't necessarily predictable.

All I used in my 300WSM was IMR4350 and at 20-degrees my average was 2900 +/- and at 80 was 2950 +/-. Resulted in about an inch at 300-yards.

Was not a concern to me since the accuracy was still good at both conditions.

I use a lot of it 25 06 up to 7 mags. Kills cshit out of deer and pigs. 50 fps isn't going to make any difference on game. 4350 ain't the powder to get the fastest speeds, but it's accurate in every thing I have ever tried it in. The guys on my deer lease say 4350 is an old mans powder.

JB-
Based on my reviews of NWS data from MT this winter, you should have lots of opportunities for cold wx testing...LOL!

Yeah, I've already run two tests, with five rifles each time, and may run another.

You picked a good winter to head south!

IMR 4350 is hard to beat, old reliable

I always say.... When all else fails, try IMR 4350.

That's an interesting way to look at it. I had a similar experience with RL17. In my 338-06 it performed very well, while in the 6.5 Creedmoor it lost quite a bit of velocity going from 70 to 12 deg.

Any results you can share? I'd like to see any RL16 results. I just tested a 6.5 CM load that did exceptionally well. But with such a small data sample it's nice to see additional results. I don't know why, but I am oddly fascinated with this.

I haven't even seen RL-16 anywhere, and that's not just local stores but the websites I primarily order from.

The results will be published in HANDLOADER magazine sometime this year, though I also have some more hot-weather tests to do, so probably not until fall.

I doubt case capacity has any consistent bearing on cold-resistance. Instead my tests have indicated that powder NOT specifically suggested or designed as temp-resistant will vary considerably in results in various applications, with no real pattern.

Thanks, look forward to your results. I just picked up another 3 lbs from MidSouth Shooter Supply. Seems to be really good in the 6.5 CM.

There can't be _no_ pattern or consistency to temperature resistance, otherwise one wouldn't be able to optimize a powder for a specific cartridge-bullet weight combo. Neither would Denton likely see worse temp-resistance from Varget in his 223 than surplus military ammo, but see excellent temp-resistance from Varget in his 308 (see his paper, Pressure Factors: How Temperature, Powder, and Primer Affect Pressure). There may well be general temp-resistance characteristics one can 'apply' to any powder, but it seems clear that there's more engineering to it than that.

It has always struck me as rather curious the disparity of results from one internet shooter/hunter to another, though, when supposedly using the same powder in the same cartridge.

IMR 4350 is generally the first powder I try, if it's listed in the book for that cartridge/bullet combo. I've just seen different results than the OP suggests. However I've never tried it in the 300WSM, since H4350 always seemed to get the nod from the guys here...

I always use temperature insensitive or cold tolerant powder in all my big game rifles. January temps in western mountains can vary dramatically. Last weeks hunt was pretty mundane with temperature swings - but we just missed out on a big one.
Our Saturday (1-7) morning departure was a drafty -30 on the truck reading.
By Monday, it was 43* and raining! Now for my self-imposed limit of 399 yards,
a loss in some velocity may not mean much but I don't want any surprises.

John,

I'm fortunate to have a gun range where I can drive up beside the last bench and string my Oehler into the cab.

I also spoke to a Hodgdon tech this afternoon about IMR7977 and it's temp stability. He made note of different loads having different respones to temperature, but he characterized the Enduron powders as having similar temp stability to the Extreme powders.

I have only shot IMR7977 a small amount, but I can say it burns MUCH cleaner than H4831 in my 243's, 270's and a 30-06AI.

Casey

That's my thinking too!


Casey

I'm going to try to keep H4350, H4831SC and Varget as my primary powders. If I am vigilant, I think I can keep enough on hand. An 8#er may last 4 years or so which may be about enough.