What seems to be the most temp stable powder for heavy bullets in the .300 WinMag? I ask because developing a load down here in Mississippi then taking it to the mountains for Elk in November is hard to correlate.
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Temp stable powder for COLD weather
- Thread starter former naval person
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Well, the whole concept, "temperature stable" usually means HIGH ambient temperatures that won't affect your load, ie: excessive pressures, etc.
As far as cold weather. If you develop your winter loads in the summer time, bring an ice chest to the range and keep those rounds under ice and consider using a magnum primer, but I have never had any trouble in cold weather. I have an old Model 700 in 300WinMag and my load is more H4831 than the book recommends, so I won't share it. But somewhere in that ballpark might be where to start. Good luck. BB
As far as cold weather. If you develop your winter loads in the summer time, bring an ice chest to the range and keep those rounds under ice and consider using a magnum primer, but I have never had any trouble in cold weather. I have an old Model 700 in 300WinMag and my load is more H4831 than the book recommends, so I won't share it. But somewhere in that ballpark might be where to start. Good luck. BB
^^^I'm really glad to see winter and summer loads being discussed!! For some, the very idea of developing different loads for different operating temps (regions/seasons) is something new to them, most of the guys I know have for a long time developed "hot weather" loads and "cold weather" loads, along with different loads for different ranges (highpower), this knowledge is being lost/or was never known to a lot of shooters. BuzzBoss915 thanks for posting! What may seem like "old hat" or common knowledge to you isn't that common!
I shoot Retumbo in the 300WM and have seen little shift in POI or velocity across a temp range from low 30's to near 100. But that is with very heavy bullets (230 gr).
H1000 from 100 + to well below zero.
The thing is you just cant change the physics involved. You just have to re-zero in the fall / spring. No matter what powder I have never been able to find a way to avoid a change in POI from significant temp swings + - 80 degrees
The thing is you just cant change the physics involved. You just have to re-zero in the fall / spring. No matter what powder I have never been able to find a way to avoid a change in POI from significant temp swings + - 80 degrees
Exactly my question. Years ago I did go out from +70 here to -20 there.. Misfires and delayed fires (standard primer) and low impacts (used OLD 4831)...down 10 to 12 inches at 300 yds. Learned my lesson I did. That is why I am asking about modern powders. I know about Magnum primers now, and altitude changes (generally +), but cold soaking can hurt impacts. And velocities. I might try the icebox trick. Dry ice and brass...oooohh, does brittle set in at -25 or lower? Who here has the experience? Thanks for inputs!!!
Just the change in elevation, from here on the coast to Colorado. Or, Saskatoon. You would be foolish not to check your zero upon arrival. It doesn't matter if the temperature is the same or not. I learned A LONG TIME AGO to check my zero at the place where I intend to hunt. Seeking modern formulated temperature stable propellants is an okay solution, (as far as it goes) but if you don't verify your zero when you get there, you are a fool. BB
I load H4831sc for my 300. Here is the deal tho. Are you shooting long range? If so you will have other things to contend with by going from a warm to a cold climate. Barometric pressure, elevation, temp...... If your shooting closer ranges it wont be a problem. If you shooting long range, you might want to bring some extra ammo to do a little practice when you get to your hunting spot. Good luck!
Your brass should be fine at -25. I've spent several mornings hunting coyotes when it was colder out than that and had no issues.
I shoot a 300WM with 210 VLDs for deer and have never had an issue using H1000. As others have mentioned, check your zero when you arrive and you'll be good to go!
I used 208 Gr Amax with H1000 in my 300. with outstanding results in the cold. Very temp stable. I was using CCI Br2 and probably have gotten lower ES with a hotter primer say fed 215 match.
As stated, temperature stability is primarily a concern for warmer temperatures and minimizing pressure rise. IMO, for COLD temps, the powder is less important and the primer is more important. My advice is to develop a load with the hottest primer available.
Cold temps take energy, so you need a hotter primer to light the powder consistently, while still loosing some energy to heating the ambient environment inside the case.
If you REALLY want to over think it, develop a load where you're at (80F) with a normal magnum primer and then which to a hotter primer for the cold temp load, to compensate for the energy loss........ only thing you won't know what the impact is unless you can range test it first.
Cold temps take energy, so you need a hotter primer to light the powder consistently, while still loosing some energy to heating the ambient environment inside the case.
If you REALLY want to over think it, develop a load where you're at (80F) with a normal magnum primer and then which to a hotter primer for the cold temp load, to compensate for the energy loss........ only thing you won't know what the impact is unless you can range test it first.
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Another point about cold. POI shift between cold in warm bore are a bit more when it get's cold. At least for me anyways. Cold steel has different harmonics to warm steel.
I know to check the zero upon arrival, airline baggage handling being what it is. What I probably won't be able to do is to chrono or drop test the impact at various ranges. That is the main reason I asked about temperature stability.
What he said. In July 2010, whilst at the Lapua test range in Finland, the "powder Jesus of the company" (those where HIS words), said they had developed a powder for the 338 that was not sensitive to extreme temp variations. If I'm not mistaken, the 300 win mag uses the same powder. I have not tested this personally, so I can't confirm his statement.
"Ex Umbris Venimus"
I don't use MOA. In March (40 degrees) v. yesterday (90 degrees with very high humidity) my 1000 yard elevation was .1mil off. More specifically, it took .1mil less elevation yesterday.
I had no way to measure velocity differences under match conditions.
You are seeing a 0.1 mil change, 70 degree change from low to high, that is some strong data, Retumbo it is!
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