Temp sensitive?

[adk hunter]

For those with real world experience...

Is temperature stability a problem with high temps or swings in temperature? I'm in a temperated zone 4 climate and don't shoot much during summer heat. We only have 6 weeks of that lol.

Looking back, I may have had one load that I made 50 of, that next year seemed too hot, stiff bolt lift and primers cratered. Not sure if I was running into this and I think that was with Hogdon's...

Thanks!

 

[memtb]

For those with real world experience...

Is temperature stability a problem with high temps or swings in temperature? I'm in a temperated zone 4 climate and don't shoot much during summer heat. We only have 6 weeks of that lol.

Looking back, I may have had one load that I made 50 of, that next year seemed too hot, stiff bolt lift and primers cratered. Not sure if I was running into this and I think that was with Hogdon's...

Thanks!

adk hunter, I live in a similar geographical climate, minus moisture, and do my load development "only"on the hotter days....90+F. I don't want temperature related surprises/problems. Then, when temps get near to your hunting temperatures you can do an accuracy verification! I realize that this seems very impractical, requiring several months, however....it's worked for me! memtb

 

[lancetkenyon]

Some are very sensitive to temp swings. RL22, RL25, RL26 but only above 85*, H414 is somewhat, Superformance too. Up to 2fps per 1* of temp swing.

Others are very stable. H1000, H4350, Varget, H4831SC, RL23.

 

[Gwine]

Years ago before I really new about temp sensitivity I locked up a 7RM with imr4831. Granted I left the rifle and ammo in the truck in August while scouting. I wanted to check zero at the elevation I would be hunting. First two landed 2" apart at 300yds, third one sounded funny and bolt wouldn't open. Shot hit 12" high.

 

[adk hunter]

Thanks guys. That was how I was hearing other threads. I do 90% of loading in the winter and will shoot in temps down to zero from my shooting shed. Rarely a 60* swing up from that for hunting season. RL23 is where I'm playing now.

 

[ButterBean]

Some are very sensitive to temp swings. RL22, RL25, RL26 but only above 85*, H414 is somewhat, Superformance too. Up to 2fps per 1* of temp swing.

Others are very stable. H1000, H4350, Varget, H4831SC, RL23.

^^^^^^^^^^^
Spot On

 

[Savage 12BVSS]

Develop my loads during the summer in zone 4b, never had any pressure signs or problems during hunting seasons, a non issue where I hunt and live. Zero is always on in October during POI check from summer. Use IMR4350/4064 as well as H4350 and RL15.

 

[Shane Lindsey]

Is RE23 a good alternative velocity wise to RE22. I get a significant increase in RE22 from H1000, almost 150 FPS. Almost enough to deal with the temp sensitivity. If RE23 is better, I may have to look into it.

 

[J E Custom]

Temp sensitive powder is effected most @ high temp. Temp swings of 30 or 40 degrees aren't to bad if the low temp starts at 30 degrees and goes to 70 degrees. But 70 to 90 degrees will have a larger effect in only 20 degrees and if you go to 100 degrees. The last 10 degrees can almost double the effect on the powder. In other words the higher the temp the greater the effect.

Loading during the winter months can limit use during the hotter months with some powders. A load that has very little pressure can become dangerously hot in extreme high temps. One of my favorite (Accurate) loads velocity is 3010 ft/sec during hunting season but when the temperature
reaches 90 to 100 degrees, it will soar to 3160. (A 150 ft/sec increase with hard extraction) and I wont shoot that load if the temp is much over 70 degrees.

If I hunt with that rifle during the hotter months, I switch to Varget and avoid the pressure, it doesn't shoot as well (Accurate) but it is close enough.

Sometimes heat sensitive powder just shoots better, but can be managed if you know the temp range it likes.

J E CUSTOM

 

[MagnumManiac]

I have to say after using a truck load of RE25 in everything from 25-06 thru 338-416 Rigby Improved in temps from 0°C-40°C+ it is not as temp insensitive as other RE powders like RE19 & RE22.
I develop my loads in the summer months with all powders, regardless of temp stability...no unexpected surprises doing it this way.

Cheers.

 

[memtb]

adk hunter, I first qualify this comment with......the following may be an anomaly!

Several years ago, there was much conversation about the temperature sensitivity of RL 17....which I use in my rifle. As I mentioned, I do my load development during the summer. I waited until a nice cool, calm ( I was testing groups as well) day....with the daytime high at a minus 3 F. Test temperatures ran from a -4 to a balmy -3 F. The rifle and the ammo, we're left outside for a couple of hours to equal and stabilize to the ambient temperatures. I fired a 3 shot group, allowing several minutes between rounds, as to not change bore temperatures substantially. My velocity actually showed an 8 FPS "increase" over my summer load development data. Also, exhibited a group slightly better than the summer groups. Go figure!!! memtb

 

[milo-2]

adk hunter, I first qualify this comment with......the following may be an anomaly!

Several years ago, there was much conversation about the temperature sensitivity of RL 17....which I use in my rifle. As I mentioned, I do my load development during the summer. I waited until a nice cool, calm ( I was testing groups as well) day....with the daytime high at a minus 3 F. Test temperatures ran from a -4 to a balmy -3 F. The rifle and the ammo, we're left outside for a couple of hours to equal and stabilize to the ambient temperatures. I fired a 3 shot group, allowing several minutes between rounds, as to not change bore temperatures substantially. My velocity actually showed an 8 FPS "increase" over my summer load development data. Also, exhibited a group slightly better than the summer groups. Go figure!!! memtb

My experience with RL 17 mimics yours, slightly faster in bitter cold. I cannot recall my spreads, it has been awhile, I shot a lot of 17 after Sandy Hook, it was always available. I like you made the load during warmer weather, and never had issues, if the load was not hot itself, it seemed to do better the hotter it got. Like Win 748 does in heat.
I think RL 17 has always gotten a bad rap, just like VV N 500 series powders when it comes to stability. But, IMO, just like all RL powders, characteristics from lot to lot may make one wonder if the right powder is in that jug.

 

[J E Custom]

Conditions/Temperature can effect pressure and velocity of the heat stable powder and normally it is not significant, but at higher temps even the "Non Temp Sensitive" powder will be effected and can change the velocity and pressure although not as much.

Powder burn rates are tested close to ambient temperatures and perform best in that range, Go very cold and it can be effected just like very hot temps. loads should be worked up in the normal range of temperatures you will see in your area for best results and least problems.

J E CUSTOM

 

[6.5-300 BEE]

Amazing how JOC killed all that game from sub zero to boiling hot with war surplus 4831 in his 270. chuckle.

Powder company President: " our sales have dropped."
His flunky: "Let's repackage it and claim it's not sensitive to low/high temps"
Pres: "Great and raise the price too"

Ya gotta wonder how we shot down all those enemy planes from -30 F to 120F with those 20MMs stoked w/4831 ?