IMR 7828 Temperature Sensitive
- Thread starter Mud
- Start date
DrMike
Ballistician
- Nov 8, 2006
- 37,314
- 5,983
Mud":26nn6ris said:
No more so than any other single base powder.
- Thread starter
- #3
Looking through my log book. In feb I was shooting about one moa at 200 yards. The last weekend at the range my groups opened up to about 3 moa. The only thing that was different was the temperature feb was a comfortable 75 degrees vs an extreme hot day of 95.
I was wondering if this was normal with IMR 7828. I have some powders being very sentive the temperature shifts.
Larry
I was wondering if this was normal with IMR 7828. I have some powders being very sentive the temperature shifts.
Larry
Horsethief
Handloader
- Jul 5, 2012
- 346
- 5
I have heard from many reloaders with good results using IMR 7828 when it is shot under 75 degrees, even at max loads. Handloads shot in hot temps have been inconsistent. I do not use it because of that reason.
Horsethief
Handloader
- Jul 5, 2012
- 346
- 5
I have heard from many reloaders with good results using IMR 7828 when it is shot under 75 degrees, even at max loads. Handloads shot in hot temps have been inconsistent. I do not use it because of that reason.
Silent Sam
Handloader
- Dec 22, 2010
- 294
- 0
I have used 7828 in a 270Wby for a while w/ no issue. Never have used it below freezing but have from the 40s into the 90s. Load was worked up w/ temps in the 70's. I always use Fed magnum primers. I don't cook my ammo in the sun either.
"The only thing that was different was the temperature feb was a comfortable 75 degrees vs an extreme hot day of 95."
Sure about that? You also may be dialed in on a narrow node so that any small variation in velocity blows up the groups.
"The only thing that was different was the temperature feb was a comfortable 75 degrees vs an extreme hot day of 95."
Sure about that? You also may be dialed in on a narrow node so that any small variation in velocity blows up the groups.
G
Guest
Guest
I have used IMR 7828 in previous years in my 300 RUM with 200 Partitions. The load was a hot one to say the least. The groups stayed within a nickel size, even in temps up to 75-degrees.
Currently I'm using RL-25 tested in 85-degree temps and it is a max load according to Nosler #7 manual. It prints dime sized groups at 100 yds in 35-85 degree temps.
Don
Currently I'm using RL-25 tested in 85-degree temps and it is a max load according to Nosler #7 manual. It prints dime sized groups at 100 yds in 35-85 degree temps.
Don
Oldtrader3
Ammo Smith
- Nov 6, 2009
- 8,406
- 5
I have used 7828 SSC in my 7mm Rem Mag and my .340 Weatherby with no effects on groups by high ambient temperature.
Charlie-NY
Handloader
- Mar 11, 2005
- 1,419
- 850
While I normally start load development with Hodgdon Extreme powders, I have been finding some very accurate loads with IMR7828. Both the 7WSM and my 338 RUM seem to shoot the smallest groups with 7828 and I've been shooting all summer long without an issue.
It's never hot during the hunting season to I wouldn't expect any problems then either.
It's never hot during the hunting season to I wouldn't expect any problems then either.
nvbroncrider
Handloader
- Aug 20, 2011
- 3,085
- 4
I've shot the same load at 105 and 20 degrees in my 280AI no problems it's a half MOA load and much better when I do my part.
- Thread starter
- #11
Thanks for the feedback everyone.
It's just frustrating back in February my 300 Weatherby Mark V was shooting great. Went out again today. My rifle would shoot 2 out of 4 bullets good. But I keep getting some random flyers. I consider myself a good shooter. But I can't understand why I am shooting random flyers. I have very tight tolerance when I'm doing my reloads. I was thinking it may be the temperature, but now I think something else is going on.
Larry
It's just frustrating back in February my 300 Weatherby Mark V was shooting great. Went out again today. My rifle would shoot 2 out of 4 bullets good. But I keep getting some random flyers. I consider myself a good shooter. But I can't understand why I am shooting random flyers. I have very tight tolerance when I'm doing my reloads. I was thinking it may be the temperature, but now I think something else is going on.
Larry
G
Guest
Guest
I shoot 7828ssc in my 270Wby, to good effect. I've tried it in my 300'bee, and it's good, but H1000 is better, so I use it there.
I suspect you may be seeing the effects of heat on the barrel, not the powder. Something I've learned with my 'bees is that in the heat of the summer, it works much better for me to shoot two, let the rifle cool to ambient temp (in the shade), and shoot two more. I get four shot groups in the same size class as my three shot groups in cold temps. I don't think you're seeing powder temp sensitivity as much as you may be seeing barrel heat sensitivity. For reference, I can put two shots overlapping (looks like a tiny figure-8 on the target) with my 270Wby, and the third will jump out an inch or more, if I shoot three just "bang-bang-bang." In cooler weather, those three shots will go under .75" at 100, and under 2 at 200, under 3 at 300. I have confidence it's not the powder, because the rifle (and my 300) do it with multiple loads, consistently enough that I don't believe all those powders (4-6 powders total across both rifles) would identically be temp sensitive in that way.
I suspect you may be seeing the effects of heat on the barrel, not the powder. Something I've learned with my 'bees is that in the heat of the summer, it works much better for me to shoot two, let the rifle cool to ambient temp (in the shade), and shoot two more. I get four shot groups in the same size class as my three shot groups in cold temps. I don't think you're seeing powder temp sensitivity as much as you may be seeing barrel heat sensitivity. For reference, I can put two shots overlapping (looks like a tiny figure-8 on the target) with my 270Wby, and the third will jump out an inch or more, if I shoot three just "bang-bang-bang." In cooler weather, those three shots will go under .75" at 100, and under 2 at 200, under 3 at 300. I have confidence it's not the powder, because the rifle (and my 300) do it with multiple loads, consistently enough that I don't believe all those powders (4-6 powders total across both rifles) would identically be temp sensitive in that way.
G
Guest
Guest
+1 what dubyam said.
Don
Don
Oldtrader3
Ammo Smith
- Nov 6, 2009
- 8,406
- 5
I have used IMR 7828 and SSC version in my 7mm Mag since the powder came out (what 20 years ago?). I started with it when I was living in Utah in the 95*F summer heat and kept using it living in California in the 95*F summer heat. I have never honestly noticed any deference shooting this rifle and my .340 Weatherby with 7828SSC for years. I keep my shells in plastic boxes out of the sun until I put them in the chamber of the rifle.
The chamber temperature of the rifle barrel probably has more to do with bad groups than the ambient temperature. It is just easier to heat a barrel up in the summer.
The chamber temperature of the rifle barrel probably has more to do with bad groups than the ambient temperature. It is just easier to heat a barrel up in the summer.
I actually found two bottles of 7828SCC on the shelf at Spoertsman's Warehouse about 2 or 3 weeks ago. I've been waiting for things to cool down some before working with it. I can't run the A/C out there and weigh charges. The Chargemaster flat out goes bonkers when the A/C is running. 
Probably have to wait until late September before I cnan do any serious load work. No matter. I didn't draw for antelope or elk again this year. Haven't heard on deer yet. Plenty of time. My cull cow elk hunt doesn't start until next January so plenty of time for that one.
Paul B.
Probably have to wait until late September before I cnan do any serious load work. No matter. I didn't draw for antelope or elk again this year. Haven't heard on deer yet. Plenty of time. My cull cow elk hunt doesn't start until next January so plenty of time for that one.Paul B.
- Thread starter
- #16
After doing some research I have read of other having the same issue with barrel heat and point of impact shifts. It's a little frustrating I'm only shooting four shots then letting my barrel cool. I guess my next test is to shoot one at time with very long pauses in between and letting the barrel cool down. I hope this fixes the issues.
Larry
Larry
bullet
Handloader
- Dec 26, 2007
- 4,973
- 8
At least 3 1/2 minutes between shots and five minutes between three shot groups and when it is above 80 degrees back off 1/2 grain with the IMR7828
G
Guest
Guest
Regarding warmer temperatures, when I shoot the 300 RUM I will space the shots till the barrel cools to the ambient temperature. This will take more time than normal at the range, but has worked for me.
Don
Don
longrangehunter
Handloader
- Jun 19, 2011
- 1,479
- 7
Years ago I did a test on a bunch of loads at 20 degrees and found IMR 7828 in my 280 AI w/ 175 PT was running only 10 fps difference from 72 degrees when I first developed the loads, and shot to the same P.O.A. Those same loads made over a decade ago still shoot the same bug holes a few weeks ago!
I liked that performance so much I went out and bought another two boxes of the 175 gr. PT's for whenever the day comes I run out of that ammo I made back in 2002....... I love shooting my super accurate guns, but I hate the thought of burning them up on practice shooting vs. killing a big game animal.
Sad thing is I robed the scope off that gun the next day to put on the Remington 700 R5 223 I got for Lori. One day I'll replace it with a twister turret scope so I can hammer a animal way out there with the 280 AI Jarrett Rifle!
I liked that performance so much I went out and bought another two boxes of the 175 gr. PT's for whenever the day comes I run out of that ammo I made back in 2002....... I love shooting my super accurate guns, but I hate the thought of burning them up on practice shooting vs. killing a big game animal.
Sad thing is I robed the scope off that gun the next day to put on the Remington 700 R5 223 I got for Lori. One day I'll replace it with a twister turret scope so I can hammer a animal way out there with the 280 AI Jarrett Rifle!
