The issue of the temperature sensitivity of CFE powder has been brought up several
times on this forum. I decided to run the following test. I loaded 10 rounds of AA
cases with 31.0gr. of CFE powder, Rem 7 1/2 primers, and 123gr. Nosler CCBT bullets.
I loaded 5 of these in a magazine and put them in my freezer for about 8 hours. I
then packed the magazine between two packs of frozen blue ice then wrapped them in
two towels before heading to the range. Once at the range I placed the other 5 rounds in the front seat of my car for about an hour with windows rolled up in the sun. Outside temp was upper 70's. The gun used is a PF Grendel upper with a 22" Bartlein barrel.
When everything was set up I shot the 'cold' rounds first. I would guess that they were well below 32 degrees as I noticed that there was frost forming on the bullets as I loaded the magazine in the rifle. All 5 rounds were fired within less than one minute. I then shot the 'hot' rounds which I estimate to be at a temp of 85-90 degrees.
The velocity results using a Magnetospeed:
Cold Rounds
1-2442 fps
2-2510 fps
3-2490 fps
4-2480 fps
5-2485 fps
Min=2442 fps, Max=2510 fps
Avg=2481 fps
ES=68 fps
SD=24.7
Hot Rounds
1-2553 fps
2-2565 fps
3-2565 fps
4-2553 fps
5-2552 fps
Min=2552 fps, Max=2565 fps
Avg=2557 fps
ES=13 fps
SD=6.7
While the sample size is small, but with a difference of 76 fps average velocity between cold and hot rounds it appears that CFE is a temperature sensitive powder.
I hope this is useful info for everyone.
pds
times on this forum. I decided to run the following test. I loaded 10 rounds of AA
cases with 31.0gr. of CFE powder, Rem 7 1/2 primers, and 123gr. Nosler CCBT bullets.
I loaded 5 of these in a magazine and put them in my freezer for about 8 hours. I
then packed the magazine between two packs of frozen blue ice then wrapped them in
two towels before heading to the range. Once at the range I placed the other 5 rounds in the front seat of my car for about an hour with windows rolled up in the sun. Outside temp was upper 70's. The gun used is a PF Grendel upper with a 22" Bartlein barrel.
When everything was set up I shot the 'cold' rounds first. I would guess that they were well below 32 degrees as I noticed that there was frost forming on the bullets as I loaded the magazine in the rifle. All 5 rounds were fired within less than one minute. I then shot the 'hot' rounds which I estimate to be at a temp of 85-90 degrees.
The velocity results using a Magnetospeed:
Cold Rounds
1-2442 fps
2-2510 fps
3-2490 fps
4-2480 fps
5-2485 fps
Min=2442 fps, Max=2510 fps
Avg=2481 fps
ES=68 fps
SD=24.7
Hot Rounds
1-2553 fps
2-2565 fps
3-2565 fps
4-2553 fps
5-2552 fps
Min=2552 fps, Max=2565 fps
Avg=2557 fps
ES=13 fps
SD=6.7
While the sample size is small, but with a difference of 76 fps average velocity between cold and hot rounds it appears that CFE is a temperature sensitive powder.
I hope this is useful info for everyone.
pds
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