CaptainMal
Silver $$ Contributor
Test today was to deal with velocity and NOT accuracy. Was also looking for pressure signs and to do a brief comparison with Varget.
The rifle is a 30" bbl built with a Savage action by Eric Bostrom. It has 2,100 rods down the Krieger tube and I have another Krieger to replace it with. Darn thing won the Manatee shoot last Saturday so I'm holding off. This test was also to see where I might start if I wanted to use 4166 in the other barrel.
Tested using my fireform 107 SMK bullets. For target I use Berger 105 Hybrids. I also did a direct comparison using my normal Varget load with the same amount of 4166 and the Bergers'.
Hopefully you can read the results with the picture. I put a marker sight dots on a line across both targets. The grain weight of 4166 is right below the dots. The velocity of two shots for each weight is near the bullet impacts.
Started with 31.0 gr. - far left...endd with 33.0 gr. - far right. Velocities ranged from 2849 - 2996 with the 107's.
Testing with the Berger 105's show up on the right two boxes. Left box is 32.6 gr of 4166. Right box is 32.6 gr. of Varget with the 105 Hybrids. That's my normal load. Velocities are identical for the 4166 - 3009 fps. The varget did 3003 and 2992 fps***. Normally I am right around 3000 fps for my Berger/Varget load of 32.6 gr.
***This is wrong as written in the picture.
My conclusions are that the ES is as good as my Varget experience. That means real good. Also think the velocity is near identical for equal weights of both powders. 4166 showed a bit more volume fill in the case. That may be due to the grain structure which is much like IMR 4064 to my eyes.

I am NOT an experienced benchrest shooter. I am just a "Joe" named Larry. Sometimes I even hit the target and win local club shoots. One thing I am is a shooter. I'm just not a competitive benchrest shooter and precision reloader. These were my results today. I expect to try 4166 again after I replace the old barrel on my rifle.
Oh ... Thought it was dirty like Varget. Butches Bore Shine was a mess after 5 soaked patches and then some brushing. After drying I used Bore Tech C4 to finally get clean patches. My take on that is 4166 is also a carbon fouler like Varget. That I do not like as this particular barrel came near to ruin because of Varget carbon fouling.
There's supposed to be some kind of CFE in this powder. I looked for copper fouling but saw none. This barrel has never copper fouled so that topic is probably not relevant.
Remember - ignore group size. I did not even attach my tuner brake for this test. It was for velocity and pressure signs (none) only. 100 yards and high winds from right to left would have made short-range groups tough.
Hope I helped.
The rifle is a 30" bbl built with a Savage action by Eric Bostrom. It has 2,100 rods down the Krieger tube and I have another Krieger to replace it with. Darn thing won the Manatee shoot last Saturday so I'm holding off. This test was also to see where I might start if I wanted to use 4166 in the other barrel.
Tested using my fireform 107 SMK bullets. For target I use Berger 105 Hybrids. I also did a direct comparison using my normal Varget load with the same amount of 4166 and the Bergers'.
Hopefully you can read the results with the picture. I put a marker sight dots on a line across both targets. The grain weight of 4166 is right below the dots. The velocity of two shots for each weight is near the bullet impacts.
Started with 31.0 gr. - far left...endd with 33.0 gr. - far right. Velocities ranged from 2849 - 2996 with the 107's.
Testing with the Berger 105's show up on the right two boxes. Left box is 32.6 gr of 4166. Right box is 32.6 gr. of Varget with the 105 Hybrids. That's my normal load. Velocities are identical for the 4166 - 3009 fps. The varget did 3003 and 2992 fps***. Normally I am right around 3000 fps for my Berger/Varget load of 32.6 gr.
***This is wrong as written in the picture.
My conclusions are that the ES is as good as my Varget experience. That means real good. Also think the velocity is near identical for equal weights of both powders. 4166 showed a bit more volume fill in the case. That may be due to the grain structure which is much like IMR 4064 to my eyes.

I am NOT an experienced benchrest shooter. I am just a "Joe" named Larry. Sometimes I even hit the target and win local club shoots. One thing I am is a shooter. I'm just not a competitive benchrest shooter and precision reloader. These were my results today. I expect to try 4166 again after I replace the old barrel on my rifle.
Oh ... Thought it was dirty like Varget. Butches Bore Shine was a mess after 5 soaked patches and then some brushing. After drying I used Bore Tech C4 to finally get clean patches. My take on that is 4166 is also a carbon fouler like Varget. That I do not like as this particular barrel came near to ruin because of Varget carbon fouling.
There's supposed to be some kind of CFE in this powder. I looked for copper fouling but saw none. This barrel has never copper fouled so that topic is probably not relevant.
Remember - ignore group size. I did not even attach my tuner brake for this test. It was for velocity and pressure signs (none) only. 100 yards and high winds from right to left would have made short-range groups tough.
Hope I helped.