I don't reload any .308 so I am using Southwest Ammunition (SWA) 168 SMK, Fed GMMK 168 SMK, and Rem Prem Match 168 SMK box ammo. My Savage 10 FCP-K has shot all three well in the past and I have shot a lot of the Southwest Ammunition loads with excellent results at this distance. Today I decided to shoot 5 rounds of each at the same target, same conditions, using the SWA dial in DOPE at 545 yds, calm conditions, perfect for this comparison test. Here is the overall target result, starting with the SWA on the left, Fed in the middle, and Remington on the right. All shot in about 20 minutes, very calm wind conditions, fortunately for me.
Here is a close up of the SWA target
I have shot sub 4" groups with this ammo but did not do so today.
The Fed GMMK target
and the Remington
This is a heavy 24" barrel rifle, so my first thought is that the velocities are different for the three choices. If that is correct, then the SWA is the fastest, the Federal just slightly slower, and the Remington is the slowest. I don't have a chronometer to check the muzzle velocities. But the group size appears to tighten up slightly as the velocity decreases as well. I was pleasantly surprised at the sub 2" 4 shot group with the Remington. Even with the one round just barely off the paper, that Remington group was the smallest. This is consistent with what I have seen before but I haven't shot much of the Remington lately due to availability, plus the Southwest Ammunition cartridges have been doing very well for me in this rifle. Today's group is slightly larger than average for this ammo.
What is interesting to me is that the Remington group is tiny for 4 rounds out of the 5and it had the smallest group even including the one round off the paper.
So, am I correct in thinking that this comparison is similar to what one would see if reloading and changing the powder charge slightly? If these were handloads, would I just home in on the load similar to the Remington and then vary overall length to fine tune?
I know there is a lot more to cartridge manufacture than powder charge, and I haven't measured any other differences between these three cartridges. To me, the SWA and Federal are pretty close, with the Remington being a little better combination for this particular rifle.
I welcome any input or analysis. I realize this is a very small sample, but, for a newbie like me, I thought the results were interesting. I haven't taken the time to shoot comparison groups at this distance before. All three shoot very well at 100 yds, with a slight change in zero. I couldn't hardly tell the difference in accuracy at 100 yds.
Joe
Here is a close up of the SWA target
I have shot sub 4" groups with this ammo but did not do so today.
The Fed GMMK target
and the Remington
This is a heavy 24" barrel rifle, so my first thought is that the velocities are different for the three choices. If that is correct, then the SWA is the fastest, the Federal just slightly slower, and the Remington is the slowest. I don't have a chronometer to check the muzzle velocities. But the group size appears to tighten up slightly as the velocity decreases as well. I was pleasantly surprised at the sub 2" 4 shot group with the Remington. Even with the one round just barely off the paper, that Remington group was the smallest. This is consistent with what I have seen before but I haven't shot much of the Remington lately due to availability, plus the Southwest Ammunition cartridges have been doing very well for me in this rifle. Today's group is slightly larger than average for this ammo.
What is interesting to me is that the Remington group is tiny for 4 rounds out of the 5and it had the smallest group even including the one round off the paper.
So, am I correct in thinking that this comparison is similar to what one would see if reloading and changing the powder charge slightly? If these were handloads, would I just home in on the load similar to the Remington and then vary overall length to fine tune?
I know there is a lot more to cartridge manufacture than powder charge, and I haven't measured any other differences between these three cartridges. To me, the SWA and Federal are pretty close, with the Remington being a little better combination for this particular rifle.
I welcome any input or analysis. I realize this is a very small sample, but, for a newbie like me, I thought the results were interesting. I haven't taken the time to shoot comparison groups at this distance before. All three shoot very well at 100 yds, with a slight change in zero. I couldn't hardly tell the difference in accuracy at 100 yds.
Joe
