Eurodriver
09-30-16, 11:55
One of the most frequent posts regarding POI shift is how different loads will affect POI. Many frequently state things like "62gr M855 and 64gr Gold Dot will impact to the same POI because the weight is similar." with zero evidence. Most statements are made by people who buy a lot, but shoot little or they are by people who use "good enough" zeroes and red dot sighted SBRs at 50 yards and less.
Today I conducted an experiment to seek what changes would occur in precision and accuracy. I chose 200 yards (not confirmed with a laser range finder) as I felt that was far enough to give a significant difference in POI and group size without groups overlapping. In my time on M4C I have rarely seen anyone shoot fighting carbines further than 100 (and most often 50) yards anyway.
All shooting was conducted from a concrete bench rest.
http://i1328.photobucket.com/albums/w521/6234987u02/IMG_1524_zpssktqfaad.jpg
The wind probe
http://i1328.photobucket.com/albums/w521/6234987u02/IMG_1521_zpsqehvklta.jpg
The test vehicle for this evaluation was a 20" Krieger Barreled SPR built by me. It has a 1:7.7" twist, and a 15" Geissele free float handguard. The muzzle device is torqued to 20ft lbs and is an AAC 51T. The suppressor is an AAC 762SD. The optic is a Nightforce SHV F1 4-14x
http://i1328.photobucket.com/albums/w521/6234987u02/DSC02699_zpseblgsaax.jpg
This rifle will produce sub MOA groups at 600 yards with hand loads - unless you are a hater and think I make this shit up to look cool on the internet. (https://www.m4carbine.net/member.php?55732-Noodles)
The ammunition fired was Wolf Gold, M855 (Real M855, not XM855), 64gr Gold Dot in .223, and a handload recipe given to me by member Onyx. It is over max load so I don't want to post it because people are idiots, but it is using LC brass, XBR powder, a CCI SRM primer, and a 77gr TMK.
The point of this test was not to see the how precise the rounds would be given an n=30 sample size, but just a general idea of POI differences and group sizes with a group size of 5 rounds. The main (only) reason for the small group size was to avoid overlapping of impacts. I wanted all of the impacts on the same sheet of paper for the best possible visual comparison.
The aiming point was the top of the black star. My rifle is zeroed with TMKs at 200 yards and the zero stop would not let me go below that. All of the other ammo shot high.
http://i1328.photobucket.com/albums/w521/6234987u02/Target_zpsszp4jkrv.jpg
Results? No idea, you tell me. I was surprised that the Wolf Gold, M855, and GDHPs all shot to a "generally" similar POI. I was also surprised at how well the Wolf Gold and especially the Gold Dots shot. That is a fantastic group size and would make a great hunting load (Although I use 75gr out of this rifle but with similar size groups at 300 yards)
5 shot Average velocities were as follows:
Wolf Gold - 3256
M855 - 3091
64gr Gold Dot - 2904
TMK Load - 2752
I will probably conduct this test again at a further distance. Maybe 400 yards. There was not enough distance to give a significant conclusion for my rifle. I may also conduct it again with an SBR of some sort to see if that has any bearing on the results. The key is that one should test all variables out of their particular rifle at distances they plan to shoot. You cannot substitute what your rifle will do for what some loser with too much time on his hands posts on M4C on his Friday off does with his rifle. Additionally, I shot all of the factory loads at steel out to 600 yards and the variance in POI and group size was ridiculous so there is something going on the further out you go. I inputted the velocity and projectile into my ballistics calc and adjusted my scope to meet that (per the "zero" from the 200 yard group fired previously) and could not hit shit with the M855 or the Wolf Gold. I would estimate group sizes were in excess of 24". I gave up even trying to find the Gold Dot impacts. I think they were too low.
If anyone has a problem with my testing methods, you can go do that shit yourself on your time and your dime. Additionally, any molon references are entirely coincidence ;)
Today I conducted an experiment to seek what changes would occur in precision and accuracy. I chose 200 yards (not confirmed with a laser range finder) as I felt that was far enough to give a significant difference in POI and group size without groups overlapping. In my time on M4C I have rarely seen anyone shoot fighting carbines further than 100 (and most often 50) yards anyway.
All shooting was conducted from a concrete bench rest.
http://i1328.photobucket.com/albums/w521/6234987u02/IMG_1524_zpssktqfaad.jpg
The wind probe
http://i1328.photobucket.com/albums/w521/6234987u02/IMG_1521_zpsqehvklta.jpg
The test vehicle for this evaluation was a 20" Krieger Barreled SPR built by me. It has a 1:7.7" twist, and a 15" Geissele free float handguard. The muzzle device is torqued to 20ft lbs and is an AAC 51T. The suppressor is an AAC 762SD. The optic is a Nightforce SHV F1 4-14x
http://i1328.photobucket.com/albums/w521/6234987u02/DSC02699_zpseblgsaax.jpg
This rifle will produce sub MOA groups at 600 yards with hand loads - unless you are a hater and think I make this shit up to look cool on the internet. (https://www.m4carbine.net/member.php?55732-Noodles)
The ammunition fired was Wolf Gold, M855 (Real M855, not XM855), 64gr Gold Dot in .223, and a handload recipe given to me by member Onyx. It is over max load so I don't want to post it because people are idiots, but it is using LC brass, XBR powder, a CCI SRM primer, and a 77gr TMK.
The point of this test was not to see the how precise the rounds would be given an n=30 sample size, but just a general idea of POI differences and group sizes with a group size of 5 rounds. The main (only) reason for the small group size was to avoid overlapping of impacts. I wanted all of the impacts on the same sheet of paper for the best possible visual comparison.
The aiming point was the top of the black star. My rifle is zeroed with TMKs at 200 yards and the zero stop would not let me go below that. All of the other ammo shot high.
http://i1328.photobucket.com/albums/w521/6234987u02/Target_zpsszp4jkrv.jpg
Results? No idea, you tell me. I was surprised that the Wolf Gold, M855, and GDHPs all shot to a "generally" similar POI. I was also surprised at how well the Wolf Gold and especially the Gold Dots shot. That is a fantastic group size and would make a great hunting load (Although I use 75gr out of this rifle but with similar size groups at 300 yards)
5 shot Average velocities were as follows:
Wolf Gold - 3256
M855 - 3091
64gr Gold Dot - 2904
TMK Load - 2752
I will probably conduct this test again at a further distance. Maybe 400 yards. There was not enough distance to give a significant conclusion for my rifle. I may also conduct it again with an SBR of some sort to see if that has any bearing on the results. The key is that one should test all variables out of their particular rifle at distances they plan to shoot. You cannot substitute what your rifle will do for what some loser with too much time on his hands posts on M4C on his Friday off does with his rifle. Additionally, I shot all of the factory loads at steel out to 600 yards and the variance in POI and group size was ridiculous so there is something going on the further out you go. I inputted the velocity and projectile into my ballistics calc and adjusted my scope to meet that (per the "zero" from the 200 yard group fired previously) and could not hit shit with the M855 or the Wolf Gold. I would estimate group sizes were in excess of 24". I gave up even trying to find the Gold Dot impacts. I think they were too low.
If anyone has a problem with my testing methods, you can go do that shit yourself on your time and your dime. Additionally, any molon references are entirely coincidence ;)