reason to verify zero plus night shooting is fun

[cemoulton]

Last night i switch out receivers from a bcm to a MUR-1A so i needed to re-zero. I zero at 35 yards and then verify at 50, 100, 200 and 300 yards this time i choose to do so at night. All shots were fired from a kneeling position. No more than 3 seconds per shot, i try for one shot per second but firing at night at 200 and 300 i have to admit to taking 2-3 seconds on a few shoots (ok maybe 4 lol).

Point of aim is dead center of torso / X ring.

Ammunition used is mixed brass, CCI Small Riffle primers, 77gn cannelured HPBT over 23.5 grains of TAC. Should be around 2600fps, but i did not have a crono on hand.

The rifle is a ground up build. Before switching uppers this rifle held 3/4" groups at 100 yards from a prone firing position. i had to use much more torque than i like (74 fp) to clock the barrel nut, but i have yet to shoot for true potential groups so i don't know how much this will effect overall accuracy.

Upper - Vltor MUR-1A, Vltor KM12, DD BCG, Rainer arms 16" select, OSS banner muzzle device, Troy rear buis, Vltor front buis, XS XTI set, Vltor mod 4 CH, leupold M8 6x42 in an ADM mount, shaved taper pinned F-marked fsp/gas block.

Lower- Gararms Z-15 (i just wanted a locally marked lower), DD LPK, Moe k2, Vltor A5 with A5H2, E-mod.

http://i44.photobucket.com/albums/f16/cemoulton/IMG_20150218_211525_zpsp8nqoduz.jpg (http://s44.photobucket.com/user/cemoulton/media/IMG_20150218_211525_zpsp8nqoduz.jpg.html)

light used was a Surefire HellFighter (love these lights)

http://i44.photobucket.com/albums/f16/cemoulton/IMG_20150218_211352_zpso2pnmveb.jpg (http://s44.photobucket.com/user/cemoulton/media/IMG_20150218_211352_zpso2pnmveb.jpg.html)

I fired 11 shots at 50 yards and You can see right away at that my quickie zero has me shooting left about 1/2 inch. Largest spreed is 2 1/2", group center is 1 3/4 high.

http://i44.photobucket.com/albums/f16/cemoulton/IMG_20150218_205809_zpsw4rtvm2o.jpg (http://s44.photobucket.com/user/cemoulton/media/IMG_20150218_205809_zpsw4rtvm2o.jpg.html)

Five shots at 100 yards, largest spread 2 1/8", group center is 4 3/4" high, 1 5/8" left.

http://i44.photobucket.com/albums/f16/cemoulton/IMG_20150218_210212_zpsuyl5slcm.jpg (http://s44.photobucket.com/user/cemoulton/media/IMG_20150218_210212_zpsuyl5slcm.jpg.html)

Five shots at 200 yards, largest spread 5 1/4", group center is 7" high, 1 3/4" left. I dropped one shot pretty badly but it'll do.

http://i44.photobucket.com/albums/f16/cemoulton/IMG_20150218_210617_zpszho5wxod.jpg (http://s44.photobucket.com/user/cemoulton/media/IMG_20150218_210617_zpszho5wxod.jpg.html)

Five shots at 300 yards, largest spread 8", group center is 1" low, 4 3/4" left. And yes i dropped another shot quite badly.

http://i44.photobucket.com/albums/f16/cemoulton/IMG_20150218_210948_zps1ve80u4v.jpg (http://s44.photobucket.com/user/cemoulton/media/IMG_20150218_210948_zps1ve80u4v.jpg.html)

i fired 50 round prior to shooting these groups, 15 to do a quick zero and the rest to warm the barrel up. i'll shoot some cold bore shots on another day.

Things i learned...

Always verify zero.

Shooting from kneeling position sucks.

Shooting longer ranges at night is challenging, the target kinda floats around.

I need night vision.

Always verify zero.

[Onyx Z]

Were you holding dead center on the x on the target? I'm assuming so; I just think it's interesting to see the drops on different distances on paper.

[cemoulton]

Were you holding dead center on the x on the target? I'm assuming so; I just think it's interesting to see the drops on different distances on paper.

Yes, hold was dead center of torso. With only 6 magnification and shooting at night I can't say I was dead on the X, but that was the intention. The purpose of shooting these ranges is to make sure that what the ballistics calculator says will happen on paper translates to real hits on paper.

I set up all targets in advance and shot all targets from the same position in one firing string. In this case I fired 5 at 50, 5 at 100, 2 at 50, 5 at 200, 2 at 50, 5 at 300, 2 at 50. I then pulled targets.

[cemoulton]

I just wanted to add that this is pretty much what was expected. I use JBMs excellent free ballistics calculator. If you feed it the accurate data (this is critical) it is pretty much dead on. You should still shoot to verify, but I've never had it be off by enough to make a practical difference.

http://www.jbmballistics.com/

[strambo]

Nice shooting, looks like a perfect 300yd zero for elevation with minor windage correction (~1 MOA right?) needed. I don't buy the "dropped shot" comments...but in a good way. 5 into ~2.6 MOA at 200 and 300yds in low light from kneeling position is darn good shooting.

On the ballistics, I see a lot of soldiers zeroing M4s to an approximate 300m zero. With a tad less velocity (14.5 vs 16) and a tad longer zero range (m vs yds), the distance above POA at 100 and 200 would be a skosh higher. On the qual range, I observe a lot of high misses at 100m (smaller target) and at 175-200m. The targets illustrate why, technically still on target, but less accurate ammo, more shooter wobble (average soldier not nearly as good as OP) and perhaps a slightly high POA, the bullets commonly go over a shoulder of the E-type.

I zero to 50/200, hold dead center mass out to 250m and at shoulder line at 300m.

[cemoulton]

Nice shooting, looks like a perfect 300yd zero for elevation with minor windage correction (~1 MOA right?) needed. I don't buy the "dropped shot" comments...but in a good way. 5 into ~2.6 MOA at 200 and 300yds in low light from kneeling position is darn good shooting.

On the ballistics, I see a lot of soldiers zeroing M4s to an approximate 300m zero. With a tad less velocity (14.5 vs 16) and a tad longer zero range (m vs yds), the distance above POA at 100 and 200 would be a skosh higher. On the qual range, I observe a lot of high misses at 100m (smaller target) and at 175-200m. The targets illustrate why, technically still on target, but less accurate ammo, more shooter wobble (average soldier not nearly as good as OP) and perhaps a slightly high POA, the bullets commonly go over a shoulder of the E-type.

I zero to 50/200, hold dead center mass out to 250m and at shoulder line at 300m.


Thank you.

i don't claim to be a great or even good shot, but i do manufacture ammunition for a living, I have been loading off and on ever since i was old enough follow instruction, so i have a keen understanding of ballistics and much more importantly i get to shoot a lot more than most people, and i do mean a lot.

I had never really shot for groups at night, at least not at any range over 100 yards, and it was really very dark (with out the aid of a flash light you couldn't see your feet on the ground until i lit up that amazing SureFire lol). I had never even considered how difficult it could be.

My muzzle device of choice is not shrouded on the bottom and even from a kneeling position it kicks up a fair amount of lite dust. That dust is hardly noticeable in day light, but at full darkness the beam from the SF hellfighter lit it up like fog. the 200 yard target was a little difficult to see well, but the 300 yarder was basically just a floating white torso that kind of blinked. i plan on doing more night time shooting because the whole experience left me feeling very unprepared.

I choose a modified 300 yard zero mainly because when shooting steal from 50 to 350 i just hold center of mass and get consistent hits. The hardest part is avoiding the desire to hold over that is ingrained into me from 30 years of hunting with a standard 100 yard zero. It works for me but i do not claim to know what would work well for others.

I may or may not have dropped those two shots, but either way i am not happy with the groups and need to slow down, breath for half a second longer and be more sure of my hold.

Again thank you for your insight. i am as always eager for others earned knowledge.

[Vegas]

Very interesting thread, thanks for posting and some good shooting considering the variables. I have to say though, that Jeep is in need of some love :D

[cemoulton]

So just a little update. I re-zeroed and the the receiver swap seemed to have no effect on the rifles potential accuracy, it holds easy 3/4 inch, 100 yard groups when fired from a supported prone position. I then tried to duplicate the night shoot as close as possible but in the day light. Didn't bother taking pics because other than being centered the groups where about the same size, with the same average impact points. This tells me that my zero for this ammo with this rifle is where i want it. It also tells me I really need to practice shooting from the kneeling position because it feels awkward and i suck at it.


Very interesting thread, thanks for posting and some good shooting considering the variables. I have to say though, that Jeep is in need of some love :D

I've had my old CJ5 for 20 years. She has lived through 300,000 miles of rough loving in most states west of the divide and she gets more just about every sunday. I will admit that she isn't as pretty as she used to be, she has been on her sides multiple times, fully upside down once or twice, under water up to her windshield, berried in snow drifts, frozen to the ground, washed about 200 yards down the Rio Grand, even on fire ounce, she has cancer holes big enough to fit your hand through, but her insides are all in proper working order and well maintained. We don't let each other down.

Also I hold on.