36 yard zero

[LRRPF52]

I was trying to find a good target to represent this, but the one Molon posted really nails it best. I showed some very optimistic Points of Impact for both the 36yd and 50yd zeros using M855 from 14.5” barrel at 2920fps.

All of the top 6 projected impacts on the 36yd zero are from 75 to 225yds, with an unrealistic horizontal spread that is artificially kept tight for ease of placement. The impacts in the center box are either 50yd, 225, 250, 275, or 300yds.

All of the orange/red impact simulations are from 250-300yds. Black are all 50-200. Blue is 225yds.

 

[FUNCTIONAL]

That pic and your chart only reinforced my thought 36 is the better choice. Were talking less than 4" of spread out to 300yrds where the 50 has up to almost 8. The 36 is always within the margin of the head. If you ever are even going to use an AR in the civ world odds are it won't be more than 50yrds anyway but you aren't going to have ranges nicely labeled for you. Anything past 100 (for your example of a hostage and if im ballsyenough to take a shot like that with an AR) I'm aiming for the mouth and im covered no matter how shitty my range estimation is. You get anything past 200 wrong with a 50 and your odds of shooting the hostage go way up.

You trade a tighter spread of 100 to 200 for a tighter deveation overall. For me the less i have to guess at the better. Holding nose/mouth and you are golden regardless of range.

 

[pucker]

Are we really discussing which zero sucks less for emergency UKD hostage engagements using a carbine?

If you could hear the hostage yelling from 200+yds, they're likely saying "Whoa there tiger...let's just wait for someone with a rangefinder, proper rifle, and DOPE!"

 

[deersniper]

Maybe less hostage, more humans tend to hide and expose less tissue when shot at

 

[nn8734]

How exactly are you going to "hold at the belt buckle area . . . and belly button area" in any type of realistic scenario where the tango is shooting at you from behind hard cover or while in defilade position?

....

I used the those terms as reference points to describe the difference in terms of vertical spread between point of aim relative to a desired point of impact at center mass on a man-sized target at 200 yards or so using the 36 yard zero. It’s easier for me to think in terms of a tangible object(s) (belt buckle or belly, eg “aim at the belt at 200” vs thinking about it in terms of numerical values, e.g “aim 6” low at 200”. So, referring to your image, I’d aim at the waistline and hit the upper right quadrant of the tango’s chest. Again, not taking cone or motion based shot-making errors into account.

Additionally, the 36/300 is 50% flatter to 300 (vertical dispersion is only 6” vs the 50 yard zero with is 9.1”, based on the drop charts LRRPF52 provided above...Using a red dot, I’d go with the flatter trajectory to 300 as I feel that’s the max effective range of a typical fighting carbine using typical 5.56 loads.

@LRRPF52, what’s the source for the data (ie the dots representing hits as seen on Molon’s image). Do you have a link you can post to a published article or paper on the simulation or did you just place the dots yourself based on your own testing and results?

 

[FUNCTIONAL]

Are we really discussing which zero sucks less for emergency UKD hostage engagements using a carbine?

If you could hear the hostage yelling from 200+yds, they're likely saying "Whoa there tiger...let's just wait for someone with a rangefinder, proper rifle, and DOPE!"

I know i would be lol. Shit we aren't even talking wind either. Id have to hate the hostage quite a bit to take any shot beyond 50.

 

[pucker]

fact remains...36y zero is dogshit from 75 to 250.

It's trading less deviation at 300y, for more deviation inside 200y. That is counter-intuitive IMO.

Who needs to hold dead on at 300y?

100y zero is TIGHT out to 150y, then...

200y = 0.5mil hold
250y = 0.7mil hold
300 = 1.2mil hold

Those holds = <1" deviation POA to POI.

Or if that's too much to remember...

With 100y zero...
0y - 200y = hold on
225y to 300y = hold 1.0mil
...your deviation is still less than it is for a 36y zero, and less than half as much in most cases.

 

[FUNCTIONAL]

You aren't wrong actually....idk why i never looked at it harder.

 

[Mike_in_FL]

Everything I needed to know started at 6:55 into the video. I took a class so the up and close and personal stuff was already known to me. but this has been 3 pages of interesting banter to say the least.

 

[Molon]

I used the those terms as reference points to describe the difference in terms of vertical spread between point of aim relative to a desired point of impact at center mass on a man-sized target

There's that faulty logic again.

So, referring to your image, I’d aim at the waistline

The waistline isn't even visible on that target: so more of that faulty logic.

Using a red dot, I’d go with the flatter trajectory to 300 as I feel that’s the max effective range of a typical fighting carbine using typical 5.56 loads.

Tell us of all the self-defense/civil unrest shootings that you've been involved in that occurred in the continental US at a distance of 300 yards using "a typical fighting carbine using typical 5.56 loads"


...

 

[Molon]

Pop quiz.


What is the most commonly missed target on the US Army 300 meter pop-up range, when using a 300 meter zero?

a. 50 meter target
b. 150 meter target
c. 300 meter target
d. None of the above



....

 

[nn8734]

There's that faulty logic again.









The waistline isn't even visible on that target: so more of that faulty logic.







Tell us of all the self-defense/civil unrest shootings that you've been involved in that occurred in the continental US at a distance of 300 yards using "a typical fighting carbine using typical 5.56 loads"


...

Glad you like the 50 yard zero. Use it if it works for you

 

[LRRPF52]

That pic and your chart only reinforced my thought 36 is the better choice. Were talking less than 4" of spread out to 300yrds where the 50 has up to almost 8. The 36 is always within the margin of the head. If you ever are even going to use an AR in the civ world odds are it won't be more than 50yrds anyway but you aren't going to have ranges nicely labeled for you. Anything past 100 (for your example of a hostage and if im ballsyenough to take a shot like that with an AR) I'm aiming for the mouth and im covered no matter how shitty my range estimation is. You get anything past 200 wrong with a 50 and your odds of shooting the hostage go way up.

You trade a tighter spread of 100 to 200 for a tighter deveation overall. For me the less i have to guess at the better. Holding nose/mouth and you are golden regardless of range.

Given that the most common distances are more likely misses than actual glancing impacts on the top of the cranium, the 36yd zero graphic representation should invalidate it for you, not reinforce it.

The overall vertical spread numbers are not what are important, but the vertical spread from zero within 200yds. 200yds is a stretch for a head shot or partial torso exposure as it is, even from solid support. If you look out your window at how far even 100yds is, then imagine a partially-exposed target, it’s really a precision shot that has to be made on-demand within a very small window of opportunity, while under stress. POI will rarely = POA, and people tend to miss high and with horizontal deviation due to incorrect trigger input. So those simulated impacts on the top of the skull would really be misses most of the time.

The 50yd zero gives you a much greater chance of impacting a small TGT. The 300yd trajectory is almost meaningless for a RDS-equipped carbine on partially-exposed targets. For exposed, static silhouettes, you will still get a hit with the 50yd zero.

 

[LRRPF52]

I used the those terms as reference points to describe the difference in terms of vertical spread between point of aim relative to a desired point of impact at center mass on a man-sized target at 200 yards or so using the 36 yard zero. It’s easier for me to think in terms of a tangible object(s) (belt buckle or belly, eg “aim at the belt at 200” vs thinking about it in terms of numerical values, e.g “aim 6” low at 200”. So, referring to your image, I’d aim at the waistline and hit the upper right quadrant of the tango’s chest. Again, not taking cone or motion based shot-making errors into account.

Additionally, the 36/300 is 50% flatter to 300 (vertical dispersion is only 6” vs the 50 yard zero with is 9.1”, based on the drop charts LRRPF52 provided above...Using a red dot, I’d go with the flatter trajectory to 300 as I feel that’s the max effective range of a typical fighting carbine using typical 5.56 loads.

@LRRPF52, what’s the source for the data (ie the dots representing hits as seen on Molon’s image). Do you have a link you can post to a published article or paper on the simulation or did you just place the dots yourself based on your own testing and results?

I took the 14.5” 5.56 with M855 at 2920fps and 2.5” optic height ballistics and distributed it onto the partial exposed TGT, assuming a 9” vertical head dimension for that particular target.

You don’t need to take my word for it though, because the basic math is free.

Better yet, anyone can input their own carbine data with their specific optic height over bore, mv, bullet with G1 BC, generate a chart, and superimpose that chart onto a partially-exposed target.

The short story is that you will see a very tight vertical spread between close range and 225yds, where your points of impact will be closest to the sight plane compared to any of these other zeros. The 25m and 36yd zeros are 2 of the worst zeros when you superimpose their trajectories on a small target. Put aside who is recommending the zero for a moment, and do the math using logic.

You can clearly see that the 36yd zero is a recipe for missing, whereas the 50yd zero gives you the best chances of impact on small TGTs within common fighting distances.

 

[nn8734]

I took the 14.5” 5.56 with M855 at 2920fps and 2.5” optic height ballistics and distributed it onto the partial exposed TGT, assuming a 9” vertical head dimension for that particular target.

You don’t need to take my word for it though, because the basic math is free.

Better yet, anyone can input their own carbine data with their specific optic height over bore, mv, bullet with G1 BC, generate a chart, and superimpose that chart onto a partially-exposed target.

The short story is that you will see a very tight vertical spread between close range and 225yds, where your points of impact will be closest to the sight plane compared to any of these other zeros. The 25m and 36yd zeros are 2 of the worst zeros when you superimpose their trajectories on a small target. Put aside who is recommending the zero for a moment, and do the math using logic.

You can clearly see that the 36yd zero is a recipe for missing, whereas the 50yd zero gives you the best chances of impact on small TGTs within common fighting distances.

Gotcha. Thanks for the civil reply. Think I will take my SBR and 14.5 tomorrow with a bunch of m193 to the desert and try the two different zeros on partially exposed targets. Would be interested to see for myself, the difference in hits made at 100, 200, 300 for each zero. Have a target stand set up that can be modified to look like that image for the scenario. I’ll take pics and share my results if I can make it out there.

 

[Mike_in_FL]

a. 50 meter target
....

I seem to remember my M16A1 hitting it with a combination of dirt, fragments, ricochet whatever at least once.

 

[LRRPF52]

Everything I needed to know started at 6:55 into the video. I took a class so the up and close and personal stuff was already known to me. but this has been 3 pages of interesting banter to say the least.

He even says it himself: “The 50yd zero actually has a tighter spread until we get down to 300."

He does not account for shooter error, positional error, or stress and how that really increases the spread.

I remember doing a KD range in 2002, which was really unusual for us with M4s. We were in the prone, and finished shooting groups at 300m, Aimpoint Comp Ms, flat range, nice soft grass, right near Pope AFB on Bragg. I was the only one in my Platoon with Sniper training, extensive shooting background, used a rear hold on my stock with magazine as monopod, while everyone else was doing the typical Army prone unsupported elbows in the ground with support hand under KAC rail system.

I had the best groups of all throughout the day, and my 300m “group" was atrocious. It had to have been 15-20”. I can’t remember now if it was 10 or 30 rounds, but it was a lot. It was at least consistent, whereas a lot of other groups were all over the place, lots of rounds outside of the bull, erratic patterns with low impacts, total misses, hard-to-diagnose, etc.

Non-floated M4 with M855 and RDS under no real stress, prone, really good support, from a trained shooter, and still had well over a 4 MOA pattern.

Now distribute these points of impact with even a 2 MOA pattern (not realistic with RDS, should be more like 5-8 MOA with stress) and those trajectories with the 36yd zero will be misses most of the time between 75-200yds even.

This is all re-learning what the world’s best combat shooters already knew decades ago, then adopting the wrong zero even after the evidence is right there in front of them.

 

[LRRPF52]

Pop quiz.


What is the most commonly missed target on the US Army 300 meter pop-up range, when using a 300 meter zero?

a. 50 meter target
b. 150 meter target
c. 300 meter target
d. None of the above....

I vaguely remember some statistics on this in the older FMs, but I can offer anecdotes from being in 7 different units where we qualified a lot more often than most, as well as being an NCO and running ranges.

300m was the least-hit target. Book answer also shows the lowest Probability of Hit on the 300m. A lot of guys would “save their rounds” for other targets. FM 23-9 has some PH tables in it. I remember the older FM 23-9 for the M16A1 that was still around in some of the units, where there were various recommended Points of Aim for each sil at different ranges, using the tapered 5 position front sight post on the M16A1 to determine range and holds. We had M16A1s in my first unit, with the accompanying FMs. They consolidated the M16A2 into 23-9, then later the M4.

M16A1 for ranging and holds
M16A2 with 8/3 elevation drum
M4 with irons and 6/3 drum
M4 with Aimpoint Comp M
Skipped to LPVO long ago, and now just get the best LPVO I can.

RDS is good for HD blasters, but I haven’t bought a RDS in a long time. LPVO solves a lot of the problems identified in this thread, but the 50yd zero still makes a lot of sense with them for the same reasons.

 

[TACC]

That pic and your chart only reinforced my thought 36 is the better choice. Were talking less than 4" of spread out to 300yrds where the 50 has up to almost 8. The 36 is always within the margin of the head. If you ever are even going to use an AR in the civ world odds are it won't be more than 50yrds anyway but you aren't going to have ranges nicely labeled for you. Anything past 100 (for your example of a hostage and if im ballsyenough to take a shot like that with an AR) I'm aiming for the mouth and im covered no matter how shitty my range estimation is. You get anything past 200 wrong with a 50 and your odds of shooting the hostage go way up.

You trade a tighter spread of 100 to 200 for a tighter deveation overall. For me the less i have to guess at the better. Holding nose/mouth and you are golden regardless of range.

I agree. My general rule was , if target us facing me, hold at chin. Shots covered everything needed with the 36 yard zero. I don't worry about hitting the "A" box on an ipsc target during this type of engagement.

 

[LRRPF52]

Are we really discussing which zero sucks less for emergency UKD hostage engagements using a carbine?

If you could hear the hostage yelling from 200+yds, they're likely saying "Whoa there tiger...let's just wait for someone with a rangefinder, proper rifle, and DOPE!"

No, we’re not talking about hostages. I showed the IPSC with the hostage taker plate only as an example of the size of target more likely to be seen peeking around a corner, with the IPSC sil representing cover, not a person. Molon had a much better target for that, which he posted.

 

[Mike_in_FL]

He even says it himself: “The 50yd zero actually has a tighter spread until we get down to 300."

I took what he said about the 36 yard zero applied to himself. Raiding buildings or ships, where are you going to get a shot over 100M? Obviously Afghanistan is a different story but then Mk18s and M4s don't seem like the best idea to me.

I think the misses at 300M were even after being taught, you think you need some holdover and I can't recall a lot of 300M practice but it's almost 40 years for me. I know we shot something like a 20 shot group on a mini silhouette paper at 25M before going to pop-up qualification.

The 50 to 250 spread is excellent with a 50 zero. Even my old self can remember aim at face at 300 and shoot off hat at 400. I guess we'll all have spotters and LRF in the coming debacle where 300 yards shots are normal.

All my 16" have RDS and possibly magnifier or LPVO. Even irons get 50 zero. Anecdotal as hell but whether using 55, 62, or 77, POI is pretty close for all with me shooting from a bench. Anecdotal as well but finally got to shoot at new range prone supported by gym bag and hit like 19 of 20 at 200 smallish steel using IMI 77s and 3x magnifier and T2.

With my age and eyesight, realistically I don't think I can identify a target over 100 yards without magnification. So if they're not shooting at me...

I couldn't identify targets with 3x much beyond 200-ish yards. I don't see how someone could use an RDS and no magnifier to shoot at bits and pieces of people poking out of cover with any consistency.

Another qualification story. I'm in a maintenance company in the good old FRG. For whatever reason we're shooting some type of bullseye targets I'd never seen in the Army. And they were giant like they borrowed them from the USMC, lol.

You didn't have to hit the black to qualify I think, just within the first or second ring out from the bull which was a joke. The bull could have been 12 - 24" in diameter? They started us at 300M in a two man fighting hole with sandbags. I just shot a 6 o'clock hold, 20 rounds slow fire. Nice day, little or no wind. Moved up to 200M and shot 20 more, prone using my carry sling. At 100M the same and the target was just monstrous. This is with M16A1 and never saw my target that day. I can't even remember if this was Graf or Hohenfels or? I was in Kitzingen then.

Get back to barracks and staff NCO asks how I think I did. I say, I think I shot a possible. He says, what's that? I say 60 of 60. He says you did, how did you know? I said the target was the size of a barn door, c'mon. I used to shoot 4 position rimfire as a teenager.

Viewing the world as I do now, I just can't see any long engagements within suburbs and cities unless we're talking snipers. Interesting topic but I'll stick to what works for me.

 

[pucker]

50y zero has larger deviation at 100y... than a 100y zero has at 175y.

Regarding sights...

LPVO means you can hold accurately... so you shouldn’t ever need to hold dead on, and hope... especially at 200+

Non-magnified sight means you likely can’t see accurately past 150y... the range where “muh 50y zero has less spread”.

I know these are just opinions, but the 50y zero, to me, is just a less bad version of the 36y.

 

[Carlos0311B4]

Pop quiz.


What is the most commonly missed target on the US Army 300 meter pop-up range, when using a 300 meter zero?

a. 50 meter target
b. 150 meter target
c. 300 meter target
d. None of the above



....

C: some dont even shoot at it so they can use the extra 4 rounds incase they miss something closer. If they hit all but the 300’s they still end up with a 36/40 Expert rating. Old qual...

 

[Mike_in_FL]

C: some dont even shoot at it so they can use the extra 4 rounds incase they miss something closer. If they hit all but the 300’s they still end up with a 36/40 Expert rating. Old qual...

I don't know about that. I was told targets were randomly generated and you shot pairs. You had Pvt. Snuffy handing you ammo and scoring. If a target didn't come up, you shot alibis at the end and they were random distance. I learned that when you follow procedure and have a live round stovepipe you can smash it to hell with the FA.

 

[Carlos0311B4]

I don't know about that. I was told targets were randomly generated and you shot pairs. You had Pvt. Snuffy handing you ammo and scoring. If a target didn't come up, you shot alibis at the end and they were random distance. I learned that when you follow procedure and have a live round stovepipe you can smash it to hell with the FA.

You were told wrong. One shot per target exposure. There are no alibis allowed. If they do alibies on that range it’s not to standard. The targets are computer controlled and scored. The targets come up in order. 50L is always first it the range has 50L and 50R. If it only has one 50 then that’s obviously first.

 

[Carlos0311B4]

The new qual is:
50meters standing, to prone unsupported for 9 shots, reload
10 shots prone supported, reload
10 shots kneeling supported reload
10 shots standing supported
For a total of 40 shots.

36yard zero = 36yard zero,
25meter zero = 25m zero
Etc, etc.... in my book.

don’t get me wrong if a 25m/36y/50y range is all I have available then then so be it.

the group in the pic was shot at 300m with standard M4 with 855 ammo (green tip) and an aimpoint compM2 with a 4moa dot. I “zeroed” at 25m as perfect as I could get it about a dimeish size group then shot at 300m on paper.
it’s still off to the right.... more to follow

edit: I might of just lied.. this group might have been shot with my FN Tac2 and green tip ammo, not an M4...old brain no worky.. everything else is correct.. I think

oh, side note. Don’t let the Internet lie to you on on M4 Accuracy
it’s more accurate than what most believe. 95% of the time the shooter sucks.

 

[LRRPF52]

50y zero has larger deviation at 100y... than a 100y zero has at 175y.

Regarding sights...

LPVO means you can hold accurately... so you shouldn’t ever need to hold dead on, and hope... especially at 200+

Non-magnified sight means you likely can’t see accurately past 150y... the range where “muh 50y zero has less spread”.

I know these are just opinions, but the 50y zero, to me, is just a less bad version of the 36y.

Agreed on LPVOs. They help acquire, PID, aim, and assess TGT effects better.
You might have overlooked this though:

14.5” 5.56 M855, 2920fps, 2.5” optic height
50 ZERO
75 .8” high
100 1.3” high
125 1.5” high
150 1.4” high
175 .9” high
200 ZERO
225 -1.2"
250 -2.9"
275 -5"
300 - 7.6"

At no time along the flight path does the bullet go higher than 1.5”, nor below 3” out to 250yds. You’re only 5” low at 275, and roughly 8” low at 300yds.

36yd zero is a slightly-less bad version of 25m zero. Both 36yd and 25m are worse than 50yd zero.

For partially-exposed TGTs, you don’t need to think about anything other than quickly putting the reticle center into your breathing/trigger control sequence within compressed time and breaking the shot.

 

[Carlos0311B4]

I thought I posted these before but maybe not. This was shot by a buddy. 250m zero shot at 250m then we did 3 shots each from 50 to 300 in 50m increments so he could actually see what the bullet is really doing. If you zoom in the bottom left of the white side you can see why range is what color. I wanted to do 5 shots each but ammo didn’t allow.

 

[Carlos0311B4]

His zero group before he shot this was much better than the one on this. It was about 4” or so all in the 10 ring

 

[Carlos0311B4]

Agreed on LPVOs. They help acquire, PID, aim, and assess TGT effects better.
You might have overlooked this though:

14.5” 5.56 M855, 2920fps, 2.5” optic height
50 ZERO
75 .8” high
100 1.3” high
125 1.5” high
150 1.4” high
175 .9” high
200 ZERO
225 -1.2"
250 -2.9"
275 -5"
300 - 7.6"

Ballistic program? Or shot on paper data?
This is not my experience. With an M4 a 50m zero is usually a few inches low at 200, and a 200m zero is usually 2-3” high at 50m when we put it on paper.
Edit: with an M4 and 855 green tip.

Granted for E type silhouettes it’s a hit, but if your not hitting where you’re aiming.... is it right? Even if it’s on target?

 

[LRRPF52]

Ballistic program? Or shot on paper data?
This is not my experience. With an M4 a 50m zero is usually a few inches low at 200, and a 200m zero is usually 2-3” high at 50m when we put it on paper. Granted for E type silhouettes it’s a hit, but if your not hitting where you’re aiming.... is it right? Even if it’s on target?

Program. When you change positions, your POI will often shift a little bit. Very few people are good enough to maintain an error range that is less than 1 MOA when changing positions. It’s the main reason I run dot drills in my DM courses, right after zeroing confirmation.

With dot drills, we do a shot, get up and do some PT, get quickly back down, shoot at another dot on each shooter’s TGT, get back up, more PT, get the blood flowing, get back down, repeat until all the dots are shot. That’s just at 100yds, but each little shift in position (even for shooters who don’t get up off the rifle) will have POI shift. You’ll notice it at the range when confirming zero, then move to another dot on your paper and now your POI is higher or lower. I notice it when the position I settle into feels a lot more solid, even with such a tiny change in elevation or depression on the muzzle. I settle my positions as best as possible to prevent it as much as I can, but it’s still a factor.

For all of these impacts at different ranges, assume the mechanical accuracy of the rifle/optic, ammo, position, and stress-induced error.

If you do a successive bound exercise like that with grouping from 50yd increments, you’ll often be shooting below the expected POI at one location, and above it from another, where your separate POIs will contradict what a program shows, not because the program is wrong, but primarily because of positional variations at each spot. It can still happen even with a rifle rest, because you still need to apply fundamentals to the rifle in the rest. With gas guns, the resolution is pretty fuzzy. Much less so with bolt guns, but still there.

 

[Carlos0311B4]

36yd zero is a slightly-less bad version of 25m zero. Both 36yd and 25m are worse than 50yd zero.

Agree and contrary to popular belief, again! Marines don’t zero at 36y it’s just a grouping exercise. You get your initial zero at 36 so that you are on paper at 200 then fine tune it, aka zero, then do the same at 300 and 500. The zeros are shot at actual zero range 200,300,500 yards. It’s never a, zero at 36y now go qual.
.....let me take that back... it wasn’t. I’ve been out for a minute.

 

[Carlos0311B4]

Edit post 126. Wrong rifle

 

[nn8734]

Edit post 126. Wrong rifle

You may have been the wrong rifle but the experiment was still valid (saw the pics showing the color hits - was a good visual)....I’ll be doing something similar tomorrow as this thread has gotten the better of my curiosity.

the target I plan on shooting at is below. The dark brown silhouette in the rear will actually be the target. The front silhouette will represent cover so any impacts there would be considered misses. See Molon’s post (#99) on page 2 for the target reference.

I plan on confirming zero at 36 yards, then placing the target at 100,200,250,300 and engage with 10 rounds of IMI XM193 from a partially covered position (prob behind a rock face) to see what the dispersion looks like. I’ll repeat the cof but with a 50 yard zero then compare. First run won’t be timed at least as of now, subsequent runs will likely be done under time. I’ll be aiming at the “body” portion of the target.

I’ll post pics of the results. My goal is to determine if a 50 yard zero does in fact lend itself to more hits at the various relevant distances vs. a 36 yard zero. If it does, I’m switching over to a 50y zero; if not, I’ll keep the 36 yard zero or run the test again at a later date to be sure of the results.

Rifle will be my DD 14.5” with an aimpoint m68, no magnifier (if time permits, I’ll run it again with the 3x magnifier).

Open to any other suggestions to improve the test.

 

[pucker]

Agreed on LPVOs. They help acquire, PID, aim, and assess TGT effects better.
You might have overlooked this though:

14.5” 5.56 M855, 2920fps, 2.5” optic height
50 ZERO
75 .8” high
100 1.3” high
125 1.5” high
150 1.4” high
175 .9” high
200 ZERO
225 -1.2"
250 -2.9"
275 -5"
300 - 7.6"

At no time along the flight path does the bullet go higher than 1.5”, nor below 3” out to 250yds. You’re only 5” low at 275, and roughly 8” low at 300yds.

36yd zero is a slightly-less bad version of 25m zero. Both 36yd and 25m are worse than 50yd zero.

For partially-exposed TGTs, you don’t need to think about anything other than quickly putting the reticle center into your breathing/trigger control sequence within compressed time and breaking the shot.

Was using posted data from page 2.

Either way, the mil hold at 90y (using 50y zero) is as much as 210y hold (using 100y zero).... and the holds switch back and forth from high to low to high, with a high rate of deviation change, all at ranges inside 200y. (the carbine’s sweet spot).

 

[LRRPF52]

Especially with a squirrely little carbine, maintaining any kind of consistent POI like we’re used to seeing with heavy precision rifles with floated barrels is just not going to happen. I’ve been chasing that monkey for a long time. I’ve gotten closer, but it just will never be like a bolt gun.

M4 accuracy and M4A1 accuracy were different when the big Army still had BURST FCGs in the guns. Terrible trigger, terrible mechanical system with the clutch constantly engaged with the burst cam and disconnector, applying constantly-changing and heavy tension to the trigger while in the SEMI fire control mode. Mechanical accuracy on the M4A1 is better just for that reason alone.

Instead of shooting a lot of prone, you start to see why the best shooters started using barricades and small plates.

A VTAC barricade, combined with 8” swinger plates for targets, makes a much better training set-up than shooting full-size IPSC sils from any position, when shooting beyond CQM distances.

To help with the mechanical accuracy problem, before SOPMOD, they were building in-house carbines with free-float tubes, chopped uppers with rails, little Leupold or Hensoldt optics, with Lilja or Douglas match barrels for a DM carbine. Squeals, Ranger Regiment, and JSOC were all doing it. Some people call them Recce carbines.

With SOPMOD Block II, the free float feature became standard and triggers from the SPRs started finding their way into guns, fed with Mk.262 77gr.

In JSOC, they were using the KAC free-floated MRE handguard on some of the guns. Their in-house armorer support is unmatched, so they would have access to the best barrels and fitting for guns set-up more for DM work. With that, the real breakthrough in LPVOs was pioneered there with the S&B Short Dot.

Once you go to a free-floated carbine with a good barrel, any of the great triggers available today, with the superb LPVOs we now have, you can tighten up that hit probability into the tiny vital zone in the head.

With rack-grade M4s maintained by varying degrees of armorer support, hit probability into that kind of target is difficult.

 

[Carlos0311B4]

The color coded target was an M4. The one that might have been the FN is the target with the tape for reference. Look forward to your results.

 

[LRRPF52]

You may have been the wrong rifle but the experiment was still valid (saw the pics showing the color hits - was a good visual)....I’ll be doing something similar tomorrow as this thread has gotten the better of my curiosity.

the target I plan on shooting at is below. The dark brown silhouette in the rear will actually be the target. The front silhouette will represent cover so any impacts there would be considered misses. See Molon’s post (#99) on page 2 for the target reference.

I plan on confirming zero at 36 yards, then placing the target at 100,200,250,300 and engage with 10 rounds of IMI XM193 from a partially covered position (prob behind a rock face) to see what the dispersion looks like. I’ll repeat the cof but with a 50 yard zero then compare. First run won’t be timed at least as of now, subsequent runs will likely be done under time. I’ll be aiming at the “body” portion of the target.

I’ll post pics of the results. My goal is to determine if a 50 yard zero does in fact lend itself to more hits at the various relevant distances vs. a 36 yard zero. If it does, I’m switching over to a 50y zero; if not, I’ll keep the 36 yard zero or run the test again at a later date to be sure of the results.

Rifle will be my DD 14.5” with an aimpoint m68, no magnifier (if time permits, I’ll run it again with the 3x magnifier).

Open to any other suggestions to improve the test.
View attachment 7499459

I recommend dialing yourself in with at least 1 dot drill target. Take any paper, stick on 5 or 6 dots on it, and run the drill. It trains you to maintain fundamentals with much more focus to see how well you can keep your mean radius between POA and POI.

You can get creative with dot drills, and they are great low round count drills for times of ammo scarcity. Here are some examples:

Start with the dot drill to determine what your personal mean radius is. Just shoot 1 round per dot on something like the left TGT. Do it at 50yds. Keep record of it.

Then do your successive bound field verification.

One issue with your partial exposure IPSC set-up is that we won’t be able to see any misses that go outside of the brown TGT.

That’s where a larger paper TGT might be better to see what’s going on. With RDS, as the distance gets farther, you’re a stud if you can keep them all in that head. Maybe staple some more whites around the brown so you can see and record all your shot registers from each distance.

The successive bound drill is fun though as well for low round count training. More PT, less shooting, but the shots need to count.

 

[nn8734]

I recommend dialing yourself in with at least 1 dot drill target. Take any paper, stick on 5 or 6 dots on it, and run the drill. It trains you to maintain fundamentals with much more focus to see how well you can keep your mean radius between POA and POI.

You can get creative with dot drills, and they are great low round count drills for times of ammo scarcity. Here are some examples:

Start with the dot drill to determine what your personal mean radius is. Just shoot 1 round per dot on something like the left TGT. Do it at 50yds. Keep record of it.

Then do your successive bound field verification.

One issue with your partial exposure IPSC set-up is that we won’t be able to see any misses that go outside of the brown TGT.

That’s where a larger paper TGT might be better to see what’s going on. With RDS, as the distance gets farther, you’re a stud if you can keep them all in that head. Maybe staple some more whites around the brown so you can see and record all your shot registers from each distance.

The successive bound drill is fun though as well for low round count training. More PT, less shooting, but the shots need to count.

Thanks, Will run the dot drill first. Good way to warm up as well. Pasting an additional white target to the left is a good idea as well, will bring another with me and attach it before performing the test.

 

[Carlos0311B4]

LRRPF52,

from M4 to M4A1 not having a free float 13-15”, prefer 14-15” free float rail was stupid. That dumb ass should be infront of a firing squad
I hate with a passion that stupid 7” rail.

 

[Carlos0311B4]

I like that dot torture target for a few things as well.

 

[Carlos0311B4]

Nn8734,

if you can I would put paper behind those 2 targets to see any misses.

 

[nn8734]

Nn8734,

if you can I would put paper behind those 2 targets to see any misses.

for sure, looking for some large cardboard for use as a backer. Think I have a large box I can cut up and use.

 

[LRRPF52]

LRRPF52,

from M4 to M4A1 not having a free float 13-15”, prefer 14-15” free float rail was stupid. That dumb ass should be infront of a firing squad
I hate with a passion that stupid 7” rail.

You know what the first ever carbine variant of the AR-15 was? The Infantry Leader’s Carbine, Model 605A and 605B:

The problem with it was they kept the RLGS and opened up the port. Barrel is 15”. Worked fine mostly on SEMI, started skipping beats on AUTO and in arctic temps. Had they just done a MLGS underneath....but then they would be making 2 different gas block parts.

What’s old is new. It was part of the CAR-15 family of weapons, along with the LMG belt-fed, Commando, USAF Survival Carbine, and standard infantry rifle.

 

[Carlos0311B4]

You know what the first ever carbine variant of the AR-15 was? The Infantry Leader’s Carbine, Model 605A and 605B:

The problem with it was they kept the RLGS and opened up the port. Barrel is 15”. Worked fine mostly on SEMI, started skipping beats on AUTO and in arctic temps. Had they just done a MLGS underneath....but then they would be making 2 different gas block parts.

What’s old is new. It was part of the CAR-15 family of weapons, along with the LMG belt-fed, Commando, USAF Survival Carbine, and standard infantry rifle.

I have seen some of those rifles, I did not know it was the first. I’m no history expert but I do do a little.
I don’t think a free float rail is absolutely necessary for a service rifle but these days it’s dumb not to have one, imho!

if I were to own any rifles they are all free float, or would be I should say. I don’t own any evil assault rifles

 

[Mike_in_FL]

You were told wrong. Tell that to the Senior Drill Sergeant.

One shot per target exposure. Yep, but put up two at a time.

Seriously though, I'm referring to qualification in the last century of the last millennium in 1981

 

[Carlos0311B4]

Mmm ....1981? I was 2years old. I’m not familiar with the qual in those days..
the “old qual” I’m referring to is from (not 100% on start date) 2002ish to 2019

 

[corey4]

I'm just a boofer hobbiest. I'm not advocating one way or another. People need to get out and try for themselves. I have yet to try thev 36yd zero. Here is my 50/200 results with my aero m4e1, triarc 12.5 on my DD MK18 SBR lower, fiocchi 223 55gr . I zeroed at 50 then moved to 100, 200, 300. No pics at 50 cuz I really didn't think of it plus it's my zero, so who cares. All shots were taken at the center of the white 8.5x11 paper torn in half. Why torn in half? I dunno lol.

Again, these are just my results. I'm not advocating what anyone else should do.

After confirming at 300 where I was hitting low, I have to hold or dial .5 mil

 

[deersniper]

Has @TheGerman weighed in here ?

 

[LRRPF52]

I have seen some of those rifles, I did not know it was the first. I’m no history expert but I do do a little.
I don’t think a free float rail is absolutely necessary for a service rifle but these days it’s dumb not to have one, imho!

if I were to own any rifles they are all free float, or would be I should say. I don’t own any evil assault rifles

I really like the 605. I personally haven’t had any issues with reliability, but my barrel is a bit longer. Most of the parts on mine are original, including the Bolt Carrier (Colt pre-1964 slick chromed). Lower is NoDak repro partial fence.

As far as zeros and sighting goes, it of course has the full-length sight radius of a rifle and no real practical change in ballistics.

Speaking of fire control groups, they had two variants, the 605A and 605B. 605B had SAFE, AUTO, SEMI, BURST 4-way selector with a cutout under the selector lever so it could bypass the integral quarter sphere stops:

On the 300m zero: There was a different thought process in the 1950s when the Army took a radical departure from its previous, comprehensive rifle marksmanship program of the 1920s-late 1940s. The previous rifle marksmanship program involved a 2-week intensive shooting package with all kinds of ranges, stages of fire, and positional shooting. It included walking combat lanes with pop-out targets, shooting from ditches, windows, roofs, rubble piles, simulated blown-up walls, from behind log piles, and long range engagement of men and vehicles out to 500, 600, and 800yds.

With the advent of the nuclear era and nuclear-focus, someone figured we wouldn’t need riflemen that much anymore, other than the Fulda Gap and the Northwest Corridor of the Korean DMZ, so they dumbed everything down into what was called “Train Fire”. Train Fire was basically conscript-level marksmanship and qualification, but with a cool pop-up target range that went out to 300m.

It was totally defensive-oriented with 2 primary scenarios based on the overall strategy. US soldiers would be holed-up in their fighting positions, a last line of defense in the event of Soviet or North Korean APCs having penetrated our anti-vehicle defenses. As the motorized infantry dismounts would spill out and begin the final phase of their assault after echelons of indirect fire, they would be engaged by machine-guns and rifles from men in their fighting positions.

In the event of certain positions being overrun, soldiers would bound to their supplemental positions and engage from the prone position.

From all the research I’ve been able to do on the changes to the MTO&E and thinking behind Infantry tactics over the last century, this is where you find the "foxhole-supported" and “prone-unsupported” positions becoming the emphasis in the Army’s Train Fire. Gone were all the battle-focused lanes and 2-week marksmanship packages that actually prepared a rifleman for practical shooting with high round-counts and lots of professional instruction, coaching, and feedback.

Since rifle fire was seen as the last resort in an overall organization perspective (aside from being overrun and using personal defense weapons/bayonets/sidearms), it really covers that 300m-and-in distance. This could be why the bean-counters mandated the "25/300m” zero. If someone who has done more research than I have can provide more insight into that, I would be interested.

It does really invalidate the 25m zero from a practical perspective though, considering the types of conflicts we have fought, ever since the nuclear era forced out adversaries to use asymmetric wars, where riflemen go from inconsequential...to critical in effecting the strategy for dealing with a mix of insurgents, surrogates, some uniformed soldiers, and guerrillas. You really need marksmanship more than ever, but the US Army did the opposite and shut down that focus that was there in the Two Great Wars. Some trickled into Korea, but Train Fire really killed it from an organizational perspective, outside of the AMU and a few units.

This new Army Marksmanship training program with the positional shooting, mag changes, and more practical scenarios is a nice start. I’m not sure if they’re doing 2-week marksmanship packages though. Given the current weapons and optics, there is an opportunity to have a much better shooter who has a higher hit probability on select targets in a high civilian-populated environment, with minimal collateral effects.

The 25m and 36yd zeros are not ideal for that. They both increase errant shots that instead of going into the intended target, go somewhere else, including the local populace’s families, vehicles, homes, or friendly personnel. Something to think about that might be relevant here as well, God forbid.