Combat Zeros

KevinB

KevinB

Member
Doc, I would go out with a Magnetospeed, and get some good data based on your load. The plug it into Applied Ballistics - look at your trajectory - and what your expected engagement ranges are -- then zero it at the best spot in that for minimal deviation of POI from POA. Wide areas with longer ranges will effect what you want versus close country with limited observation.
 
jmatt511

jmatt511

Amateur
My RDS rifles have a combat zero of 50 yards. Scoped rifles are zeroed at 100 yards. Handguns zeroed at 20 yards POA/POI. I'm a big believer in commonality and not trying to overthink multiple systems and trying to remember which goes where with a particular set up.
 
Turkishroy

Turkishroy

Newbie
jmatt511 said:
My RDS rifles have a combat zero of 50 yards. Scoped rifles are zeroed at 100 yards. Handguns zeroed at 20 yards POA/POI. I'm a big believer in commonality and not trying to overthink multiple systems and trying to remember which goes where with a particular set up.
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I pretty much track with this. My RDS/carbine isn't going to see much use outside of 200yds and even then my 2MOA dot just about covers a torso at 200yds. A little difficult for me to confidently take that shot past 200yds.

I've contemplated an intermediate zero with my DMR rifle, I just haven't had the time to confirm the drops my ballistics app gives me for a 300yd zero and 75gr BTHPs. Ideally, with the standard mil-dot the ballistics app gives me hold over to 400 and 500 using the two dots just below cross hair, with 200yds in between the crosshair and first dot above, and 100yd at first dot above. It's not a precision deal, we're talking torso targets with a 3-9x without having a terribly complicated hold over scheme or having to adjust elevation for those distances. For now it stays zeroed at 100yds, and that gives me 300-500yds on the three dots below the crosshair. Roughly, anyway.
 
DocGKR

DocGKR

Dr.Ballistics
Staff member
Moderator
Roland--Lot's of LE agencies here have access to a 100 yd range, very few have access to 200 yds. For folks stuck in that situation, would you recommend a 50 or 100 zero?
 
jmatt511

jmatt511

Amateur
For LE shooters, a 100m/y zero is a bit long. Engagement at over 50m/y is hard to justify unless you've got a bad guy with a rifle. Military zero is based on their MOS or SOP. For the average non-LE citizen, it's hard to justify an engagement over 50m/y. You need to be able to articulate why you do something rather than rely on what LE/MI does. Especially if that's outside your training.
 
G

Greg "Sully" Sullivan

Too Established
Vendor
VIP
My preference is an AR15 with a same plane rear sight aperture and tritium front sight post, zeroed for 50yd/200yd, and this would be the same distance if equipped with an Aimpoint or Reflex sight. My rifles that are equipped with a TA01 Acog is zeroed for 100yds. I used to be old school of the traditional 25M zero as that is what we were taught decades ago. After we had 3 Officers shot in a gunfight in 2001, some serious soul searching of our gear and training showed where our strengths and weaknesses were, and from there the evolution began.

CY6
Greg Sullivan "Sully"
 
rob_s

rob_s

Member
jmatt511 said:
For LE shooters, a 100m/y zero is a bit long. Engagement at over 50m/y is hard to justify unless you've got a bad guy with a rifle. Military zero is based on their MOS or SOP. For the average non-LE citizen, it's hard to justify an engagement over 50m/y. You need to be able to articulate why you do something rather than rely on what LE/MI does. Especially if that's outside your training.
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What is the relationship between "zero" and engage,net distance?
 
TomF

TomF

Member
Grizzly said:
Ya, to me though I don't care if he shot it at 1 yd, used a drill bit or a sharpie. The information contained about drop is accurate and the reasons to pick a zero are good.
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No they aren't. That video is all sorts of fucked up.
I don't know shit about combat, but any schmuck like myself with a ballistic computer, an accurate rifle, a rangefinder and time behind the gun can calculate external ballistics.

Assuming M855, 62gr, .304 bc, 2900fps, 2.6" height above bore:

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25 yd zero
50 yd +2.3"
75yd +4.3"
100yd +6"
200yd +9.4"
300yd +6.2"
400yd -5.2"

Shown: 50 and 75yd impacts almost on top of each other

-----------------------------------------------------------------------------

50yd zero
No discrepancy in data shown. See the 200yd zero below.

-----------------------------------------------------------------------------

100yd zero
25yd -1.5"
50yd -0.7"
75yd -0.2"
100yd 0
200yd -2.6"
300yd -11.7"

Shown: 25 and 50yd "impacts" ~3" above the POA. With a 100 yard zero there are never impacts above your dot.
300yd "impact" is shown ~3" above a previously quoted -24" impact from the 25yd target. It should be half of that.

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200yd zero
25yd -1.2"
50yd -0.1" (Almost zero)
100yd +1.3"
200yd 0
300yd -7.8"

Shown: 25yd "impact" right next to the 50 and 200 "impacts." He speaks like the 200 yard zero is different/better than a 50 yard zero, when they are almost identical, and he has the 50/200 impacts right next to each other.

-----------------------------------------------------------------------------

300yd zero
25yd -0.5"
50yd +1.2"
75yd +2.7"
100yd +3.9"
200yd +5.2"
300yd 0

Shown: 25yd "impact" ~1.5" above POA.


-----------------------------------------------------------------------------

His math is off and he didn't shoot it at the stated distances. There is nothing credible about this video.
 
Grizzly

Grizzly

Regular Member
TomF said:
No they aren't. That video is all sorts of fucked up.
I don't know shit about combat, but any schmuck like myself with a ballistic computer, an accurate rifle, a rangefinder and time behind the gun can calculate external ballistics.

200yd zero
25yd -1.2"
50yd -0.1" (Almost zero)
100yd +1.3"
200yd 0
300yd -7.8"

Shown: 25yd "impact" right next to the 50 and 200 "impacts." He speaks like the 200 yard zero is different/better than a 50 yard zero, when they are almost identical, and he has the 50/200 impacts right next to each other.

His math is off and he didn't shoot it at the stated distances. There is nothing credible about this video.
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Wow, thanks for the info. The 50/200 fell into the close enough (-.75 vs -1.2") and I didn't realize how bad off the others were. It is past the edit window or I'd edit my post to remove the video.
 
TomF

TomF

Member
The only thing worse than bad published information is bad published information left unchecked. I say leave it up even if you could edit it so others can find it.
 
A910

A910

Member
TomF said:
The only thing worse than bad published information is bad published information left unchecked. I say leave it up even if you could edit it so others can find it.
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Not calling you a liar or defending the video but my question is did you actually shoot to confirm your calculations?

I'm a guy that likes to see proof on both paper and in the field. Seen a lot of "on paper" that was a hell of a lot different when it was applied in the field. Seen a lot of field that was hard or impossible to explain on paper. To me if it's only on paper or "calculated" it is is just theory.

As I said, I'm not calling bullshit on your post, nor am I defending the video. But if you want to drive the nail in, post your physical results also.
 
KMo1205

KMo1205

Member
It also gets a little confusing when people are making the mistake of interchanging meters with yards. Almost all of the civilian and LEO ranges that I've seen or shot at have targets measured off at yards. I've yet to see a civilian range set up at meters, perhaps that comes more from the military side of things? As someone who does not have a military background, yard zeros make more sense than meter zeros. So my rifles are at 50 yard zeros confirmed at 200 yards and my MOA scoped rifles are at 100 yard zeros. I'm assuming if you had an MRAD scope, you would zero it at 100 meters.
 
TomF

TomF

Member
A910 said:
Not calling you a liar or defending the video but my question is did you actually shoot to confirm your calculations?

I'm a guy that likes to see proof on both paper and in the field. Seen a lot of "on paper" that was a hell of a lot different when it was applied in the field. Seen a lot of field that was hard or impossible to explain on paper. To me if it's only on paper or "calculated" it is is just theory.

As I said, I'm not calling bullshit on your post, nor am I defending the video. But if you want to drive the nail in, post your physical results also.
Click to expand...

Yes, I've confirmed a ballistic table on my rifles numerous times. The data I posted was from Hornady's ballistic computer. My actual table is within .5" of each of those with 50 or 100yd zero. I don't generally shoot M855 so each gun/ammo/barrel will be slightly different. It won't be egregiously different like Travis' video though.

As far as my own video, I don't have a regular spot to shoot 400 yards nor the time to change my zero four times just to post it to the internet. You're absolutely right that the proof is on paper. Viewers should shoot their own rifles against the video's "data" and compare for themselves.
 
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