Point of aim with AR15 in close

[hminsky]

I've been doing some practice with my AR15 with a carry-handle mounted scope, and the iron sights on the carry handle.

The iron sights are quite high above the barrel, and for shots within 20 or 30 feet, the point of impact comes a few inches below the point of aim. What do people generally do to practice aiming accurately at close distances when the sights are set for 50 or 100 yards?

 

[andy t]

Aim higher? That's pretty much what I do. When my AR is set for 50 yd zero, at short ranges, I use a poing 2/3 of the way up on the front post to aim. I think there are also aftermarket front sight posts available with different configurations.

 

[JimConway]

AR 15 shooting high

The best solution is to zero the gun in at 25 yards for the first zero. This will give you a second zero at about 225 yards (if my memory is still good)

 

[Adam_MA]

(if my memory is still good)

OK.. I'll just leave that alone!

 

[Davidk]

I find that with a 50-yd zero, I get +- 2inches from 10 yards to 200 yards

 

[TonyD]

A fifty yard IBZO will give you the same POA / POI at 200 yards using iron sights. At PBR your round will strike low of center the same distance as your sight's HOB (Height Over Bore) and continue to get closer to the center out to the 50 yard zero. You'll be about 1.5 - 2 inches high at 100, and back to center at 200. This gives you a MPBR out to almost 300 yards.

 

[hminsky]

A fifty yard IBZO will give you the same POA / POI at 200 yards using iron sights. At PBR your round will strike low of center the same distance as your sight's HOB (Height Over Bore) and continue to get closer to the center out to the 50 yard zero. You'll be about 1.5 - 2 inches high at 100, and back to center at 200. This gives you a MPBR out to almost 300 yards.

Can you define a couple of terms there:

IBZO = ??
PBR = ??

 

[TonyD]

IBZO = Improved Battle Zero
PBR = Point Blank Range
MPBR = Maximum Point Blank Range

 

[TY43215]

A fifty yard IBZO will give you the same POA / POI at 200 yards using iron sights. At PBR your round will strike low of center the same distance as your sight's HOB (Height Over Bore) and continue to get closer to the center out to the 50 yard zero. You'll be about 1.5 - 2 inches high at 100, and back to center at 200. This gives you a MPBR out to almost 300 yards.

+1 this is the best advice here. Only thing I would add is if you are using an optic, put it down on the hand guard to solve some of the height problems.

http://www.mountsplus.com/miva/merchant.mvc?page=MSP/PROD/21_AR-15-Accessories/AIM-RAR-174


Add one thing, At 250 you will be roughly 2.5" low, 275 5" low and 300 about 8" low. At 300 yards I hold on the neck of an IPSC target and the bullets will drop into the A zone. Assuming 55gr bullet. Dan S may have some better data.

 

[TonyD]

My 69 gn's are 1 1/2 to 2 minutes low at 300 with a mV of 2840 fps - just outside a comfortable MPBR for me. I'd suspect the hotter milspec stuff would be a little less.

 

[TY43215]

My 69 gn's are 1 1/2 to 2 minutes low at 300 with a mV of 2840 fps - just outside a comfortable MPBR for me. I'd suspect the hotter milspec stuff would be a little less.

Thanks Tony, I use Lake City 55gr as much as I can find. Some day If I ever do any serious rifle shooting other than IPSC, I may have to reload.

 

[TonyD]

Thanks Tony, I use Lake City 55gr as much as I can find. Some day If I ever do any serious rifle shooting other than IPSC, I may have to reload.

No prob. What are you shooting it with?

It's actually a little difficult to tell what my drop actually is. I use a 6:00 hold for service rifle. My drop from 200 to 300 is 2 MOA but the 300 yard target aiming black is 6" in diameter larger than the 200 yard so I'm actually holding 3" lower from center. I need to try it using CM just to see.

 

[TY43215]

No prob. What are you shooting it with?

16" Bushmaster V Match Flat top and as of today it is on a 1991 manuf Bushmaster lower with a match trigger or my other lower with a JARD 3# trigger.

I use optics on the flat top that have no iron sights. Either a TR21 scope or a Trijicon Reflex. Both are fast acquisition and work both eyes open for wider field of view. Makes it easier moving just wish I could move faster Hell to get old.

 

[TonyD]

16" Bushmaster V Match Flat top and as of today it is on a 1991 manuf Bushmaster lower with a match trigger or my other lower with a JARD 3# trigger.

I use optics on the flat top that have no iron sights. Either a TR21 scope or a Trijicon Reflex. Both are fast acquisition and work both eyes open for wider field of view. Makes it easier moving just wish I could move faster Hell to get old.

What's the barrel twist?

I'm still of the mind of using the FSP of an A2. I haven't had the priviledge of using / testing high-dollar optics for CQB that Pat Rogers advocates. He just has more connections than I have for testing current stuff.

I would always advocate the use of a back-up iron sight.

 

[TY43215]

What's the barrel twist?

I'm still of the mind of using the FSP of an A2. I haven't had the priviledge of using / testing high-dollar optics for CQB that Pat Rogers advocates. He just has more connections than I have for testing current stuff.

I would always advocate the use of a back-up iron sight.

1-9 twist//Use of back up irons is for battery powered optics. The Trijicon Reflex and TR21 are both Tritium and work into lighting that make irons useless.

I am lucky in that I have a Trijicon Rep I do work for so I get to try before I buy. I chose these over the three ACOGS I tried. For what I am using them for they work great. For CQB, the reflex is the better of the two.

 

[Wingwiper]

I gotta ask, why are you using an AR-15 at 20 or 30 Feet?
At that range use the bayonet.


As far as BZO for the NEW 1 in 9 twist, it is as follows;

MCRP 3-01A

Zeroing Process
During the zeroing process, all elevation adjustments are made on the front sight post. Once a BZO is established, the front sight post should never be moved, except when rezeroing the rifle. (The rear sight elevation knob is used for dialing in the range to crosses the line of sight on its upward path of trajectory at 36 yards/30 meters, and again farther down range at 300 yards/meters (see fig. 9-13). Therefore a rifle’s BZO may be established at a distance of 36 yards/30 meters and the same BZO will be effective at 300 yards/meters. To establish a field expedient BZO at 36 yards or 30 meters when a 300-yard/-meter range is not available, a Marine performs the same steps as the zeroing process outlined in paragraph 9006. However, since wind does not affect the round at 36 yards/30 meters, wind- age is not added nor is it removed from the windage knob after confirming the BZO. To be accurate, the target must be placed exactly 36 yards (or 30 meters) from the muzzle of the rifle.

for added info, if you shoot at different times of the year this may be of good note.

Temperature An extreme change in temperature (i.e., 20 degrees or more) will cause the elevation BZO to change. Chang- es in temperature cause chamber pressure to increase when hot and decrease when cold. This causes shots to impact the target high in hot temperatures and low in cold temperatures. Climate Changing climates (i.e., moving from a dry climate to a tropical climate) can mean changes in air density, moisture content, temperature or barometric pressure. Any of these elements can affect the rifle’s BZO. Ammunition Inconsistencies in the production of ammunition lots can change a rifle’s BZO. Ground Elevation Drastic changes in ground elevation can create chang- es in air density, moisture content, temperature or barometric pressure. Any of these elements can affect the rifle’s BZO.

 

[speedy]

.

 

[Bill Nance]

I keep my zero at 50 yards with iron and my optic. My POA at 3 yards is about 3-4 inches low. Zero the weapon to 50 and practice at very close range. it's not hard to find the Kentucky windage. I can consistently take ocular cavity headshots at 3, 5, 10 and 15 yards with a zero at '50. I prefer the zero at 50 because from there everything else is just adjusting my POA and I'm still solid at longer ranges.