.223 AR shooters

[Ridge Runner]

The 223 actualy shoots pretty flat, but in the AR platform if the scope is mounted at the right height for proper cheek weld (3-3.5" above bore center to center) then when sighted in at 100 yds,  The bullet raises 3-3.5" in 100 yds so its 1/2 of that low at 50, here is a drop chart I worked up for my 24" RRA
   AR 15 223 drop chart    4/20/05
       R       tr      c/ups      w/5mp   c/ups
      100   1.64    MOA                    MOA
      125   2.28                    .9
      150   2.61                    1.4
      175   2.62                    1.9
      200   2.27                    2.5         
      225   1.56                    3.3         
      250   .45                      4.1         
      275   -1.10     .5           5.1         1.75
      300  -3.13     1             6.1         2.0   
      325  -5.66     1.66        7.3         2.1
      350  -8.76     2.4           8.7         2.25
      375  -12.44   3.2          10.1       2.5 
      400  -16.76   4.3          11.8       2.75
      425  -21.80   4.9          13.5       3
      450  -27.62   5.5          15.2       3.2
      475  -34.26   6.5          17.6       3.5
      500  -41.79   8             19.8       3.75
      525  -50.31   8.5          22.3       4.0
      550  -59.85   10.          24.9       4.3
      575  -70.57   11           27.8       4.6
      600  -82.57   12.          30.8       4.9     
   
RR

[clousewt]

I have been in the military for 16 years, we sight the M-16 in at 25yds with a 55 grain full metal jacket bullet. Sighted in at 25 yards it will hit the same spot at 300 yards. It does rise between the 25 yd and the 300 yard mark.

[ohiobob]

A little help on the Chart ??? so you are saying that if your gun shoots .75" LOW at 50 yards it will be 1.6" high at 100 yards and then .45" High at 250 Yards ??? where did you get the info for this ??? did you use one of those Trajectory programs on Powder/Bullet makers Websites and if so,,which one ???
Thank you very much
Bob

[Ridge Runner]

thats close bob, but what I do is find the window where most of my shots occur, with this rifle its 150-350 yds.  so my zero ended up to be "dead on" at 258 yds, I used a caliper to make an "X" exactly 1.64" above the POA, then zero'd at 100,  I then shot at 200,300, and 400 yds and compared my actual drops to the chart that I printed from a program called "Load from a disc for windows" my actuasl drops were a bit different from what the chart said so I changed the bullets BC in the program till my actual drops matched the chart, this established my actual BC shooting here under my conditions, yours may vary depending on when and where you shoot. I do this with all my rifles and it makes hits relatively easy to 700 yds if the wind co-operates. lots of good ballistic programs on the net look up JBM's web page, they have a nice one that enables you to print your own charts.
RR
PS that chart is for a 55 gr sp with a BC of .241 at 3200 fps, scope height is 3.5" above center of bore, using this info on this chart I have killed chucks (2) at a lazer ranged 550 yds and 1 very near miss at 600 (1" over its head)

[ohiobob]

Good Deal Ridge Runner,,did you BUY this Program or did you get it from a site on the Internet ??? I need to get my Chronograph out and check my NEW Loads ,I am sleeping on the Job 
Bob

[Ridge Runner]

I bought the load from a disc for windows, but lots of free ballistic programs on the net, JBM is good as is "point blank" and its a downloadable free program
RR

[ohiobob]

Ridge Runner
Thanks for all the info,,do you have a link ??? or can I just "GOOGLE" it ???
Thank You very much
Bob

[Ridge Runner]

here is a link to JBM's trajectory calculator http://www.eskimo.com/~jbm/calculations/traj/traj.html , send me a blank email to james720603@HardyNet.com and I'll send ya a zip file of point blank to install on your computer. Now when I deer hunt with long range stuff I have a PDA with exbal loaded on it it gives me info to take shots to 800 yds and beyond, its all simple math to 700, then the bar pressure starts taking a toll on the numbers so you have to have a way to figure in current atmospheric conditions, bar pressure, altitude, tempature, humidity being the main ones with bar pressure being the most important (bar pressure changes with altitude, and will actualy change the bullets BC.
This rifle is more than capable to 1500 yds but I'm not, my range for game animals is limited to 900 yds
RR

[ohiobob]

Ridge Runner
What Caliber is the Rifle in the Pic ??? sounds like it is a pretty good Program to have on yor Computer 
Thank You Very Much
Bob

[Ridge Runner]

Its called a 7mm Allen magnum, developed by kirby allen of APS of fort shaw montana, basicly its a 7mm dia based on a 338 lapua mag. improved, H2o case capacity is 122 gr, it'll send a .284 nosler accubond downrange at 3700 fps MV. I shoot a load that consists of 110 gr of WC872 (mil surp powder designed for the 20mm vulcan cannon, and its 5 bucks a pound) with an average accuray of less than 3/8's MOA
A typical 100 yrd group from it

here's a preliminary group, fired after adjusting per drop chart, from a 100 yard zero, group was fired from 660 yds, only 2 shots but for hunting purposes its an outstanding group (measures 1 7/8's) I've since tweaked the BC and increased the standard zero to 300 yds to get cold bore 1rst shot closer to POA

RR

BTW the doe in the pic was shot at 532 yds

[ohiobob]

532 Yds  :shck: that is a bit farther then my Muzzleloader will reach !!! in what State was the deer Shot ???
That is some GOOD SHOOTIN for sure
Thank you very much
Bob

[Ridge Runner]

west virginia
RR

[browning204]

SO I guess I want to start at. Is it true that the 1/9 twist likes heavier bullets?

When our 3-4 feet of snow melts and I can get on the range, I want to really get this AR sighted in well. I have been shooting 55 grain factory loads. I have a box of 60 (i think) from black hills I will try also.

thanks

[KySongDog]

SO I guess I want to start at. Is it true that the 1/9 twist likes heavier bullets?

Here's one man's opinion......

Click Here

[Ridge Runner]

The reason the AR's shoot high up close is because of the scope heighth, the scope on a normal flattop, if set the right height for a good cheekweld is about 3.5" c to c scope to bore, here is how I sight mine in, and just hold  for a heart shot inside of 200 yards
   AR 15 223 drop chart    4/20/05
       R       tr      c/ups      w/5mp   c/ups
      100   1.64    MOA                    MOA
      125   2.28                    .9
      150   2.61                    1.4
      175   2.62                    1.9
      200   2.27                    2.5         
      225   1.56                    3.3         
      250   .45                      4.1         
      275   -1.10     .5           5.1         1.75
      300  -3.13     1             6.1         2.0   
      325  -5.66     1.66        7.3         2.1
      350  -8.76     2.4           8.7         2.25
      375  -12.44   3.2          10.1       2.5 
      400  -16.76   4.3          11.8       2.75
      425  -21.80   4.9          13.5       3
      450  -27.62   5.5          15.2       3.2
      475  -34.26   6.5          17.6       3.5
      500  -41.79   8             19.8       3.75
      525  -50.31   8.5          22.3       4.0
      550  -59.85   10.          24.9       4.3
      575  -70.57   11           27.8       4.6
      600  -82.57   12.          30.8       4.9     
   
Lots of folks don't like a scope setting high, but that 3" of scope height amounts to 15" of trajectory that you don't have to worry with at 500 yards. This chart is generated shooting an 8 twist 24" RRA using ultramax 55gr sp reman ammo.
RR

edited to add this pic, this 3 shot group which was fired from an 8 twist, 223 wylde chambered AR, measures around .26", according to some an 8 twist won't shoot 55 gr very well, and the long leade of the 223 wylde chamber hurts accuracy, this was cheap re-man ultramax. I've also found from experience that the faster spin on the bullet helps expansion so I get better terminal performance at longer ranges.