[dave3006]

Can anyone tell me what the ballistics (0 to 600 yds) will look like on a 55gr .223 zero'd at 25 yards on my Mini-14 with a 14.5" barrel?

Thanks,
Dave
- living in occupied Kali

(Please no mini jokes. This is all our masters will let us have...)

[SodaPop]

Your ballistics will end at about 350yds with that bullet weight. Even though the 62gr/M855 round is a terrible man stopper it is ballistically superior to the 55gr round. That 55gr bullet is going to be lost in the wind and at 350-400yds out of a 14.5inch barrel. I have enough problems with windage with 55gr bullets.......... out of an 18.5inch barrel at 400yds.

I believe I have 25meter targets I got from Bushmaster that are suppose to zero at 300yds with the 55gr. But that is out of a 20inch barrel.

Switch to 62gr if you want the capability to make hits at longer ranges. I know guys that can take 600yd shots with M4s but only with the 62gr.

[Northwest Cajun]

Try

www.eskimo.com/~jbm/ballistics/traj/traj.html

All you need is speed and BC you can fill in the rest. it's really easy.


Cajun

[444]

http://groups.msn.com/TheMarylandAR15ShootersSite/zeroingmethods.msnw

This is a very good website that deals with zeroing the AR15 (I realize you have a Mini-14, but it might help or at least give you some ideas). It covers the 25 meter zero.
The way to go is the Improved Battlesight Zero, but whatever floats your boat.

[Grump]

Front sight height above the bore centerline can affect this GREATLY. Sierra Ballistics III (Old DOS version) uses this variable to the nearest 0.10 inch. Give us that and your velocity at ___ feet (center between the chrono screens) and the temperature and altitude, and you'll get some good reliable numbers.

14.5-inch barrel? Using an M4gery-style flashider/muzzle brake or something?

Having belted a gong repeatedly at 600 yards using M193 loads from an 18-inch barrel, I can understand your desire to know the ballistics of the rifle which you HAVE. Ya just gotta know.:cool:

[dave3006]

Thanks Northwest Cajun. What BC and Drag should I use for a standard military FMJ round?

[artherd]

Why on earth zero at 25? What's the max rise for a 100yd zero, 1" at 60yds?

[444]

I am more interested in why you would zero for 100 yards ?

[Northwest Cajun]

Try
.307 BC speer 62gr FMJ BT
G1 drag

Cajun

[go8dalejr]

You can download a free ballistic caculator at remington.com only has remington ammo on it,but they have a 223 55gr fmj.

[WhiteKnight]

Can anyone tell me what the ballistics (0 to 600 yds) will look like on a 55gr .223 zero'd at 25 yards on my Mini-14 with a 14.5" barrel?

I just don't understand Kalifornia. You cannot have CETMEs or AUGs, but you can have a short barreled (<16 inch) rifle? :rolleyes:

[dave3006]

The barrel is 14.5". It has a muzzlebrake to make it to the legal length of 16". Because we all know how much more deadly a 14.5" barrel is! 16" barrels shoot friendly happy bullets.

[Grump]

By my rule of thumb of up to 75 fps per inch of barrel length changed, your M193 ammo could be launched at as little as 2,750 fps. Is that close to what you have chrono'd or figure?

[Bartholomew Roberts]

The BC of 55gr M193 ammo is .243

[RepublicanMan]

Soda...according to the Army marksmanship manual, a 25 yard zero on a 20in M-16A1/A2 gives a zero at 250 yards as well.

[Grump]

And with a 14.5-inch barrel, that's going to be a bit off. I'm going to run Norma or whatever Java program using 1.0-inch sight height to see what it shows.

Okay, I'm back. At 2752 fps, 1.0-inch sight height and .243 BC, your 25-yard zero crosses back into the line of sight at 147 yards, where 10-mph wind drifts is 3.8 inches. It's a half-inch low by 159 yards, 200 is -3.0/6.3 inches drift, 300 is -15.6/15.1, 400 is -40 inches/ 28.9, and 500 is -81.5/48.6 inches. 600 is -146.4 (12.17 feet) and 74.3 inches drift, velocity down to 1109, and 150 fps energy (what? less than half a 9mm Parabellum?).

Add another full minute of drop at 600 if the sight height is .8 inches. Crossover then would be at 121 yards.

Sight 1-inch high with .8 sight height, and your crossover goes out to 250 yards, and max height above sight line is 4.9 inches at 121 yards. It's 3.5 inches high at 200 and 5.9 inches low at 300. 400 would be -27.3, 500= -65.5 (five 'n half feet), and 600 would be -127.3.

Got a flavor for it now? I love this stuff.

[Onslaught]

Man there's a lot of 5.56 going on today...

Gee, where to start.....

I'm not saying it's easy, but you ABSOLUTELY can make hits on a torso sized target at 500 yards with a 14.5" barrel and 55gr ammo. Without a scope, it's maybe 50/50, but with a scope and proper holdover it can be done consistently. I know it can be done because all three of us in our "work shooting group" do it with our AR's every time we get together. But it is true... if there's wind... :eek:

That's a great program you're running there Grump. It's very helpful info, although 75fps per inch of barrel is too high of an estimate for the .223. It's more like 30fps down to 16", and drops down to 3064fps at the muzzle from a 14.5" barrel on an AR15 according to Bushmaster. I would guess that the Mini would actually have a slightly HIGHER muzzle velocity given the same barrel since the gas system only bleeds off a tiny bit to move that piston. It's been reported that the AR180 has a higher muzzle velocity for this same reason. Now, if you're gonna crank that software back up with those numbers... I've got my pen ready :)


But to answer your question... I don't know what the ballistics work out to, since height over bore is less than the AR, so you have slightly less curve to work into the space between the bore and the sights... but I sight my AR's at 50 yards, and I can point and shoot out to 250. Barrel length makes no difference on mine.

Sounds like your best answer (short of actually testing it out on the range) is going to come from Grump and his Norma ;)

[Grump]

1109 fps is in the transsonic zone, so wind drift at 600 is going to be severe and erratic.

Data will be much more reliable if we get chrono and temperature info.