Problems with ballistics

[pierrecham]

Hi, Remington experts.
I’m having problems figuring out ballistics. I have a Remington 700, 22-250 and I’m using Remington Premier Accutip Boat Tail 50 gr ammo. I have a Bushnell 4200 (6 x 24 x 40) tactical scope. The whole thing is zeroed at 100 yrd. And of course I want to play with the top turret to be able to zero at 200, 300, 400 and 500 yrd . But here’s where I’m having problems. If I use the Remington ballistic chart, (which starts at 150 yrd), it says that my bullet will drop the following inches:
-1.2 inch at 200 yrd
-3.5 inch at 250 yrd
-7.0 inch at 300 yrd

But if I use Remington Shoot computer application, it gives me the following:
-.91 inch at 200 yrd
-2.1 inch at 250 yrd
-3.5 inch at 300 yrd

If I’m shooting gophers at 300 yrd, it could give me a no-hit. I’m I missing something here? Which of the two charts should I rely on?

By the way, where can I find a ballistic chart that will start zero at 100 yrd, instead of 150 like the Remington ballistic chart?

Thank You

[dtdtdtdt]

Each ballistics program will give different results depending upon the assumptions made. Since you don't give a velocity, barrel length, or height above the bore for the scope it is a bit troublesome to get too precise. I am not familiar with your scope so you have to do some work. I recommend and like the Sierra calculator. I have found it to be very close to range results.

If the only range that you have available is 100 yards, I suggest tinkering with the Sierra Ballistics program V6 to find the maximum point-blank-range for your rifle and load. That is, you determine an acceptable circle of hit to be able hold dead-on and expect a hit within that circle. Conventional wisdom suggests a zero 1 to 3 inches above the aim point at 100yds to give a point-blank-range (PBR) out to 300 yds for deer sized targets with high velocity rounds. Gophers are much smaller 2-3"vital zone so it will be much more limited.

Your 22-250 may have a PBR similar to that shown below.

Calculated PBR for 100yd zero with a 2" (gopher) vital zone is: 181yds. This means that a rifle zeroed at 100 yds should hit a 2" circle out to 181yds.

Max PBR 2" vital zone is 207 yd zero with max PBR 236yds
with 3" vital zone is 231yds zero max of 266yds.


Attached is a ballistics chart for a 22-250 with the bullet that you specified with the zero set at 100yds.

Two different sources give a velocity of 3725 or 3800 fps. I used 3725 as the best guess.

Results for 100yd zero:

Trajectory for Remington .224 dia. 22-250 Rem. 50 gr. AccuTip -V BT at 3725 Feet per Second
At an Elevation Angle of: 0 degrees
Ballistic Coefficients of: 0.242 0.242 0.242 0.242 0.242
Velocity Boundaries (Feet per Second) of: 2980 2980 2980 2980
Wind Direction is: 3.0 o'clock and a Wind Velocity of: 0.0 Miles per hour
Wind Components are (Miles per Hour): DownRange: 0.0 Cross Range: 0.0 Vertical: 0.0
The Firing Point speed of sound is: 1113.37 fps
The bullet does not drop below the speed within the max range specified.
Altitude: 1785 Feet with a Standard Atmospheric Model.
Temperature: 59 F

Range Velocity Energy Bullet Path Time of Flight
(Yards) (Ft/Sec) (Ft/Lbs) (inches) (Seconds)

0 3725.0 1540.2 -1.6 0.0000
25 3613.1 1449.1 -0.94 0.0204
50 3504.3 1363.1 -0.45 0.0415
75 3398.2 1281.9 -0.13 0.0633
100 3294.9 1205.1 0.0 0.0857
125 3194.2 1132.5 -0.07 0.1088
150 3095.8 1063.9 -0.36 0.1326
175 2999.7 998.8 -0.87 0.1573
200 2905.7 937.2 -1.62 0.1827
225 2813.7 878.8 -2.63 0.2089
250 2723.6 823.4 -3.91 0.2360
275 2635.3 770.9 -5.49 0.2640
300 2548.8 721.1 -7.38 0.2929
325 2464.0 673.9 -9.6 0.3228
350 2380.7 629.1 -12.18 0.3538
375 2299.0 586.7 -15.15 0.3859
400 2218.9 546.5 -18.52 0.4191


Sorry, the spacing got messed up but you should be able to figure it out.

[Wulfman]

.

Hi, Remington experts.
I’m having problems figuring out ballistics. I have a Remington 700, 22-250 and I’m using Remington Premier Accutip Boat Tail 50 gr ammo. I have a Bushnell 4200 (6 x 24 x 40) tactical scope. The whole thing is zeroed at 100 yrd. And of course I want to play with the top turret to be able to zero at 200, 300, 400 and 500 yrd . But here’s where I’m having problems. If I use the Remington ballistic chart, (which starts at 150 yrd), it says that my bullet will drop the following inches:
-1.2 inch at 200 yrd
-3.5 inch at 250 yrd
-7.0 inch at 300 yrd

But if I use Remington Shoot computer application, it gives me the following:
-.91 inch at 200 yrd
-2.1 inch at 250 yrd
-3.5 inch at 300 yrd

If I’m shooting gophers at 300 yrd, it could give me a no-hit. I’m I missing something here? Which of the two charts should I rely on?

By the way, where can I find a ballistic chart that will start zero at 100 yrd, instead of 150 like the Remington ballistic chart?

Thank You

What you're missing (in my opinion) is that you're relying on the published ballistic tables. They can make for interesting reading and comparisons, but for the real world, they're almost meaningless.
Why would you sight in a rifle for 100 yds. if you're going to be shooting at 200, 300 or longer ranges? Are you actually putting the shots in the center of the bullseye at 100 yds.?
The only way you're going to KNOW is to take it out and shoot it at various distances. The vast majority of shooters can't judge distances beyond about 100 yds, anyway (if even that). They think 200 yds. is about 400 or 600 and it can get ridiculous. Most of them can't even hold a rifle that steady to hit something the size of a gopher out at 300 or 400 yds. I once read a hunting story by the famous blowhard Elmer Keith where he actually admitted to shooting an antelope at what he guestimated was about 400 yds and it turned out to be a much, much shorter distance.

My rule of thumb with most of my centerfire rifles is to sight them in between 1" and 1 1/2" high (depending on which caliber) at 100 yds.......get a good, tight group and then take it out and see where it shoots at longer distances. For that sighting-in, most of them would be good out to around 200 yds. Depending on the terrain, shooting up and down hills can alter the bullet drop and the shooter's perception of distances. The best way to figure it out is to practice, practice, practice.


Den


.

[dtdtdtdt]

I agree with Ken. The most important accessory for a firearm is ammunition and meaningful practice. Spend several years at a range wearing out a few barrels shooting at all feasible distances to get good enough to kill gophers at 300 yds.

I attempted to answer the question that you asked and hint at the point that Ken was making. Zero the rifle to give an effective range of up to 300 yds and practice at that range. The 2-3" vital area I suggested is pretty accurate for a gopher. To kill gopher sized animals at 300 yds is very difficult. Mind you, it can be done but you must be very good to hit anything that small at that range. The 2" vital zone of a gopher translates to 0.6 Minute of angle shooting (about 0.6" groups at 100 yds or 2" groups at 300 yds.) No matter what your buddies say about their accuracy and their rifles there are very few hunting style rifles (EVEN REMINGTONS!!!) that will shoot less than 0.6" groups at 100 yds or 2" groups at 300 yds. There are even fewer shooters who can do it. All those 1000 yd shots you hear about are mostly hot air, poor range estimation or luck.

The most serious complications for long-range accuracy is wind speed and direction, air temperature and pressure, ammunition quality, and mirage. Wind can easily move a 22 bullet off course by inches at the range you suggest. You specified commercial Remington ammunition. At best it is loaded for some average Remington rifle to certain specifications that are likely looser than the needed 0.6 MOA. The only way to get close to that level of accuracy is a very carefully tuned rifle and handloads with high quality components.

With 50 years of shooting experience and practice, I still probably wouldn't try a 300yd shot on a gopher even if I could see one (eyes aren't that good!) I kill chipmunks with my air rifle at 30-40yds regularly but don't guarantee a hit anytime. I specialize in head shots as I don't like to wound anything so my accuracy is in the range that you aspire too.

I have a friend who is a member of the 1500yd club. He made a witnessed, laser-measured, kill of a prairie dog at 1523 yds last year using a custom .300 Ultra Magnum. He didn't tell me how many he missed to get the one though. You will probably see an article in Precision Shooting magazine about it sometime soon. He writes for them regularly.

So, good luck, practice a lot, and have a great time with a great rifle/caliber combination!

Dave

[pierrecham]

Many thanks to both of you. Maybe I was dreaming when I wanted to shoot a gopher at 300 yds. I'll try to find a farmer that will let me use his open field to practice at 200, 300 and 400 yds. But they're not easy to find, they're afraid you might shoot a cow or something. Like you say, it all comes down to practice, practice and practice again.
I appreciate your help.
Pierre

[dtdtdtdt]

Many thanks to both of you. Maybe I was dreaming when I wanted to shoot a gopher at 300 yds. I'll try to find a farmer that will let me use his open field to practice at 200, 300 and 400 yds. But they're not easy to find, they're afraid you might shoot a cow or something. Like you say, it all comes down to practice, practice and practice again.
I appreciate your help.
Pierre

Pierre:

Join the NRA and start learning about long-range shooting. Separately, there is a magazine called Precision Shooting that lives and breathes long-range precision shooting. It is a tough read sometimes because of the high level of expertise among the members.

I suggest that you find and join a local rifle / pistol club that has an outdoor range that will give you a safe place to shoot. Virtually every US city will have multiple such clubs and ranges available. Many have weekly or monthly matches where you can meet and learn from real experts. Learning to shoot responsibly is the most important thing you will gain. I don't know where you are but a google search for rifle clubs with your city name will probably give you a good start. Each US state has a Rifle & Pistol association that can also direct you to the clubs. Most are private, some are very open, some are very exclusive (and ridgid) in their charters and rules. There are commercial ranges that provide a range for a fee for a specified time. There are many options. Look around to find what you need.

The farmers are rightly concerned about casual shooting on their property. It takes a long time to develop that level of trust with a shooter to allow them to use a field for a range. Safety is the big and main issue. Bullets go a long way and are lethal at ranges measured in miles so be careful, be safe, and have fun!

Dave