questions on bullet angle and ricohet

[Butleroutdoors]

Hello
Having discussions with shooting buddies on bullet arc, arc when past the target and ricohet. Hopefully my questions make sense.

When shooting past ELR yards, any thoughts on the actual bullet angle when it impacts the target?

For example, using ballistic AE, 300 Win Mag, 29.92, 59.9 degrees, 0% humidity, zero wind, 190gr Sierra MK BTHP, 2900 fps. The drop at 1200 yards is 509.2"

1. what would be the impact angle into the target? Does it arc into the target or is it straight in?

2. If one was shooting paper at that distance, when the bullet impacts, does it continue it's downward trajectory and impact a few feet pass the target?

3. At these distance, assuming the argument of the bullet is arcing down, on a miss, what is the probability of a ricohet?

Thank you in advance for your wisdom

 

[TripleBull]

For example, using ballistic AE, 300 Win Mag, 29.92, 59.9 degrees, 0% humidity, zero wind, 190gr Sierra MK BTHP, 2900 fps. The drop at 1200 yards is 509.2"

2. If one was shooting paper at that distance, when the bullet impacts, does it continue it's downward trajectory and impact a few feet pass the target?

Depending on the overall geometry of the setup, impact can be a ways past, not just a few feet.

3. At these distance, assuming the argument of the bullet is arcing down, on a miss, what is the probability of a ricohet?

In my experience, most bullets ricochet at ELR, but I shoot at a spot with a clay base and a gravelly surface. If you have a backstop, bullets often auger in. As is: it depends.

 

[J!m]

509 inches over 43,200 inches is 1.1%, so not a huge arc despite "shooting" 42+ feet high. I'd say it's coming in fairly flat. assuming no wind pushing it strangely anyway.

Ricochet will depend on what it hits and how. It will also depend on how much energy it has at the point of impact as well. Triplebull's answer to #3 is accurate I'd say.

 

[lash]

When talking angle of approach, consider what you dial on your scope to impact at 1200 yards. Chances are its somewhere around 11-13 mils or 35-45 MOA. Well, then you realize that it takes 60 MOA to make up 1 degree of angular elevation, you'll have a better idea of the angle of approach, even though angle of launch and angle of approach are not equal.

 

[Hoffer]

As far as ricochets check your velocity at target on your calculator. Even at very long distances velocity can be well over 1000 FPS. Thats more that a 45 ACP at the muzzle.

I also have been thinking about angle of impact at our 2000 yard targets. Usually when there is a miss that can't be spotted it just over the top of the target. Hopefully someone has an idea of impact angle at distance.

Quick common sense solution
2000 yards with my 338 improved is 66 moa elevation. That is 1.1 degree barrel angle. Assuming that max height is 5/8 - 3/4 of the way downrange the angle from there to the target will be greater than the initial angle. Maybe 2 degrees or more at target (2000 yards) 2 degrees = .4" per foot

 

[Ankeny]

I was a wild land fire safety officer a few years back for some firefighter training exercises at Camp Gurnsey in Wyoming. I had to coordinate my safety plan with the military safety officer before we were given the green light by the Colonel. Thus, my introduction to Danger Surface Zones. The military has studied and over analyzed ricochets in great detail. If you Google danger surface zones you can find all kinds of information, including DSZ calculators.

 

[Bravo6niner]

I don't have anything scientific to add to this but will say ricochets at the last machine gun shoot I shot at was impressive and eye opening. We had targets to about 1.25 miles and a lot of 50 bmg's with tracers on the firing line. Even with impacts in the dirt close to 1.5 miles out some of the ricochets went a lot farther than expected and the direction they ricocheted was very random and unpredictable. Even 308 tracers at a 1+ mile still had enough energy to impact the dirt and continue on for a long ways!!!

 

[Mordamer]

You can get a very close approximation of impact angle from your ballistic calculator and a little trigonometry. Take your shooting distance and see what the drop difference is if you add 10 yards. Arcsine(drop difference/360) will give you a very close approximation of impact angle.

For example, my 6.5x47 lapua at one mile is dropping 26 inches every 10 yards. Arcsine(26/360)=4.1 degree impact angle.

 

[SIDS01]

Hello
Having discussions with shooting buddies on bullet arc, arc when past the target and ricohet. Hopefully my questions make sense.

When shooting past ELR yards, any thoughts on the actual bullet angle when it impacts the target?

For example, using ballistic AE, 300 Win Mag, 29.92, 59.9 degrees, 0% humidity, zero wind, 190gr Sierra MK BTHP, 2900 fps. The drop at 1200 yards is 509.2"

1. what would be the impact angle into the target? Does it arc into the target or is it straight in?

2. If one was shooting paper at that distance, when the bullet impacts, does it continue it's downward trajectory and impact a few feet pass the target?

3. At these distance, assuming the argument of the bullet is arcing down, on a miss, what is the probability of a ricohet?

Thank you in advance for your wisdom

1. I put your inputs into AB Analytics and guessed at the remainder. The 1190 yard elevation was 11.59 mils, 1210 yards was 11.99 mils, for a 0.4 mil drop over 20 yards. 0.4 mils at 1200 yards is 1.2 * 36 * 0.4 = 17.3". It covered 20 yards or 720". ATan(17.3/720) = 1.4 degrees. The required elevation was 11.79 mils * 3.45 moa / mils * 1 degree / 60 moa = 0.7 degrees. It goes through the target at about twice the angle it left the muzzle at. 2000 yards gave a similar ratio.

2. It definitely keeps falling, but probably not at as severe an angle as most think. The football like arcs you see in trace are an illusion created because you don't sense the distance out nearly as well as the height. 509" seems like a lot, but it's not compared to the 43,200" it's covering straight away from you.

3. As discussed in earlier posts, it depends on the angle of the backstop and how hard the whatever it hits is.

 

[TripleBull]

I agree that these are good starting point approximations for impact angle. But are you assuming a level shooting range? Where I shoot ELR, the terrain is rolling hills so at 600 yards, the impact zone is 30' below the firing line, at 1K, the impact zone is about level with the firing line and at 1 mile, impact is 20-30' above the firing line. All those differences will have finite impact. Now imagine a large delta, like shooting from a canyon rim down into the drainage, etc. Similarly, once you get out into lower transonic and especially subsonic, bullet drop gets pretty steep compared to the estimates above.

Bravo6niner, with respect to ELR shots ricocheting a long way, it blows my mind to listen to bullets tumbling so long after impact. With the target at 1 mile, I often hear 2 to 4 seconds of tumble after impact. As an example, a 338 LM at a mile, depending on the gun, load, altitude, bullet, etc., you're somewhere in the lower supersonic range down into transonic. I don't know how much velocity gets scrubbed off by ground impact, but even if the velocity is only 500 fps after impact, the bullet is probably going 300 to 500 yards on the first bounce on some of the ricochets I've witnessed - maybe double or triple that. I'd guess it's highly variable as some sound like they get kicked up fairly high.

The sounds of ELR out in the target zone are pretty awesome.

 

[strikeeagle1]

I use the distance of a known size target within a calculated distance (Applied Ballistics) of a "danger space", the interim distance being where the bullet will strike just the top of the target and subsequently its lower edge. Using this type of model is also useful if the shooting position is at a different elevation than the target elevation.

Then simple trigonometry to get a first order approximation of the angle of incidence to the target. As the bullet path is a parabolic curve with a constantly changing radius one can imagine that the bullet position anywhere along that curve is just the trigonometric "tangent line"; from calculus are infinite number of tangents along a radius. The tangent is an infinitesimally small "straight line".

 

[Gunfighter14e2]

Even 308 tracers at a 1+ mile still had enough energy to impact the dirt and continue on for a long ways!!!

What 308 tracer were they using to still be lit at that range? Because every 308/7.62x51 tracer I've seen has went dark at 1200-1400 yds. I've seen Russian 7.62x54r stay lit at a mile but never a US made projo.

 

[strikeeagle1]

^^^ I was only addressing the this aspect of the OP's inquiry and not any ricocheting aspects.

When shooting past ELR yards, any thoughts on the actual bullet angle when it impacts the target?

1. what would be the impact angle into the target? Does it arc into the target or is it straight in?

2. If one was shooting paper at that distance, when the bullet impacts, does it continue it's downward trajectory and impact a few feet pass the target?

#2 is essentially the concept for danger space calculations.

For the common shooter, it's all mathematical speculation as it would be virtually impossible to actually measure such angle, however beginning with the calculated danger space for any DOPE provides the required variable of distance to get a sense of solutions to the question. At short range the danger space is somewhat like PBZ because the angle of incidence is very small. At greater distances the danger space is increasingly smaller, thus the angle of incidence to the target margins ("drop-in zone") proportionately greater, as appreciated by viewing the illustrative diagram.

 

[lash]

So, if the OP was really inquiring about danger space, then why would he have posted in the ELR section (unless it was a mistake)?

Originally posted by Butleroutdoors View Post
When shooting past ELR yards, any thoughts on the actual bullet angle when it impacts the target?

 

[strikeeagle1]

It seems clear from the syntax that the OP was inquiring about bullet angle impact. I only interjected danger space as it is a distance that can be mathematically modeled and it seems to be quite a natural extension of understanding how an angle of interest could be calculated. The bullet impacting any target is always impacting via an arc, the tangent to such an arc at any given point on the trajectory path will provide the angle of incidence on the arc, thus the answer to the OP's inquiry. The reliability of the angle information is based on uncertainties in the mathematical modeling.

 

[Bravo6niner]

What 308 tracer were they using to still be lit at that range? Because every 308/7.62x51 tracer I've seen has went dark at 1200-1400 yds. I've seen Russian 7.62x54r stay lit at a mile but never a US made projo.

The m25 pulled projectiles from 30-06 ammo can stay lit for past a mile. Like all tracers the distance from which they light and burn out is inconsistent but some will burn for a good distance past a mile.

 

[Butleroutdoors]

This is good and educational discussion and very professional. Thank you, Much to ponder.

I had not heard of the Danger Space concept so very interesting to read the army manual that was referenced above. Makes sense the math on the bullet angle into the target, really very shallow.

Yes, wanting to make sure private range continues to be safe and good to do a 5 year safety review.

Have one range 0-500 yards with decent hill behind it. What is now making think is if I miss the 500 yard target that has less chance of a ricochet going over the hill because the target is at the base of the hill verses missing say the 100 yard target which may go over the hill?

On the second range 935 to 1300 yards (static target, shooter moves), the target has gentle sloping prairie hill which starts maybe 300 yards behind it and is probably 3 degrees above shooters straight line (but the actual shot is a down angle into the target). Two and a half miles from the shooters position in line of fire to the target are structures.

Both hills on the two ranges are prairie hills, flint rock base with 1-2" soil and prairie grass.

So im really starting to think thru back stops and richocts. Sorry to ask another question, is there a calucator that will tell you maximum distance a bullet will travel at a certain angle? My thought if someone was shooting what we think is "safe" 100 yards and by accident pulls the trigger with the gun 30 degrees in the air, how far will that bullet travel before it impacts I read last night the optimual angle is 35 degrees, is that correct?

 

[Gunfighter14e2]

The m25 pulled projectiles from 30-06 ammo can stay lit for past a mile. Like all tracers the distance from which they light and burn out is inconsistent but some will burn for a good distance past a mile.

Interesting, as I've never seen an Orange tip stay lit past 1400, be it issue ammo or reloads.

 

[TripleBull]

is there a calucator that will tell you maximum distance a bullet will travel at a certain angle? My thought if someone was shooting what we think is "safe" 100 yards and by accident pulls the trigger with the gun 30 degrees in the air, how far will that bullet travel before it impacts I read last night the optimual angle is 35 degrees, is that correct?

I can't find a bookmark but in the last year or so, I ran across an article written by (IIRC) Marine instructor that gave some info he'd generated with 50 BMG and 308. An elevated muzzle like you mention (30-35 degrees) is a serious accidental discharge. I seem to remember them observing highly variable impacts in the 3 to 5 mile range for the 50 BMG. See post # 7 here:

https://www.thehighroad.org/index.php?threads/50-cal-effective-range.159729/