Effective Range

[danteh]

I have been wondering this for awhile now. The C7A1 has an effective range of 400m does that mean that after 400m the bullet will begin to drop and the wind and gravity will take into place?

Basically if I'm at a target range and I shoot at a target 350m away. If I aim dead on him, will it hit? Likewise, if I'm shooting at a target 500m away, would I need to aim a few inches above him to compensate for bullet drop?

 

[dangerboy]

You will be taught all this on the BMQ and if you are qualified ask your Sect Comd

 

[Recon 3690]

A 62 grain 5.56 mm bullet leave the 20" barrel of a C7 at Approx 3300 feet per second with about 1200 foot pounds of  energy, as it travels down range it looses both velocity & energy. Effective range is the calculated distance that the bullet will still do what it was intended to do, remaining energy is the most important at this time. In theory at 1500 meters the bullet will still punch through a paper target but will only bruise skin on a person because energy is pretty much exhausted at this point. Same bullet from a 16" C8 barrel would probably bounce off the paper at 1500 m. Barrel length has a lot to do with velocity & energy that's why effective range of C7, C8, & C7-CT are all different. With your 5.56 ammo a 26" barrel would give you the optimum ballistics but is tactically impractical. Check out the barrel lengths on the C14 & C15.

 

[brihard]

'Effective range' simply means that it can be reasonably assumed that a trained soldier can effectively hit a target at that range under normal conditions.

The 5.56mm round will carry on significantly farther than that with the ability to kill, but from the instant the bullet leaves the barrel a massive number of factors begin to impact on the flight of the bullet. Moreover, as the distance to target increases there is a great impact on time- time for the bullet to vary in its path, time for the target to continue any movement that was underway when the bullet fired. Also, at increasingly greater ranges the bullet has less lethal terminal effects on entering a soft target. It's absolutely possible to kill a person with a C7 at 6 or 700m, it's just not likely to happen.

The effective range quoted simply means that the average soldier, proficient with his or her weapon, should be able to put rounds effectively into a man sized target.

Say your C7 is zeroed in for 200m. At that range, assuming a perfect shot, the bullet will strike exactly where you aim. Since your sight is mounted a couple inches above the barrel, the bullet is actually rising in its trajectory for the first two hundred meters. At 100m, for instance, a bullet will strike the target below the point of aim because it has not yet risen to the apex of its trajectory. From there it then starts falling at an increasing rate. Throughout all this, wind resistance is slowing the bullet down, wind across the bullet's path will blow it laterally at an increasing rate, and so on an so forth.

'Effective range' is not a hard and fast rule by any means. It's just an approximation of at what distance a soldier can be expected to employ the rifle in a tactically effective manner. Just because you can hit a dude with a C7 at 400, for instance, doesn't mean that may be your best bet- at that point you're in the envelope for support weapons and indirect fire from any number of sources.

 

[Fusaki]

Say your C7 is zeroed in for 200m. At that range, assuming a perfect shot, the bullet will strike exactly where you aim. Since your sight is mounted a couple inches above the barrel, the bullet is actually rising in its trajectory for the first two hundred meters. At 100m, for instance, a bullet will strike the target below the point of aim because it has not yet risen to the apex of its trajectory. From there it then starts falling at an increasing rate. Throughout all this, wind resistance is slowing the bullet down, wind across the bullet's path will blow it laterally at an increasing rate, and so on an so forth.

Not quite.

For a 200M zero your point of impact should be roughly 3" higher than your point of aim (with your C79 set on 200m) from the 100m firing point. The bullet will reach the apex of it's trajectory prior to 200m.

I'm sure someone will come by with the exact numbers...

 

[Recon 3690]

For the most part he's right except effective is a calculation of ballistics of the weapon, cartridge, powder, & bullet not the soldier, give me a C7-CT [MRS] and a Leatherwood ART IV & I will hit targets all day at 700 m (but they will only die with perfect shots head or heart) with a C3 or an AR-10T [MRS] 700 m they will die, with a C14 1000 m, with a C15 1500 m +. With a standard C7, C7A1, or C7A2 at 700 m all you are going to do is wound them if you even hit them. Effective Range is a mechanical & physical limitation of the weapon & ammo combination. Or is the effective range of a artillery piece the physical ability of the Bombardier pulling the firing lanyard?

 

[Michael OLeary]

Wow, anyone else have a bucket-full of irrelevant numbers to toss in the mix?

The one point that has been missed is that the "effective range" of any weapon system has less to so with physical weapon characteristics under ideal conditions, or possible training competencies, than it has to do with tactical planning considerations under (ultimately) unknown or "any" conditions on the battlefield.

The effective range of the service rifle is used for planning tactical engagements and ensuring troops are placed where they can engage appropriate enemy personnel. It doesn't matter if you put together a platoon of sharpshooters, you don't suddenly plan for a different effective range based on employing that group of soldiers, because when your unit gets replaced by another unit in location, they're screwed because you changed the parameters of the planning process.

 

[Recon 3690]

I have been wondering this for awhile now. The C7A1 has an effective range of 400m does that mean that after 400m the bullet will begin to drop and the wind and gravity will take into place?

Basically if I'm at a target range and I shoot at a target 350m away. If I aim dead on him, will it hit? Likewise, if I'm shooting at a target 500m away, would I need to aim a few inches above him to compensate for bullet drop?

part of the question was what is meant by 400 m effective range thats what I replied to before getting off track effective range of a C7 is 400 m maximum range is about 2000m (but useless) that the bullet will pysically travel before hitting a zero zero point. Tactical range is usually 200 m thats why you zero your weapon at 200 m. I imagine in Afganistan it is probably 50 m of less.

 

[ballz]

You zero your rifle at 100m... The Elcan optic that is issued is meant to be zeroed at 100m. It has different markings on it to help judge distance and such, which you can adjust your optic accordingly to, which would be all haywire if you zeroed at 200m.

Also, you don't normally zero a rifle at the top of the bullet's trajectory anyway, or at least I don't. I have a .243 (not much bigger than a 5.56) that I use .243 Win ammo with. My friend who has a huge hard-on for rifles and ammunition helped me determine the cross-trajectory point for 300m which was about 103m. I zeroed 'er in for 103m and now a 103m or 300m shot needs no compensation for elevation, and a 200m shot doesn't need much compensation.

EDIT: I guess I should say that you are "taught" to zero at 100m, obviously each individual soldier that spends a lot of time with his rifle will probably do it whichever way works for him.

 

[Recon 3690]

So you know then that due to sectional density & ballistics coeficient that a 6mm or 25 caliber or 243 bullet has the flatest trajectory of any bullet on the market and that your numbers also work for a 6 mm Remington or 25-06. A 243 Winchester is just a necked down 308 Winchester (7.62 x 51 mm NATO) with a better effective range than said 308 and would be a better cartridge for the marksman's rifle then the 7.62.

 

[Recon 3690]

With a Leatherwood you insert the proper caliber adjustment cam and zero at the muzzle with a bore sighter. Then when operational you use the onboard range finder dial in the range with the cam and where the the cross hairs are is where the bullet goes out 1200 m.  A Canadian issue Pattern 1914 (Lee Enfield # 3) or a issue M1917 (Lee Enfield # 3) has an effective range of 1000 m with iron sights that made that range feasible when zeroed at 100 m. Thus each piece of equipment you use has its own characteristics and effective, maximum effective, & maximum range is is determined by the weapon, internal ballistics, & external ballistics of its cartridge. 

 

[ballz]

So you know then that due to sectional density & ballistics coeficient that a 6mm or 25 caliber or 243 bullet has the flatest trajectory of any bullet on the market and that your numbers also work for a 6 mm Remington or 25-06. A 243 Winchester is just a necked down 308 Winchester (7.62 x 51 mm NATO) with a better effective range than said 308 and would be a better cartridge for the marksman's rifle then the 7.62.

Well, to answer your question, which could have been more easily worded "Do you know that a .243 has flatter trajectory than .308 and do you know why?" Yes I did know that a .243 is a more accurate rifle and no I did not know why (I certainly won't pretend to be a ballistics expert).

Seems you are somehow offended by my response though since you are gone off on some fit trying to make simple things sound complicated ("6mm or 25 caliber or 243 bullet").

My question for you is wtf does your little "I'm smarter than you" rant have to do with what I said about zeroing the service rifle at 100m? Or what I said about somebody else finding my cross-trajectory point for me so I could zero my own personal rifle at that range?

 

[Recon 3690]

I am a trained & fully qualified gunsmith and ballistician. I also never failed to qualify Marksman on the C1A1, C3A1, or Browning high power on yearly quals.

Long distance is the next best thing to being there.

One shot one kill.

 

[ballz]

And in no way did I doubt your qualifications or credentials, or put my own (very limited) above them..... so the question still stands, wtf is your point?

 

[Recon 3690]

I probabily get way to wordy trying to explain things, point is when the pam says effective it is a mechanical function not a human one. The 243 was just trivia for you. I'm not offended like I said I just get to wordy, might be a left over from Jr NCO.

 

[Fusaki]

You zero your rifle at 100m... The Elcan optic that is issued is meant to be zeroed at 100m. It has different markings on it to help judge distance and such, which you can adjust your optic accordingly to, which would be all haywire if you zeroed at 200m.

Also, you don't normally zero a rifle at the top of the bullet's trajectory anyway, or at least I don't. I have a .243 (not much bigger than a 5.56) that I use .243 Win ammo with. My friend who has a huge hard-on for rifles and ammunition helped me determine the cross-trajectory point for 300m which was about 103m. I zeroed 'er in for 103m and now a 103m or 300m shot needs no compensation for elevation, and a 200m shot doesn't need much compensation.

I can see how the terms and wording that you're using here could get confusing.

-The C7 and the C79 scope are normally used with a 200m zero.  This is the army standard, and I don't see why 99% of us would want to use anything different.

-Typically, we get our 200m zero by shooting on a 100m range and adjusting our point of impact slightly higher - about 3" - then our point of aim. Shooting at 100m instead of 200m allows guys to shoot tighter groups for the purpose of calibrating the weapons system, which is really all zeroing is.

 

[ballz]

Okay, granted, but I just did the better part of a weekend BMQ course in order to prepare for my upcoming BMOQ course in May, and I could swear we were being taught to zero at 100m. My memory is obviously deceiving me, oh well, it's probably because I was thinking "I'll zero this how I damn well please when it really matters" in the back of my head.

 

[Fishbone Jones]

Go see your instructors and tell them you want a copy of 'Shoot to Live' - B-GL-382-001/PT-001.

In it, you'll find gems like:

C7/C7A1 Service Rifle. The C7/C7A1 Service
Rifle is the principal personal weapon of the
Canadian Forces, and has a maximum effective
range of 400m. Its role is virtually universal as it
can be employed throughout the entire spectrum of
conflict.

ZEROING
96. General. The purpose of zeroing is to “superimpose the
Mean Point of Impact onto the Correct Zero Position” so that the
grouping will form centrally at all ranges, given the appropriate sight
setting and correction for wind. Zeroing is the adjustment of sights
achieved by live firing and the actions of the shooter, the coach and
the Weapons Technician to bring the rifle sights into a position so
that when accurately fired by the soldier for whom it has been
adjusted, the weapon fires bullets to the centre of the target.

and,

Distance. Zeroing should be carried out on the
100 m range, which affords accurate reading of
error. Zeroing may be carried out at the 25 m
range if the 100 m is not available. It should be
noted that the shorter the zeroing range, the greater
the inaccuracies at longer ranges. As a general
rule zeroing at 25 m should only be conducted for:
(1) instructors, to ensure reasonable
alignment of sights for preparatory
training of recruits; and
(2) trained soldiers when facilities are not
available.


Just about everything the common dog needs to know about musketry is in this publication.

Get a copy and read it, all will become clear.

As far as Leatherwood optics is concerned, it's a non starter and a waste of discussion here. Most, if any, will not have an opportunity to use that item during their service, let alone even see one. Unless, of course, you buy your own and put it on your gopher gun.

 

[geo]

Ballz...
You don't really zero your weapon however the he!! you feel like it.
- Under normal circumstances, you will 1st bore sight your C7 with the Elcan C79 sight...
Then you will zero your weapon on a range - at what should be 200m.

It always matters

 

[Fishbone Jones]

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