Author Topic: long distance shooting  (Read 16625 times)

northmn

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Re: long distance shooting
« Reply #25 on: September 21, 2010, 08:20:56 PM »
The velocity determines "flat" shooting, period.  Sight in determines the distance that one can hit.  some rifles give a higher velocity with a given powder charge than others which may make one seem to shoot "flatter" than another.  Given the same sight in point, ball size and muzzle velocity, two guns will shoot the same at any given distance.  That is simple physics and nothing can change it.  Generally round ball can gain a bit from higher muzzle velocities, but after about 1800-1900 fps most seem to claim that the gains are very small.  Larger bores can retain velocity for longer shots better than smaller bores but take a lot of fule to get the same muzzle velocity.  To get a a dead on sight in hit at 150 yards with a roundball, typically one has to have a very high midrange sight in.  Any statements to the contrary are BS.

DP

Offline Dan

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Re: long distance shooting
« Reply #26 on: September 21, 2010, 09:39:31 PM »
Perception is 90% of reality, give or take.  "Flat" is relative and I think Crow Killer understands that or he would not have mentioned that his other rifles didn't shoot that way.  In ballistic speak 'flat' is a layman's term subject to layman's  interpretation and is undefined.  My flinter came to me "zeroed" at 50 yards with a 50 gr. charge of 3F.  I cannot distinguish a different point of impact at 25 yards, ergo, it shoots flat out to 50 yards, in lay terms.  100 yards is another tale entirely.  I dunno if it goes into the grass or orbit, but it surely doesn't hit the target.  Since CK thinks his rifle shoots 'flat' at 150 yards I'm not going to antagonize him from that distance. ;D  You all can pick on me from 100 yards and be reasonably safe so far as I can figure....assuming I'm using my flinter.  Otherwise, get behind something solid.

I watched a fellow shooting a target ML not too long ago, an odd gun to my eye, also one of recent manufacture.  Barrel was round, about 36" long and 2.5" in diameter.  .56 caliber as I recall, with very sophisticated aperture sights of modern origins.  His load was 200 gr of Swiss 2 FG for this underhammer design. Now I don't know what his take on drop was for this beast but the TOF was VERY short.  Watching the target it was but a barely perceptible delay between the concussive shock wave that slapped my face and the hole appearing on the target...at 200 yards. 

Dunno what you call such a gun...if it was shooting conicals I'd call it a slug gun, but it was a PRB shooter.

All in all I don't think this discussion worth getting spooled up about.  OTOH, I'll get back after a pot of coffee, maybe it is?

Mildly Bored Dan

Offline bob in the woods

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Re: long distance shooting
« Reply #27 on: September 21, 2010, 10:20:48 PM »
Perception of "shooting flat" comes down to what the sight in distance is. If different rifles are sighted in to the same 50 yd zero, and one shoots "flatter" than the other at 100 or 150 yds , then one is getting more velocity for a given load. Gravity always wins, no exceptions. I shoot blackpowder bullet guns out to 1000 yds and beyond. Compared to them, the guy next to me shooting a 7.62 might say that his shoots flat out to 300 + yds...but it doesn't.  Gravity is a constant.
Now, if you think that a gun shoots flat out to a practical range for hunting..then perhaps it is sighted for it's ideal range given it's trajectory.  That's why modern cartridges often have a recommended sight in of 3 inches high at 100 yds [ as an example] which will give a more or less dead on hold  for hunting out to 250 yds to 300 yds or so.  Personally, I sight my flintlock rifles in to shoot dead on at 50 yds, which eliminates any guess work when hunting in the bush here.  If I had a dollar for every time one of our deer hunting group has shot over an animal, I'd be wealthy. They sight in high at 100 yds because that is what the magazines say they should do...and then they take too much front sight 'cause they're excited, and ...miss!!   

karwelis

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Re: long distance shooting
« Reply #28 on: September 21, 2010, 10:30:56 PM »
semantics here?  "flat" is a relative term and it has been acceptable in shooting circles for years to refer to "flat-shooting" guns when in fact we know that the natural laws of physics do not allow true 'flatness' in trajectory.  All inert projectiles follow a ballistic arc. However it is fair to say that some have a 'flatter' arc than others. If that is what crow killer is saying then all need to chill...if he really believes that his trajectory is geometrically flat, then he needs to read up on ballistics, but I think he is speaking in relative terms--right?

yes this is what im talking about. like ive mentioned, my other rifles drop about 12" at that distance, for what ever reason, my hawken seems to be zeroed at 150. i dont see more than 3" of difference at shorter distances, and i havent had the chance to try farther distances with that rifle

Offline Dan

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Re: long distance shooting
« Reply #29 on: September 21, 2010, 11:20:34 PM »
Any y'all remember the write up John Barsness did a few years back 'bout the cartridge he developed called the B29?  Amazing stuff it was, immune to gravity and other magical things.

Offline Leatherbark

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Re: long distance shooting
« Reply #30 on: September 22, 2010, 06:03:17 AM »
I've seen rifles both zeroed at 50 yards. Rifle a shoots 6 inches low at 100 yards . Rifle b shoots dead on at 100 yards.  The reason is that the way the sights are set/filed/height or whatever. Rifle b's sights are set so that the ball is still rising after hitting dead on at 50 yards. Its then high at 75 and then starts falling to be dead on at 100yard.
Rifle a's sights are set/filed and height so that a ball is already starting its downward arc right after 50yards making it low at 100..

Could this be?.........Does any of this make sense?

California Kid

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Re: long distance shooting
« Reply #31 on: September 22, 2010, 06:08:30 AM »
Sure, depends on velocity and weight of ball.

2ndCharter

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Re: long distance shooting
« Reply #32 on: September 22, 2010, 04:58:50 PM »
Calculating ballistics is not an easy thing to do and as such, they give modern snipers handheld computers to setup long distance shots. If you throw out all the other forces, drag, bc, wind etc and just concentrate on the effect of gravity, that is simple to see how quickly a round drops. The gravitational constant is 9.8 meters per second squared.

Someone mentioned earlier that muzzle velocity played a huge part in this. The faster a round gets from point A to point B, a known distance to target, the less time elapses for the gravitational constant to affect drop. You can adjust your sights to shoot a given acceptable range with a degree of consistency but as others mentioned, there is an arc.

Throw in all the other forces and things get squirrelly and complicated really quick. The round is not only moving towards the center of the Earth away from the plane of the barrel the moment it leaves the muzzle but it is also slowing down. Its enough to make your head spin.

Theoretically, you can have a gun shooting flat out to 150 yards but that depends on, again as others stated, what is your perception of flat?

At 1400 fps to a 150 yd target, assuming that the round doesn't slow down which we all know it does, it takes 0.321428571429 seconds to hit. The round will have fallen 0.506593526787 meters from that barrel plane or 19.944627039 inches.
« Last Edit: September 22, 2010, 04:59:39 PM by 2ndCharter »

northmn

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Re: long distance shooting
« Reply #33 on: September 22, 2010, 06:24:15 PM »
I think Jack OConnor started the idea, but it used to be recommended to sight in scoped rifles to hit 3" high at 100 yards.  That would give a "point blank" for decent hits out to beyond 200 yards for varying cartridges.  For a hunting rifle, point blank is where you can hold dead on and still get a lethal hit, but is not the point of aim as such.  They used to also recommend sighting in at 25 yards as that was a distance where the rise equaled the drop farther down range.  This priciple varied according to caliber.  My 270 shoots flat, my 30-30 does not depending on the distance and frame of reference.  At 100 yards it does not matter at 250 it does. 
Dpharsis mentioned the retained velocity of round ball at 100 yards at about 1000 fps, which pretty much holds for the more common calibers of 45-58.  You have to really soup up a 50 to get much gain above that at 100 yards.  If you check the tables a 54 can leave the muzzle about 100 fps slower than a 50 and still hit at the same speed at 100 yards.  Its that rapid loss that messes up a round ball for longer ranges and makes hits beyond 100 yards fairly tricky.   Big bores will have a longer point blank than smaller bores given reasonably similar MV's.  One of the things that may also cause a little perception problem is that some of us used a light charge at 25-50 yards and a hotter one at 100.  Typically 50 users used about 50 grains at 25 -50 yards and 70 or more at 100 yards.  100 yard sight in's may have been a little high.  Also if shot off a rest, different rifles react differently to rests and usually shoot higher. Sight view may be changed if shot off a rested position.   One reason I used to sight an offhand rifle in offhand.   Still, two ball of the same size etc. shot at the same speed drop the same.

DP

Daryl

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Re: long distance shooting
« Reply #34 on: September 22, 2010, 06:25:28 PM »
I didn't have my BC chart handy- so assigned a BC of .080 which is high but close for a .54, I chose 225gr. for ball weight and a .54 cal. as Crow Killer didn't say what it was. Due to the higher BC of the .54's ball, it will be flatter shooting at any mormal hunting velocity than a .50. This will give the most credence to what Crow Killer is claiming for his rifle.

Crow killer noted his rifle "seems to be sighted or zero'd at 150 yards"(who adjusted the sight?). Seems is a strange way of putting it as we choose to sight our rifles at a definite range - our choice - not what someone else has done. If wrong, we re-sight the rifle.  Really doesn't matter here. What does matter, is the midrange trajectory noted - glad it has been acknowledged that there is a midrange.  Zero'd at 150yards but only a 3" midrange seemed a mite flat shooting to me.

I assigned a velocity of 1,900fps - somewhat higher than 100gr. powder will give. We don't know Crow Killer's load nor the velocity he is getting. I assume he has no chronograph.

At 1,900fps and zero'd at 150 yards, that 225gr. ball with a BC of .080 will be 5.1" high at 90 yards, the highest travel in it's arc to the target.

At 1,900fps and zero'd at 140 yards, that ball with a BC of .080 will be 4.1" high at 80 & 90 yards, and will 1.7" low at 150 yards.  It would be difficult to see in a low-shot group if the rifle was zero'd at 150 yards or closer to 140 yards.

In order to hold the midrange to 3" as Crow Killer noted, the rifle would have to be zero'd at 127 yards.  This would give a 70 and 80 yard impact 3" high, and at 150yards, the ball would be 3.7" low, not zero'd - that is impossible to achieve with a round ball with normal, heavy hunting loads.

If we raise the velcity to 2,000fps, which would probably take something like 120gr. of powder, we see perhaps the best possible trajectory.  Sight for 131yards, and the ball would have a 6" kill zone to 150yards. That means the highest midrange is 3" high at 80yards, zero'd at 131yards and 2.9" low at 150yards.  Given one hole accuracy at every range, all the balls would strike within 6" to 150yards. Of course, I hope we all realize this just isn't possible either.  No rifle will put every ball (or bullet) into the same hole - at any range, when hand-held - even rested.

Thus we see it is impossible to have this rifle zero'd at 150yards and give only a 3" midrange trajectory.  It is impossible, whether it be a .50, .54 or .58 - smaller than .50 or larger than .58 - does not compute - won't happen.

When a person says his rifle shoots -------- 'about'     or    'seems to'    or    'approximately'   -  he is talking about perceptions, not actual fact.

« Last Edit: September 22, 2010, 06:33:46 PM by Daryl »

karwelis

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Re: long distance shooting
« Reply #35 on: September 22, 2010, 07:43:26 PM »
Crow killer noted his rifle "seems to be sighted or zero'd at 150 yards"(who adjusted the sight?). Seems is a strange way of putting it as we choose to sight our rifles at a definite range - our choice - not what someone else has done. If wrong, we re-sight the rifle.  Really doesn't matter here. What does matter, is the midrange trajectory noted - glad it has been acknowledged that there is a midrange.  Zero'd at 150yards but only a 3" midrange seemed a mite flat shooting to me.

its not so strange if you take into account that the rifle is 32 years old, and i liked the way it shot when i got it

Daryl

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Re: long distance shooting
« Reply #36 on: September 22, 2010, 07:53:17 PM »
If a 5" midrange is just right for you, than that's what is important. You are the final judge as to what's right.  In my opinion, a 5" midrange is a bit high for dear, too high for anything smaller actually less than what can be used for moose or elk.  For the larger game, a 5" midrange, giving a 150yard zero would make for easy hitting at any range to about 165yards, about the farthest I'd be shooting at one of them with a .54 with a 110gr. to 125gr. powder charge.  A130yard zero would be a better sigthing for hunting - for me.  Here, the odd shot across a timber slash is necessary for elk, however bull moose are usually easily called in to 100 yards or closer - generally very much closer - to within 10feet sometimes.

mike e

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Re: long distance shooting
« Reply #37 on: September 23, 2010, 05:43:28 AM »
Crow Killer, some people gotta see it to believe it. Shoot a three shot group on a bulls eye target (one that has graduated lines on it) at 150 yards with a center of mass sight picture.  Then shoot a second three shot group at 75 yards on the same target using the same center of mass hold.  Take a picture and post it. If the rifle shoots flat both groups will be in or near the center of the bulls eye. I think the 75 yard group will be higher on the target than the 150 yard group.

karwelis

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Re: long distance shooting
« Reply #38 on: September 23, 2010, 08:11:08 AM »
im pretty sure the 75 yard ones gonna be a taste high also, like 3" like i said in an earlier post

mike e

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Re: long distance shooting
« Reply #39 on: September 23, 2010, 04:25:32 PM »
A picture is worth a thousand words.

Daryl

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Re: long distance shooting
« Reply #40 on: September 23, 2010, 06:05:17 PM »
It appears the 3" trajectory over 150 yards is being claimed for a 60gr. 3F load.  Considering 80gr. 2F gives between 1,400fps and 1,420fps from a .50 cal. having a 42" barrel, I assume the velocity for 60gr.3F  to be between 1,400fps and 1,600fps as a very high outside-the-box-type speed.  The .50 RB has a ballistic coefficient of .072.

note, Crow Killer- this is pure fact - ie: physics - taken for an elevation of 500 feet ASL, sight height of .75" above the bore's axis at fired at  70degrees.
Yes- some guns shoot differently, in that some give better accuracy, or higher speeds - but - the do not make a projectiles defy the laws of gravity.


The 1,400fps highest trajectory for a .50 cal zero'd at 150 yards is 8.86" (80yds).  - midrange, ie: 75 yard height is 8.79"
The 1,600fps  highest trajectory for a .50 cal. zero'd at 150 yards is 7.54"(80yds). - midrange, ie: 75 yard height is 7.46"
« Last Edit: September 24, 2010, 05:52:42 AM by Daryl »