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Posted: 8/19/2004 5:29:55 PM EST
I went shooting the other day and did some longer range shooting. It seemed that about 200 yards I would get about 10 inches of bullet rise. I am shooting a 16" Bushy with Federal ammo, I also noticed the same rise with Winchester white box and Wolf. I have the weapon sighted in at 50 yards, is this normal?
Link Posted: 8/19/2004 5:57:56 PM EST
Yes, because the sights line up at an angle to compensate for drop (ie you are actually aiming up a little). For example if you do a proper BZO at 25 meters, it will also be point of impact at 300 meters. So any target within 300 meters will impact above a couple of inches or at the point of aim and below a couple of inches after 300. That is why the .mil teaches to shoot COM, and why the platform is so effective.
Link Posted: 8/19/2004 6:25:22 PM EST
line of sight and bullet path - two different things
Link Posted: 8/19/2004 7:07:36 PM EST

Originally Posted By firehawk-356:
I went shooting the other day and did some longer range shooting. It seemed that about 200 yards I would get about 10 inches of bullet rise. I am shooting a 16" Bushy with Federal ammo, I also noticed the same rise with Winchester white box and Wolf. I have the weapon sighted in at 50 yards, is this normal?



The short answer is ... maybe.

If your 16" Bushy is zeroed at 50 yards, you should be hitting pretty close to zero at 200 yards as well. If you were using the same sights (not a different rea aperture, for example), what often happens at distance is one tends to cover more of the target with the front sight causing high hits.

If you hold center at 50 and hit center, then if you hold center at 200 you should hit center.

The term "bullet rise" can be a little misleading. The instant a bullet leaves the muzzle, it begins to drop. The reason a bullet will hit higher (or lower, for that matter) than Point of Aim at distances is because of bullet trajectory.

With your gun, when you zero at 50 yards, the bullet is still going up as a result of your barrel being pointed slightly up at the time the bullet left the muzzle. Somewhere around 125 yards, the bullet will start to descend in its trajectory until it again passes your Point of Aim at 200 yards. Beyond 200 yards it will continue to strike lower as a result of its trajectory.

Clear as mud, right? Anyway, hope it helped.
Link Posted: 8/20/2004 5:14:18 AM EST

Originally Posted By firehawk-356:
I went shooting the other day and did some longer range shooting. It seemed that about 200 yards I would get about 10 inches of bullet rise. I am shooting a 16" Bushy with Federal ammo, I also noticed the same rise with Winchester white box and Wolf. I have the weapon sighted in at 50 yards, is this normal?



Yes you should have rise.

But 10" at 200y? If you rifle is really zeroed at 50 yards - and assuming your optics are the proper 2.6" over the bore (not a scope mounted on top of a carry handle). Then your round should only be 1"-2" high at 200 yards.

If it's 10" then you need more practice...
Link Posted: 8/20/2004 5:20:45 AM EST
Link Posted: 8/20/2004 5:47:54 AM EST
[Last Edit: 8/20/2004 11:55:23 AM EST by Vector_Joe]
*I* think that edited to add: SOME rise should be normal at intermediate ranges but not 10 inches, but by the time it gets to 200, then it should be hitting a bit lower than poa. But I guess it depends on the ammo. If by WinWhite, you mean q3131a then it may be a bit higher, but see below for a generic 55gr .223.

This picture is just using generic 55gr .223 remington and it shows that you should be about 2 inches low at 200Y for a 50Y zero.
Link Posted: 8/20/2004 5:52:34 AM EST
Tagged
Link Posted: 8/20/2004 6:39:28 AM EST
Was this with iron sights or an optic, and was the optic on a carry handle or flattop?

Sight height above the bore makes a difference in trajectory above or below the sight line.



Lonny
Link Posted: 8/20/2004 7:31:36 AM EST
I wish every one of my uninformed buddies would surf this site. I've aurgued till I'm blue in the face that bullets will not rise coming out of a level barrel. Laws of physics state that it will start to drop as soon as it leaves the barrel. Like someone said line of sight is different than trajectory. If your barrel is slightly point upwards then yes, the bullet will rise before it starts to fall. I know this reply wasn't really appropiate for this thread so please excuse my ranting.
Link Posted: 8/20/2004 8:25:14 AM EST

Originally Posted By Vector_Joe:
*I* think that rise should be normal at intermediate ranges, but by the time it gets to 200, then it should be hitting a bit lower than poa. But I guess it depends on the ammo. If by WinWhite, you mean q3131a then it may be a bit higher, but see below for a generic 55gr .223.

This picture is just using generic 55gr .223 remington and it shows that you should be about 2 inches low at 200Y for a 50Y zero.
iceknightconsulting.com/traj_50yz.jpg



Your trajectory graph shows a sight height of about 1.5"

Normal sight height for an AR-15 is 2.5"

I think if you re-run the numbers with the correct sight height, you will find the POI at 200 pretty close with a 50 yard Zero.
Link Posted: 8/20/2004 8:37:48 AM EST
[Last Edit: 8/20/2004 9:22:34 AM EST by StealthyBlagga]
The following data and chart shows the trajectory of XM193 from my 16" carbine (a Dissipator with regular iron sights):



Note that M16/AR15 iron sights are marked in meters, but most ranges here are in yards; I have added yellow highlighting to indicate the yardage closest to the metric zero. Hope this helps.
Link Posted: 8/20/2004 9:18:26 AM EST
Bullet arch path, and sight line of view threw the sights.

The bullet never rises above it initial flight path (bore line of the barrel), its just the bullet is shot at a upward arch to allow gravity to pull it back down to strike the target at the desired point/distance. Since the sighting plain is above the bore line, then the sight path will be looking down and intersect with the bullets travel in space at two different points. Often, when referring to sighting in at short ranges, the bullet is referred to as climbing, but in fact, its the increased angle of the sights to looking down to intersect the bullet path at the shorter distance that is being referred to.


P.S. The last small arms bullet that I am aware of that had to ability to climb, dive, go both right and left of the bore flight line was the one used to kill JFK. Since I’m not buying the ricocheting story given by the goverment, my guess is that this smart bullet/ rifle was invented and produced at Area 51 way back. Now some years later since the military is "designing" rounds that are smart (can do just that), maybe the bullet/ rifle has already been issued to black ops/ people in the know, and they are designing a cover story to one day release it the public sectors of the government.

[Just another conspiracy theory, and that possibility that that your friend are in the loop regarding the truth. The problem now that you have posted this information of the climbing bullet, have broken their cover, they may just have to take you out to conceal the secret. If you don’t post anymore, then at least we know what happen.]



Link Posted: 8/20/2004 10:16:32 AM EST
[Last Edit: 8/20/2004 11:57:07 AM EST by Vector_Joe]
Gaijin,

You are correct. Changing that made the difference (edited to add:) between zero at 50 yards and impact at 200 yards is something like .001".

Basically my point was that 10" is a bit much.

Here is the revised for the proper sight over bore height:

dashed line at 0 inches is the line of sight/line of aim
arced line is actual trajectory of projectile

Link Posted: 8/20/2004 11:17:20 AM EST

Originally Posted By Vector_Joe:
*I* think that rise should be normal at intermediate ranges,



No it is not.

A rifle zeroed at 50 yards will only have variance of 2" off the point of aim to around 220y.

The only time 10" would be seen at around 200y would be if he zeroed at 25y. I think we're all assuming he zeroed on a measured range and his 50y comment was accurate.
Link Posted: 8/20/2004 11:22:19 AM EST

Originally Posted By Vector_Joe:
You are correct. Changing that made the difference something like .001".



How is 2" low vs 0" low a difference of .001? Your second chart plainly shows the bullet intersecting the line of sight at 200y.
Link Posted: 8/20/2004 11:50:40 AM EST
[Last Edit: 8/20/2004 11:52:07 AM EST by Vector_Joe]

Originally Posted By Forest:

Originally Posted By Vector_Joe:
*I* think that rise should be normal at intermediate ranges,



No it is not.

A rifle zeroed at 50 yards will only have variance of 2" off the point of aim to around 220y.

The only time 10" would be seen at around 200y would be if he zeroed at 25y. I think we're all assuming he zeroed on a measured range and his 50y comment was accurate.



I didn't say it would rise 10 inches, I just that it would rise.

eta: I see that it could be read that I said that 10 is normal but that is not what i meant.

I meant to say that SOME rise should be normal at intermediate ranges.
Link Posted: 8/20/2004 11:53:47 AM EST

Originally Posted By Forest:

Originally Posted By Vector_Joe:
You are correct. Changing that made the difference something like .001".



How is 2" low vs 0" low a difference of .001? Your second chart plainly shows the bullet intersecting the line of sight at 200y.



I'm not comparing the 2 charts. I was saying that according to the computer, if you zero at 50 yards, the bullet should be .001" low at 200 yards (with the new sight over bore height).

Jeez relax.
Link Posted: 8/20/2004 1:14:34 PM EST
With iron sights issues of size of aiming point and exact sight picture can have an effect on zero that makes zeroing an as-is deal. Either that or you have to change your sight picture a little to make it work.

Mild (Mostly White Pasters) Bill
Link Posted: 8/20/2004 7:50:38 PM EST


firehawk-356,

Is any of this making sense to you?

If not, let us know and we will try to make it clearer.

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