# .223 trajectory question



## ckamanao (Mar 20, 2010)

I have a question on bullet travel for a .223. I'm shooting a 55gr sftpt out of an LMT Defender with a 16" barrel. I've got a IOR Valdada 1.5-8x scope mounted. The information I've read says to zero this scope at 200 yards. After a 200 yard zero, I step up and shot at 15 yards-expecting POI to be higher than the POI for the current zero. Except, my bullet impacted almost 8 inches low. Is this normal?


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## DallanC (Jan 13, 2009)

That sounds wrong. Do you have 20MOA rings mounted backwards? Your barrel should be angled upwards towards line of sight, at close range its point of impact shouldnt be more than the distance from the center of the barrel to the center of the scope.

Until you shoot over a cronograph to measure your muzzle velocity, you simply dont have enough information to compute a accurate longer range trajectory, to even know if its going to match a particular scopes setup.

Free ballistics software: http://www.HuntingNut.com

-DallanC


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## Cooky (Apr 25, 2011)

How far apart are line of sight and the center line of the bore at the muzzle?


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## DallanC (Jan 13, 2009)

Rough guessing several variables here:










-DallanC


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## BPturkeys (Sep 13, 2007)

There is no load that can give you those results, period. This has to be a mechanical problem. Either the scope or your mounts failed in some way. Did you re-shoot the 200 yard range after the 15 yard group...if you did, I'll bet you weren't even on the paper. You would have to be way way low. Check all the parts and then re-shoot starting with the 200 yard zero.


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## ckamanao (Mar 20, 2010)

Thanks for the info. I'll go back and shoot again, I thought it was wrong. As far as the mounting went-I just followed the directions. I do know that I am hitting p-dogs out to 200-300 yrds now. But I'll shoot close range again tomorrow and let you guys know how it goes. Sounds to me like user error.


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## bigbr (Oct 24, 2007)

At fifteen yards your bullet should strike the aimpoint low, depending on your scope hight to center of bore, maybe as low as three inches but should not be much more than that. Is your AR an A2 or M4 configuration, meaning have you mounted a scope on top of an Hbar.
Big


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## Bax* (Dec 14, 2008)

bigbr said:


> At fifteen yards your bullet should strike the aimpoint low


This has always been my understanding as well. I am not entirely sure I understand why this is, but that is my understanding / observation as well. It always seemed odd to me that the bullet actually climbs a bit before it begins to drop, but the charts and experience show it to be true


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## DallanC (Jan 13, 2009)

Bax* said:


> This has always been my understanding as well. I am not entirely sure I understand why this is, but that is my understanding / observation as well. It always seemed odd to me that the bullet actually climbs a bit before it begins to drop, but the charts and experience show it to be true


You throw a football slightly up into the air when throwing it to your boy some distance away on level ground right? Soon as a bullet exits the barrel it beings to drop, you have to offset that by launching it with an upward component. Yes for any longer range than pistol ranges, a bullet will generally cross the line of sight twice.

-DallanC


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## Cooky (Apr 25, 2011)

That's why I asked about the height of the scope. If the scope were mounted way up on top of a carry handle it may be possible to create the situation the OP describes. It would have to be way up there though.


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## Kdub (Sep 6, 2010)

I could be off base here, but I think what is happening is known as mechanical offset. Your scope is mounted higher than the barrel. When shooting that close your bullet hasn't had time to rise to where your crosshairs are. I bet if you shot at 30-50 yards it would impact center of target on its way up, then again impact center at 200 on its way down. Try it and report what happens


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