From: kdlin@advtech.uswest.com (David Lin)
Newsgroups: rec.guns
Subject: AR15 Questions
Date: 23 Nov 92 14:24:21 GMT
Organization: U S WEST Advanced Technologies

I took a rifle shooting class a few weeks ago and shot my AR15 for
the first time ( any rifles for that matter). Now I have a number of 
questions. I'll appreciate it if I can get some comments. Note that 
it is a Colt Competition Sporter HBAR with a 1 in 9" twist rate barrel.

A. Sight

	1. The owner's manual suggests that the bigger rear sight should
 	   be used for shorter ranges ( 0 to 200 m). I like the smaller
	   rear sight. If I want to use it for shorter range, do I need
	   to adjust anything? In another word, is the center of the small
	   hole at the same position as the center of the larger hole?

	2. Where are the zero crossing points? Are the around 50m and 200m?
	   ( Maybe depends on the weight and the velocity of the bullets? )
	   How much higher will the bullets hit at its highest position?

	3. The owner's manual also says the smaller rear aperture should
	   be used for longer range ( 300 m to 800 m ) and the elevation
	   knob should be adjusted. However, my elevation knob only goes
	   up to 600m; i.e., it has the 6/3 mark instead of the 8/3 mark.
	   Is it normal?
	
	4. How practical is the 6/3 or the 8/3 iron sight? I could use 
	   the sights to knock down bowling pins at 200m away in my first
	   rifle shooting session. But, bowling pins at 200m aways are so
	   tiny. I had a tough time to see them at that distance. Considering
	   that I have a 20/10 vision ( better than normal ), I have a
	   difficult time to imagine that people can use iron sights to hit
	   small objects at 500 m away. ( I was told that in High Power Rifle
	   Competition, shooters shoot targets at 600m away. ) Any comments?
 
B. Scope

	1. When I use the iron sights, I can adjust the elevation knob for
	   various distances. However, there is no such knob on the scope.
	   So, if I zero the scope at 50 m, what should I do when I want to
	   shoot a target, say, 400m away? If I have to zero the scope again
	   for different distances, what is the distance that the military
	   zero their scope? 

	2. I mount the scope on top of the detachable carry handle. The
	   mounting device has a hollow center, so that I can still use
	   the iron sights when the scope is not functioning. Besides, I need 
	   a cheekpiece so that I can see the scope better. However, the
	   cheekpiece prevents me from using the iron sights. So my question
	   is that are there any configurations that allow you to use both 
	   the scope and the iron sights?
C. Ammo

	1. How much penetration and stopping power and do I get with 
	   various types of bullets and weights? ( For example, FMJ, soft
	   point, HP, 55gr, 62gr, 69gr, etc. ) My reading tells me that
	   this .223 cartridge gets its stopping power by fragmentation.
	   How do you interpret this statement with the selection of ammo?

	2. A guy at the gun show tried to sell me "super explosive ammo"
	   for my HBAR. What is the super explosive ammo? ( His price is
	   about $140 for 1,000 rounds, if that helps to identity this
	   ammo. ) Again, what are its penetration and stopping power?

Any comments on some of the above questions will be appreciated too. I think
I should get the most question award. :)

David
-- 
 K. David Lin, Ph.D.              | E-mail: kdlin@advtech.uswest.com  
 Communication Services Research  | Defend your life in STEREO - Beretta & SIG 
 U S WEST Advanced Technologies   | Disclaimer: Only personal opinions