The Down Range Forum

Member Section => Tactical Rifle & Carbine => Topic started by: lhprop1 on February 21, 2013, 11:30:26 AM

Title: Adjusting front sight
Post by: lhprop1 on February 21, 2013, 11:30:26 AM
I recently built an AR and I got the barrelled upper assembly from PSA.  After finding some ammo, I took it to the range.  At 25 yards, I was consistently shooting 3 1/2" to 4" to the right.  After cranking the rear sight as far left as it will go, I got it zeroed.  

This might sound strange, but is it possible the front post was put on crooked?  Is it a fairly easy fix to adjust it?
Title: Re: Adjusting front sight
Post by: PegLeg45 on February 21, 2013, 11:39:50 AM
I don't know, but to give an answer, I'll ask a question to those in the 'know' about AR's: If the sight is on the gas block, could it be slightly rotated on the barrel.... just enough to throw it off, but still let enough gas through the port to function the gun?
Title: Re: Adjusting front sight
Post by: tombogan03884 on February 21, 2013, 02:07:22 PM
It could very well be since this sounds exactly like the problem Century had with their Cetme's.
If that is the case  then here's the deal.
The front sight post contains the gas block and is pinned in place.
You would need to redrill the hole for the pin in either the barrel, or the sight, in order to keep the drill from walking , or just following the original hole you would need to have the old hole filled with weld .
the other choices are measure from the holes to the bottom centerline of the part on each side the one that is different from one side to the other needs to be replaced.
Otherwise replace both parts.
Title: Re: Adjusting front sight
Post by: lhprop1 on February 21, 2013, 02:50:34 PM
It could very well be since this sounds exactly like the problem Century had with their Cetme's.
If that is the case  then here's the deal.
The front sight post contains the gas block and is pinned in place.
You would need to redrill the hole for the pin in either the barrel, or the sight, in order to keep the drill from walking , or just following the original hole you would need to have the old hole filled with weld .
the other choices are measure from the holes to the bottom centerline of the part on each side the one that is different from one side to the other needs to be replaced.
Otherwise replace both parts.

Thanks, Tom.  That doesn't sound like something that a novice like myself should try to attempt.  I'll take it to a gunsmith this weekend and see if they can confirm this.  
Title: Re: Adjusting front sight
Post by: Swamp Yankee on February 21, 2013, 03:29:24 PM
Your front sight post could be bent it is a very common issue and easy to replace if you have to. Also could be the rear sight if you have a flat top it might be canted slightly to one side if it is not installed on the rail correctly.

Mike Mc
Title: Re: Adjusting front sight
Post by: lhprop1 on February 21, 2013, 03:38:40 PM
Your front sight post could be bent it is a very common issue and easy to replace if you have to. Also could be the rear sight if you have a flat top it might be canted slightly to one side if it is not installed on the rail correctly.

Mike Mc

Good point about the rear sight.  I'll check into that. 

I'm going to take it to the gunsmith to have him take a look at it. 
Title: Re: Adjusting front sight
Post by: twyacht on February 21, 2013, 04:55:20 PM
If you have access to one, throw a laser bore sight either the bullet style or toggle in the muzzle. Should reveal what's off.



Title: Re: Adjusting front sight
Post by: fightingquaker13 on February 22, 2013, 12:03:39 AM
If you have access to one, throw a laser bore sight either the bullet style or toggle in the muzzle. Should reveal what's off.




And we have a winner. Get it bore sighted. Then play with the sights. That will tell you where the problem lies. I am in agreement on getting a good smith to do this.