M1A Front Sight

[r2nailer]

I just picked up a new to me SA M1A1 and I have just noticed the front
site mount is canted to one side. To the left as you look down range IIRC.
Is this an indication of a posible headspace issue that I need to worry
about?
And if so, where should I look for repair?
R2

 

[Jimmy2Times]

Maybe I'm missing something, but what does the front sight have to do with headspace?

 

[ShadeWPI]

R2nailler

Head spacing is about the depth of the chamber reaming, specifically of the case shoulder, with respect to the bolt face. It is basically the "slop" between a properly sized round and the bolt face. It has nothing to do with the cant, position or condition of the front site.

However, if the front sight is missaligned, you wil find a problem when zeroing the rifle at different ranges - it will be off right to left. You'll be able to zero it at a specific distance, but as you move from that distance, you'll have an error. Typically the best thing to do then is sight the rifle left to right at as far a distance as possible as this will minimize the error.

Example:
Rifle with an 18" sight radius (distance from rear sight to front sight) has the front sight 0.025" left off center. If the weapon is then zeroed at 25 yards, the rear sight is moved further off center to correct for the right to left error and the line of aim is drifting left to right. It's off by a 1/10" at 100 yards or a half inch at 500 yards. If you then re-zero at 500 yards, you'll be about 0.005" of an inch left at 100 yards.

 

[r2nailer]

Thanks for that great insight.
I was under the wrong impresion that there was a corelation
between the depth of the barel in the reciever and the headspace.
Like the M2.(50 cal)
In your example the error seems oh so small, and with my ability,
I might not even see it.
Can it be fixed, or should I just live with it?
R2

 

[vellnueve]

Should be something you can fix yourself, if it's what I think it is.

 

[r2nailer]

Interesting post I got on another site.......FWIW


Here is the message that has just been posted:***************The mount isn't tilted, the barrel is over-indexed (tightened past the 12 o'clock position) and is very common in SAI rifles. In general, so long as the front sight doesn't hang over the flash suppressor dovetail, it is okay. The barrel has to be torqued to a certain spec and sometimes that torque is just past 12. If the barrel is backed off to exactly 12, then the headspace will change ever so slightly. The headspace was set after the barrel was torqued and it should be left as is. If it really bothers you, SAI has an excellent warranty policy. Contact them and see what they say.

 

[r2nailer]

I decided to return to ZHA and they let me upgrade to a loaded unit
on a direct exchange basis. great bunch of people there.