Like the title says, is there much of a noticeable difference?
Thanks!
We know that the 22" M14 rear sight moves 1 MOA per click so we can deduce the actual rear sight movement as so...
Sight Radius x Impact Movement / Target Distance = Sight Movement
26.75 x 1.047 / 3937.01 = .007113
Notice the distance is in 100 Meters converted to Inches, Remember the M14 is regulated in Meters.
So each click of the rear sight moves the sight .007113 inches
Using the same formula for the 18" rifle...
22.75 x 1.047 /3600 = .006616"
Notice I used Yards for the M1a, The 18" rifle rear sight would need to move .06616" per click in order to move 1 MOA.
This isnt going to happen, we must use the .007113" as it is the built in mechanical movement of the rear sight. So how much will each click move impact on the 18" rifle?
.007113 x 3600 / 22.75 = X X = 1.126" or 1.178 MOA
The rear sight on an 18" M1a will move impact 1.178 MOA per click
Using the chronographed velocity of M80 ball from my 18" scout the rear sight indications are surprisingly close to actual values.
The normal 300M tick or "200M plus 3 clicks" now corresponds to 314yard or 287meters
The normal 400m tick is now 439yard or 401meters
The normal 500m tick is now 545yard or 498meters
What are the failed bolt issues that they have had?
There was a thread a few weeks back where someone had one of the lugs give out. I haven't heard of any other recent incidents regarding the bolts other than this. The cause was never determined, but it was suspected to be lack of hardness in the metal, reloaded ammo, or both. There was a similar incident with a springfield where both of the lugs gave out and bolt hardness was the issue I believe, so its not a Norinco exclusive defect. I own two, and don't worry about either having issues.