Miscellaneous causes of fliers.
by Joe Carlos
Let’s move on from basic AR design flaws and ammunition into other contributors to fliers. The first of these are iron sights that fail to track, have lags in tracking, or dead spots. I have been shooting Stoner firearms ever since the 1960s Viet Nam era. The early versions started out with fairly coarse sight adjustments. As time went on adjustments became finer by substituting parts with finer threads, with current iron sights down to 1/4 minute clicks these days. It seems to me that finer threads of modern sights wear out much sooner than coarser threads. I believe the finer threads are also more susceptible to debris causing temporary and permanent issues. Ray-Vin makes a stellar iron sight checker but it must clamp onto a carry handle so it may not work with some of the backup sights on the market today. Wear out of rear sight parts was so common that in my decade as match Armorer for the Army Reserve Shooting Team it was my number one repair chore.
Issues with scopes is next. If you suspect a problematic scope, begin checking the mount and rings for tightness. Parallax is another issue. A scope that is parallax free (or nearly so) at one distance can exhibit lots of parallax at some other distance. I ask the shooter early on if he is having more fliers at a given distance. This obviously assumes using the same ammo at all distances. In some shooting disciplines it is common to shoot magazine-length ammo at shorter distances and then switch to long seated ammo at longer ranges. If the shooter’s problems coincide with an ammo switch that points to the need to check both parallax and ammo at the distance the shooter is having problems with.
On scopes that do not have parallax adjustments the owner’s manual will often list the distance it should be parallax free. If the bread crumbs are leading to a parallax issue, the scope will need to be field tested at all distances with emphasis on the range where the shooter is having greatest problems. I don’t claim to be an expert on scopes but I will describe the method I (and others) use to field test for parallax. After ensuring that the…
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