Wednesday, March 3, 2010

FNAR Review - What's In The Box - Stock Shims

The FNAR comes with six stock shims.  The shims fit between the stock and receiver, allowing customized adjustments to fine tune the cast and drop of the stock.  Each shim is labeled for a specific amount of adjustment.  The rifle comes with the neutral shim (No. 2) already installed. 

Just to be clear, I think it is important to define a few terms because this blog uses these terms to describe what the shims will do to the buttstock. 
  • Comb - the upper edge of the buttstock
  • Heel - the upper edge of the recoil pad
  • Drop - at the comb is the place on the comb where your cheek rests when taking aim.  If the drop is correct, your eye will naturally fall in line with the sight.
  • Cast - is the offset of the buttstock from the center line of the rifle. Some right-handed shooters like the stock to angle away (cast off) from their face, making the line of sight more directly in line with the barrel.  Angling the stock to the left for left-handed shooters is "cast on".
The shims marked 1, 2 and 3 only affect the comb and heel positions (no cast).  The stock will remain straight and adjust the drop only.
  • Shim 1 - raises the comb ~1/16" and the heel ~1/8"
  • Shim 2 - is neutral and comes already installed on the rifle
  • Shim 3 - lowers the comb ~1/16" and the heel ~1/8"
The shims marked 1R1L, 2R2L, and 3R3L will adjust the drop at the comb the same as shims 1, 2 & 3 and will also adjust the comb right or left ~1/8".  For example, 1R is marked on one side of the shim and 1L is on the other side. The cast will be to the right or left based on which letter is facing towards the buttstock.  An R facing the buttstock would be cast off (to the right) and an L facing the buttstock would be cast on (to the left).
  • Shim 1R1L - raises the comb ~1/16" and the cast on or off by ~1/8" depending on the shim letter facing direction (or which side the thicker side of the shim is placed)
  • Shim 2R2L - keeps the comb at the neutral position (out of the box) and the cast on or off by ~1/8"
  • Shim 3R3L - lowers the comb ~1/16" and the cast on or off by ~1/8"
Just like with my last post on the inserts, I'm going to hold off on making a final decision on the stock shims until I get my scope mounted.  Even then, with all the possible combinations, it may take me a while to zero in on the best configuration for my shooting style. The engineer in me is already leaning towards keeping the barrel and stock on a common center line, so I may have already down select some of the combinations.

You can see all of my posts on my FNAR rifle by going to my Summary Page.  Also, don't forget you can click on a photo and it will give you a high definition image so you can see more details.

1 comment:

  1. I found this very helpful. I changed the shim on my FNAR right after reading this. Thanks.