Rifle Scopes How to grade "shooting the box"?

[Fred_C_Dobbs]

I'm having something improbable happen with my FN PBR and I decided I needed to shoot the box to rule out my 10x42 SuperSniper as a factor. The problem now is, I can't find the "official" rules for scoring a shooting of the box.

Anyway, I shot three boxes @100 yards, 12 clicks/3" on a side (in hindsight, I probably should have shot a bigger box). The rifle typically shoots about 1/2" 3-shot groups @100 yards. The distance from the first shot to final one was 0.6", 0.5" and 0.3". Measuring each side C-C, the average length of all twelve sides was 3.21". The shortest "perimeter" of the three boxes was about 12 3/4". The longest was very close to 13".

So what's your evaluation of my box? Am I within the "margin of error" that you would expect for a scope that's supposed to have 1/4" clicks @100 yards?

 

[Fred_C_Dobbs]

Re: How to grade "shooting the box"?

I decided to re-score the test, using "Olympic" judging rules. If I throw out the longest length side and the shortest length side, the average for the remaining ten sides comes to 3.08".

 

[Ratbert]

Re: How to grade "shooting the box"?

Get a piece of cardboard and dial 10x that. Makes it much easier to see if there's any variation.

 

[Magnumdood]

Re: How to grade "shooting the box"?

Low Light advises, that at a minimum, you need to shoot 20 MOA per side, otherwise you can miss small errors.

 

[gugubica]

Re: How to grade "shooting the box"?

I recommend using 36 MOA.

You need to know both what your scope actually dials and if there are any errors goig back and forth.

I have found that ALL scope have some error in their adjustment (albeit some very minor) but you need to know exactly how many MOA your scope moves as opposed to how many it says it moves.

If it has a 2% error, you wont be able to pick that up with a 3" test.

 

[Fred_C_Dobbs]

Re: How to grade "shooting the box"?

This test caused more questions than it answered so I suppose I'd better go do it again and shoot a bigger box. 36 MOA is doable.

Thanks for the input.

 

[Pavlata]

Re: How to grade "shooting the box"?

I did a BOX test using my Barrett M-99 and Sightron SIII.
I taped 4 targets together and used 21 MOA up and down of scope adjustment in elevation and 20 MOA left and right for azimuth adjustments.

If your scope is calibrated in MOA (and I believe my Sightron is because of my results), then for every click you ar actually moving it 0.262"/click or 1.047"/4 clicks. Your 12 clicks should actually have moved it 3.14"

here is the thread of my post. Before any of you flame me for my small shot groups, this was done before LowLight came out with the rules, plus I wasn't not shooting for a "Record" I was merely evaluating my scope. Not to mention shooting 50 cal is ...

http://www.snipershide.com/forum/ubbthre...390#Post1448390

If you look at my target(s) you will see that my 21 MOA adjustment actually had the bullet impacts over 22" (21 X 1.047 = 21.99") and the 20 MOA adjustments were at approx 21" (20 X 1.047 = 20.94")

I concur with others that have posted that you need to at least use min 20 MOA or if you plan to use the extreme capability of your scope, then 36 MOA as suggested.

 

[KTDLS7]

Re: How to grade "shooting the box"?

You are correct, 3" is not a valid "box test".

The following link is a detailed procedure for validating optic adjustments. It is authored by Lindy, a Hide member, whose knowledge and opinion I value.

http://www.arcanamavens.com/LBSFiles/Shooting/Downloads/ScopeChecking/

Read carefully. Lindy explains why initial setup is important. In your case, you want to validate "1/4 inch clicks at 100yd" adjustment. The distance to target has to be a measured 100yd. You cannot depend on a LRF or your local public "100yd range" - it may be close, but close is not good enough.

Good luck,

Kevin