Author Topic: Experimenting with BSZ at 25 yds  (Read 722 times)

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Offline rjinga

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Experimenting with BSZ at 25 yds
« on: November 16, 2017, 02:05:31 PM »
After reading conflicting posts and seeing conflicting graphs on the internet (25 yds = 200 yds; 25 m = 200 m; 25 yds = 200 m; 25 m = 200 yds; BSZ position = 200 m; BSZ position = 300 m) I decided to (try to) zero in the BSZ position at 25 yds and then see what happens as I shoot at different distances.  The rifle is a Chinese Type 56 SKS; the ammunition is Golden Tiger.  Unless noted, I was shooting off of a bench rest (big rubber notched block and airsoft BB tube sock) with the iron sights set on the BSZ position.

This is my “even a blind squirrel” photo.  Believe it or not, that is two bullet holes at 25 yds:
   

This is a scaled “Dog” target at 25 yds.  Eight rounds; 40 out of 40 possible points, with six rounds in the “V” circle and a seventh touching it:


Next I put a BC-27 target at 100 yds (max distance at the public range):

I can’t actually see the “X” at that distance, but I thought I was aiming in its general location.  The first 10 rounds are shown in the photo on the left.  After seeing how high and to the right the shots were, I fired another 10 rounds (photo on the right) while focusing on holding a little lower, and as centered as possible.  I was able to tighten up the width from the first group to the second group by just over 1”; and, if you discount the one low shot as a flyer, then I cut 3” off of the height.  I’m still shooting to the right; however, in a combat situation, those nine shots would all be in the heart/lung area.

I ended up by placing one target at approximately 29 yds and another at approximately 33 yds:

Then I stood and fired snap-shots offhand at both targets (raise rifle, fire at 1st target, transition and fire at 2nd target, pause, repeat):


Once I get back to the gun club, I'll see how the BSZ position does at 200, 300, and maybe even 400 yds.

Offline rjinga

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Re: Experimenting with BSZ at 25 yds
« Reply #1 on: November 18, 2017, 12:19:52 AM »
More Experimentation

After doing more reading on the internet, I headed back out to the public range this afternoon, shortly before it closed at sunset.   A poster on another forum wrote that zeroing at a distance of 41 meters, with the rear sight on the 100 meter position, will put you back on zero at 100 meters.  So, I decided that I'd give it a try.

I went out to the 50 yd marker and then walked back six strides to get pretty close to 41 meters.  Here's my forth and final target as I shot and adjusted the elevation:


Next I went out to the 100 yd marker, and then paced off nine more strides to get close to 100 meters:


After seeing the shot placement at 100 meters (high and to the right again), I came home and ordered a sight adjustment tool, so that I can finally adjust the windage (and fine tune the elevation better than I can currently with my small needle-nose pliers).  I also ordered another pack of green silhouette targets (pay for shipping or order something else you need and get the shipping for free).  Next time, I think I'm going to attach a blank sheet of 11x8.5 copy paper to the chest area of the silhouette, to give myself something more defined to aim at, at 100 meters.

Offline rjinga

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Re: Experimenting with BSZ at 25 yds
« Reply #2 on: November 25, 2017, 12:06:07 AM »
I got my sight adjustment tool on the Wednesday before Thanksgiving, so I took a quick trip to the public range that day to do some adjusting (no photos).  In anticipation of getting the tool, I'd sprayed the front sight with PB Blaster three different times starting Monday night and then just let it soak in. 

I bought the adjustment tool primarily for the windage adjustment; however, it was so much easier to adjust the elevation with the tool instead of my small needle-nose pliers.  [Note to self:  take bent pliers to Sears for replacement under the lifetime warranty.]  I ended up adjusting the windage at least one full (180 degree) turn with the tool also.

I went back to the public range today (day after Thanksgiving) and set some 12" diameter targets at 100 meters.  I shot off of a bench rest with the rear sight set on the 100m position.  At that distance the target is just a little bit wider than the front post.  I was using a 6:00 hold, so I tried to touch the bottom of the target with the top of the front post.  I say "tried to" since I've got 57 yo eyes looking through progressive lenses at a black front post and a black target.

I fired five rounds each at the three targets:


Then I checked, patched, and fire five more at each target:


And then I checked again, patched, and fired 10 rounds each at each target:


Next up will be a trip to the gun club to see how these adjustment translate at 100, 200, 300 and 400 yds.

Offline rjinga

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Re: Experimenting with BSZ at 25 yds
« Reply #3 on: November 25, 2017, 12:52:06 AM »
And, just in case you're were curious, here are the targets with the mean radius for each one.  The mean radius is the method of measurement of the dispersion of shot-groups used by the US Military for accuracy testing of ammunition. It provides a more useful analysis of the consistency of ammunition and rifle accuracy.  Mean radius as defined in Hatcher's Notebook “is the average distance of all the shots from the center of the group. It is usually about one third the group diameter (extreme spread).”






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Re: Experimenting with BSZ at 25 yds
« Reply #4 on: November 25, 2017, 07:28:49 PM »
I'm guessing the 25m battle setting didn't work to zero?
      
1776 will commence again if you try to take our firearms... It doesn't matter how many Lenins you get out on the street begging for them to be taken.

Offline rjinga

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Re: Experimenting with BSZ at 25 yds
« Reply #5 on: November 25, 2017, 07:58:07 PM »
I'm guessing the 25m battle setting didn't work to zero?

Well, since my 25m shooting seemed to be dead-on, but then the 100m shooting was still high and to the right, I just decided to set, shoot, and adjust it to 100m.

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Re: Experimenting with BSZ at 25 yds
« Reply #6 on: November 25, 2017, 08:30:26 PM »
I have usually just zeroed at 100m with the rear sight on 100.  I haven't 'actually' used the battle position to zero even though I have seen/read it a million times.  Im guessing the battle setting height is not actually equal to the 300.  I was afraid this may be the case.

One way to zero at a close range and know for sure you on for the leaf scale of 100,200,300 is to simply zero at 25 meters with the sight leaf set to 300m.

Easy cheesey
      
1776 will commence again if you try to take our firearms... It doesn't matter how many Lenins you get out on the street begging for them to be taken.