Math, Blind Pigs and Acorns, Sighting In

[Marcruger]

I'd like to say that sighting in a rifle is a blind pig finding an acorn at times.  The engineer in me disagrees and says "use math".  So I did. 

John Bergmann replaced my sights for me with some desired non-adjustable ones.  John's a super guy. 

I knew what load the rifle likes, so I shot a group.  It shot low, just as John said it would, and left a little. 

I took my target home, and got out the Starrett caliper.  I just used "similar triangles" from geometry, and figured out the distance between my sights in inches, how many inches are in 50 yards, and how much off the target's group was in inches.  In other words, an example would be 27 inches is to 1,800 inches, as (?) is to 4 inches low.  Comes up to .06". 

I measured, and filed in the front sight.  I also tapped the rear slightly after making a pencil mark to see how far things move once tapped. 

I took it out today and plinked a fouler shot. I them settled in at the bench to see how my math worked.  Here's the result of the first shot.  My thought was "I'm good!"   :-) 

The remainder of the group clustered right around it.  Love those Green Mountain barrels.   Amazing how geometry still works in a digital world. 

Best wishes, and God Bless,   Marc   PS, my day-glo poster paper target really works for my old eyes.  Try it sometime. 




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[nosrettap1958]

I got a headache just reading your post. 

Good job on sighting in and I love Green Mountain barrels also.

[Joe S.]

And my eyes glazed over too,but it sure looks like that MIT education works on such things as well.Who says it ain't rocket science,just funnin on ya,well done

[n stephenson]

People lie, math doesn't. Nice job!!   Nate

[Daryl]

And my eyes glazed over too,but it sure looks like that MIT education works on such things as well.Who says it ain't rocket science,just funnin on ya,well done

LOL - me too - twas a stuggle, so I just sort of glazed over it quickly.  I see the results - that's what is important.

[hanshi]

I use the trial and error method.  The downside to this is that you have to - "OH, the humanity" - Ahem, shoot a lot.

[Maven]

My eyes didn't glaze over and I liked your logical approach to the problem.   Fortunately I also have a much longer article from "Muzzle Blasts," which says the same thing.

[oldtravler61]

  Marc well done an nice shooting. An yep those GM barrels are accurate.
 But why does my eyes only see glowing green everywhere...Oldtravler

[Marcruger]

I am sorry I put everyone to sleep. 

Maven, of course many folks know how these "similar triangles" work.  I certainly did not invent it, and learned about it way back.  Glad to see someone published it in the past.  It can be used for pretty much any open sight guns. 

OldTraveler61, I use big pieces of day-glo poster paper for my targets.  I tape or glue on a 12" triangle as my aiming point.  The contrast in the sun gives my weakening eyes a good aiming point, and it increases my accuracy.  Below is a portion of a target I shot a while back, so you can get a better idea. 

As an aside, for anyone shooting a peep sight with a bead front, I use the same green or yellow poster paper, but with a 1" wide black cross.  The cross at 100 yards looks like a "crosshair" behind the bead, and you can do some fine aiming that way. For some reason (unknown to me), I get a distortion of this cross aiming point when shooting open sighted muzzleloaders.  Works fine for handguns though.  Odd. 

I hope this helps someone.   

Best wishes, and God Bless,  Marc

[Marcruger]

To follow up my above post, here is an example of my peep sight friendly target.  It was shot (obviously, due to small holes) with one of those unmentionable other kinds of firearms, but the concept works for muzzle loaders with peep sights.  That's a 1" black magic-marker cross, which looks like a crosshair at 100 yards.  For those curious, I was doing load development, and the 33.5 is grains of powder.  Best wishes, and God Bless,   Marc


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