Bore sighting

[Harter]

Observations , stories , discussion.

I've used 3-4 different tools and methods to "get the first shot on paper" . Like so many of us vision changes have changed the means . In my 20s , enough light to make out the bottom dot through the bore and a post-it at the end of the hall from the kitchen about 25-30' with 2 spots was good enough. By my mid 30s it took good light preferably with a door knob to line up the doors and a square post it turned diagonal. The first laser bore sight tool after 40 was a godsend and as long as I made sure it was centered at its 12/6:00 reference I was golden for most of my checks . I don't know where that one went and I replaced it with another just like it only it was straight. It to was lost from the hunt bag we took to Texas for hogs .....

I'm approaching 60 now and I have Dad's rifle which always shot well but like every other rifle he set up it didn't shoot where I was aiming it . For range play and working up cast loads I don't and really and haven't cared that it hit the exact spot . Seriously if it's not business who cares if the 5 under quarter are 6" low and 4" left ? The thing is as I shot more it bothered me more with his 700 BDL Varmint Master. Then I shot Grandpa's M70 fitted with 4-12x50 in high mounts and it was even further out but the same direction. Elevation was about the same but the windage was nearly doubled.

Just for giggles and believing it was just me , I shoot a dozen different rifles with triggers ranging from the heavy 3# target factory wide shoe in Dad's M700 to the 7# 2 stage more or less GI triggers in the 98's , Carcano , and Arisakas, I slapped the new laser bore sight tool on the muzzle of 3-4 of my working rifles and found that 35' down the hall and 62yr out on the chicken house the red spot was just over or just under the horizontal and general split out the right side of the vertical . Since I was comparing a 222 to a 358 to a 7×57 the various points weren't a big surprise. Dad's 25-06' however required a substantial cant to get the dot anywhere near the vertical, on the chicken house it was about 7" low and 6" left regardless of whether in mounted left or right side . I fixed that on the M70 when I changed out the x50 for the fixed 4x Weaver .

It explains a lot of my accuracy issues from 12-21 yrs old , and why when I started setting up my own rifles my shooting improved so much .

[Harter]

Dad's M700 . This is where Dad shot his load zeroed at 200 yd 100gr SMK or PH at 3100 fps I haven't run the cast loads over the Chrony yet but the 125 gr cast should be about 1900 with Unique and 2400+ with H4831 both loads go 12"+ high and right .
Tasco 4-12×50 w/parallax range finder circa 1972
IMG_20240623_104219850_HDR~2.jpg

My 275 Rigby /7×57. This is set up for the current cast load development work it lets me shoot loads with an X hold 3,6,9:00 holds on an NRA PISTOL SLOW FIRE target it hits about 6" high at 50yd .
Tasco 3-9x40 Pronghorn Duplex circa 1998
Attachment 1903

The Santa Barbara 98 358 . This one lets me place a 1" circle in the right upper corner + cross point with hits more or less centered on the dot at 100 yd with a 2100 fps MV 250 gr cast .
El Paso Weaver K4 late 1960s
Attachment 1904

All laser spots at 18' .
I wonder if it's the parallax that's doing it . Poi is flipped vertically....... If not for the happy magnet I'd think it was upside down.