Register
Log In
Home
February 21, 2011
Offline
how much movement (on the target) is "one click" on the rear sight at 25 yds?
I have to move the poi from a 6" to a 4 " (minus 14" on the paper) & the math is escaping me.
The same setting for the 6" @ 15 yds is 14" high with the 4"
Thanks.
Matthew Quigley on handguns:
“I said I never had much use for one. Never said
I didn't know how to use it.”
Supporter
Dans Club
March 25, 2013
Offline
February 21, 2011
Offline
the movement per click at a fixed distance is variable?
How does that work?
Matthew Quigley on handguns:
“I said I never had much use for one. Never said
I didn't know how to use it.”
DWF Supporters
July 12, 2020
Offline
One click at 25yds is a different value than a click at 50'. Same goes for sight distance, one click on a 6" barrel is a different value than one click on a 4" barrel. If someone has the values worked out for different such set ups and distances that would be worth a pinned post!
February 21, 2011
Offline
Yes I agree.
BUT what I'm trying to find is not that complex.
lets assume
distance for all is 25 yds.
question 1:
What is the angular movement from a 4" BBL at that distance. Per one click of the sight.
1/4MOA
1/2MOA
1 MOA or something else.
Question 2:
question 1: what is the angular movement from a 6" BBL at that distance. Per one click of the sight.
1/4MOA
1/2MOA
1 MOA or something else.
This is easily available (or at least used to be) for just about every firearm.
I can even assume that if we know one (4" or 6" we can calculate the other dimply by multiplying or dividing by (4/6) or (6/4).
Matthew Quigley on handguns:
“I said I never had much use for one. Never said
I didn't know how to use it.”
DWF Supporters
July 12, 2020
Offline
I briefly looked today for a formula but pretty sure it has to do with that sine/cosine stuff which shows relationship of the angles/sides of a triangle (been way to long since I had trig).
February 21, 2011
Offline
Yes there is.
Its Trig.
BUT you still need to know 2 sides & one angle.
Matthew Quigley on handguns:
“I said I never had much use for one. Never said
I didn't know how to use it.”
DWF Supporters
July 12, 2020
Offline
Wouldn't height of rear slide and distance to target (900") and a 90' angle be the three variables you need?
Well a bench rest day at the range is another option and probably a funner way of figuring it out
!
February 21, 2011
Offline
You'd need vertical height change (rear sight adjustment. thread screw pitch divided by number of clicks per full rotation) sight base distance, front to rear (This will change with barrel swap). This would calculate out the change in angle.
solve that & you have the movement on target, not the opposite way round.
I give up. I'll just go to the range fire a supported "base" group, change say 10 clicks & fire another group then just measure it. Dividing the measurement by 10 will give inches per click.
Once I have the 6" (for argument's sake) barrel measurement the 4", 3", 8" & 12" can easily be calculated.
Matthew Quigley on handguns:
“I said I never had much use for one. Never said
I didn't know how to use it.”
DWF Supporters
July 12, 2020
Offline
Very interested to see what full screw rotation is equal to per each barrel length. If you will give up some of that hard earned info.
February 21, 2011
Offline
I can actually test 4" & 6".
Anything else will be calculated (Unless someone has "Loaner" barrels to "donate to the cause"). 
Matthew Quigley on handguns:
“I said I never had much use for one. Never said
I didn't know how to use it.”
February 21, 2011
Offline
EDITED TO REMOVE/CORRECT MATH ERROR)
Ok, got to the range with the 15-2 & its 4" & 6" BBls.
Here's how the windage & elevations shook out. The 4" & 6" were measured.
At 15 Yds with the 4" BBl each click is 1/3 inch. That shakes down to 1/2" at 25 yds.
At 15 Yds with the 6" BBl each click is 1/4 inch, actually 0.2222".
I checked this 3 ways.
I fired a group, measured the error & "just clicked in" till it was POA to POI & counted the clicks.
Next I dialed in 10 clicks, measured the movement on target & divided by 10.Then the opposite amount 20 clicks & measured to center from both.
This is on a Monson made 15-2, I have no way of checking different sights manufacturing dates or locations or even types of sights from the "Old & Wobbly" to the new & more precise.
Matthew Quigley on handguns:
“I said I never had much use for one. Never said
I didn't know how to use it.”
February 21, 2011
Offline
605Dart said
Very interested to see what full screw rotation is equal to per each barrel length. If you will give up some of that hard earned info.
Just multiply the "per click" movement by the number of clicks.
Matthew Quigley on handguns:
“I said I never had much use for one. Never said
I didn't know how to use it.”
DWF Supporters
July 12, 2020
Offline
Excellent info sir!!!! I will take mine and bench it at 15yds with the 4 and 6 inch barrel and see what I find. This may take a bit as my schedule is crazy for the next few weeks. Mine is a 715-2 Monson made in first quarter of '79.
February 21, 2011
Offline
That would be interesting.
Matthew Quigley on handguns:
“I said I never had much use for one. Never said
I didn't know how to use it.”
February 29, 2020
Offline
No. That can´t be. There´s something wrong with mr. Callans experiments. The value of one click - vertical or horizontal - can´t be greater with 6 inch barrel than with four-incher. The longer the barrel is, the smaller is the value of correction on target per one click. So, with four-inch barrel the group movement on target at 25 yards MUST be greater than with six-inch barrel when you take a windage or elevation click (or clicks) from the rear sight. Think: with shorter barrel the effect of lifting or downing the rear sight blade becomes more apparent, because the front sight (or the barrel mouth) moves downwards or upwards in more steeper angle than if the barrel is longer. If the barrel would be 25 yards long (ha ha ha), the moving effect on target would be minimal, the same that rear sight actually moves with one click (maybe 0,15 millimetres or under 0,01 inches). But, if the barrel would be 12 yards long, the the same click moves the barrel mouth up- or downwards TWICE that amount, understand? That being, it is not possible that using the same gun and same rear sight, the amount of correction per click could be 1/2 inch with 4-inch barrel and 1 inch with 6-inch barrel. Vice versa I would believe...
February 21, 2011
Offline
actually he's correct the calculated numbers are wrong (reversed) for the differing barrel lengths, my apologies.
Matthew Quigley on handguns:
“I said I never had much use for one. Never said
I didn't know how to use it.”
1 Guest(s)
