Rear Sight Elevator Adjustment to Point of Impact
- Thread starter Puma
- Start date
- Location
- Western Manitoba
I believe that Winchester used to make specific rear sights for some of their lever action guns - the "notches" were claimed to match the trajectory of their "standard" rounds - did nothing for windage, of course - and I have seen too much go wrong to trust those notches or markings blindly - I would want to verify, first - but apparently was part of the sales pitch, then. Mostly, I played with various Cooey .22 - maybe there was a similar plan on their elevators, but was pretty much as posted above - "by guess and by gosh". I do believe, among collectors, that the Winchester rear sights and the appropriate elevator for that chambering and the original barrel length, is a "thing" of significance.
One could use fairly basic trigonometry to work out how much to raise or lower the rear sight, or raise or lower the front sight, to move the group up or down, a specific distance, at a known range - or look up various charts on Internet - I think Brownells website has such a chart, or at least an explanation how to calculate the required adjustment (or replacement).
One could use fairly basic trigonometry to work out how much to raise or lower the rear sight, or raise or lower the front sight, to move the group up or down, a specific distance, at a known range - or look up various charts on Internet - I think Brownells website has such a chart, or at least an explanation how to calculate the required adjustment (or replacement).
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I think that Gunblue guy on YouTube has a video on this. What I do with my Winchester is just sight it in 3” high at 80yds and use point blank aim. There is a formula, but there are so many variables that I doubt it’s all that reliable.
What variables? Does your rifle barrel extend and retract? If you are capable of taking accurate measurements the results will be exact.
Variables like bullet weight, bullet shape and BC, powder charge, etc. - anything that affects trajectory.
I see what you mean by exact results in one rifle with one specific load, but if I read the OP correctly, he’s asking if there’s a repeatable, “standard” set of measurements that applies to elevators on marlin lever guns. Eg, one step up=X MOA. It just isn’t going to work that way without controlling the variables I listed above.
He can develop his own scale for his rifle and his load once he figures that out, but he was asking us if figuring it out for himself is necessary, or if there’s a standard out there that’ll do it for him.
The point of impact will always change exactly the same, there are no variables to this. It is the same as 1/4"(moa) click adjustments on a scope, it doesn't matter is the bullet is 500gr. going 1000fps or a 50gr. bullet at 4000fps, the change in poi is always the same. Different loads out of the same gun of course usually strike to a different point of impact, but the sight adjusments per notch are always the same value. It is not that difficult to work out the math for this, Now manually laying out old school non DRO or CAD say 15 8.35mm holes on a 3079.6mm circle with an manual milling machine requires some pencil time.....
- Location
- Western Manitoba
I think you are correct for these days, but I do not think that was how it started with the iron sights? For example, I think original 30-30 was 160 grain bullets - what you bought from Winchester was considered to be "the same" - I think that is what those rear sight ladders were based on. As time went by, then got various 150 grain, or 170 grain bullet choices, Pneumatic tip, flat tip, round nose tip - lots of "choices" that all threw that rear sight setting thing out the window - a shooter needed to play with his own sights to get it "set" and to understand the adjustments that resulted from the load that he used - but many, I think, did not notice that - they assumed that the rifle was properly sighted in at the factory when made - using "standard" ammo - if the shell fit, then fire it. I do believe lots of things got killed that way - not really much into shooting at a target to get a "group" - typically.
Right. The change is always the same, but it’s not the same from one load/brand/bullet/etc to the net. That will depend on your trajectory and all the other “variables” I mentioned.
Whatever, the point is, to the OP, the answer is no. Moving the elevator up one notch isn’t going to raise your POI a pre-determined amount. It will be a generally-incremental move from one point on the ramp to the next. You can change your POI vertically by adjusting velocity, trajectory (BC), by installing a taller or shorter front sight, AND/OR by raising/lowering the rear sight. (These are all the variables)
We’re all getting carried away here. lol. It’s a lever gun with iron sights. If you can hit a pie plate at 80yds it’s sighted in. Go hunting.
amount of error X sight radius/range = sight correction needed. You have to use the same units for everything including range. Feels funny to give the range in inches.
At least some thought was given the sight elevators on some rifles. or at least it once was. Take a Win 1894 for example. While people tend to use whatever notch on the elevator works; a bit of inspection will show that there are a couple of screws that would allow the entire sight blade to be moved vertically without touching the elevator at all. If you started on the second notch then slid the blade to sight in at 100 yards, going up one notch would get you on at 150 and down one notch would be on at 50. Individual rifle models and calibers had different part numbers for the elevators, it wasn't necessarily one size fits all. Of course shooting verification is/was recommended, and the accuracy level of iron sighted carbines wasn't expected to be at the F-Class level.
Jack O'Connor once joked about burning up a few boxes of shells to get a one dollar sight shooting right, but that was the tech of the day.
At least some thought was given the sight elevators on some rifles. or at least it once was. Take a Win 1894 for example. While people tend to use whatever notch on the elevator works; a bit of inspection will show that there are a couple of screws that would allow the entire sight blade to be moved vertically without touching the elevator at all. If you started on the second notch then slid the blade to sight in at 100 yards, going up one notch would get you on at 150 and down one notch would be on at 50. Individual rifle models and calibers had different part numbers for the elevators, it wasn't necessarily one size fits all. Of course shooting verification is/was recommended, and the accuracy level of iron sighted carbines wasn't expected to be at the F-Class level.
Jack O'Connor once joked about burning up a few boxes of shells to get a one dollar sight shooting right, but that was the tech of the day.
