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I have a pre-64 model 70 with iron sights (front globe and receiver peep sights by Lyman). A gunsmith has looked at the front sight and told me that it is dead center.
When I approximately center the Lyman rear sight, using my eyes, it shoots about 2-2.5 inches to the right at 50 yards. Not sure if it was me or the gun, I had someone else shoot it, with similar results. A third gentleman at the range took a look, moved the sight 10 clicks left, and it shot 1 inch to the right (in other words, about the same results).
When I moved the rear sight 20 clicks to the left (1/4MOA adjustments), it shoots center.
I’ve tried factory 150 grain, 180 grain cartridges from Remington, Winchester, Federal, and S&B with similar results.
I’m wondering if this is “normal” for pre-64 Winchester 70’s. Any of you experienced a similar amount of windage offset from mechanical zero?
I wouldn’t mind if this is just manufacturing variances. It’s just strange that any firearm not shoot straight by this much, but if this isn’t unusual for pre-64’s, I’m totally fine.
I just can’t but wonder if there is something else going on, like a misaligned barrel/receiver, etc., that is damaging the rifle whenever I shoot it. It does seem to produce a lot of copper fouling. I might take it to a gunsmith to check it out unless folks tell me this is pretty common.
Thanks in advance for your insights.
Ron P said
I’m wondering if this is “normal” for pre-64 Winchester 70’s.
No, not normal, but I can’t suggest what to do about it beyond making that adjustment in your rear sight. Hard to believe it passed test firing in this cond.
The one potentially positive thing is that the previous owner had the same rear sights centered (in fact, a bit right of center), along with factory front irons (which I took out and replaced with a front globe sight). I’ll take it to the smith and see if it’s something on my end.
Hi Ron-
I assume we’re talking about a Lyman 48WJS receiver sight (or 48WH if a Target model)?
Having the rifle checked over is always a good idea, but I suspect the issue is simply that the receiver sight is not original to the rifle. Hence it was never factory sighted with its current sight combination. If it is not a Target model and was made after 1950, it is very unlikely that the receiver sight was factory installed since the factory dropped the Lyman 48WJS sight option from the catalog after 1950.
The usual procedure with those receiver sights was first to sight them in for the desired “zero” range (usually the shortest distance the rifle would be fired), then move the index plates on the slide and base to line up with the “zero” on windage (top) and elevation (side) scales scribed on the sight staff. The windage index plate is held by two small screws and has some lateral movement to allow adjustment after loosening the screws. The elevation index plate, that small pointer thing on the front of the sight is held in place by one small screw and has some vertical movement.
The final thing to do once the index plates were lined up and everything zeroed was to run the elevation set screw on top of the cross bar near the elevation knob (visible in the first pic) down until it touched the top of the sight base. This was supposed to allow the shooter to remove the cross bar and quickly return it to the “zero” setting without having to fiddle with the turning the elevation knob one click at a time.
Those Lyman sights have 1/4 minute clicks, or about 1/8th inch per click at 50 yards. So I would expect it to take about 20 clicks to move the point of impact 2.5″ at 50 yards.
Final thought is that if, once sighted in, the index plates cannot be moved far enough (left/right and up/down) to line up with the scales on the slide then there is something wrong with the way the block is mounted to the receiver. You might want to check that the base of the sight is firmly in contact with the side of the receiver. On those post-1947 Lyman 48 sights, with the coved out back of the sight that eliminated the need to cut a rectangular chunk of wood from the stock (first pic), the bottom edge of the block that hangs down over the stock would often come into contact with the wood before pulling tight against the receiver. The factory would take care of this when they were installing the sight, but I’ve seen many (carelessly) owner-installed sights where contact with the side of the stock is preventing the base block from sitting firmly against the receiver.
Hope this helps… Let us know the answer when you figure it out!!!
Lou
WACA 9519; Studying Pre-64 Model 70 Winchesters
This mystery has been SOLVED and it was a simple explanation, not worth a post on here.
It turns out, the front sight was canted…!
What threw me off was that a few weeks ago, I went back to the gunsmith (who installed the new Lyman 17 AMI front globe sight), who “verified” that it was centered. So I never paid attention to it again, assuming it was not the problem.
Two different people at a different gun shop took a look yesterday and immediately saw that it was “obviously” canted. Well, it wasn’t obvious to me, but I put on the original Winchester 103C front sights, and now it shoots pretty much dead center.
It is reasonably accurate – 2-4 MOA with iron sights.
Only thing now, is the Winchester 103C front sights are too short, with the Lyman 48 WJS at lowest setting, it’s shooting around 4 inches high at 50 yards. But at least I know exactly what is going on!
Hi Ron-
I’m glad you got that sorted out. Thanks for the update!!!
You haven’t mentioned the serial number or style of the rifle, so this may/may not be relevant. But Winchester used two different height silver bead 103C front sights on M70s. They were initially 0.310″ high, like the Lyman 31W they replaced in about 1941. Later, around 1952, when the MC comb stocks came out, Winchester raised the line of sight about 0.050″, which involved a taller/folding rear sight (Marbles 69 and later Lyman 16A/B) and a 0.360″ tall 103C.
So if the 103C on your rifle happens to be the 0.310″ tall earlier one (1941-1952), you might get enough height out of the 0.360″ tall variant (1952-1963) to solve the problem.
Best,
Lou
WACA 9519; Studying Pre-64 Model 70 Winchesters
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