Rifle shooting high, out of adjustment.

V

Vet66

New member
My .220 Swift with a 20x Lyman Super Target spot scope. I am out of adjustment, windage is fine just can't lower the elevation. What can be done?
3" high at 100 yards.
 
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I'm sure there's some shimming that can be done or swapping of sight rings and such....

A person better qualified to talk about it will be along shortly
 
Vet, got to get the nose of that scope up.
Are the bases correct (And OR) did they swap… is it barrel/barrel or receiver/barrel base?
My old H&R was just bassacwards from yours…
 
T. O'Heir, the rifle is a 1903 Springfield converted to a .220 Swift, it has a heavy Hart barrel, bases are Unertl I agree with Tater and, Doyle, front of scope needs to go up. Now I have to find a Unertl "C" front base there is a "B" on it now. I really don't think 20x is over the top for a .220 Swift....got to see the fleas when dropping those groundhogs...LOL.
 
I've got some bases left over from my use of Unertl and DeSimone target scopes.

I'll see if I've got a short 'C' .315" high base. Baby chicken noise: "Cheep"
 
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Bart, I would really appreciate that. Even a CL would work, I am using an "L" at the rear.
 
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4V50, shimming the rear base higher would mean the scope would be higher at that point making impact more than 3" high at 100 yards.

He needs a lower rear base or higher front one. I'd suggest one at least .100" higher. .002" change in base height moves impact only 1" (1 MOA) at 100 yards if the bases are on the standard 7.200" spacing.

He could shim the front base with a couple of thin washers I've done that.
 
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I've shimmed bases with small squares cut from soft drink cans and they worked well. You can cut them out with scissors and it's easy to work with. I would suppose an adult beverage can would work as well also..
 
The best shims I ever made came from the brass off of a magnum shotgun shell. I used a Dremel cutoff wheel to remove the rim, then I split it equally on 2 sides. Each shell gives you 2 nice brass shims that are already rounded to almost the right shape.
 
I'd recenter the up/down scope adjustment and shoot it again to give you an idea of just how much height you need to add for the desired POI
 
He could also count the clicks up from the bottomed out elevation to where the scopes tube is centered in the rear mount then divide that by 2. The adjustments move the scope tube .0005" per click at their contact points (40 tpi threads, 50 clicks per turn = 1/4 moa per click for the standard 7.2" mount spacing). The answer is in thousandths of an inch. This saves a trip to the range. I think he knows that.

A popular thing with external scope mounts for Lyman, Unertl, DiSimone and other target scopes was to use bases that allowed a 100 yard zero to have the scope tube about 1/16" above the rear mount's bottom. That allowed the most elevation adjustment range.
 
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Snyper,

What's the other thing besides the E and W knob positions about Lyman Targetspot (or any other of its type) externally adjusted scopes that has to be moved the same for each shot that ensures elevation and windage adjustment repeatability?

You can't do this with internally adjusted scopes; there's no need nor way to.
 
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Well, did some shimming on that front base, have no shim stock so, I used aluminum foil From the kitchen…..worked ok, set the bore sighter in the muzzle and, kept shimming till all was centered. Total height was .325 everything was center…….great. Off to the range, first shot was windage left @ 3.250” Elevation @2.125” and, elevation center. high. Moved the reticle to the impact hole (while still aiming at original point) Second shot was ¾”left Another adjustment and….yes right on with 5 shots touching, center of scope is very good, lots of adjustment both elevation and windage. Bart, I’m sure the “C” base will work fine, I don’t want to leave the shims there as on hot days and, dissimilar metals could prove problematic. I’m a happy shooter.
By the way range was 100 yards.
 
Good to hear your test proved out OK. I shimmed up a rear base with two beheaded finishing nails to get a DiSmone 20X scope in Unertl mounts high enough on my .264 mag match rifle one day. Used an extra long 'A' base on the receiver bridge to put the rear mount back more for easier use shooting prone. It was 10.8" back from the front mount giving 1/6th MOA per click.

I don't think dissimilar metals are an issue with scope mount bases. People put aluminum scope tubes in steel rings, don't they? And aluminum scope mount rails on steel receivers, too.
 
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