Balky adjustments

[rickt300]

Have been using a SWFA SS 10x42 on my 260 Remington for a while, maybe 600 shots fired under it. Today my project was to fireform some Nosler 260 brass using a load of 32.5 grains of 3031 under a 120 gr. Barnes Matchburner. This load is right in the middle of the lower node and gives me 2650fps, typically 1/2 moa and better. In fact today it turned in a .203 three shotter. But zero was a bit low and to the left, I'd guess less than 1/2 inch. Several attempts to adjust seemingly made no difference then suddenly POI shifted in the direction I wanted but further because of the extra clicks trying to get poi moved when it didn't. Then I ran into another variable. I was shooting unsized new brass and hit the ten pieces I had already fired, sized and loaded again. These hit at 1 oclock but 1 1/2 inch high. Once again no poi movement until I had run twice as many clicks trying to get poi to where I wanted it. So now 1 1/2 inches low and left at 5 oclock. So twice in the firing of 35 rounds I had the same issue. Should I send it back or run the adjustment travel all the way out and back for both knobs and try again? Though I have fired a good number of rounds with this scope mounted I have not actually done a lot of adjusting it as I have been using the same loads and just shooting groups.

 

[SSL]

I don't have your particular scope, but have run across others that have acted in a similar manner. On some, adjustment followed by a couple firm bumps to the turret jogged the adjustment. It is commonly recommended to double the adjustment and then back them off again by half to compensate for 'slack' in the mechanism. In other words, if you need 3 clicks, turn 6 and then back off 3.
Maybe others have more suggestions.

Have been using a SWFA SS 10x42 on my 260 Remington for a while, maybe 600 shots fired under it. Today my project was to fireform some Nosler 260 brass using a load of 32.5 grains of 3031 under a 120 gr. Barnes Matchburner. This load is right in the middle of the lower node and gives me 2650fps, typically 1/2 moa and better. In fact today it turned in a .203 three shotter. But zero was a bit low and to the left, I'd guess less than 1/2 inch. Several attempts to adjust seemingly made no difference then suddenly POI shifted in the direction I wanted but further because of the extra clicks trying to get poi moved when it didn't. Then I ran into another variable. I was shooting unsized new brass and hit the ten pieces I had already fired, sized and loaded again. These hit at 1 oclock but 1 1/2 inch high. Once again no poi movement until I had run twice as many clicks trying to get poi to where I wanted it. So now 1 1/2 inches low and left at 5 oclock. So twice in the firing of 35 rounds I had the same issue. Should I send it back or run the adjustment travel all the way out and back for both knobs and try again? Though I have fired a good number of rounds with this scope mounted I have not actually done a lot of adjusting it as I have been using the same loads and just shooting groups.

 

[rickt300]

I took it off the rifle, made sure the bases screws were tight, spun the dials all the way around and back, remounted the scope and shot it again. The POI had only changed 1/2 MOA. Backed off ten clicks and went back 12. Exact zero obtained and a 5 shot group of .487.

 

[AccelR8]

I don't have a lot of experience with many scopes, but in the past I have experienced what you've described.

Through both my own experimentation and talking to several other shooters who shoot Service Rifle with different low-power variables, including the ones I have, it seems shooters are doing several things. As has already been mentioned, exercising the adjustments by running them all the way in and out seems to help a lot. Also (already mentioned) dialing beyond and coming back can help, and also shooters will rap gently on the turrets after an adjustment. I do this sometimes and also rap gently on the tube across from the turrets, like where the spring is.

The last technique has given rise to the “National Match Hammer.” I'll see if I can provide a link. Spoiler; it's a joke. I think.

Unfortunately sticking and friction a.k.a. stiction is a thing in many devices and can play havoc with fine, sensitive adjustments. I don't know how well really high-end scopes deal with it.

National Match Dead Blow Hammer

Visit the post for more.

thenewrifleman.com

 

[AccelR8]

I'll add I have a SWFA SS 20X42, same as yours just different magnification. I've dialed up and down from 200 to 1000 yards and back again, numerous times, and had no trouble. But mine is fairly new. I actually love the thing despite it being "cheap." I should have bought a 10X though...

 

[wildcatter]

I have had this happen with a few, usually lower priced scopes, but it can happen with any. If it does, I would send it back, it is not right, but I would not use a scope doing this if it can't be fixed, I would move on, it is unexpectable performance, for target or hunting.

Oh forgot to mention, I have never suffered from ring marks or dented tubes using those Premier rings as well.