Running out of scope adjustment.

[Norrick]

I have a Super Blackhawk Hunter in 45 colt. I am shooting handloads and I've run into a problem.

I am shooting at 25 yards with a Nikon Encore 2.5-8x and getting excellent groupings. Naturally I want to shoot farther to see how much they open up. When I move out to 50 yards I completely run out of vertical adjustment and am having to use the lowest circle on the ballistic reticle to aim with.

The handloads I was using were pushing a 250 gr. bullet @ 1030 fps. It only has 40 MOA of internal adjustment, which is less than I am used to, but even still I'm not so sure this is right.

The only thing I can think of is that the rings I am using were previously lapped for another setup. The rings supplied are much too low for the scope I bought. I am using #5 rings and can barely fit my scope on after lowering the rear adjustable sight all the way.

Any ideas? I took off the rings and switched the front to back and vice versa to see if anything changed and it is the same deal.

I know the 45 is a relatively slow bullet, is it simply falling too far for the scope to compensate?

 

[Old Ranger]

It's probably the mounting - get the scope remounted, new rings, and by someone who knows a lot about handgun scopes. Then try it. You should be able to shoot way out there.

 

[svtruth]

I put

a scope on a GP-100 and now realize I should have used taller rings so the iron sights could stay.
Live and learn.

 

[Norrick]

I have re mounted the scope using some burris ruger to weaver adapters and some posalign rings. If I am still having trouble after my next range visit I will post some pics. But I was looking at the reciever integral ring mounts and the right hand side looks significantly different than the left side. One side looks cast and the other side looks machined, and the sizes are different (right side is deeper and larger). I am just a bit worried because the ring marks on the right side dont look like theyre gripping very deep into the groove, it actually clamps partially on the thin flat lip right above where the scalloped shape groove begins.

 

[tguil]

Sure would like to hear if others have noticed this about the Ruger scope mounts. Something else to look for when buying a new or used gun? I just returned a new Super Blackhawk Hunter that appeared to have "messed up" scope mount.

Norrick, did you purchase the Hunter new? If not, the previous owner could have messed up the mounts when the installing rings. This problem was mentioned on one of the Ruger forums.

 

[Norrick]

I got it new from gunbroker. It did not appear to have any marks on the ring mounts aside from the machining marks described above. The shiny spots where you can see where the rings apply their clamping force is from me. I'm going shooting tomorrow so I'll take some pics after I clean the gun afterwards.

 

[Tilos]

The same reason the front sight is so TALL on this gun.

When you mount a scope parallel to the barrel you will run out of verticle adjustment the further the distance you try to shoot.
Most of the adjustment is used up just getting a "sight-in" at close range.

Removing the mount and setting the gun upside down on the sights will reveal the angle between the bore and the sights.

I have machined this angle on the BOTTOM of the scope mount(one piece) to allow a greater range of verticle adjustment.

That is one way I have gotten around this problem, there may be others.
YMMV

DO NOT shim the forward ring up, that will mis-align the rings and may DAMAGE the scope.

You could shim the front of BASE/MOUNT but it would not look very nice.

 

[Norrick]

Back from the range today... the new scope setup did help alleviate the problem. I can zero at 50 yards now, but I am still only 10 MOA from "topping" out the adjustment. I feel like that wont really get me much past 100 yards. Just off hand I remember that a standard velocity 22 drops 8 MOA from 40 to 100m and the velocity/ballistic coefficients are similar. Does that sound normal to use up 10MOA from center (20 up, 20 down total) to get on target @ 50?

I do have 20MOA inserts but I'd much rather be using factory rings for this setup so I don't have all the additional chunkiness and weight from the Ruger to weaver adapters.

No pictures still of the gun as of now, will definately get them on here soon to describe in more detail the possible integral base defects that I'm looking at.

But for now... the best group of the day:


I was getting one ragged hole at 25 with my last batch of handloads using Accurate No. 7 and I would have loved to see 50 yards, but back then I was having the initial problem of running out of adjustment. I am using Blue dot, in this particular picture. It was pushing a 250gr Speer Deepcurl JHP @ 960ish fps. I'm noticing alot of unburned powder. Any suggestions? I've heard increasing the pressure can give a cleaner burn. I guess this is a bit off topic but I figure I'd just throw it in.