[RAMMAC]

One of the things that a lot of us do to improve our rifle is install a scope. Then we go out and shoot some paper and some of us are disappointed because we don't get the groups that we had hoped for. There are lots of reasons for that but I wanted to talk a little about two things that I have found that help me get tighter groups. The most important is ensuring that the reticle is perfectly horizontal and vertical and the second is ensuring that you keep the reticle properly aligned as you squeeze off the shot. The first is a crooked reticle and the second is a canted rifle. They both can cause a group that contains two smaller groups. Typically there will be a couple of impacts close together and then a short distance away a second tight group of impacts.

So, to ensure that the reticle is not crooked and therefore perfectly horizontal and vertical you have to align the scope with the rifle. This is the process that I use and have found it to be very precise.

These are the tools you will need;

• A gun vise, I use a Tipton
• A torque wrench with the appropriate bit for your scope screws, I use a Wheeler Fat Wrench
• A bubble level, I use a CTK Precision gun level
• A laser level, I use the Ryobi Tek4 self leveling level
• A pencil

Put the rifle in gun vise and level it using a bubble level.

My CTK bubble level installed on the flat spot behind the rear sight. This is the most convenient and reliable flat spot available.

Once the bubble is centered the rifle will be leveled.

Make a witness mark on the scope and an adjacent ring using a pencil. The pencil marks will wipe off without causing any damage to the finish. The witness mark provides a reference point that helps you make small adjustments to the scope.

Loosen the screws on your scope rings.

Setup the laser level. The Ryobi model levels itself so the crosshairs will automatically be vertical and horizontal. If your laser level does not have this feature then you will have to level the device before you attempt to adjust the scope. I put the laser level on a surface other than the one my rifle is on so that I don't cause the projected crosshairs to move while I'm working with the scope. The laser level is sitting on the blue boxes on the work bench.

Turn on the laser level (I staged this photo so the laser level is not where I put it when I actually adjust the scope).

Now turn the scope until the reticle crosshairs align with the laser level's crosshairs. Tighten the scope's ring screws with the torque wrench and recheck the reticle for proper alignment. You can use blue loctite on the ring screws but in most cases it isn't necessary. Some people use the cap over the elevation adjustment for a level reference because they assume that the cap is flat. Sometimes that will work but most often it doesn't. After adjusting my scope I put a second bubble level on the top of my scope to see if it would show level, this was the result;

You now have your scope's reticle properly aligned with the rifle but how do you ensure that you are not canting the rifle as you take your shot? I use a anti-cant bubble level. There are several available but the one I use attaches to my picatinny rail and projects out to the side. The first thing you have to do is install the device and verify that it is leveled to the rifle. You do that by putting a bubble level on the flat behind the rear sight and level the rifle. Then make sure that the anti-cant device's bubble is centered. Finally, tighten the screws that hold the device to your rifle and you are done. When I take my shot I check to ensure that the rifle is not canted by verifying that the bubble is centered. You would be surprised at how much tighter these two things make my groups.







Super dog, Maggie, put this information together so if you find any errors please feel free to address your comments to her as I'm sure she will respond...of course I will have to do the typing since her nails need trimming. JESTER

 

[yellowthunder]

Terrific post Rammac! I'll have to get myself a gun vise now!

 

[BLACKTAIL 8541]

Very good write up.

 

[NoExpert]

Great write-up RAMMAC, good pics too, and a good looking dog there.

One stupid question if I may... What if the reticle is canted a few degrees as seems to be allowed by many scope makers (I think Leupold allows 5 degrees either way)? Wouldn't your adjustments be off then if the reticle is perfectly level? That's what I've heard the proponents of leveling off the turrets say at least. I certainly don't know what the best method is but yours looks good. Heck, I may do both just to see if my reticle is out of whack when my new scope shows up.

 

[RAMMAC]

Great write-up RAMMAC, good pics too, and a good looking dog there.

One stupid question if I may... What if the reticle is canted a few degrees as seems to be allowed by many scope makers (I think Leupold allows 5 degrees either way)? Wouldn't your adjustments be off then if the reticle is perfectly level? That's what I've heard the proponents of leveling off the turrets say at least. I certainly don't know what the best method is but yours looks good. Heck, I may do both just to see if my reticle is out of whack when my new scope shows up.

Well Maggie got a little upset the other day because she found out that my Nikon Encore scope had exactly that problem. But under closer inspection it was the bottom half of the vertical hair of the reticle that was slightly crooked so we were able to use the horizontal hair and the upper half of the vertical hair for alignment. It looks like the cross point of the hairs is still in the center of the scope but in this case the scope may get returned to the manufacturer for repair or replacement since it has BDC bubbles and they may be off on windage. I will check how it performs out to 300 yards before I make a decision. The rifle is intended for medium sized game so the problem with the scope may not be important considering the size of my targets. Now if I were using the scope for accuracy shooting and printing tight groups I would probably return the scope without a second thought. So I guess what I'm saying is if your cross hairs were assembled crooked then you either have to compromise on the alignment or return the scope.

I really don't trust leveling off the turrets because I've seen cases where the turret itself was either loose or had no flat surface of large enough size to allow the bubble level to sit properly. To me, using the turrets is just adding another part to the process and sort of muddies the water; is the crooked reticle the turret, the cap, the tube, the cross hairs themselves? With this process all I worry about is getting the bubble level tight to the receiver and then I adjust the reticle as best as possible.

 

[awmp88]

great post !

 

[NoExpert]

Totally understand your reasoning and gotta do what works for you. I may be spoiled too in that USO scopes with at least illuminated reticles have a flat on the turret housing ahead of the elevation knob to level them with. But I think I'm going to do both ways and check them against each other. Then I can see if the internal bubble level is off also. I really like that receiver level you have there, I think I may order one, or two.

 

[RAMMAC]

Totally understand your reasoning and gotta do what works for you. I may be spoiled too in that USO scopes with at least illuminated reticles have a flat on the turret housing ahead of the elevation knob to level them with. But I think I'm going to do both ways and check them against each other. Then I can see if the internal bubble level is off also. I really like that receiver level you have there, I think I may order one, or two.

I suspect that when you buy a better quality scope like yours you get...well...better quality DI2

Here is a picture through my Nikon to give you an idea of how the reticle lines up with the laser level. Now keep in mind that the bubble level on the turret cap was way off.

I purposely offset the two cross hairs so that you could see their relationship a little better. If you compare the two sets of cross hairs very closely you can just see the slight error in the scopes reticle. It isn't a large error but it doesn't take much to through the impact off at 300 yards.


Ya' know, after looking at the picture a little while it looks more like the horizontal is the one that is off a little...hmmmm, I think I need to go to the garage for a few minutes.

 

[NoExpert]

Move your eye side to side and up and down behind the reticle and see if it curves as you move.

 

[RAMMAC]

Move your eye side to side and up and down behind the reticle and see if it curves as you move.

I do that as a test for parallax, is it useful for something else?

 

[NoExpert]

It can tell you if there's an optical issue on a SFP or fixed power scope. Not so much on an FFP scope.

 

[RAMMAC]

It can tell you if there's an optical issue on a SFP or fixed power scope. Not so much on an FFP scope.

I understand, you are talking about actual lens issues. Well like I mentioned, I've done the test to look for a shift in the cross hairs but I've never looked for any other oddities. I'll give it a try and see if the reticle bends or changes shape. Thanks.

 

[NoExpert]

Only reason I mention it is you mentioned the vertical line first and then the horizontal so that's why I think it could be an optical thing going on.

 

[RAMMAC]

Only reason I mention it is you mentioned the vertical line first and then the horizontal so that's why I think it could be an optical thing going on.

Yup, it makes sense, I'll definitely check it out, and if I get confused I'll have Maggie double check me. DI2

 

[RAMMAC]

Alright, I checked the scope like we discussed NoExpert and I found nothing of note about the lenses. But Maggie noticed what was happening and she straightened me out. Specifically it was the surface of the wall that the laser cross hairs were projected on, it wasn't exactly flat. That dog just keeps showing me up. DI2

I also used Leupold's Zero Point Bore Sighting tool to verify the reticle's position by a second process and it came out well too.

The reticle compared to the laser level cross hairs

The reticle compared to the Leupold tool

 

[NoExpert]

Man, the guy that built your walls must have done mine too, can't find a straight one to save my life.

Glad it worked out RAMMAC.

 

[tonyben]

That's good stuff RAMMAC! I did the same with a plumb line hanging off the ceiling in my garage. This, combined with M14'srock's excellent ring lapping instructions will help a lot of people.

Tony.

 

[BC762]

What a great post - thanks for helping others.

 

[Dredsen]

Just want to add for long range shooting you might add a wheeler scope mounting kit. This will let you check and lap rings as well as torque all screws identically.

Another "trick" is to buy a one piece scope mount. Lets you skip lapping.

Not a great option with the m1a though due to height.