One piece mount with 20moa

[DannC]

New here and new to LR shooting, so my apologies if this post is in the wrong forum. I have a Ruger Gen2 PR in .308 with a Vortex Gen2 5-35x50. Originally mounted in Vortex extra high rings. Was convinced by an experienced shooter that I would run out of elevation long before I could dial to 1,000 yards. Have 55 1/10 mils left after 100 yard zero [19.8 moa]? If I needed to add elevation I decided a one piece mount would be better. Ordered a mount with 20moa from a company known to make quality but inexpensive mounts. Leveled the rifle by the picatiny rail and mounted the one piece. Moved the level from the picatiny to the top of the new base rings. There was almost a half bubble difference in level and the front was different than the back. Reasoned that I was going to level the scope to the rail and not the rings that it would not matter. Finished installation and found when bore sighting that I had used over half my right windage. Have not shot it but am concerned that these errors will be compounded at the range. I NEED HELP!

Thanks DannC

 

[308pirate]

The picatinny base that comes with the RPR is supposed to have a 20 MOA tilt in it. You should have had way more than 5.5 mils of elevation left after zeroing at 100 yards (more like double that).

Adding a 20 MOA rail on top of the existing 20 MOA rail makes no sense and isn't fixing your issue.

I also find it hard to understand why you needed "extra high" rings with a scope that has a 50 mm objective. I'm pretty sure medium height rings will work.

I would remove everything you've bolted on to mount this scope and do the following:
1. Buy a set of medium height rings
2. Set your scope to mechanical center (run elevation all the way down, run it all the way up counting clicks, go back down 1/2 that many clicks, same left to right with windage)
3. Remount the scope, making sure it's plumb and level
4. Bore sight the scope
5. Re-do your 100 yard zero
6. Count how many mils you have left upwards in elevation

If you still don't have 10 plus mils of elevation left, either the picatinny base that came with the rifle is defective (doesn't really have 20 MOA of tilt) or there is something wrong with your scope.

 

[DannC]

Hello Gunny, I have about two hundred rounds thru the rifle with the Vortex rings and have several almost dime size five shot groups. The reason for the extra high rings is because of extensive laser surgeries that have left me with zero vision in the right quadrant of my eye. The high rings allows a more erect head position so I can see. The rifle was bought new and the rail definitely is higher in the back than the front so I am assuming it is 20moa as appropriate for this rifle. The scope has only a total of 90moa available so I thought 55 mils was good. The initial setup and zero were done just as you described.
On another note about this scope is the difficulty in rotating the illumination knob and the magnification ring. Just read of these problems on another thread. The illumination knob requires a full fist and is like turning a rusty bolt. Put a cattail on the mag ring but it is still very hard to turn.
So do I have a bad scope and need to return it to Vortex for service? Thanks for your response. DannC

 

[jda2631]

I have somewhat the same issue. I have a gen 1 RPR with a vortex 6-24 HST. This scope has 65 MOA of total travel. I only have about 29 MOA of usable travel left after zeroing at 100 yards. And that is with the 20 MOA base on the RPR. So without that 20 MOA base I would only have 9 MOA! I contacted Vortex and Ruger about this issue. I haven't returned anything to either manufacturer, but the best theory that I came up with after talking to them is the barrel isn't aligned perfectly, it's angled down slightly. If I just look at the barrel and hand guard with my eyes, I can tell the barrel isn't perfectly aligned in the center of the hand guard, but that could be the hand guard not being perfectly straight.

Ruger said they would take it back and look at it, see if that was in fact the issue. But the gun is a real shooter, so I just never bothered to send it back to them to see if that was the case.

 

[buffybuster]

Something doesn't sound right. The rifle is supposed to come with a 20MOA base and you only have about 20MOA of elevation on your scope. You shouldn't need to add another 20MOA to that. I would take everything (scope, rings, base) a part and start over.

Clean and degrease EVERYTHING relating to the scope and mount, including your fingers.

1. Make sure the picatinny base is on straight and in the right direction. It's supposed to be a 20MOA base and it should have "20MOA" engraved on the back end. Get all the screws started before you snug anything up and make sure the base goes not without any stress. Torque the screws to 25in-lbs. Level the rifle.

2. What rings are you using? Get some quality AR height (1.3 - 1.5") picatinny spec rings. Set each ring in the picatinny slot, with at least one slot on either side ensuring the recoil lug is fully in the slot and push the ring forward and snug the crossbolt. If you're going with a one-piece ring mount, same deal. Confirm the rifle and rings are level.

3. Set the scope on the rings. The scope should be sitting in the rings with NO stress, gaps or interference. If the scope is not sitting square in the rings, then loosen the cross bolts and check what's not right. DO NOT FORCE ANYTHING. Set the top ring halves and start the screws. At this point level the scope and set the eye relief.

4. Torque the cross bolts to the recommended torque. Double check scope hasn't moved then snug up the ring screws and double check eye relief. If everything is GTG then torque the ring screws in the cris-cross pattern to 15-20 in-lbs.

If you find you need to adjust the eye relief, if you placed the rings with one slot on either side, then you can adjust the scope forward or back one slot as needed and torque the crossbolts.

 

[308pirate]

The reason for the extra high rings is because of extensive laser surgeries that have left me with zero vision in the right quadrant of my eye. The high rings allows a more erect head position so I can see. The rifle was bought new and the rail definitely is higher in the back than the front so I am assuming it is 20moa as appropriate for this rifle. The scope has only a total of 90moa available so I thought 55 mils was good. The initial setup and zero were done just as you described.
On another note about this scope is the difficulty in rotating the illumination knob and the magnification ring. Just read of these problems on another thread. The illumination knob requires a full fist and is like turning a rusty bolt. Put a cattail on the mag ring but it is still very hard to turn.
So do I have a bad scope and need to return it to Vortex for service? Thanks for your response. DannC

OK, keep the extr high rings. I seriously doubt they are why you don't have more elevation left over from 100.

I suggest just doing everything I listed in my first answer except changing the rings. The advice from buffybuster is also along the same lines.

Also, from your account, you don't have 55 mils left of elevation right now. You have 55 clicks each worth 1/10 mil. That means you have 5.5 mils of elevation left. You should have more than that.

If your scope has a total of 90 MOA of travel, that should be 45 from dead center. 45 MOA is 13.1 mils (1 MOA = 3.43 mils). By angling the scope down, the base will force your 100 yd zero to be below mechanical center meaning you should have more than 13 mils left in elevation.

To give you an idea, my SWFA 3-15X42 on a 20 MOA base has nearly 14 mils left of elevation from a 100 yard zero. More than enough to dial for a 1000 yard shot with about 3.5 mils left over.

 

[DannC]

OK Gunny, I have really screwed up! The only time that I have run the elevation up and counted the clicks was after setting the zero stop. That was three months ago. I have only shot at 100 yards so I have not needed to dial for distance.

I am old, bad eyes and a poor memory. It was 155 clicks or I/10 mils.

When a friend at the range asked me how much elevation I had left I also told him 55 clicks !/!0 mils. His response was that I would run out of elevation long before 1,000 yards, that lead me to purchase the one piece 20moa mount.

You are right, I don't need an additional 20moa so the problems with the out of level mount have gone bye bye. Returning the mount and called Vortex about the stiff controls and sending it in for service.

I am way to old for the run & gun that I still try to do. I thought that long distance shooting where you sit at a bench or lay on your belly would be something I could do for a few more years. I am finding that maybe my brain is not up to this either!

I am having fun and will be back with some more stupidity when I get my scope back.

Thanks to all DannC

 

[308pirate]

You'll be fine. The math ain't that hard and everyone makes new guy mistakes.

Glad you're getting it figured out.

 

[buffybuster]

DannC,

DO NOT COUNT CLICKS. Zero the scope knobs and use the hashmarks.

 

[DannC]

Just realized that everyone is a Private or a Gunny {smack face with hand]. Many thanks 308Pirate and buffybuster. I will get the hang of this forum in a few years or so.

 

[308pirate]

DannC,

DO NOT COUNT CLICKS. Zero the scope knobs and use the hashmarks.

+1

Force yourself to discuss trajectory in actual angular units (minutes of angle or milliradians) for two reasons:
1. A click in an MOA scope is not the same as a click in a milliradian scope
2. A click in a 1/4 MOA scope is not the same as a click in a 1/2 or 1/8 MOA scope

The word "click" means absolutely nothing to knowledgeable riflemen when discussing bullet trajectory adjustments.

 

[DannC]

I did note that the clicks that I had counted were 1/10 mils. My first mil/mil 1FP scope and trying to understand the relation ship to MOA and inches because that is the whey my mine thinks.
.I unfortunately was educated without the benefit of the metric system so I have to do a mental calculations for zeroing a mil/mil scope even though I know there is no relationship..
308pirate in your post No. 6 you stated that 1 MOA = 3.43. I had understood that it is 3.6 inches. I want to create a ladder board as shown in SH by LowLite to verify tracking and scope drift / parallel.
Foe example if I turn my turret up 10mils in ten one mil increments how high in inches could I expect in inches when using the same bottom aiming point and the spacing of each shot?
Also help me with the math, if I have 155 1/10 "clicks what is my elevation travel in Mils.
Thanks for you patience and advice.

DannC

 

[308pirate]

You don't need to know the metric system because milliradians are not a metric unit. It's a base ten system but that doesn't make it metric.

I made a mistake yesterday because I was in a hurry. The correct relationship is 3.43 MOA = 1 milliradian. Likewise 3.6 inches per 100 yards = 1 milliradian.

Remember that 1 MOA is NOT 1 inch per 100 yards, it's 1.047 inches per 100 yards.

The derivations of all these relationships is found online.

So to answer your questions
Q: if I turn my turret up 10mils in ten one mil increments how high in inches could I expect in inches when using the same bottom aiming point and the spacing of each shot?

A: I'm going to assume this will be done at 100 yards. So, since 1 mil = 3.6 in/100 yds, you would expect that 1 mil up from your aim point will be 3.6", 2 mils up will be 3.6x2 = 7.2", 3 mils would be 10.8", and 10 mils up from the aim point will be 36"

Q: if I have 155 1/10 "clicks what is my elevation travel in Mils.
A: If each adjustment click is worth .1 mil (1/10 mil), then 155 clicks would move your point of impact 15.5 mils (155 x .1, or 155 / 10, same thing)

When it comes to actually using your scope to adjust your impacts, use the ruler in front of your eyeball. The reticle in your scope is marked in increments of a milliradian. Use it to measure how many milliradians are there between the bullet hole and the aiming point, and that's how many milliradians you need to dial to get centered up. With that method, it doesn't matter how many inches you missed by and it doesn't matter how far away the target is.

I'm assuming that you have a Viper PST Gen2 5-25X50 with milliradian adjustments, so this is what you're reticle measures (MRAD = milliradian):
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/www.vortexoptics.com\/uploads\/sub_vpr-pst_5-25x50_ebr-2c_mrad_web.jpg"}[/IMG2]​

 

[DannC]

308pirate, thanks for the info and clarification. I knew when I referred to the metric system that it was not equal to mils other than both being based on 10. I am trying to make sense out of this mess by something that I already know. I almost wish I had bought a MOA/MOA scope. It was cheaper and would allow me to think in inches and feet.
I have a Bushnell one mile CONX rangefinder that once I have chrono'd my loads I will let it tell me my correct mils for distance.

Thanks DannC

 

[308pirate]

I almost wish I had bought a MOA/MOA scope. It was cheaper and would allow me to think in inches and feet.

You would be making the same mistake by thinking in inches and feet with an MOA scope.

My dope card has my drop in mils for every 25 yards between 100 and 1200. I take the range and look up the drop then I dial it in. If I miss I measure with the reticle the difference between impact and aim point in mils and either dial the correction or offset the reticle and fire again.

If I had an MOA scope I'd do the same thing as above but measure everything in minutes.

Scopes don't adjust in feet or inches so I don't give a shit how many inches I am off target by or how many inches the bullet will drop at any distance. It's pointless and all it does is confuse what is otherwise a very simple operation.