Gunsmithing Education on how to mount a rifescope on PRS competition rifle

[harry_x1]

Hi,
I recently got a good PRS type rifle assembled. MPA chassis, Patriot valley heavy profile barrell, TL3 action (6.5 creedmore) and timney trigger.
I also bought a sphur mount and atacr 5x25 riflescope. While rifle has been neatly assembled by a gunsmith friend of mine, I was looking to mount the scope on my own. Are there any good recommendations/educational videos/links on how to accomplish that? Also, would any of you experienced guys also recommend for me to not do it on my own? This will be the first time I will be mounting a scope and not sure, what can go wrong.

Link to the mount I am using:

Spuhr SP-4001: 34mm Picatinny Mount 0 MOA - 1.181"

Spuhr : SP-4001 - Spuhr SP-4001: 34mm Picatinny Mount 0 MOA - 1.181"

www.milehighshooting.com

best
Harjeet

 

[Moe Ron]

Don’t know if you’re familiar with the base and rings bedding part of mounting or if you want to do it.
Use the search feature. Lotta threads about it. I did my base. Pretty easy.

 

[_Windrider_]

Oh boy, this is gonna open up a lot of opinions.
first off, DO NOT lap those rings on that spuhr. They aren’t budget rings and it is not necessary. In fact you would ruin them.
there are a lot of techniques on how to do this, and there are an equal number of threads as mentioned. Feeler gauges, decks of cards, badger dead level with a plumb bob (my preferred method), shining a flashlight through it. The key is to make sure the reticle is level with the fall of gravity which is why a plumb bob is used. The spuhr should have come with a leveling wedge, that would work as well.

 

[Tweedycarcass23jonb]

You can install it yourself.
Personally the hell with the wedge. It doesn’t always work with the scope you have purchased.
1- Set your rifle on a secure platform. Recommend the back yard on a solid table.
2- place the spuhr mount onto the scope rail with the top half of the rings removed. I recommend starting a little forward on the rail with the spuhr. Snug but don’t torque yet.
3- place your scope in the mount. Check your eye relief
Adjust as needed. If you run out of room within the the mount because the turret hits the front or rear ring, move the mount on the rail as needed so you have more room to slide the scope which ever direction you need within the mount.
4. Once you have the mount in the right spot for tour eye it’s time to torque it down the mount. 45 in lbs 1.2.3.4 screws.
mount is secure time to level.
5- With the scope in the mount set the top half of the rings on and just get the screws installed without snugging them. You want to be able to rotate the scope slightly when leveling the reticle.

Leveling- This method works for me because I have a backyard that’s at least 25 yards and a scope parallax that goes below that. If you don’t, buy a scope level kit and watch a video on leveling.
my method-
You can use a piece of cardboard and Staple it to your fence. Using a level draw a vertical and horizontal cross hair on the carboard. The longer you make the lines the easier it is to line up the reticle. This is in place of a plum bob, or if you don’t have a scope leveling kit. Even using a leveling kit, I would still double check with the plum bob or method I’m describing. It’s no different than hanging a scope tracking test target except for the distance.
6 -Get the spuhr mount level and make sure scopes reticle lined up with the crosshair on the cardboard start snugging the screws little by little in a crisscrossed pattern get them snug first. Line the ring gap up evenly on each side of the rings(top half and bottom half) until the scope is snug. Then apply proper torque 15-20in lbs.
Verify torque and that the reticle is still level with your target. Any questions pm me please.
go shoot.
More than one way to skin a cat. This method works for me. I haven’t needed rosin either. Sure as shit don’t lap those rings.

 

[Moe Ron]

Oh boy, this is gonna open up a lot of opinions.
first off, DO NOT lap those rings on that spuhr. They aren’t budget rings and it is not necessary. In fact you would ruin them.
there are a lot of techniques on how to do this, and there are an equal number of threads as mentioned. Feeler gauges, decks of cards, badger dead level with a plumb bob (my preferred method), shining a flashlight through it. The key is to make sure the reticle is level with the fall of gravity which is why a plumb bob is used. The spuhr should have come with a leveling wedge, that would work as well.

Thanks Ignorance on my part

 

[loveha]

Do you have a quality in-lb torque wrench? Don't have one, don't bother till you have one from someone like Borka or Fix It Sticks.

 

[Dthomas3523]

Thanks Ignorance on my part

At times you’ll see uber OCD smiths (Jim Borden for example) who will lap and bed even expensive rings/bases. But, they are chasing accuracy/precision on levels that most wont/can’t achieve.

For everyone else, don’t worry with it.

 

[_Windrider_]

At times you’ll see uber OCD smiths (Jim Borden for example) who will lap and bed even expensive rings/bases. But, they are chasing accuracy/precision on levels that most wont/can’t achieve.

For everyone else, don’t worry with it.

With today’s modern CNC machinery, the precision is so good I just can’t justify it, unless they are caBella’s brand rings.

 

[_Windrider_]

@harry_x1 if you think this is something you will do more of, save yourself a lot of frustration and buy one of these.

Dead Level

P/N 200-50

www.badgerordnance.com

this makes leveling a reticle so easy I can do it in under 10 minutes. Here @lowlight demonstrates.



i cannot recommend this tool enough.

 

[Krazy_jim]

Dont have to ensure the reticle is level with the rifle level, but ensure its level in your natural hold. Slightly canted rifle in a natural hold, and level your reticle to gravity beats having the reticle level to the rifle, and then canting it all in a natural hold

 

[DownhillFromHere]

There's an easier (to me) way of leveling the reticle than using a plumb bob or whatever.

1. Cut a piece of sewing thread about 3-4 feet long. Use thread. String is too thick.
2. Tie a weight of some sort to one end. Just heavy enough to pull the thread straight.
3. Hang the weighted thread from a picture hanger or similar so the thread is very close to the wall.
4. Set your rifle on a table or chair or whatever with the butt against the wall, with the hanging thread "bisecting" it vertically. While acknowledging natural-hold cant as mentioned above, I prefer to set up the rifle so its pic rail is level fore-aft and left-right using the leveling function of my phone's compass app.
5. With the scope loose in the mount, shine a good flashlight through its objective (a phone flashlight isn't really bright enough). The reticle will be "projected" onto the wall, ideally right on top of the thread.
6. Rotate the scope until the projected image of the reticle's vertical is aligned with the thread.
7. Tighten the rings per Spuhr specs.

 

[_Windrider_]

There's an easier (to me) way of leveling the reticle than using a plumb bob or whatever.

1. Cut a piece of sewing thread about 3-4 feet long. Use thread. String is too thick.
2. Tie a weight of some sort to one end. Just heavy enough to pull the thread straight.
3. Hang the weighted thread from a picture hanger or similar so the thread is very close to the wall.
4. Set your rifle on a table or chair or whatever with the butt against the wall, with the hanging thread "bisecting" it vertically. While acknowledging natural-hold cant as mentioned above, I prefer to set up the rifle so its pic rail is level fore-aft and left-right using the leveling function of my phone's compass app.
5. With the scope loose in the mount, shine a good flashlight through its objective (a phone flashlight isn't really bright enough). The reticle will be "projected" onto the wall, ideally right on top of the thread.
6. Rotate the scope until the projected image of the reticle's vertical is aligned with the thread.
7. Tighten the rings per Spuhr specs.

You know that’s just a home made plumb bob right?

 

[DownhillFromHere]

You know that’s just a home made plumb bob right?

Absolutely - all shrunk down for convenience! (Poor word choice on my part... I'd blame it on being tired from a day of cleaning up hailstorm debris, washing cars, etc. but SH ain't a place to whine about getting old... )

 

[308pirate]

Do you have a quality in-lb torque wrench? Don't have one, don't bother till you have one from someone like Borka or Fix It Sticks.

None of them are necessary: https://www.badgerordnance.com/media/bo_media/Mounting_rings_and_bases_2017.pdf

I've always followed Badger's advice and never had a scope move on me or be so tight that any internal functions are impaired. At the end of the day, that's all that matters.

 

[smoothy8500]

Nobody likes the Wheeler FAT wrench anymore?

 

[Wheres-Waldo]

As far as leveling the scope to the rifle, all you need is a set of feeler gauges. Snug fit between the flat of the turret housing and the optic platform. Hand tighten the ring caps so the scope won’t rotate, remove feeler gauges, torque down. Done.

 

[n00g7]

Spuhr mount... I just get comfortable behind the rifle in a few different positions with the scope snug in the mount to:
1) adjust eye relief, and
2) note where the bubble likes to end up.

Then I just lock down the bipod with the bubble in the noted position, which you can mark with a sharpie or however else you see fit as your level position, and rotate the scope to level the reticle based on a gravity reference (door frame, plumb bob, whatever) and call it a day.

 

[sirhrmechanic]

Dont have to ensure the reticle is level with the rifle level, but ensure its level in your natural hold. Slightly canted rifle in a natural hold, and level your reticle to gravity beats having the reticle level to the rifle, and then canting it all in a natural hold

You can get away with this for deer rifles, rifles you shoot at short ranges, rifles that don't use a down base or on rifles you don't run the turrets on... But if you are going to shoot at long ranges and use your turrets or use your reticle for hold-overs, you want to avoid canting. Both in setting up your scope and in shooting/holding your rifle! Canting is your enemy because your natural cant when shooting off a bench may not be your natural cant shooting over a barricade. Or off a table. Best thing to do is make sure the rifle and scope are perfectly aligned and then not cant at all when shooting.

When everything is aligned correctly (and this includes your rifle to your eye) then you eliminate any tangential movement of the aiming point as defined by your cross hairs vs. actual bullet impact as you move your erector. If the scope is canted... coming up 10 Mils might mean coming UP 10 mils and going a half mil to the left or right... The bigger the cant, the greater the error as you move your erector. What is really happening is that the erector is moving away from the actual point of impact. At 100 yards... not going to matter. At 600... it starts to matter a lot! This is why some folks use bubble levels on their scope mounts (I think my Spuhr has one built in) to eliminate the 'unknowns' of canting when holding their rifle. And they work very hard to align scope to the machined top of the action.

Lots of good advice in this thread. Not lapping rings... good advice. Using shims and feelers to level... good advice. Getting a torque wrench set... very, very good advice. Don't forget putting on some indexing marks on your screws with a paint pen or small brush. And check your torques regularly. Doesn't have to be 'every' day. But check them regularly.

Scope mounting is not hard. But requires attention to detail. Good luck with your setup!

Sirhr

 

[Wheres-Waldo]

Don't forget putting on some indexing marks on your screws with a paint pen or small brush. And check your torques regularly. Doesn't have to be 'every' day. But check them regularly.

Sirhr

Advice to live by on any torqued fastener on your precision rifle.

I don’t paint mine, but I do check them every time I clean.

 

[n00g7]

You can get away with this for deer rifles, rifles you shoot at short ranges, rifles that don't use a down base or on rifles you don't run the turrets on... But if you are going to shoot at long ranges and use your turrets or use your reticle for hold-overs, you want to avoid canting. Both in setting up your scope and in shooting/holding your rifle! Canting is your enemy because your natural cant when shooting off a bench may not be your natural cant shooting over a barricade. Or off a table. Best thing to do is make sure the rifle and scope are perfectly aligned and then not cant at all when shooting.

Either the reticle is plumb to gravity when you pull the trigger or it isn’t. Whatever small amount of cant of the scope relative to the rifle exists when leveling the scope to natural hold can be ignored or accounted for separately if one really wants to split hairs. Two separate things, one can produce relatively large errors and the other doesn’t.

 

[Anointed1]

@harry_x1 if you think this is something you will do more of, save yourself a lot of frustration and buy one of these.

Dead Level

P/N 200-50

www.badgerordnance.com

this makes leveling a reticle so easy I can do it in under 10 minutes. Here @lowlight demonstrates.



i cannot recommend this tool enough.

So question @lowlight, is the purpose for the placement of cards underneath the turrets, hold the scope on a level plane in relation to the reticle so a plumb bob is not needed ?

 

[loveha]

I'm no Lowlight, but having seen this question enough on here.
There are two methods.
Level scope to rifle.
Level scope to rifleman.
Deck of cards, set of feeler gauges, couple levels, or purchase tools designed for it. That will level the scope to the rifle.
The plumb bob method sets the scope to the shooter. Whatever natural cant is implied to the rifle by the shooter is ignored when the scope is set with a plumb bob.
Whatever method you choose, is up to you. It's a debate probably as old as mils vs moa.

 

[Anointed1]

I'm no Lowlight, but having seen this question enough on here.
There are two methods.
Level scope to rifle.
Level scope to rifleman.
Deck of cards, set of feeler gauges, couple levels, or purchase tools designed for it. That will level the scope to the rifle.
The plumb bob method sets the scope to the shooter. Whatever natural cant is implied to the rifle by the shooter is ignored when the scope is set with a plumb bob.
Whatever method you choose, is up to you. It's a debate probably as old as mils vs moa.

I wasn't asking about the debate of slight can't versus no cant, I was asking about using the badger ordinance leveling tool in the video @lowlight made and the purpose of the deck of cards.

 

[_Windrider_]

I wasn't asking about the debate of slight can't versus no cant, I was asking about using the badger ordinance leveling tool in the video @lowlight made and the purpose of the deck of cards.

The assumption is the reticle is plumb inside the scope In relation to the turret. So by using the cards under the scope between the rail and the flat of the turret, you are essentially ensuring that the reticle will be plumb. It works. But if you have a bob and the time, it never hurts to double check it.

 

[Lowlight]

Man this one looks like fun, but I am working and just got back into civilization with a lot to do before Dinner

The manufacturers I have been too, which is more than one less than 6, all use the flat on the bottom of the scope to align the reticle. So mating the Flat of the scope to another flat, should assume the reticle is level, but as noted you want to check

We have taken to testing every scope for their reticles when we test them tall target wise because at least a 1/3 of every class, at least 4 scope the Reticles are canted in the rings by improper tightening of the ring caps usually.

The elaborate mounting system as a complete waste of time, and energy all the bullet cares about is gravity, so plumb the reticle to the fall of it. We use a plumb even in class, no fancy bullshit

And the guys saying you cant mount a scope crooked or shoot canted at distance are fucking clueless and should stop reguritating bullshit it smell worse the 100x around. It’s a math problem nothing else. I have several videos of me shooting stuff purposely canted and I every fucking thing I point the rifle at, trust me.

Yes you want to work to eliminate angles but sometimes a cant happens and other times some people have heavy heads and you have to set them off center because their center is wrong. For them 11:30 is Midnight, not 12. But that is a different topic

Don’t get crazy with it, use a plumb line check it with you in position, because it‘s in position you‘ll screw it up, ask me how I know. On bench everything you do is right, off the bench you suck something awful which is why I stayed employed, as noted above, what we did all day today, classroom, set up scopes, zero said scopes, shoot to distance, we do it every week.

 

[Anointed1]

The assumption is the reticle is plumb inside the scope In relation to the turret. So by using the cards under the scope between the rail and the flat of the turret, you are essentially ensuring that the reticle will be plumb. It works. But if you have a bob and the time, it never hurts to double check it.

Man this one looks like fun, but I am working and just got back into civilization with a lot to do before Dinner

The manufacturers I have been too, which is more than one less than 6, all use the flat on the bottom of the scope to align the reticle. So mating the Flat of the scope to another flat, should assume the reticle is level, but as noted you want to check

We have taken to testing every scope for their reticles when we test them tall target wise because at least a 1/3 of every class, at least 4 scope the Reticles are canted in the rings by improper tightening of the ring caps usually.

The elaborate mounting system as a complete waste of time, and energy all the bullet cares about is gravity, so plumb the reticle to the fall of it. We use a plumb even in class, no fancy bullshit

And the guys saying you cant mount a scope crooked or shoot canted at distance are fucking clueless and should stop reguritating bullshit it smell worse the 100x around. It’s a math problem nothing else. I have several videos of me shooting stuff purposely canted and I every fucking thing I point the rifle at, trust me.

Yes you want to work to eliminate angles but sometimes a cant happens and other times some people have heavy heads and you have to set them off center because their center is wrong. For them 11:30 is Midnight, not 12. But that is a different topic

Don’t get crazy with it, use a plumb line check it with you in position, because it‘s in position you‘ll screw it up, ask me how I know. On bench everything you do is right, off the bench you suck something awful which is why I stayed employed, as noted above, what we did all day today, classroom, set up scopes, zero said scopes, shoot to distance, we do it every week.

View attachment 7677604

Perfect...that's exactly what I thought but I wanted to make sure. I'm mounting the Vortex Razor 4.5-27X56 to a MPA BA Pro and using the tool, but on this scope there's not a lot of flat surface space under the turret so I'll double check with a plumb bob. This is the first time I'm mounting a scope so I wanted to make sure I'm doing it right.

 

[_Windrider_]

Perfect...that's exactly what I thought but I wanted to make sure. I'm mounting the Vortex Razor 4.5-27X56 to a MPA BA Pro and using the tool, but on this scope there's not a lot of flat surface space under the turret so I'll double check with a plumb bob. This is the first time I'm mounting a scope so I wanted to make sure I'm doing it right.

Using the dead level, you’ll be dead nuts on.

 

[Anointed1]

Using the dead level, you’ll be dead nuts on.

 

[NewsShooter]

I just lay down prone in the living room, open the front door and use the door frame across the street, I even put a level on it once just to be sure, don't even need to hang a plumb bob.

 

[JohnCarter17]

I just lay down prone in the living room, open the front door and use the door frame across the street, I even put a level on it once just to be sure, don't even need to hang a plumb bob.

What if the house across the street isn't level?

 

[n00g7]

What if the house across the street isn't level?

You put a level on it once just to be sure.

 

[JohnCarter17]

You put a level on it once just to be sure.

What if the homeowner objects?

 

[n00g7]

What if the homeowner objects?

Better to ask forgiveness than permission.

 

[Lowlight]

Unless you see the house leaning, I would suspect the accuracy of the walls are plenty fine, I have personally fixed and squared a dozen + reticles on rifles using nothing but the levels in my head. I am well known for dropping on rifles and finding the problem in setup.

This idear you need 4 levels to set something up is crazy

I teach Basic, what I call Day One Precision Rifle Classes, we call it the Fundamentals. We focus on rifle set up and adjusting the rifle to the shooter, the analogy I use is your car. If I move a seat or mirror in your car you would immediately know.

If the shooter sets the rifle up correctly, understanding their own body, and comfort level, things go much better. Instead, people randomly set up their rifles to a concept vs a certain level of comfort. Because of this fact we pull every scope today to test for tracking and to demonstrate parallax as well as check the reticles. We find at least 1/3 of scopes are canted in the rings.
Once that is fixed, we have just over a 1/3 of students who are either heavy-headed or pull the rifle over on a loose bipod, so they are inducing cant.

In all these cases, levels are usually viewed before Shot One, you check before you shoot, then once you start shooting you ignore it, meanwhile, shot 2, 3, and 5, are canted. You can see the groups tipped over. This happens every day, with a noticeable amount of students.

The level itself is an idiot light saying your car has a problem, it does not fix the problem if you don't understand the problem and nobody understands it. They think if they match the rifle to the scope via a $6 vial of liquid, they are good. Never understanding how they go smell blind to the issue, and induce the cant while shooting.

I would rather have a crooked scope on a comfortable rifle than one setup level to the rifle that I constantly push over. I can fix the shooter with a predictable lean, it's the ones that fight the notion to move the system so it fits you better.

Here I physically roll the rifle over, enough that would bury a level, (if I used one), I wanted it noticeable, but sort of on the edge of what a person would notice themselves. Because at a certain point everyone who cants notices when they go too far and fix it. The 5-degree examples often used a STUPID because nobody cants that far accidentally if you do it on purpose you probably understand (like I show) who to account for it.)



Lastly what I will say is get up a bit higher on your elbows. Think of our children, go back in time when we used to lay on the floor and watch TV for hours. We never had to teach kids or ourselves as children how to hold our heads up comfortably. If you get off your forearms the raising of the body keeps the head straight. When your head is rolled your odds are canting the rifle increase 10 fold. This stuff matters.

Any my contribution while i am here ...

 

[Anointed1]

I teach Basic, what I call Day One Precision Rifle Classes, we call it the Fundamentals. We focus on rifle set up and adjusting the rifle to the shooter,

I could sure use going to one of those @lowlight...any chance one might be in the Northwest states sometime coming up ? I saw the one in Texas in early November I would love to go to but I just can't make it =/

 

[Wannashootit]

I just lay down prone in the living room, open the front door and use the door frame across the street, I even put a level on it once just to be sure, don't even need to hang a plumb bob.

I use the corner edge of a two-story home down the street...

 

[Dolomite_Supafly]

I used to use levels on everything and was very meticulous, spending a few hours to make sure everything was square and level to the action. Then I started using feeler gauges between the scope and mount to ensure the scope was level and square. Most of the time now I start by setting the rifle up to make sure everything feels good. THEN I mount the scope and square the reticle to a plumb line or distant edge.

I do use a bubble level while shooting and before I started doing it this way I found myself always readjusting after each shot to get the bubble level again. Now that the rifle is comfortable it seems like I spend less time adjusting to the level, because it stays pretty level, than I did before.

And if I check to see if everything is level and square to the action, it probably won't be.