Xtreme Hardcore Rail

[tnwill]

Exactly! Level is level is level, doesn't matter how straight it is on the gun. I still don't see his point a out the adjustable bubble...

Level is level but unless your verticle cross hair is aligned perpendicular through the center of the bore you will have trouble when you start dialing elevation.

Level the scope base and then mount your scope level. Zero your scope at 100 yds. Make a 30" tall target with a line running from top to bottom with an aiming point 2" from the bottom. Set the target up at 100yds with the line plumb. Shoot a group at your aiming point then dial up 24MOA and shoot another group at the same POA. If your group does not print on the verticle line then your scope is not mounted true to the center line of the bore.

Did this exact thing last weekend with a buddy's rifle. He leveled the scope base and mounted the scope level. When he dialed 24 MOA, his group was almost 3/4 MOA left of the verticle line. This was on a custom action with a "high end" 20 MOA base.

Before mounting a scope, I level my action off of the bolt raceway, not the scope base.

 

[MudRunner2005]

Hard to avoid with a 20 MOA rail. With that much cant you're going to have to have a high rail to keep the front of your scope from digging into the barrel unless you have a pencil barrel and/or a small objective.

Very true.

 

[MontanaRifleman]

How do you align your baseline then? How exactly do you set for square with the bore?

What level system are you using that is adjustable?

What I do is...

Mount the scope in the rings and snug them up allowing enough play to rotate the scope for adjustment.

Set up a table about 30 ft from a plum line. or as close to the plum line as my scope will focus on the line, and set the rifle up with rear sand bags to keep it stable.

I remove the bolt and sight down the bore to align the bore to the plumb line. I basically split the bore with the plumb line by sight.

Then I rotate the scope until the windage reticle is parallel with the plumb line, then align the windage reticle to the plumb line. This puts my camber and bore in the same sight plain (line of sight) as my scope.

Then I tighten down the ring screws incrementally and double check the bore and reticle alignment to the plum line. This usually takes a few minutes because tightening the screws twists the scope left and right.

Once the ring screws are tight I mount the level. (I use the Sinclair anti-cant level) I recheck the bore and reticle alignment to make sure everything is plumb. Then I tighten the level screws the same way I did the ring screws, ensuring the bubble stays centered in the process with bore and windage reticle aligned to the plumb line.

There are 2 basic errors induced if you don't get things right. 1- if your scope is not aligned with your bore, then your bullet will not travel in the same path as your scope's LOS. 2- If your scope is not level (plumbed to gravity) then when you dial in your elevations your POA will wander from your intended POI.

 

[MontanaRifleman]

Here are some pics, setting up the rifle with plumb line hanging from the gutter of the shed. This rifle has the NF top ring level.

 

[MontanaRifleman]

Having trouble loading multiple pics, this rifle has the Sinclair level

 

[WildRose]

Sighting through the bore to the line is doing nothing but adding a step that doesn't matter. You have no means by which to ensure it is passing straight between 12:00-06:00 other than "eyeballing it".

If your receiver is milled so poorly you are going to have an issue leveling off of the top of it, I can't see how you can correct such an error by leveling through the bolt raceway.

All you are doing essentially here is eye balling the bore alignment to ensure that both the scope and bore are aligned similarly left to right.

If the top of your receiver is off, then you will not get proper squaring no matter where you choose to set your level, but, if you use a level on the top of the receiver/rail and align your vertical crosshair with it, you will be square and level.

The top of the reciever becomes the cross of an upside down T when you mount the scope. If it is milled with a left to right can't to it, no matter what you do above or below it you will still be slightly off center because the leg of the T is essentially your vertical cross hair which is then leaning left or right.

No matter what, it is then out of center to the bore. You will know this as soon as you mount the rail because the rail will twist as you torque it down.

If you are using your raceway to level from you will also know instantly whether or not the top of your receiver is out of square when you level the rail anyhow.

If it's out of square enough to matter you are already screwed because as I said above unless you shim it to square it your scope will never be centered exactly above the bore no matter what type of mounting system you are using.

 

[MontanaRifleman]

Sighting through the bore to the line is doing nothing but adding a step that doesn't matter. You have no means by which to ensure it is passing straight between 12:00-06:00 other than "eyeballing it".

Eyeballing the plumb line through the bore is not a perfect method, but IMO it is quite accurate if you are careful about it. Kinda like reading a level... that is also "eyeballing". Being a construction contractor, I have quite a bit of experience with plumb lines, bubble levels and laser levels. If you accurately align your bore and reticle to the plumb line you most definitely are ensuring that your reiticle is aligned (pointed to) the bore.

If your receiver is milled so poorly you are going to have an issue leveling off of the top of it, I can't see how you can correct such an error by leveling through the bolt raceway.

Either your receiver is milled perfectly or it isn't. If it's not, then using it as a reference will induce error. Once again, any error in the receiver machining, hole drilling, rail machining and holes and contact irregularities between the rail and receiver and error of setting the bubble tube itself in the rail will induce errors to what you read on that in-rail level.

That rail level is nothing more than a placebo. There's a chance it could be accurate but there's a greater chance it isn't. To "assume" that is accurate is to assume that...

The receiver is machined and drilled precisely and accurately.

The rail is machined and drilled precisely.

The torqued contact between rail and receiver is precise.

The bubble tube is set precisely in the rail.

That's a lot to assume.

All you are doing essentially here is eye balling the bore alignment to ensure that both the scope and bore are aligned similarly left to right.

I am using the a straight and plumb line as reference to align the scope to the bore and then mount and accurate level in reference to no kidding gravity.

If the top of your receiver is off, then you will not get proper squaring no matter where you choose to set your level, but, if you use a level on the top of the receiver/rail and align your vertical crosshair with it, you will be square and level.

The top of the receiver becomes the cross of an upside down T when you mount the scope. If it is milled with a left to right can't to it, no matter what you do above or below it you will still be slightly off center because the leg of the T is essentially your vertical cross hair which is then leaning left or right.

Wrong. You can properly align your scope to your bore, them mount a level to ensure everything is aligned and tracking according to the pull of gravity. If your receiver is off, then it will be canted to properly align the scope to bore to gravity. Drawings can show this very easily. You can see an extreme example of it in the picture of a rifle that David Tubs set up. I will attach in the next post.

No matter what, it is then out of center to the bore. You will know this as soon as you mount the rail because the rail will twist as you torque it down.

If you are using your raceway to level from you will also know instantly whether or not the top of your receiver is out of square when you level the rail anyhow.

Using the raceway to level from is assuming the race way is square to the mounted scope.

If it's out of square enough to matter you are already screwed because as I said above unless you shim it to square it your scope will never be centered exactly above the bore no matter what type of mounting system you are using.

See the picture below

 

[MontanaRifleman]

Here is a picture of a rifle of David Tubbs purposely set up to cant the action. It doesn't matter how much the rifle is canted as long as the scope is aligned to the bore and they are both aligned to gravity.

 

[WildRose]

Here is a picture of a rifle of David Tubbs purposely set up to cant the action. It doesn't matter how much the rifle is canted as long as the scope is aligned to the bore and they are both aligned to gravity.

You have by posting this destroyed your entire premise.

That scope is in no possible way alighted with the bore other than both being pointed in the same direction.

The scope is set to level, the rest is out of level and out of alignment.

You cannot say it is aligned to the bore when it's setting several inches to the side.

Thank you however for making my point.

 

[MudRunner2005]

You have by posting this destroyed your entire premise.

That scope is in no possible way alighted with the bore other than both being pointed in the same direction.

The scope is set to level, the rest is out of level and out of alignment.

You cannot say it is aligned to the bore when it's setting several inches to the side.

Thank you however for making my point.

I was thinking that, but didn't want to say it, until someone else did......

 

[MontanaRifleman]

You have by posting this destroyed your entire premise.

That scope is in no possible way alighted with the bore other than both being pointed in the same direction.

The scope is set to level, the rest is out of level and out of alignment.

You cannot say it is aligned to the bore when it's setting several inches to the side.

Thank you however for making my point.

No, you're missing the point. By aligned to the bore, I mean the scope reticle is aligned with the bore. In other words, if the scope reticle were extended downward, it would intersect the bore (that is why I use a plumb line). The rifle in the picture is being held by the man's hand and is not accurate representation of the scope to bore, left and right. You can not see how the reticle is oriented. The point is when shouldered or placed on a rest, the scope is directly above the bore, when properly leveled.

Now imagine how the in-rail level would work on Tubb's rifle. It would indeed set the scope several inches to the right. This is an extreme example of why an nonadjustable in-rail level might not work.

Sorry you're not getting it. I didn't intend to get in a ****ing contest, so I'll bow out now.

You go ahead and get the rail, install it, mount the scope, zero it in, then dial up up about 15 or 20 MOA and see what happens. It might work and it might not. The only way it will work is if everything is right ...or... you have some compensating errors. Bottom line is you just don't know. As for me, I'll take the steps to align and plumb everything the best I can.

Cheers

 

[MudRunner2005]

Can't you use a Bushnell bore-mounted style bore-sighter with the grid and adjust your crosshairs up and down to see if they are aligned? Level the rifle, level the scope, and then check side travel with the grid on your boresighter...That's what I do. Works great for me.

 

[kcebcj]

Here is a picture of a rifle of David Tubbs purposely set up to cant the action. It doesn't matter how much the rifle is canted as long as the scope is aligned to the bore and they are both aligned to gravity.

If the fella holding the rifle was to cant the rifle a little more as it looks to me the scope would be in perfect alignment with the bore and would shoot perfectly. Aligning the bore with the reticle is not brain surgery!

How come the picture did not come with the quote????

 

[highridge1]

It's aluminum so I wouldn't be interested.