0 vs 20 MOA Scope Rail

[lancetkenyon]

I have a 36X Sightron 1 inch tube , on a 20 MOA Leupold rail on my Heavy Savage in .308. Impossible to see clearly at 100 yards. Very Foggy . The problem is that the Scope Elevation is dialed down as low as it can possibly go. Sent scope back to Sightron and the owner/ president called me and asked why this scope is adjusted down do low, until it cannot go any lower. I said 20 MOA rail. He said please remove that rail and just use regular bases. I am going to take his advice and correct that this summer. My thinking is that to a range 500 / 600 yards, a 20 MOA rail is not necessary, and this 308 is not a 1000 to 1200 yard rifle. My Weatherby Mark V in .270 Weatherby Mag has a 8.5X to 25 X Leupold VX3HD Wind plex. Its on Leupold D D steel bases. ZERO MOA . With a 100 yard Zero, there is plenty of Elevation out to 1100 yards as used at the Bang Steel Shooting school. Not real sure when I would really NEED a 20 MOA rail. ???? I think it's important to the guy's that shoot the 1200 yard to a Mile( 1700). They may really need one. Just my opinion.

Does that scope only have 40MOA of total elevation travel? Meaning 20 up and 20 down +/-? You could do a 10 MOA rail.

 

[338 dude]

I need some help, i'm new to picatinny scope rails. I just bought a Tikka t3x Roughtech Ember in 6.5 Creedmoor. I'm going to install a Leupold VX-5HD 3-15x44mm scope on it.
I would like to have fun at the range shooting 1000 yards or so but I would also like to use it to for hunting. Some hunting shots might be 50 - 100 yards or so. Would a 20 moa rail be too much for the closer shots? Thanks, Sam

20 will be just fine as already mentioned

 

[Rum Man]

Just roll with the 20 moa rail as talked about above !

I'm in a different mode ...
I ran a 55 moa base and 100 yard zero, 200min. Adj.base and diled to 3027 yards....but I'm a special kind of Rum Man!

Rum Man

 

[Bob Wright]

? I might need a picture of short video for clarity.

If you have any loose scope laying around, try it.
You'll see both images as the light goes through the mirror glass around the objective.
I take no credit for the video.

 

[lancetkenyon]

So the mirror trick CENTERS the reticle, but doesn't actually have anything to do with sighting it in. Got it.

If you are on a 20MOA rail, or your mounting holes are off center, it doesn't correct for any of that.

 

[Bob Wright]

So the mirror trick CENTERS the reticle, but doesn't actually have anything to do with sighting it in. Got it.

If you are on a 20MOA rail, or your mounting holes are off center, it doesn't correct for any of that.

Correct.

 

[lancetkenyon]

What is the purpose of centering the reticle in the scope body?

What if you run through your entire range of windage (say 25 MOA or 100 clicks) L-R and then go back 50 to ceter your adjustment. Then back off the zero stop all the way and do the same with elevation (say 100 MOA or 400 clicks) then go back 200 clicks from top to center adjustment. Most scopes from the factory come fairly centered for adjustment.

What if you recheck, and your reticle is not centered in the tube? But you are centered in adjustement.

Then, you zero your rifle (even on a 0 MOA rail) and your reticle is not centered in the tube?

Also, what if the etched lens or wire x-hair is not truly centered in the tube? Or if the front of the objective bell is not 100% square?

I guess I am not seeing the purpose for this now that I understand what the trick does. I can be dense sometimes.

 

[Bob Wright]

What is the purpose of centering the reticle in the scope body?

What if you run through your entire range of windage (say 25 MOA or 100 clicks) L-R and then go back 50 to ceter your adjustment. Then back off the zero stop all the way and do the same with elevation (say 100 MOA or 400 clicks) then go back 200 clicks from top to center adjustment. Most scopes from the factory come fairly centered for adjustment.

What if you recheck, and your reticle is not centered in the tube? But you are centered in adjustement.

Then, you zero your rifle (even on a 0 MOA rail) and your reticle is not centered in the tube?

Also, what if the etched lens or wire x-hair is not truly centered in the tube? Or if the front of the objective bell is not 100% square?

I guess I am not seeing the purpose for this now that I understand what the trick does. I can be dense sometimes.

I guess it would only be necessary if you mounted a used scope and wanted to start "fresh" at a known point as being centered before its mounted and bore sighted. I only did it a few times.
If something is way out of alignment in mounts it might point you there by knowing your scope probably isn't the problem.
Bottom line, it's kind of a way to do a collimitor test that scopes are tested to at the factory. Nothing more.

 

[Philward]

I'll stick with counting turns and stopping half way. I tried the mirror on a rifle I had out but just saw black through the scope.

That video was kind of like the guy who mounts a scope and doesn't bore sight it(at the least) and is at the range wondering why he can't hit paper, cranking the adjustments.

NEF handi-rifle, hunted with one of those in 270win for a few years. Kind of a cool compact little rifle.

 

[B P Shooter]

I need some help, i'm new to picatinny scope rails. I just bought a Tikka t3x Roughtech Ember in 6.5 Creedmoor. I'm going to install a Leupold VX-5HD 3-15x44mm scope on it.
I would like to have fun at the range shooting 1000 yards or so but I would also like to use it to for hunting. Some hunting shots might be 50 - 100 yards or so. Would a 20 moa rail be too much for the closer shots? Thanks, Sam

Always Go with a 20 moa rail. Then add on a NEAR Alphamount 20 moa, 1 piece scope mount.
(http://trg42.com/alphamounts/) It always returns to zero if you remove scope fo any reason. Also, with total of 40 moa, gives a person full range of scope elevation

 

[lancetkenyon]

I guess it would only be necessary if you mounted a used scope and wanted to start "fresh" at a known point as being centered before its mounted and bore sighted. I only did it a few times.
If something is way out of alignment in mounts it might point you there by knowing your scope probably isn't the problem.
Bottom line, it's kind of a way to do a collimitor test that scopes are tested to at the factory. Nothing more.

Great explanation. Thanks.

 

[lancetkenyon]

Always Go with a 20 moa rail. Then add on a NEAR Alphamount 20 moa, 1 piece scope mount.
(http://trg42.com/alphamounts/) It always returns to zero if you remove scope fo any reason. Also, with total of 40 moa, gives a person full range of scope elevation

40 MOA....always?

What if you are running something like a Swarovski Z5 that has 43MOA total elevation adjustment, but has a single turn turret and only gets you about 10MOA of usable elevation adjustment?

 

[B P Shooter]

40 MOA....always?

What if you are running something like a Swarovski Z5 that has 43MOA total elevation adjustment, but has a single turn turret and only gets you about 10MOA of usable elevation adjustment?

Than go with 20 moa rail and std scope mount.
Simple physics and math.
Scope total moa /2, minus 10% = total rail and mount moa.

 

[atepointer]

Go for the 20 MOA rail.

Center the reticle with a mirror before mounting scope (make reticle reflection coincide with reticle) - better than counting lots of clicks.

Mount scope on 20 MOA rail then level/plumb reticle with axis of barrel.

Determine impact at 200 yards with centered reticle, then adjust for 200 yard zero. Adjustments should not be extreme low but near lower middle with a 30 mm or bigger tube scope, leaving 40 or more MOA to hit at 1,000. Impact at 100 will be 1.5 or so inches high with a 200 yard zero. Point blank range on deers & such close to 300 with a 200 yard zero.

My 6.5 CM has a 25-26 26-28 MOA drop with pointy 140 grain bullets at 1,000 with a 200 yard zero. Adjustments are about 75% up from reticle center.

Optics perform best when light path is directed thru center (axis) of lens, & extreme elevation settings will cause light path to move from lens axis.

"Light rays that strike a spherical surface off-centre are refracted or reflected more or less than those that strike close to the centre. This deviation reduces the quality of images produced by optical systems." - quote from optics wizard Wikiwhatever.

With scopes it's refraction.

When done -shoot a nice sub .5 MOA group at about 36 inches directly above point of aim using 1000-yard setting & ammo- this will give some indication of scope adjust setting & reticle leveling needed for 1000 yards.

The 6.5 CM is not a dopey or bloopy round but 30mm or fatter scope tubes help.

I had a 50moa rail custom cut for a Bighorn Origin SA from Mirage ULR in TX great folks there. It's paired with a Sightron SVIII 5-40x56, Proof pre-fit 6.5 26", 140g pills and with a zero distance that would drive a lot of folks nuts. I shoot the mile berm right at the dead smack middle of my 40mil elevation travel. Summer conditions are just under 20mils and at 40x the image in thick south FL humidity is nothing short of amazing. My buddy with a safe full of ATACRs was blown away at the mid day image quality and I know he is doing some thinking on getting away from the upper limits of his elevation travel for ELR. My rifle is a one trick pony and 90% of my time is at the 1mile or 2k berm. I shoot paper on load dev and that's it the other 10% of rounds are at 1k/800 on days we can't get the camera down range. Not for everyone, but with ELR my only focus it fits my desires perfectly.