Rifle shooting five feet low!


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WhiteKnight
November 5, 2009, 08:32 PM
Guys,

I tried to sight in a new .308 rifle tonight. I had an IOR 20moa base, Badger rings, and a Bushnell Elite 4200 4-12x40AO. I completely ran out of elevation adjustment, and my rifle still shot approximately five feet low at 100 yards. Is the base hurting me? I have it installed like the guy below (with the 20moa wedge to the rear) of the rifle.

http://img3.imageshack.us/img3/4081/savxcr006.jpg

http://www.bushnell.com/products/scopes/riflescopes/elite4200/424164SF/

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jmr40
November 5, 2009, 08:41 PM
Just a SWAG, but could the base be mounted backwards. I'm not familiar with this type of mounting system

GregGry
November 5, 2009, 08:42 PM
are you positive the scope is good?

Horsemany
November 5, 2009, 08:48 PM
Are you sure you've adjusted the scope the proper direction? Sounds like the base is correct with the thicker portion in the rear toward the shooter. At 100yds you should actually be a little high with a 20MOA base and an optically centered scope.

dmazur
November 5, 2009, 08:50 PM
In order for POI to be 5 feet below POA, your scope has to be limited out in UP adjustment. With a 20MOA base, your POI at 100yds is going to be above the POA, so you should be adjusting DOWN to move POI closer to POA...

At least, that's how it sounds to me.

So, the question is, which end of elevation limit have you reached, UP or DOWN?

lobo9er
November 5, 2009, 08:56 PM
spin the scope 25 degrees clock wise i did that once but man 5 feet holy smokes

Walkalong
November 5, 2009, 09:01 PM
Are you sure you've adjusted the scope the proper direction?That's what I am thinking, assuming the scope is OK. If anything, it should shoot high at 100 yards before you adjust anything when using that base .

johnmcl
November 5, 2009, 09:03 PM
Hi all,

Wedge to the back for tapered bases.

WhiteKnight
November 5, 2009, 09:04 PM
I am completely out of "up" adjustment (as in "I keep needing to go up but can't click up any more"). I adjusted it completely down just for kicks -- I was then shooting 30 FEET below the target instead of 5 feet below it.

Walkalong
November 5, 2009, 09:04 PM
I am not real familiar with them, but I though only the 1000 yard shooters used those tapered bases.

kanook
November 5, 2009, 09:05 PM
Try the redneck boresighter.

Set the rifle on a bench,

pull the bolt out,

line up your rifle at about 50 yards looking thru your barrel at your target at what looks like center,

now look thru your scope and see how far off you are.

This is not perfect but will get you on paper till you get your boresighter from the store.

WhiteKnight
November 5, 2009, 09:12 PM
Please note: I seem to be pretty much dead-on as far as left-right adjustment; I am simply shooting five feet lower than where I'm aiming even after completely using up my "up" adjustment.

MGD 45
November 5, 2009, 10:33 PM
Try the redneck boresighter.

Set the rifle on a bench,

pull the bolt out,

line up your rifle at about 50 yards looking thru your barrel at your target at what looks like center,

now look thru your scope and see how far off you are.

This is exacty how I start the sight in process for any bolt gun I put a scope on. However, I start it at 25 yards with a small bullseye target.....fire a shot, adjust, move to 50 yards...repeat again then go to 100.

USSR
November 5, 2009, 10:44 PM
WhiteKnight,

A couple of checks: 1. the taller portion of the picatinny rail is to the rear. 2. The scope is mounted with the turrets at the top and to the right (don't laugh, a buddy mounted his scope with the elevation on the left and the windage on top). Using a 20MOA rail causes your rifle to shoot higher, not lower. Lastly, the scope you have chosen is not a good one for use at 1k with a .308, since it has very little W&E adjustment built into it.

Don

browningguy
November 5, 2009, 10:48 PM
I think the 4200 should work fine at 1000 yards with the 20 moa base. I haven't bothered to do the math on this one but I suspect it has enough elevation built in with the base under it.

Brazos
November 5, 2009, 10:52 PM
I bought a brand new CZ 527 a few years ago that was about 3'-4' low at 100 yards after adjusting the scope all the way up. Turns out the rifle came from the factory with a bent barrel. I need to send it back but haven't because I shimmed the scope (a bunch) and got it to point of aim at 100 and it is extremely accurate. I still need to send it back because it does bother me. I talked to CZ on the phone about it and they said no problem send it to them. The point of this is that things like this happen time to time so don't rule it out.

chevyforlife21
November 5, 2009, 10:57 PM
that base does look huge...

USSR
November 5, 2009, 11:07 PM
I cannot find a Bushnell Elite 4200 4-12x40AO listed on Bushnell's website, so I am assuming he meant the 3200 model. If so, it only has 50 inches of built in elevation. Assuming with a standard base he could zero at 100 yards with 25" up and 25" down available to him, a 20MOA base would only net him 45" of total up available to him. Depending upon his load, he could be at the extreme edge of his elevation adjustment, which is not a good place to be, since it limits available windage adjustment. I stand by my statement that Bushnell scopes with their limited W&E adjustment are not a good scope for a .308 rifle for 1,000 yard shooting. If you are shooting a flatter shooting cartridge, then fine.

Don

sprice
November 5, 2009, 11:18 PM
Just aim higher! (sorry, I just had to make a smart-ass comment) ;)

Sport45
November 5, 2009, 11:26 PM
Are your rings both the same height? Just wondering if you have a matched pair or just a couple pulled out of a drawer. If the front ring is taller than the back it would cause this as well as possibly bending the scope.

wyohome
November 5, 2009, 11:54 PM
Just aim higher! (sorry, I just had to make a smart-ass comment)
Or put more powder in your cases.

Horsemany
November 6, 2009, 12:05 AM
I adjusted it completely down just for kicks -- I was then shooting 30 FEET below the target instead of 5 feet below it.

I hope this is an exaggeration. Scopes don't have 25' of elevation @ 100yds. Do you have another set of mounts to try?

janobles14
November 6, 2009, 01:05 AM
sounds like the round to me. i have a load for a .30-06 that is only 1 grain of 4350 less and shoots almost 2.5 ft lower. barrel harmonics dont play! i would try a different round. one of the gurus may correct me but i have found that in this situation you need to use a hotter load to stabilize.

Afy
November 6, 2009, 05:07 AM
I had a problem with running out of left adjustment. Bad rings was my issue.

R.W.Dale
November 6, 2009, 05:48 AM
I had a problem with running out of left adjustment. Bad rings was my issue.

A distinct possibility!

Swapping the scope rings front to rear is a good way to see if this variable can be ruled out

strambo
November 6, 2009, 06:52 AM
Assuming your statements of being 5 ft down and 30ft down are correct, something is majorly wrong not having anything to do with the 20MOA mount. I'm with the "redneck boresight" crew.
Try removing the bolt and looking down the bore at a target dot even 10 yds away with the rifle sandbagged. Then...adjust the scope crosshairs to be on or maybe 1" above the dot. You can do this in your home. At the range, you will be on paper at 25. Adjust then go to 50, adjust then go to 100.

With this large a problem, missing 5-30ft low @ 100...you either a) shouldn't be able to get the crosshairs on the dot your looking at through the bore at all, or b) if you are able to, then due to a broken scope, it will get out of wonk when you fire a live round and confirm the scope is messed up because you know the crosshairs were in line with the bore at some point before the recoil of the live round.

Or, if you have any other scope, mount that and see what happens?

kanook
November 6, 2009, 09:16 AM
Don't forget to check your crown/muzzle for dings

If you removed your rifle from the stock, did you retorque the screws properly?

If it's a freefloating barrel is it being touched by the stock?

Try a different grain of ammo.

lobo9er
November 6, 2009, 10:24 AM
i have been watching this one, sounds fishy. if you could show a pic if the scope mounted that would help a little. something is way wrong or broken especially if all the way down is 30 feet low lol. If your having these kinda of problems mounting a scope i'll stay off the side walk when your driving.

lobo9er
November 6, 2009, 10:25 AM
Don't forget to check your crown/muzzle for dings
it'd have to be a heck of a ding.

BruceB
November 6, 2009, 10:47 AM
That rail mount is clearly mounted backwards.

BUT....with the scope mounted on the pictured mount, the rifle would shoot a mile HIGH, not low. That is, the line-of-bore would be FAR above the line-of-sight.

Is this a late April Fools' joke?

tkopp
November 6, 2009, 11:44 AM
It's not backwards. Imagine a laser mounted to the top of the rail. Because of the base it will drop below the bore line fairly rapidly as it travels in a straight line downrange. Now mentally pull that laser up to hit the target. Your bullet's going *high,* but that's what you want. It's traveling in an arc, whereas your line of sight (the laser) just keeps going straight. Ideally your 'laser' (line of sight) will cross the bullet arc at point of impact. With a 20 MOA base you should have plenty of down adjustment on the scope to compensate for the difference in angle at medium ranges.

I'd say swap your rings. Failing that swap your scope. If you only have the one set of rings, you could always reverse which one is positioned up front and see if it swings your point of impact wildly.

Dr. Tad Hussein Winslow
November 6, 2009, 11:59 AM
Mout is correctly mounted. Makes no sense at all. Should be shooting way high.

Question: How can you tell that it's shooting 5 and/or 30 feet low?

The Gunman
November 6, 2009, 02:27 PM
IF the specs shown in the link are for your scope it shows about 50MOA of total adjustment, which should be about 50inches at 100yds.(4ft2in)
"Adj Range in@100yds/ mm@100m 50 / 1 "

The scope shows 50MOA of adjustment and the base is another 20MOA.
That's 70inches @ 100yds.
You are hitting 60inches, 60MOA , low.

It seems odd that you're off by almost the total amount of adjustment as the scope and base has total??????

I adjusted it completely down just for kicks -- I was then shooting 30 FEET below the target instead of 5 feet below it.
-WhiteKnight

That's another 25feet, HOLY CRAP!
That's 300MOA.

I am thinking the scope is bad, by adjusting the scope the full range you should have only seen about 4ft2in of movement. (the 50MOA the scope has available to travel per manufacturer specs) Or did you start shooting 600yds?;)

Horsemany
November 6, 2009, 02:40 PM
And how doesn one determine they'e 30 ft low @100yds. You must have some high target stands!

rcmodel
November 6, 2009, 02:41 PM
I'd shxx-can the 1,000 yard base and buy a cheap set of Weaver rings & bases.

Put the scope on it with them, see if you can bore-sight it, then shoot it.

That will quickly prove if it is the base, rings, rifle, or scope.

rc

WhiteKnight
November 6, 2009, 10:29 PM
Update:

I tried to boresight the rifle tonight, and found out:

After aiming the bore at an object approximately 20 feet away (inside the house), the scope picture is approximately 4-5 inches high! All of the walkthroughs I read online say "physically adjust the scope in the rings so the sight picture then lines up with the bore." The problem with this is that, to make this work, I have to tilt the eyepiece end of the scope up about a full inch (lifting it completely out of the rear ring, and thereby obviously preventing me from mounting it or even coming close).

WhiteKnight
November 6, 2009, 10:30 PM
BTW I tried to boresight after changing the order of the rings.

Omaha-BeenGlockin
November 6, 2009, 11:11 PM
Something doesn't look right with that mount to me----maybe its just the pic.

WhiteKnight
November 7, 2009, 12:47 AM
Will shooting with a 20moa base put the scope so far up off of the bore line that it causes problems when shooting at close distances? Should I get a 0moa base?

Uncle Mike
November 7, 2009, 02:35 AM
Your not going to get the crosshair on the same point as what your seeing through the barrel at 20 feet!

You don't have that much scope adjustment!

Stretch out to 50y at least and try it.

Also, is that mount for a square bridge Savage or a round top Savage?

You may have a mount for a round top on that square bridge....

strambo
November 7, 2009, 09:17 AM
Your not going to get the crosshair on the same point as what your seeing through the barrel at 20 feet!Maybe not, but if the bore is only 1.5-2" below the center of the scope, then the worse case scenario should be his crosshairs are 1.5-2" above the point he is looking through the bore. If he can't adjust the crosshairs to w/in 2" of the boreline at all...something is very wrong...especially with a 20 MOA base which should be throwing the crosshairs way down anyway (not up, which is his problem).

4-5" high at 20ft equates to roughly 63MOA above the boreline at 100yds. (20ft = roughly 7 yds X 14 = roughly 100. 14X 4.5" = about 63 MOA.

Bottom line, a scope always has to point down towards the bore by some minute amount (even at max down elevation travel) for the rifle to be zeroed at any range. For the bullet to cross the line of sight, the crosshairs have to point towards the bore to some degree, otherwise the bullet would always be at least 1.5" or so (bore to sight distance) below your point of aim...and dropping.

If his crosshairs are 4-5" high at 20ft...unless his scope is 5-6" above his bore, then the crosshairs are pointed up and away from the bore even in spite of a 20MOA downward base. His bullet will never intersect the line of sight. Based on what he is saying, this rifle and scope will never zero. The reticle must be broken or way off center.

USSR
November 7, 2009, 02:27 PM
Will shooting with a 20moa base put the scope so far up off of the bore line that it causes problems when shooting at close distances? Should I get a 0moa base?

The 20MOA base puts the scope down from the bore line. I don't know what your problem is, but if you have the correct base for your rifle, it's not the base. Personally, I'd try putting a known good scope on it and see if you still have the problem.

Don

Sport45
November 7, 2009, 04:03 PM
After aiming the bore at an object approximately 20 feet away (inside the house), the scope picture is approximately 4-5 inches high! All of the walkthroughs I read online say "physically adjust the scope in the rings so the sight picture then lines up with the bore." The problem with this is that, to make this work, I have to tilt the eyepiece end of the scope up about a full inch (lifting it completely out of the rear ring, and thereby obviously preventing me from mounting it or even coming close).

Try to be a little more precise with your measurements when you describe the problem and we might be able to help more. The exagerated numbers are confusing the issue.

Just look at this last description. You said the crosshair was 4 to 5 inches off at 20 feet. If your rings are 12 inches apart (they're not, but it makes the math easy), lifting the scope 1 inch from one ring while it stayed in the other would move the point of aim 20 inches (almost 2 feet) at 20 feet. To move point of aim 4" at 20' the scope should need to move less than 0.25".

If the point of aim is moving as much as you describe I wonder if the reticle in the scope may be loose and just flopping around in there.

Runningman
November 7, 2009, 04:08 PM
I can't help but wonder if the correct mount is being used? If your receiver is the newer round receiver style? any chance you have a gotten mount for an older rear square Savage receiver? If you could post a picture of YOUR set up looking at it may help. Picture posted is older style rear square Savage receiver hence the more than usual (for a 20 MOA) extra hight at the rear.

Dr. Tad Hussein Winslow
November 7, 2009, 04:18 PM
More and more I'm thinking your scope must be broken.

O-neg
November 7, 2009, 04:19 PM
Try a shim under the rear mount.

Runningman
November 7, 2009, 04:35 PM
What is the history of this scope? The 4 -12 X mentioned doesn't seem to be listed on the web site.

Their is always a chance the receiver was cut out of square. My Savage Model 12 was this way. Ran out of adjustment also. Their also has been posts in the past on a few Savage rifles at Benchrest Central. About Savage rifle barrels not pointing where they are supposed to be.

1858
November 7, 2009, 05:01 PM
Some comments:

1. This is a bizarre thread.

2. IOR doesn't have a one-piece 20 MOA base for the Savage according to their website. Do you even have a Savage? If so, are you sure that you have the proper base for your Savage action, round (rear)/round (front) or flat (rear)/round (front) as shown in your photo. The newer Savages are round/round by the way.

http://www.valdada.com/product/1acb0de2-c79e-45f7-91c3-5376fbdb8588.aspx

3. Is the base hurting me? I have it installed like the guy below (with the 20moa wedge to the rear) of the rifle.

So the photo at the top of the thread isn't YOUR rifle, scope and base. All very odd.

4. Removing the bolt and bore sighting is the THE way to get on paper. I do it ALL the time, EVERY time when installing new scopes/rings and am 4" or less off the POA at 100 yards using this technique. A bore sighter is only useful for rifles where you can't look down the barrel from the receiver end.

5. This is a VERY bizarre thread.

:)

SeekHer
November 7, 2009, 06:31 PM
There is a really simple solution to this, borrow another scope and try it...if it shoots to the same POI then the rail is flawed if it doesn't then the original scope is...

These are the type of mounts that I have on my LR rifle:
http://i143.photobucket.com/albums/r130/SeekHer/SeekHer%20-%20Firearms/Skytwomile5.jpg http://i143.photobucket.com/albums/r130/SeekHer/SeekHer%20-%20Firearms/Skytwomile4.jpg

taken from the Accurate Rifle article The Two Mile Prairie Dog (http://www.northfloridashooting.com/Misc/2MilePrarieDogs/2MilePrarieDogShooters.htm)

Your concept and execution is correct but I really think your scope is broken.

Before trying it at 100 yds, sight in at 25 yards to be 5" high and then move out to 100 yds...

DRYHUMOR
November 7, 2009, 08:06 PM
Take your scope and gently turn the elevation adjustment fully to the stop, then go the other way. This will tell you how much elevation your scope actually has.

I would think you would want at least 100 MOA of adjustment on a 20 MOA base.

lobo9er
November 8, 2009, 01:15 AM
i doubt the story

WhiteKnight
November 10, 2009, 12:05 AM
The rifle is a Remington SPS Tactical.

And for the record, no, this is not a joke. I could also care less if you "doubt my story," friend.

If I decide to stick with a 20moa base when this is all said and done, will it create any issues for me shooting at short distances? I know that as a general rule it's better to have the scope as close to the bore as possible.

1858
November 10, 2009, 12:26 AM
If I decide to stick with a 20moa base when this is all said and done, will it create any issues for me shooting at short distances? I know that as a general rule it's better to have the scope as close to the bore as possible.

A .308 Win rifle shooting a typical 168gr load with a scope zeroed for 200 yards will be zeroed at 25 yards and about 2" high at 100 yards. So in other words, if you can zero your rifle at 25 yards or 200 yards you'll be fine.

:)

Steve Marshall
November 10, 2009, 07:21 AM
So when will you try a different scope?

ZXD9
November 10, 2009, 10:53 AM
Maybe your bullet is dropping too fast because it's only going 500 fps?

SeekHer
November 10, 2009, 11:46 AM
The rifle is a Remington SPS Tactical.

And for the record, no, this is not a joke. I could also care less if you "doubt my story," friend.

If I decide to stick with a 20moa base when this is all said and done, will it create any issues for me shooting at short distances? I know that as a general rule it's better to have the scope as close to the bore as possible.
I think he was doubting the 2 mile story not yours but all that means is he is ignorant of the facts...there are at least three others who have printed stories on making shots at that distance and if you check at longrangehunting.com you'll see lots of "VERIFIED" shots at over 3,000 yards...VHA--Varmint Hunters Assoc has lots of kills in their 2,000 yard club...

Horsemany
November 10, 2009, 12:08 PM
I'm still waiting to hear how tall the target is if you know you're shooting 30' low. If you have a 25' swing in elevation @ 100yds the scope is BROKEN. No question.

Uncle Mike
November 10, 2009, 02:21 PM
WOW...!

This is good...!

1858
November 10, 2009, 03:10 PM
After aiming the bore at an object approximately 20 feet away (inside the house), the scope picture is approximately 4-5 inches high!

I did a couple of calculations and if what you describe is correct, the center of your scope is diverging downrange from the center of the bore by 40 MOA (39.06 assuming that the center of your scope is approximately 2" above the center of the barrel). This makes me wonder if your 20 MOA base is on backwards, or if you have mismatched rings, or if you crushed the scope tube in some way. As has been mentioned, the center of the scope and barrel must converge downrange.

:)

O-neg
November 10, 2009, 05:08 PM
I had the same problem with a lefty 700 BDL in 308. I shimmed up the rear mount,( 2 piece mount) and now its fine.

The rear of the reciever may have been ground to low, I'm thinking.

Try the shim.

Legionnaire
November 10, 2009, 06:04 PM
With an adequate scope, you should be able to zero at 100 yards with no problem. The whole point of the 20 MOA base is so that you can zero at 100, and adjust the scope's elevation for distance, and windage for, well, wind. That's why you need good, repeatable adjustments. So if everything is lined up properly, a 20 MOA base will allow you to set a 100-yard zero in the lower end of the scope's elevation adjustment range, so you have a lot of upward adjustment available for dialing in a dead-on hold at longer range.

The Gunman
November 15, 2009, 07:42 PM
If I decide to stick with a 20moa base when this is all said and done, will it create any issues for me shooting at short distances? I know that as a general rule it's better to have the scope as close to the bore as possible.

Most likely.

MachIVshooter
November 15, 2009, 08:22 PM
If I decide to stick with a 20moa base when this is all said and done, will it create any issues for me shooting at short distances? I know that as a general rule it's better to have the scope as close to the bore as possible.

an angled base has nothing to do with sight height above bore. That is a function of the bases and rings. But yes, you should keep the scope as low as possible.

The purpose of an angled base is to compensate for the adjustment your scope will run out of at a given range; Most scopes lack the adjustment to be sighted at 1,000 yards with a zero angle base.

MT GUNNY
November 15, 2009, 08:59 PM
Quote; Something doesn't look right with that mount to me----maybe its just the pic.

Im going to have to agree here. That scope base is somthing ive never seen before, let alone the angle of it. Are you Positive that that is the corect base?

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