6 feet low at 200 yards

Pixuma · September 22, 2011, 02:00 AM

So i went out to the plinkin' spot this last saturday and shot my .222 for the first time. There's a steel plate up the hill about 200 yards away, and i put the crosshairs right on it, pulled the trigger, and it hit the dirt 6 feet low. Compensated for the obvious misalignment of the scope and hit the plate every time after that, so the windage seems pretty dead on, but 6 feet low at 200 yards?!

Rifle is a Savage 340B and the scope is a Lyman All-American 6X.
There was a little shim thing under the rear scope ring that was probably correcting the issue, but i haven't a freaking clue where i put it.

What's the proper way to correct such a misalignment?

hogdogs · September 22, 2011, 02:06 AM

Quote:

What's the proper way to correct such a misalignment?

Sight in the scope to be dead on at the distance you expect and use "kentucky windage" to adjust for closer or further shots...

Brent

Jimro · September 22, 2011, 02:17 AM

You can shim the scope base or see if you can get a set of Burris Extreme Z rings with inserts. http://www.brownells.com/.aspx/sid=3...814606_d_11392

6 feet low at 200 translates into 36 MOA. So that is how much shimming or offset you need.

Depending on the distance between your scope bases will tell you how much shimming is necessary. The formula you need is [(distance between bases x2pi)/(3600)]multiplied by the MOA you need to correct for.

Jimro

HiBC · September 22, 2011, 02:54 AM

I do not recall,is the Lyman All American a 1" scope or a 7/8 scope?Seems like some Lyman's were 7/8.That would be a problem with the Burris ring idea.
If you have access to a gunsmith with strong machinist skills(if he has a mill,that is a positive sign)you might just turn it over to him.
Each ring has an axis;the center of the bore through it.Assembled,you want both rings and the scope to be co-axial.If they are not,the scope is distorted when you tighten all the screws.Just using a shim may work,but there is more to look at.Example,a 1.300 dia receiver,is a .650 radius.Suppose your base is actually machined at a .650 radius Put in a .020 shim.Now the receiver is in effect a .670 radius.They won't mate up.There will be daylight under the screws,and the edges will bear.
Another way to determine the shim thickness,take the center distance between the rings(caliper inside,outside,and average)That will be in inches.Then you need your distance to the target,in inches.That would be 3600 in for 100 yds.Divide the ring center distance into the target distance.That number is the multiplier,lets call it "X" The thickness of the shim,times "X",will be effect on the target.To make a simple example,if the ring center distance was 3.6 inches,the shim would get multiplied 1000 times.A .001 shim would get you an inch at 100 yds.
I would first confirm you have the correct bases for your rifle,and then I would look to see if they are machined correctly.I have seen some really horrible machining on bases that were considered "quality".

Pixuma · September 22, 2011, 03:45 AM

d'oh!

Probably should have included that the rifle has one of those old weaver side mounts... From what i've been told, that's the only way to scope this particular rifle.

Sorry about the shallow depth of field in the pictures... not enough light

huntinaz · September 22, 2011, 03:52 AM

How's it hitting at 100 yards? My guess would be almost 6 feet low...

Pixuma · September 22, 2011, 04:07 AM

i wish i knew... i'd like to get out to the range, but i gotta find ammo first, and i'd like even more to get it at least closer to where it should be so i burn up the least amount of ammo possible trying to get this thing dialed in... $18 for a box of 20 rounds ain't cheap!

Dr. Strangelove · September 22, 2011, 04:13 AM

I'm guessing that this isn't a new scope and one you've had for a while?

If not, return the scope and get a replacement.

If used, center the scope adjustments. Go one way all the way with the elevation adjustment until it stops, turn the other way till it stops, counting the clicks. Go back half way.

Repeat for the windage adjustments.

This will get you back to center.

Re-zero from there.

Jimro · September 22, 2011, 05:26 AM

Yup, should have mentioned the side mount. You can ignore everything I wrote before as it does not apply to your particular situation.

If the base is mounted correctly then the scope is at fault.

Jimro

tobnpr · September 22, 2011, 06:50 AM

I used that same mount on my Mosin-Nagant sporter.
Since the rifle is new to you, there's a good chance that the mount was installed incorrectly, in which case I can think of only one option that's not ideal. You'll need to shim under the scope on the front ring, which creates the uneven pressure on the scope as Hi-BC mentioned.

Clifford L. Hughes · September 22, 2011, 01:11 PM

Pixpuma:

You must start looking for a cause to your problem by going back to the basics: is the scope mount tight? Is the scope tight in the rings? Is the scope defective? From your post I would install a different scope of known accuray. I strongly feel that you have a scope problem because Weaver makes a good mounting platform.

Semper Fi.

Gunnery sergeant
Clifford L. Hughes
USMC Retired

tobnpr · September 22, 2011, 07:39 PM

It's not the Weaver mount- mine is rock solid.
I was saying that if it was not installed correctly- meaning not perfectly parallel to the bore- he'll end up exactly with the symptoms he has now.
If the front end of that mounting plate was set a few thousandth's low, there's no adjustment to take it out.

Mobuck · September 23, 2011, 08:00 PM

Have you tried adjusting the elevation knob on the scope???????????????

September 22, 2011, 02:00 AM	#1
Pixuma Member Join Date: July 24, 2011 Posts: 24	6 feet low at 200 yards So i went out to the plinkin' spot this last saturday and shot my .222 for the first time. There's a steel plate up the hill about 200 yards away, and i put the crosshairs right on it, pulled the trigger, and it hit the dirt 6 feet low. Compensated for the obvious misalignment of the scope and hit the plate every time after that, so the windage seems pretty dead on, but 6 feet low at 200 yards?! Rifle is a Savage 340B and the scope is a Lyman All-American 6X. There was a little shim thing under the rear scope ring that was probably correcting the issue, but i haven't a freaking clue where i put it. What's the proper way to correct such a misalignment?

September 22, 2011, 02:17 AM	#3
Jimro Senior Member Join Date: October 18, 2006 Posts: 7,097	You can shim the scope base or see if you can get a set of Burris Extreme Z rings with inserts. http://www.brownells.com/.aspx/sid=3...814606_d_11392 6 feet low at 200 translates into 36 MOA. So that is how much shimming or offset you need. Depending on the distance between your scope bases will tell you how much shimming is necessary. The formula you need is [(distance between bases x2pi)/(3600)]multiplied by the MOA you need to correct for. Jimro __________________ Machine guns are awesome until you have to carry one.

September 22, 2011, 03:52 AM	#6
huntinaz Senior Member Join Date: September 21, 2010 Location: az Posts: 1,332	How's it hitting at 100 yards? My guess would be almost 6 feet low... __________________ "When there’s lead in the air, there’s hope in the heart”- Hunter’s Proverb "Feed me, or feed me to something. I just want to be part of the food chain." -Al Bundy

September 22, 2011, 04:13 AM	#8
Dr. Strangelove Senior Member Join Date: August 1, 2008 Location: Athens, GA Posts: 1,436	I'm guessing that this isn't a new scope and one you've had for a while? If not, return the scope and get a replacement. If used, center the scope adjustments. Go one way all the way with the elevation adjustment until it stops, turn the other way till it stops, counting the clicks. Go back half way. Repeat for the windage adjustments. This will get you back to center. Re-zero from there. __________________ Just remember, when you pull the trigger, the bullets come out going very, very fast. So make sure to keep the weapon pointing away from you.

September 22, 2011, 05:26 AM	#9
Jimro Senior Member Join Date: October 18, 2006 Posts: 7,097	Yup, should have mentioned the side mount. You can ignore everything I wrote before as it does not apply to your particular situation. If the base is mounted correctly then the scope is at fault. Jimro __________________ Machine guns are awesome until you have to carry one.

September 22, 2011, 02:54 AM	#4
HiBC Senior Member Join Date: November 13, 2006 Posts: 8,287	I do not recall,is the Lyman All American a 1" scope or a 7/8 scope?Seems like some Lyman's were 7/8.That would be a problem with the Burris ring idea. If you have access to a gunsmith with strong machinist skills(if he has a mill,that is a positive sign)you might just turn it over to him. Each ring has an axis;the center of the bore through it.Assembled,you want both rings and the scope to be co-axial.If they are not,the scope is distorted when you tighten all the screws.Just using a shim may work,but there is more to look at.Example,a 1.300 dia receiver,is a .650 radius.Suppose your base is actually machined at a .650 radius Put in a .020 shim.Now the receiver is in effect a .670 radius.They won't mate up.There will be daylight under the screws,and the edges will bear. Another way to determine the shim thickness,take the center distance between the rings(caliper inside,outside,and average)That will be in inches.Then you need your distance to the target,in inches.That would be 3600 in for 100 yds.Divide the ring center distance into the target distance.That number is the multiplier,lets call it "X" The thickness of the shim,times "X",will be effect on the target.To make a simple example,if the ring center distance was 3.6 inches,the shim would get multiplied 1000 times.A .001 shim would get you an inch at 100 yds. I would first confirm you have the correct bases for your rifle,and then I would look to see if they are machined correctly.I have seen some really horrible machining on bases that were considered "quality".

September 22, 2011, 04:07 AM	#7
Pixuma Member Join Date: July 24, 2011 Posts: 24	i wish i knew... i'd like to get out to the range, but i gotta find ammo first, and i'd like even more to get it at least closer to where it should be so i burn up the least amount of ammo possible trying to get this thing dialed in... $18 for a box of 20 rounds ain't cheap!

September 22, 2011, 06:50 AM	#10
tobnpr Senior Member Join Date: August 1, 2010 Location: Tampa Bay Posts: 4,556	I used that same mount on my Mosin-Nagant sporter. Since the rifle is new to you, there's a good chance that the mount was installed incorrectly, in which case I can think of only one option that's not ideal. You'll need to shim under the scope on the front ring, which creates the uneven pressure on the scope as Hi-BC mentioned.

September 22, 2011, 01:11 PM	#11
Clifford L. Hughes Senior Member Join Date: February 24, 2011 Location: Southern Californis Posts: 795	Pixpuma: You must start looking for a cause to your problem by going back to the basics: is the scope mount tight? Is the scope tight in the rings? Is the scope defective? From your post I would install a different scope of known accuray. I strongly feel that you have a scope problem because Weaver makes a good mounting platform. Semper Fi. Gunnery sergeant Clifford L. Hughes USMC Retired

September 22, 2011, 07:39 PM	#12
tobnpr Senior Member Join Date: August 1, 2010 Location: Tampa Bay Posts: 4,556	It's not the Weaver mount- mine is rock solid. I was saying that if it was not installed correctly- meaning not perfectly parallel to the bore- he'll end up exactly with the symptoms he has now. If the front end of that mounting plate was set a few thousandth's low, there's no adjustment to take it out.

September 23, 2011, 08:00 PM	#13
Mobuck Junior member Join Date: February 2, 2010 Posts: 6,846	Have you tried adjusting the elevation knob on the scope???????????????