HELP: Out of Windage - Scope Base Screw Hole Alignment Check?

Discussion in 'Gunsmithing' started by Farmerbeau, Sep 22, 2012.

  1. Farmerbeau

    Farmerbeau Member

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    I did run a search and found a similar issue someone had with their rifle, however I did not find the answer to my question.

    Background: I bought a new Savage 110 FCP HS Precision chambered in .338 Lapua Mag to take on this year's elk hunt and to get my feet wet in the future with a long range hunting rifle. Using the factory EGW Aluminum 20MOA base and TPS rings, I mounted my new Nightforce 8-32x56mm on it, bore sighted it with a quality boresighter and ran out of windage in the process. I shot it hoping the boresighter was wrong but sure enough it hit 6 inches to the right of center at 100yds with the left windage adjustment bottomed out... Crap

    I took it to a gunsmith and he said he thought the rings and bases looked good (he didn't have the means of checking the alignment of the screw holes to make sure they're parallel with the rifle so he "eyeballed it) and pointed at the scope. I called Nightforce and they said they'd be happy to look at it but it would take 4 weeks or so for them to get to it. The friendly Nightforce rep suggested I try a different set of rings and/or bases.

    I bought a Ken Farrell 20 MOA base and set of Nightforce Rings and shot it yesterday with very similar results to the first outing with the rifle. This time I was 4" to the right of center but with the left windage still bottomed out. $250 later and still at square one.

    Rant: Everything is spanking new on this rig (16 rounds through it total - 10 of which were spent trying to find out where it was shooting after using a POS Leupold Magnetic bore sighter when I first set it up...junk) and I'm a bit perturbed that I spent this much money and things aren't lining up right. I don't buy the gunsmith's eyeball technique for a minute so I went all over Houston trying to find some one worth their salt with the proper equipment. I guess around here aren't very many gunsmiths worth the title or the ones that are worth a hoot are swamped with work. I'm running out of time until my hunt and I'm beginning to think I'll be having to borrow a rifle because this turd won't be ready.

    Question: Is there any way I can check the alignment of the screw holes myself? I have an idea of what I need to do but can anyone outline what I should do to check this. I'm half-way mechanically inclined so any help is appreciated.

    My notion (correct me if I'm wrong please) is that the scope base mounting screw holes are intended to be parallel with the barrel/receiver, assuming the receiver and barrel are square. I'm more inclined to point fingers at where the holes are tapped versus the Nightforce being messed up. Just to check, I'm gonna mount it on another well functioning rifle I have to see if it works as advertised but I'm still pointing fingers at the holes. Both bases mounted up without any trouble so I think the alignment of the holes are fine.

    If the holes aren't parallel to the barrel, wouldn't this be something Savage would have to remedy?
     
  2. SidecarFlip

    SidecarFlip Well-Known Member

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    In a nutshell.....Yes.

    I have the same scenario with a target pistol I own, the rail mounting threaded holes aren't parallel to the centerline of the chamber bore, creating an offset windage situation that causes offsetting of whatever sight I install, in this case a railway sight.

    I don't run out of windage because it's a target pistol and the range is 50 feet but it is a definite quality issue that the maker is going to address with a new receiver

    My misalignment is severe enough that I can visibly see the offset of the sight in relationship to the rail. At 50 feet, my issue is workable. Yours isn't.

    Just because both bases mounted to the receiver without an issue don't mean the mounting holes are on the same (exact) centerline in respect to the centerline of the chamber. Manufacturing tolerances in respect to the mounting holes and aftermarket rails will allow for substantial offset before binding or difficult insertion of the mounting screws would occur and it would be difficult at best for you ro ascertain if, indeed they are (or are not) simply because the barrel/receiver would have to be separated and the receiver fixtured and then the drilled and tapped holes gaged for parallelism and alignment in relationship to the chamber centerline, a job best left to the manufacturer in their QC lab.

    In my case, the chamber/receiver/barrel are one machined part, unlike your separate barrel/receiver.

    It's impossible to 'eyeball' alignment unless the alignment is so skewed that it's very obvious..... We all take for granted that the quality control of these firearms precludes just this, but it does happen.

    Keep in mind that the receiver is the BATF registered part (serialized) so replacement is going to entail a re-registering on the part of the manufacturer.

    Unless you have access to a machine shop or tool makers facility, gaging the parallelism of the mounting holes in relationship to the receiver/chamber centerline is beyond your (or most gunsmith's) capabilities. better left to the manufacturer.
     

  3. Farmerbeau

    Farmerbeau Member

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    Thanks! I think I'm coming to grips more and more that the rifle will not be accompanying me to Colorado and going back to Savage. I called them last week and they said their turnaround time is 5-7 weeks. Damn
     
  4. Dr. Vette

    Dr. Vette Well-Known Member

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    A possible way to check alignment -

    Remove scope, rings, bases, etc. Use your studfinding laser or similar (you do have one for doing stuff around the house, right?) to run a laser line down all 4 mounting holes, and look at where that line goes in relation to the barrel. If you can line up all 4 holes and the laser doesn't essentially run down the middle of the barrel you now know they're off. You can also reverse the process and run the laser down the middle of the top of the barrel and see if you can "catch" all 4 mounting holes.

    Hey, it's free and probably worth trying. :D
     
  5. SidecarFlip

    SidecarFlip Well-Known Member

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    There is always next year. I did a bit of agonizing over Len's 2015 booking but thats too far off. The way things are going in the world today, 2015 migh be never.

    I certainly would not think what you and I have going on is a common occurence. QC is god with both Savage and my manufacturer, in this case Strum Ruger so IMO. it's a fluke and not the norm.

    It seems that more Savages suffer from tight chambering than anything else and Rugers from very clunky triggers.

    As an aside, my personal Savage rifles have no issues whatsoever in build quality or fit and finish.
     
    Last edited: Sep 22, 2012
  6. Farmerbeau

    Farmerbeau Member

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    I have a laser level. I never even thought of that... Definitely gonna give that a go! THANKS!!!

    I thought the same thing: How could this happen to me twice? I had to use a traditional Leupold 1 Piece base on my Remington 700 in .300 WSM due to either the screw holes being misaligned or the base being trash. I didn't investigate that much because it was a used rifle and the issue was solved with $20 and a set of rings I already had. With this brand new gun, I refuse to go that route because I bought it new and a $1200+ rifle shouldn't have this issue IMO.

    I've heard great things about Savage. I've seen tons of posts ranting and raving about these rifles being extremely accurate out of the box. This was my first Savage purchase... Hopefully it doesn't have to be my last. I'll run a few tests on the scope another rifle and certainly give that laser level idea a go before I call customer service again and prepare to have it sent back.
     
  7. SidecarFlip

    SidecarFlip Well-Known Member

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    My 11-111 in 338 shoots very well and exhibits none of the tendencies or quirks discussed on this site in many threads. Of course I don't chamber Hornady brass. It's a Lapua so it chambers Lapua. Why buy anything else.

    If the mount tappings are out of alignment, it's a quirk just like my pistol is.

    Keep in mind that even though their firearms (Savage) are made on machines, some of them CNC, the human factor is still present so the chance of a fock up is present too.

    Also keep in mind that an mis-alignment of just a few thousands of an inch will be greatly amplified and extreme distance, the longer the shot, the more agregious the alignment becomes which is why at 50 feet, I can still shoot my pistol accurately but I'd never be able to hit anything if the target was at 200 yards and the pistol was a rifle with the same alignment error.

    I know it's misaligned (pistol) by looking at the sight's relationship to the rail and the rail's relationship to the receiver. That is something you can't see with a scope because the compensation for the misalignment is done internally in the erector mechanism, the scope's physical alignment never changes.... Which is why I say the chamber/receiver has to be fixtured (jigged) and aligned and the rail/base mounting holes need to be cherked for parallelism and trueness to the receiver/chamber centerline, not something you can do at home or an average gunsmith can do. That takes very specialized precision equipment and skill.

    Gun manufacturers already have that equipment as well as go and no go fixtures for checking alignment as it pertains to production firearms. Yours (and mine) somehow escaped that check, like I said previously, the human factor rears it's head.

    If it was me, in lieu of fiddling with it, I'd be calling Savage on Monday, explaining exactly what is occuring and ask their opinion or if they want the firearm returned directly or through an FFL.

    As I said before, the BATF registers the firearm based on the receiver so if the receiver has to be changed out, it will have to be re-registered.

    You need to consider another firearm for hunting this year......:)
     
  8. Dr. Vette

    Dr. Vette Well-Known Member

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    Ironically, I have a set of Leupold bases with a significant alignment error of the double dovetail slots. Even worse, the error has the slot offest to the left in front and to the right in back which results in an additive error of my scope pointing to the left compared to the barrel. It took quite a while to figure it out, and for years I just used offsets in my Burris Signature rings to straighten it out. I've now removed those bases but you are correct in that only a small misalignment can cause significant scope alignment errors.

    As he's already tried 2 different sets of bases I doubt that is his problem. I just wanted to add to your comment with my own example.
     
  9. bruce_ventura

    bruce_ventura Well-Known Member

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    Farmerbeau,

    With such short time left, you may not be able to use the proper tools to sort this out exactly. Here's an approach that will help you identify the problem. This method is a bit crude, but is accurate enough to diagnoae a problem of this magnitude.

    First, find the optical center of the scope. That is done by placing a mirror against the objective rim. I've used my wife's small make-up mirror. You will see two reticles - one is the reflected image. If it's too dark to seethe reflected image, shine a light onto the mirror next to the objective. Rotate the turrets until the two reticle images over lap. If the problem is your scope, you won't be able to do this. I'll bet you a box of ammo your scope is fine.

    The base holes could be off, but more likely the problem is with the barrel. I'm guessing either the barrel is mounted crooked in the receiver, or the bore is bent, or both. You can check for a crooked barrel by placing a 24-36" metal ruler against the right side of the receiver. Measure the gap between the ruler and the barrel 18" from the receiver. Then repeat for the left side. I'm guessing that the difference between these measurements is at least 0.15".

    If not, then the problem is either the base mounting holes or the bore is bent. Install the base and back out the mounting screws at least two full turns. If the holes are misaligned the base shouldn't fit properly when you press down on it with your fingers - it will rock like a table with one short leg.

    If the base fits snug, install the base and tighten the base screws. Now repeat the test above using the metal ruler, only this time place the ruler against the left and right side of the base. If the barrel was centered in the first test, but not in this test, the problem is with the base holes.

    If everything checks out fine so far, install the base, rings and the optically centered scope. Pull out the bolt and sight something through the bore at least 20 yds away. I would print or draw a 1" dia circle with a cross centered on it. Tape it to a wall or other suitable target stand. Precisely center this target in the bore. If the problem is a bent bore, the scope will be aiming a few inches to the aide of the cross.

    The real question is how to fix a problem with your rifle in time for the hunt. I would buy a set of Burris Signature rings. The 30 mm rings come with offset inserts. You can orient them to correct for the problem with the rifle. If the misalignment problem is not too severe, Signature rings should get you zeroed. Bed the base if it doesn't fit properly. Then use a torque wrench to tighten all the screws.
     
  10. SidecarFlip

    SidecarFlip Well-Known Member

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    In theory, the bores of the rings should be parallel to each other so if the base dovetail is cut on a diagonal to the bore and you mount the bases and rings and then use an alignment/lapping bar (like a Wheeler) or in my case a shop ground length of bar stock, the misalignment would be immediately apparent when you wiped the ring set with the bar and lapping compound.

    The lapping compound would remove the oxide finish inside the rings only at one extreme end instead of across the bore face. On silver rings, I use Dykem blue or red, on black rings, the oxide coating becomes the 'bluing'....

    Lapping/alignment is SOP with me before I ever set any optic in the saddles. One, I want to visually ascertain if the rings are close to alignment and two, I want maximum ring to tube contact which basically eliminates any chance of the scope moving on recoil (so long as the rings are torqued to manufacturers specification) and it eliminates any chance of ring marks on the optic or in the extreme case, crushing the aluminum scope tube, rendering the optic useless, the main reason why I stay away from sopes with ring marks of any kind.

    Ring marks are caused by one thing and that is misalignment of the rings thenselves in relationship to the scope tube brought about by not carefully aligning the tube to the rings or lapping the ring bearing surface beforehand. Your alignment and final accuracy will only be as good as the preperation and execution done prior to that first shot.

    Along that line, I also use the lapping bar as an alignment tool when fixing the rings to the base/rail. I clamp the rings loosely to the bar and set the rings on the base/rail and attach them loosely as well. Then I go back and progressively tighten the rings to the alignment bar and then tighten the rings to the base/rail. That aligns the rings independently and parallel to the base/rail. Of course all this is predicated on the bar being true and parallel as well.

    If you shoot short distance, none of this is necessary. Long distance compounds the slightest misalignment and necessitates precision, error free mounting and of course precision, error free machining by the manufacturer as well.

    No manufacturer is exempt from error, or as it's been said before, shitte happens. We just don't want to be the recipient.:D

    I read Bruce's synopsis of how to check the alignment and while that will distill the problem, the problem remains and needs to be addressed. IMO, I don't think it's a bore or barrel issue, though it may be in as much as Savage barrels screw in and lock with a retainer nut. I still would lean toward parallel misalignment of the machined mounting holes in relationship to the centerline of the chamber, a more likely scenario, at least in my opinion from owning a machine shop and having an understanding of the different operations, how they are performed and what and when inspections take place.

    Barrel fixing to receiver/chamber alignment is critical and is highly likely to be hand inspected on every firearm whereas receiver/chamber rail/base hole alignment is fixture aligned and most likely not individually inspected but rather inspected on a frequency basis.

    Never having been to Savage Aems or touring their shop, I can only guess, but using common machine shop practices, I can crudely deduce their inspection regimen.

    Every manufacturer has to balance the human factor against the profitability factor. Savage produces what I consider to be a quality product at a reasonable cost. To do that is a fine balance between profitability and how much each firearm is, shall we say, 'carassed' by humans.

    Not to demean any manufacturer on this site like Kirby (Allen Precision) but in order for Kirby to make a profit on his offerings, he has to charge appreciably more because the human factor and that skill is put into each unit. Savage is a production facility. Mass production and one off are entirely 2 different animals.

    It all distills down to what you are willing to pay and what you will tolerate as far as a less than ideal situation, and, of course, how well the manufacturer stands behind their product (in this case and mine, I expect 100%).

    Thats why I said earlier that the OP should contact Savage Arms and allow Savage to decide the outcome, exactly what I'm going to do with Ruger shortly.

    I could very intentionally machine a rail with the through holes offset the deviate amount and bring the rail into parallel alignment with the receiver but that isn't the solution to the issue. The solution to my issue and the OP's, lies with the OEM and how thay address it.
     
  11. Trickymissfit

    Trickymissfit Well-Known Member

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    before I'd go nuts, I'd have the barrel recrowned by somebody that knows what they are doing. If the crown has a ding or even the last inch or so of rifeling is dinged you will push the bullets in one direction or another. I don't recommend lapping the last two to four inches of rifeling, but that's your call. Slugging the barrel might be a problem with a .338, but you might get by with a shaved .357 lead bullet. The results may scare you to death, but then you'll have a much better idea what's going on inside it. Recrowning at least gives you a good starting point.
    gary
     
  12. MachV

    MachV Well-Known Member

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    There really should be a sticky for this. Its a Savage! The actions tend to not be straight, The barrels not bored straight and the threads are not true to the bent action and/or the off center/bent bore. I've got one Savage out of a couple dozen that lines up with the scope=only one!
    Bruce_ventura gave some great advise but I'll add a couple more solutuons to the problem but be warned I use to milk cows for a liveing. The Burris Z rings are great if you can find them!
    My favorite and easiest fix is to put on an IOR or Sightron fixed power scope in 16-20x that has LOT of adjustment=80- 150 MOAs worth. The NF br scopes are great scopes but lack much adjustment!
    Leupold makes a one piece base that has windage adjustments in the rear that can get you lined up too but you usually end up shimming the back to get the ellivation required.
    A couple of my red-neck fixes infolves setting the headspace to the die wich may or may not help the scope alianment? The other quick fix is putting a piece of shim on the rear ring to push the scope into alienment but unless you lap the rings afterwards its going to bend the scope and/or put some nasty ring marks on it.
    Or you could send it to Fred and have him true everything up but your going to wait a long time and have just as much into it as a custom.
     
  13. Trickymissfit

    Trickymissfit Well-Known Member

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    obvious that you've never trued an action, because if you had you'd know that Savage actions are known to be the straitest mass production actions on the market. Typically less than .0015"
    gary
     
  14. MachV

    MachV Well-Known Member

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    obvious that you've never trued an action

    Is it really that obvious:D
    The action may start out life straight but getting that factory nut loose has bent as many actions then it has fixed! Maybe buying cheap actions off the net has found me more problem childs then starting off with new units?
    At any rate I was not really bashing Savage as they outnumber all other actions in the safe 5 to 1. They are not however without thier little issues.