Reply With QuoteBase MOA numbers are not exact, but it sounds to me as if a 20 MOA base is what you need to replace the shim.
Ok i have savage 280 that i bought a warne O MOA base for.Well im out of scope adjustment.and still 6"-7" from zero.I installed a .020 shim under the REAR base and its good to go now plenty of adjustment up and down.Im not realy likeing the shim under the base so i want to buy the correct moa base.
My questions is do i need a 20 moa or 10 moa?Thanks.
Base MOA numbers are not exact, but it sounds to me as if a 20 MOA base is what you need to replace the shim.
I'd go with a 20MOA just to make sure. What distance are you zeroing the scope at that you need an inclined base?
Another option is to keep the base and get a set of Burris Signature Zee rings and use the offset inserts to correct the mis-alignment.
Im trying to zero @100
Did you buy the correct base? Just asking because I see a fair number of people come into the shop with the same problem only to find they have a round/round base on a round/flat action.
Ye si have the correct base.Its a flat rear action with a flat rear base.I had the stock pillar bedded by a smith and i think he got the pillar in the front a bit to high.
Even if the front pillar is pillar is too high, it should not affect the relationship between the rifle, barrel, base, and scope.
The receiver could be slightly warped which would throw it off. It's been known to happen.
The flats were hand filed to finish them up. I always use 2 piece bases and Z rings to absorb the misalignment's, when given the option on them.
.223 Rem AI, .22-250 AI, .220 Swift AI .243 Win AI, .6mm Rem AI, .257 Rob AI, .25-06 AI, 6.5x300wsm .30-06 AI, .270 STW, 7mm STW, 28 nosler, .416 Taylor
The answer is a lot simpler than folks are making it.
Since you have the scope adjusted all the way out and are 7MOA off without the shim, count the number of clicks per revolution of the turret (C). Count how many turns you get from all the way up to all the way down (T). Take the max number of turns and divide by 2 and multiply by clicks per revolution (R), then divide by clicks per MOA (M) (most scopes clicks/MOA is 4). Add your unresolved adjustment requirement (U), which is 7 in this case. This is how much adjustment you need in the base to be exactly in the middle of your scopes adjustment range. Most inexpensive scopes will have 40-50" of adjustment between the extremes. Better scopes have more.
For example: You find you have 1/4MOA per click adjustment, get 10MOA per revolution (40 clicks) and your scope allows 4.5 rotations from the top to the bottom of elevation.
So you've got 45MOA of vertical adjustment in total available in the scope, half is 22.5, plus the 7MOA you're under still is 29.5 so you'd be looking for a 30MOA base in that case.
using the formula at top to make a mathematical expression to show the example above:
4.5 / 2 * 40 / 4 + 7 = 29.5
using the variable declarations from above: T / 2 * C / M + U = BASE-MOA
Last edited by r3dn3ck; 10-25-2012 at 11:40 AM.
I didn't see anything complicated about the answers given, although you're formula is correct for getting the adjustments centered in the scope. That's how I get mine centered and then add the right inserts in my Zee Rings to get it as close to being bore sighted as possible so I have to use very little of the scope's internal adjustment.
The complicated bit was 10 replies, only two of which came with any sort of answer which were just guesses as to the actual answer but nobody bothered trying to teach the guy to fish and no sure fire answers were given. Guesses, hunches, assumptions and distractions aren't warm and fuzzy. That complicates the hell out of a thread don't ya think? I do.
One or two of you might remember what it was like before you knew all this stuff but it's anxiety inducing hell for most shooters to try and figure out until you give them the tools to figure it out.
NOTE: There was no snark in this post but if someone cares to read it in, they're free to do so.
Yes, I can see how asking questions to help solve a problem and teach someone what to look for can get complicated.
Park,
Please continue to try and figure out why you have the issue before you start spending more money on it. Use a straight edge and a level to get the amount of drop on the rear of the action and then measure the thickness of the base you have and another for a Savage flat reciever. If the reciever is out of spec there is several ways to correct it, the easiest being Signature Zee Rings.
Last edited by Jamie; 10-25-2012 at 01:32 PM.
I can tighten my front base screws just snug and i have a gap of around .010-.020 in the rear. i have a .020 shim under it now with no issues.I just do not like the shim.Looks liek my action is not level how can i fix this issue?I dont shot past 300 yards much so i dont need all the moa but i want my scope to still have some adjustment It is a custom gun by the way.112 action.
The easiest way would be to use the Burris Signature Z rings as stated earlier. You will need the offset inserts. This will allow you to angle the scope inside the rings to compensate for the alignment issue or you can have a one piece base ground to the specific MOA you will need to even it out.
You're fully adjusted out and still 7 -8 moa out of range. How much verticle adjustment does your scope advertise? Divide that advertised # in 2... that will give you how much adjustment you have above and below center. If its 40, you have 20moa up and 20 moa down. If you slap a 20 moa base on there, you will be +13 moa (you were adjusted all the way up.. and still -7 , you add 20 moa and you are +13moa high for POI without any adjustment). You'll be able to lower your scope that 13moa remainder and be approximately zeroed. and have 13 moa of adjustment up from there. You're still using 1/3 of your vertical adjustment though.
"One or two of you might remember what it was like before you knew all this stuff but it's anxiety inducing hell for most shooters to try and figure out until you give them the tools to figure it out."
Obviously you had a different perception of the answers than I did. I don't think anyone here was trying to talk down to him. We all know what it's like to be new at something and we never quit learning. The answers may not have been what you wanted them to be but we're all just trying to help here.
Using a 20 moa base will still not resolve the fact that the rear bridge is .020" lower than it should be when compared the the height of the front. A shim would be the best solution. At least it's flat, and doesn't have to wrap around a radius.
"As long as there's lead in the air....there's still hope.."
agreed sharpshooter, but is it due to the base being off spec or the reciever off spec?
Some excellent advice here. And, for that matter, great instruction as to how to determine the "center" of your scope and compensate with a canted bases. But, a couple "alarms" if you will went off for me:
1. The gap you have at the rear of the base isnt, unfortunatly, (from what I hear in a few of even the finer rifle names) that uncommon. I had @ .007 of a gap on my newer model 10. You can do what you have done and shim it with something like a piece of an alluminum can (thats what I did) or you could bed it with epoxy. Of course the epoxy would "stay" with the base, and as such, may not work on any other rifle until removed from the base.
2. But the bigger alarm is that you cant adjust (down enough I assume?) the scope for a 100 yard zero. Have you mentioned what the height your scope is from the barrel? As the farther away you get (outside lets say @3/16th's of an inch) the more adjustment you will need to make (in the scope, rings or base) to achieve that 100 yard zero. Perfect world is slide a piece of heavier paper between the scope objective bell and the barrel. Any more than that is excessive. But I have yet to see a scope that needed a canted base to get a 100 yard zero. Because when you have to go there, you wont have much, if any, more to go ANYWHERE.
Good luck!
I have bought some burris xtb bases 0 moa .the gun is heading back from smith from being cerakoted now ill let yall know if its the base or the action.Thanks for all the help by the way.This is my first custom build and its been one thing after the other.First miss fires,8 months to get barrel.trigger adjustments screws losing up.and the base issue.Ithink next time ill just buy one complete...
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