Win Model 70 300WM Vortex Viper6.5-20x50 Need help- Not enough MOA

[105Coues]

I am new to the site and am hoping some of you can help me with my current issue. I have a win model 70 300 win mag with a vortex viper 6.5 to 20x50 mounted with a weaver extended 20 MOA rail and weaver grand slam rings. I am zeroed at 300 and I only have 20.5 MOA available which gets me out to 950 but not 1000. The rail is not backwards (it slopes toward the barrel) andI have verified the 20MOA rail measurements are correct and the ring heights match each other. The viper should have 65 MOA. This means I should have roughly half of that plus 20 minus 4 for the 300 yard zero. This puts me at roughly 48 and I have 20.5 on one rifle and 9.5 on the other????

I thought I would have more adjustment so I need ideas on how to get there???? I have to wonder if others owning the M70's have had similar problems. Seems odd that two rifles with the same setup have the same problem. I have emailed Burris about their signature rings to see if they will sell me the eccentrics for a 30mm tube to get an additional 20MOA but have not heard from them.

Also I have a 270 win with the exact same setup and I only have 9.5 MOA to work with which only takes me to 650. Bummed out is an understatement when the rifle will shoot .3 MOA groups.

I have been having a ball shooting the longer ranges but am stopped for now until I get past this.

 

[PeterPHWS]

A number of factors could explain this. A barrel when being rifled can have the direction of the drill wander ... this means that some barrels when threaded and screwed on have a slight upward path for the bullet or downward or even left or right. If yours is slightly downward then you are going to use more internal elevation in the scope for distance and bullet drop.

The other is that the scope is sticking in the elevation movement and not giving a full delivery of 65MOA. You need to test the scope at 100 yards on graph paper whilst the rifle is in a very steady locked down position and see how much true movement the scope gives. A tape measure pinned vertically should also be able to work if graph paper is not available. At the top magnification you should be able to see the numbers on the tape and get an idea of total travel. Do the same on windage too whilst you are there.

If the scope works fine for 65moa movement then the answer lies in checking the height of the scope above the bore and the true incline of the rail and then working out what is happening there. You will need to remove the rail and micro the front and rear height and the length and work out the MOA drop. This info should tell you how much internal scope movement is being lost to gain a 100 yard zero. Work on 100 yards for the zero so the MOA information is more easily processed.

Whichever way ... you are going to need a steeper rail from the look of it - but working out how much movement is being lost in the scope for 100 yards lets you know how steep to go on the rail.

So in simple terms if you have lost 35 MOA for your 100 yard zero - get a 35MOA rail so all the scope movement is available to you.

 

[half]

Have you verified you actually have 65 moa of travel in your scope? How much of your travel did you use to get your 300 yard zero? I had this happen once, turned out to be the bore in the barrel wasn't concentric.

 

[105Coues]

I just verified both scopes to have 66.75 MOA full travel. However I only have 20.5 in the up direction on the 300 and 9.5 on the 270 with the 20MOA rails. This would mean that if I did not already have 20MOA rails that after sighting in the 300 I would only have 1/2 MOA adjustment up and the 270 would be 10.5 inches away from even being able to sight in?????
What really puzzles me is that my previous scope on the 300 was a simmons 44mag 6.5-20 and i had standard redfield/leupold steel bases and rings and I had at least 10 MOA up on it(never shot further than that at the time). That already exceeds what I have with both of these and I didn't have and extra with my base???

 

[roggom]

What height are your rings? Your center of reticle may be too high over the bore. If you can, swap out with a set of low rings and see if that gets you out further. Remember, when you dial for elevation you are moving the reticle closer to the bore, hence a 20 moa rail tilts the obj lens towards the bbl.

 

[Bigwheels]

My 20 moa base didn't fit the action properly @ the rear. When I tightened down the front screws the rear would tip up about .015". I shimmed the rear, & now it's right, but also closer to a 30 moa base.

 

[PeterPHWS]

If the scopes work ... you need to change your rails or add tapered rings to the set up. I would price a gunsmith increasing the taper on the rail. Over here we usually get the gunsmith to bespoke the rail for a rifle / scope combo so that most of the movement in the scope can be used. You need to have a little bit unused to allow for a replacement barrel and some variable.

Pic's of the set up would be helpful. Never heard of a 65MOA scope losing so much elevation when mounted.

 

[105Coues]

I had never seen this issue as well.
Here is a link with pics I posted. I would just add pics but I deleted them

I need HELP!!!! Not enough MOA - Long Range Hunting Online Magazine

 

[jetmd]

105,

I just finished looking at both of my Win Mod 70's, a SA in .308 win and the other is a 7mm WSM. The 308 has an EGW rail and the 7wsm has a Badger Ord rail, comparing these to your pictures it appears to me the rail is not truly 20 moa. The thickness of both of my rails look to be just like yours on the front of the receiver, but the rear section on both appear to be much taller than yours.
I don't think it's your rings, I have a spare set of NF rings if you need them to try just pay for shipping and make sure I get them back when your done.
I hope this helps.

 

[FCS]

I had never seen this issue as well.
Here is a link with pics I posted. I would just add pics but I deleted them

I need HELP!!!! Not enough MOA - Long Range Hunting Online Magazine

Hard to tell from that picture but scope appears to be pretty darn high above bore.

I've got Badger or NEAR 20 MOA rails on my 70 / FN SPRs, haven't had the elevation issue with scope you are running into. I'd pull the base, take some measurements and confirm you really do have 20 MOA of taper on base.

What method did you use to verify 66.75 MOA of travel?

 

[Eric B.]

Guess I'm happy I just bought a Bushnell ERS 3.5 - 21 X 50. Got 27 MOA on the turret, 10 more MOA with the H59 reticle and a 40 MOA NF Unimount on a zero MOA Larue rail.

Same rifle as the OP: Rem.action W/HS Precision barrel and stock in .300 Win mag.

 

[Rhyno]

Guess I'm happy I just bought a Bushnell ERS 3.5 - 21 X 50. Got 27 MOA on the turret, 10 more MOA with the H59 reticle and a 40 MOA NF Unimount on a zero MOA Larue rail.

Same rifle as the OP: Rem.action W/HS Precision barrel and stock in .300 Win mag.

... The op has a Winchester.

~Joseph~
Via Tapatalk

 

[105Coues]

update now that I have a little time- I have now spoke to everyone who's product I have and cannot explain anything other than the recievers are not true but I do not have a way to test this. I just did a mirror test on the vortex scope to center it mechanically and I have 33 MOA in each direction which is perfect. My rings are the exact same height. The scope is high above the bore but the math does not support this being a cause. The winchester receiver has the front .125 inches higher than the rear. The weaver rail specs are .399 rear to .247 front for a difference of .027 (approx.032 should be 20MOA). This should mean that I would get 17 additional MOA from my rail. I talked to Burris about their Signature ZEE rings and they said I could get 20MOA by using the +.010 and -.010 eccentrics. Math supports that I would only get an additional 12.5 MOA if I go with this option which won't take me much further at extended ranges. My best option is going to be a 40 to 45 MOA rail so if anyone knows where to get one I would appreciate the info.

Sorry it took me so long to update but life happens.

 

[105Coues]

105,

I just finished looking at both of my Win Mod 70's, a SA in .308 win and the other is a 7mm WSM. The 308 has an EGW rail and the 7wsm has a Badger Ord rail, comparing these to your pictures it appears to me the rail is not truly 20 moa. The thickness of both of my rails look to be just like yours on the front of the receiver, but the rear section on both appear to be much taller than yours.
I don't think it's your rings, I have a spare set of NF rings if you need them to try just pay for shipping and make sure I get them back when your done.
I hope this helps.

Thanks, I appreciate your offer. I am quite sure it is not the rings though. I am going to try to get the extra rail I have mic'd by a machinist i know to make sure my electronic caliper measurement is correct so that when I buy a 45MOA i am not on the other extreme.

 

[spamassassin]

Burris has 20MOA eccentrics available. Drop in a +20 and -20 and you get 40MOA from it. I've had the problem on all of my browning rifles.

 

[105Coues]

Burris only has the +10 and -10 for the 30mm. Did you actually get 40 MOA from the 20's?

 

[spamassassin]

Oh hell... that's odd. I didn't know they didn't have the big eccentrics for the 30mm scopes. hangs head in shame.

On 1" rings with 20MOA eccentrics front and back in opposite orientations I got closer to 35.75MOA on my Browning BLR with the bushnell scope, extra high rings and flat base it was wearing at the time. I'm not one to quibble over 10% in as big an adjustment as that is. But yeah, they're not precise just really really close.