Rifle Scopes Think I have a bad optic :(

rangeryo

rangeryo

Sergeant
Full Member
Minuteman
Feb 7, 2013
432
2
40
Central Virginia
#1
I have a Vortex Viper FA 6.5-20x44 PA, which I put on my new rifle a couple months ago. Rifle hasn't shot very well at all since then, but I attributed it mostly to the factory ADL synthetic stock, and barrel. Received my new XLR Chassis last week so I grabbed 3 boxes of overly priced 308 ammo to shoot yesterday. I also spent hours cleaning every bit of copper fouling out of my barrel, as the rifle was shooting about 1/2-3/4 MOA with an el-cheapo Bushnell optic. I go prone, on my 200 yard range and begin to shoot, and this is what I see...

First - 1" high 4" left
Second - .25 low 4.5" left
Correction - 6 mrad right
Third - 0 elevation 6" right
Scratch head
Scratch ass
Fourth - 3" low 3" right
Fifth - 0 elevation 4" right

At this point I'm fairly frustrated so I pick another target and decide I'm shooting a 5 round group with no corrections. Give my barrel, and my temper a few minutes to cool and lay back down.

First - .5" high 1.5" right
Second - 1.5" high .25" right
Third - .5" low 1.5" right
Assumed things settled down, and adjust .1 mrad left
Fourth - 5" high 4" right
Fifth - Nowhere on paper looked to be WAY right and high from impact

I understand factory Remington barrels are not the greatest, but I feel like this is definitely an optic problem. Would you agree?

Rifle specs:
Remington 700 ADL synthetic ($350 @ Dicks on black Friday)
XLR Evolution Chassis
Vortex Viper 6.5-20x44 PA - Mil Dot Reticle
Nightforce 20 MOA base
Burris Xtreme Tactical rings (aligned and lapped)
Jewell Trigger @ ~ 2 lbs
Tubb Speedlock firing pin
 
#4
Slap that "el-cheapo Bushnell" (or a better scope that you know is working) back on and see if the accuracy comes back. If it does, you found your problem.

Also, some guns take a while to get their accuracy back after a full copper scrub. Normally, it's not as bad as you seem to be getting, but something to consider. It does sound like an optic problem to me, though.
 
#5
rangeryo said:
Yep, I've went 65 in lb on both action screws, and 25 in lb on both scope base and rings.
Click to expand...

well that might be part of your problem. The ring clamps (where it clamps to your rail) should be about 55 in/lb and the ring caps should be 15-25 in/lb.

You're rings are clamped to the rail at half the torque they need to be. My money is on that!
 
#9
Also, how are you shooting these, bag/bipod, rest, or what? Just because you bought over priced ammo doesn't mean it will shoot good. Try and find some 168gr hornady BTHP or Amax or some fedral gold metal match. If the bullet is too heavy, it might not stabilize correctly.
 
#10
Temp9 said:
Slap that "el-cheapo Bushnell" (or a better scope that you know is working) back on and see if the accuracy comes back. If it does, you found your problem.

Also, some guns take a while to get their accuracy back after a full copper scrub. Normally, it's not as bad as you seem to be getting, but something to consider. It does sound like an optic problem to me, though.
Click to expand...

Unfortunately, I sold the Bushnell scope, and don't have another on hand to replace it with currently. Also, the accuracy was terrible before the full copper scrub, which is why I went through the process in the first place.

deadnbrkn84 said:
well that might be part of your problem. The ring clamps (where it clamps to your rail) should be about 55 in/lb and the ring caps should be 15-25 in/lb.

You're rings are clamped to the rail at half the torque they need to be. My money is on that!
Click to expand...

Sorry, I didn't mention that I had them torqued to 55 in lb already. I was just referring to the base screws and the top screws.

I'll call vortex today, and hopefully they can help me out.
 
#11
BigJohn141 said:
Also, how are you shooting these, bag/bipod, rest, or what? Just because you bought over priced ammo doesn't mean it will shoot good. Try and find some 168gr hornady BTHP or Amax or some fedral gold metal match. If the bullet is too heavy, it might not stabilize correctly.
Click to expand...

I'm shooting prone off of bipod and rear bag. Setup is solid, and I maintain clear sight picture throughout recoil. The ammo from the weekend was just some Winchester 147 FMJ. However, I've also shot Hornady Match 155 Amax, 165 Amax and several other loads with similar results, prior to the addition of the chassis.
 
#12
I don't ever like to scrub a bore that much, but I don't think it would hurt your accuracy that much. There could be all sorts of things going on, including something funny with how the recoil lug is fitting up, etc. Check the torque on the action screws too, just in case they have loosened up on you. I would put the rifle on a rest and see if I could find some kind of repeatability in the groups. Also, does the rifle shoot ok at 100 yards, or is it just as crazy as 200 yards? I would move in to a closer distance and see if you can get a better idea of what is happening. Finally, is this the same ammo that the rifle was shooting 1/2 to 3/4 MOA with? If not, there is the real possibility that the bullet is not stabilizing and that is causing your problems. I have a .223 with a slow twist, and tried some 69gr FGMM in it. It is a sub 1/2 MOA rifle all day long, but those 69gr were not even on the paper.
 
#13
nso123 said:
I don't ever like to scrub a bore that much, but I don't think it would hurt your accuracy that much. There could be all sorts of things going on, including something funny with how the recoil lug is fitting up, etc. Check the torque on the action screws too, just in case they have loosened up on you. I would put the rifle on a rest and see if I could find some kind of repeatability in the groups. Also, does the rifle shoot ok at 100 yards, or is it just as crazy as 200 yards? I would move in to a closer distance and see if you can get a better idea of what is happening. Finally, is this the same ammo that the rifle was shooting 1/2 to 3/4 MOA with? If not, there is the real possibility that the bullet is not stabilizing and that is causing your problems. I have a .223 with a slow twist, and tried some 69gr FGMM in it. It is a sub 1/2 MOA rifle all day long, but those 69gr were not even on the paper.
Click to expand...

I typically wouldn't scrub the bore that much either, but I've been chasing this problem for some time now, and thought that maybe the fouling had something to do with it. Accuracy problems have persisted throughout a scope remount/ring lap, stock replacement with XLR and several different types of ammo. Moving groups, or non-grouping just seems to me that there is something wrong with the scope. I'm no expert, but I've tried everything except replacing it. I've heard many good reviews from the Vortex owners, but so far, I'm not convinced.

I should also add, that there is one small chip out of the crown of my muzzle, but it's been there since I got the rifle, and it has shot bug hole groups at 100 yards, so I've mostly been writing it off as the cause of my accuracy problems. It doesn't seem that a sub MOA group would open up to 5 MOA when adding an extra 100 yards
 
#14
Its the scope I had a brand new Zeiss Conquest 4.5x14x50 that was doing the same thing. I would get it to shoot a 2-3 inch group make an adjustment and it would not even hit the target. I sent it to Zeiss repair shop. Three months later I get the scope back with an apology from Zeiss. To fix it they had to install a new erector system. It's the scope send it back to Vortex.

Jim
 
#15
Check the crown with a Qtip. A damaged crown will throw shots all over the place. This is the most overlooked aspect of accuracy. Just put the Qtip in the bore and pull up with a light touch and see if you have any strands comming off. If you do, you have a burr on the crown.
 
#16
jde650 said:
Its the scope I had a brand new Zeiss Conquest 4.5x14x50 that was doing the same thing. I would get it to shoot a 2-3 inch group make an adjustment and it would not even hit the target. I sent it to Zeiss repair shop. Three months later I get the scope back with an apology from Zeiss. To fix it they had to install a new erector system. It's the scope send it back to Vortex.

Jim
Click to expand...

This is what I was thinking. I don't particularly want a 3 month wait, so I hope it wouldn't take the long. Although, that would be a good excuse to get my barreled action out to Crescent Customs for a rebarrel and action truing job.
 
#17
when you mounted the scope to your rifle ..I have to ask did you zero your scope then ?? and did you test it to be sure it was tracking right? I'm just asking bcause you didnt mention if ya did when ya mounted it and if so you would have noticed the problem then not months later ??
 
#18
I had tried zeroing it before, with the same problems but like I said I pretty much attributed the horrible accuracy to my factory stock. When I replaced the trigger, I apparently didn't get one of the pin's fully seated, and it was gouging the bedding surface on the synthetic stock. Additionally, the jewell trigger needed additional relief in the factory stock, so I thought it was possible that I had some inconsistent contact, resulting in poor accuracy. Didn't much worry about it, knowing that I already had the XLR in production. Also, I'm not sure if you've ever shot one of these $350 R700's, but the factory stock is like a noodle. Recoil was more sideways than backwards, and would put my crosshairs about six foot off the side of my target.
 
#19
Just got off the phone with Vortex support. He recommended that I reset top ring screws to 15-18 in lbs. He suggested I go with 15, being that I'm using the Burris extreme tac rings. He also said that if the rear ring is too tight, it doesn't allow the erector to move properly and if the front ring is too tight, it will not allow the parallax adjustment to function the way it should. It's very possible that this could be my problem, as I've noticed that I've had troubles getting the parallax adjusted properly, even though there is a 200yd mark and my range is exactly 200 yards. I figured this was due to the fact that I'm not using a top of the line optic, and never really put it together with my accuracy problem.

I'll try this this afternoon if I still have daylight when I get home from work.

Also, thanks all for your input!
 
#22
When I came home I immediately came into the house and grabbed my rifle and torque driver and reset torque on top screws to 15 inch pounds. Grabbed a few sheets of paper and burned some powder. The results? Well see for yourself...

rangeryo-albums-targets-picture4828-fedps150sp.jpg


Edit: Before anyone else points it out, I know my scope is no longer level. I can see the elevation rise between my .7 mil correction.

Edit #2: Forgot to mention, that I didn't see the last two in the bull, and fired the last of that 3 rd string at a separate target, center punching the bull. The two 3 rd strings prior to adjustments were rushed, as I was mostly just trying to see if I was holding zero and that adjustments were accurate.
 
Last edited:
#25
seems like you may have it figured out ... after ya get her level and don't rush try her again let us know if that was indeed the fix and again thanks for sharing
 
#26
I ordered a set of .5" rings today anyway, so I'm not too concerned with the scope being level. Should be here next Monday. I really need to find more decent ammo, or find someone willing to reload for me with the components that I have currently (Lapua brass+155 Lapua scenars). I was actually quite surprised to see sub MOA out of the factory Federal Power-Shock 150 soft points.
 
#27
Looks like you have found the problem. I bet with some good ammo you will be in good shape. I always like to eliminate the easy stuff first, and it looks like that is what you did.
 
#28
I didn't exactly eliminate the easy stuff first. I did remount my base/rings/scope, to the specs listed on each part. But I didn't actually contact Vortex until after buying a chassis system to hopefully resolve the issue. Don't get me wrong, I'm glad I got the XLR, since my former 100 yard group sizes are now my 200 yard group sizes. I first thought it was pretty silly that 5 in lb difference in torque would make any difference in accuracy, but it surely does.
 
#32
Here was my groups with top screws torqued to 20in lbs. You can see the difference from this and above. All groups shot with same ammo, same scope and rings, and same gun at same range.

rangeryo-albums-targets-picture5306-before-retorquing-scope-rings.jpg
 
Last edited:
#33
A couple of things. Is the action torqued in the the chassis correctly and did you check for any damage to the barrel crown yet? If you are good to go in both those areas the only other option is to borrow or even buy a cheap scope to see if it changes any.
 
#34
BigJohn141 said:
A couple of things. Is the action torqued in the the chassis correctly and did you check for any damage to the barrel crown yet? If you are good to go in both those areas the only other option is to borrow or even buy a cheap scope to see if it changes any.
Click to expand...

See above. Issue was resolved by resetting torque on top ring screws to 15 in lbs instead of 20(ring mfgs specs)
 
#40
Wheeler, like most lighter load torque wrenches, was inaccurate; the problem was that is was randomly inaccurate.
The Borka Tool is stupid simple and hard to screw up. And it's small enough to pack with you.
 
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