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Old June 12, 2017, 11:11 PM   #1
RevLimiter
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Issue with new scope

Hey, guys and gals. First post here so I'm not sure if it's been covered or not. Here's my problem:
I have a post 1964 Winchester model 70. 1969 I think. Anyway I used to have the factory stock on it and a cheap tasco scope that came with it when I bought it. I just replaced the stock with a Hogue and the scope with a vortex crossfire ii 6-24x50. I was about 1.5-2 inch groupings at 100 yards before with the old equipment but I wanted to start running out to 3-600 yards at a new local range. My vortex after sighting it in at 100 yards today was maxed out but still shooting about 2 inches low. Within an inch grouping but low.
I pulled the scope off when I got home and noticed the front sight base is lower than the rear and at a bit of an angle slanting toward the muzzle. Windage was almost perfect out if the box, 3 or 4 clicks to the right.
Scope mounts are high and also from vortex. I think the scope bases are standard Winchester 2 piece but I don't actually know as they were on the rifle when I bought it.
How can I fix this, preferably by myself and without breaking the bank?
Thanks, everybody
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Old June 13, 2017, 03:44 AM   #2
Leaveammoforme
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What you're describing doesn't make sense. A lower front base would cause the opposite effect. You could run out of "Down" adjustment when attempting a closer zero. I do not intend to offend you but I will mention that infrequent shooters have been known to mix up scope adjustment directions. You got your windage zero'd ,which is where people tend to confuse themselves, so you're probably adjusting the elevation correctly. But I'll say it anyways. "Up" on the elevation dial moves the projectiles impact up.


Just for clarification;

Point of impact is lower than point of aim and the scope is out of "Up" adjustment?

Something is major funky if this is the case.

Since the scope elevation is maxed, I would start with checking the available elevation, proper operation and recenter the reticle. Turn it all the way the opposite direction while counting your clicks. Let's assume an example scope has 160 clicks and 1/4 MOA adjustments. This shows that our example scope has 40 MOA total adjustment. You would then turn back 1/2 of your clicks for a mechanical center (80 in this case).

Your front base sounds suspect if it is on two different planes than the rear (lower and canted). Disassemble then reinstall bases, rings and scope. Secure rifle pointing in a safe direction and remove the bolt. Find an object/target around 25 yards and aim the rifle by looking down the bore. Without touching the rifle, glance through the scope and it should be close.

Until you get this figured out, I would also say reinstall your original stock. While the stock is unlikely to be putting you three feet off at 100, I still swap it back for now.
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Old June 13, 2017, 06:15 AM   #3
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Check the front and rear base alignment with a straight edge. As mentioned, it sounds like mis-matched bases.
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Old June 13, 2017, 09:46 AM   #4
RevLimiter
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Leaveammoforme you are correct. I am turning the elevation knob in the "U" direction to raise my point of impact at the maxed out position I am still low. Not much but I am. I've pulled the bases and reinstalled them to no avail. The front is still low. I've also put a straight edge on them and I can see light above the front base. If I put the edge on the front base I can see an obvious cant. Perhaps some new bases are called for?
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Old June 13, 2017, 07:51 PM   #5
Leaveammoforme
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Bases would be a good place to start.
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Old June 14, 2017, 06:39 AM   #6
std7mag
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Another point to consider.
The CrossfireII is meant to be sighted in at 200 yards. Not 100.
If you use Strelok ballistic calculator you will get all kinds of funky data imputing 100 yard zero.
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Old June 14, 2017, 07:35 AM   #7
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" I've pulled the bases and reinstalled them to no avail. The front is still low. I've also put a straight edge on them and I can see light above the front base."

If the front base is LOWER than the rear, the POI will be high not low. Place the lower ring halves on the bases and lay your straight edge on the bottom of the scope saddle. Bore, base, and ring alignment is fairly basic. Does the M-70 have same level front and rear rings? If so clamp the rifle in a holding fixture with the top of the receiver level and then add parts until finding the mis-alignment. If not, level the front ring and work from there.
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Old June 14, 2017, 02:30 PM   #8
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Hmm std7mag... My manual said 100yds for effective range to around 500yds at the bottom of the bdc reticle. Perhaps the projectile is still climbing when it strikes my target.
Mobuck, I agree. Nevertheless my poi is low with elevation maxed out. I will break everything down tonight and see what I find. Any suggestions for something to use in lieu of a clamp? I have a small apartment without a shop and just have basic hand tools.
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Old June 14, 2017, 03:28 PM   #9
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"Any suggestions for something to use in lieu of a clamp? I have a small apartment without a shop and just have basic hand tools."

You might try to balance the barreled action in an open drawer or make some cuts in a cardboard box. I use a piece of heater hose slipped over the barrel and clamped in a vise.
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Old June 14, 2017, 04:06 PM   #10
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scope

Are you absolutely certain the scope is mounted correctly?

The elevation dial on the top and the windage dial on the side...not trying to be a wise guy, but I've seen this happen even with experienced shooters.

I would suggest changing your two piece bases for a one piece base.

Have you contacted Vortex as regards this problem?
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Old June 14, 2017, 08:09 PM   #11
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Yes it is mounted with elevation on the top and windage on the right. I sent vortex an email last night detailing the issue. Waiting to hear back. I am rather perplexed by this conundrum...
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Old June 14, 2017, 08:48 PM   #12
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If I understand correctly, you installed a new scope but left the old bases in place. The Tascos were not bad scopes, but were made to a price, and the package came with mounts from ??. And then the previous owner may have swapped bases trying to get something to work.

The answer might be simple - spring for new bases made for that rifle and toss the old ones.

Jim
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Old June 14, 2017, 09:17 PM   #13
RevLimiter
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I'm not sure who the mounts are thru. I'll check out a new base. Leopold makes one I like and their reputation is good
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Old June 15, 2017, 07:49 AM   #14
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The only other possibility is a bent barrel.
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Old June 15, 2017, 10:54 AM   #15
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Quote:
The only other possibility is a bent barrel.
Bent barrel? At one time I made tools for checking bent barrels, today it seems it is more fashionable to talk it to death. A couple of years ago I got between an old smith friend that built a rifle and the old owner. Both of them were wrong and there was no way to make both of them look good. After the scope was replaced and the mounts were re-aligned(?) the rifle went back to what is was designed to be; one of the most accurate rifles I have ever taken to the range.

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Old June 15, 2017, 08:17 PM   #16
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"Bent barrel? At one time I made tools for checking bent barrels, today it seems it is more fashionable to talk it to death."
OK, toss out another possibility. The OP's comments indicate a low POI even though his measuring and use of a straight edge on the bases should produce a high POI. I'm just throwing mud at the wall to see what sticks.
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Old June 16, 2017, 12:05 AM   #17
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A bent barrel is not impossible but on a Winchester 70 is pretty darned unlikely. And a bent barrel should throw the POI off by a lot more than 2 inches. Still, with a bolt action, it is easy to check and correct.

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Old June 16, 2017, 08:09 AM   #18
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If the front base is lower than the rear you probably have the wrong bases on the rifle. The rear receiver bridge is machined lower than the front. The rear base has to be thicker in order for it to be the same height as the one on the front. It is sometimes possible to reverse them, but the front base would be a lot higher than the rear in that case.
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Old June 16, 2017, 01:32 PM   #19
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" And a bent barrel should throw the POI off by a lot more than 2 inches. Still, with a bolt action, it is easy to check and correct. "
Rethink this comment. The scope has run out of adjustment and the POI is still off 2" so the total "off" would be much more-maybe 3 FEET. A person with limited knowledge might not notice or even look for the shadow that indicates a bent barrel.
I had an old Mauser wall hanger with the barrel bent to the left. It was fairly accurate and could be zeroed to hit POA at one specific range. Past that range, the bullet just kept going further left.
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Old June 17, 2017, 09:01 AM   #20
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I don't think it's bent. Let me know how to check for that though without taking it in. The front halo ring is off center a bit as if maybe from a drop or a bump into something but that's it. No other visible damage. I've gotten the barrel hot to be sure but not so hot as to warp it. I've gotten my AR15 much hotter and its still shooting on point. I did replace the base with a 20 moa single piece so I'll take it to the range asap to see if I can sight it in. I recentered the vertical on the reticle. Counted 215 clicks so I moved it 107 back. We'll see what happens...
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Old June 17, 2017, 05:55 PM   #21
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What are the chances that its the scope? Maybe the Chinamen that made that Vortex didnt get his ration of tea that morning. I had a brand new Simmons that was bad and an old Weaver that was bad.
Curious to hear the outcome of this.
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Old June 17, 2017, 08:04 PM   #22
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"The front halo ring is off center a bit as if maybe from a drop or a bump into something but that's it."

Please explain as I'm not sure what you're referring to.
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Old June 17, 2017, 09:26 PM   #23
RevLimiter
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The stamped sheet metal guard over the forward sight post is cocked slightly to the right so that the bead sight is no longer centered in it. The bead sight itself is untouched. As I mentioned above I believe it is merely cosmetic and does not affect the poi whatsoever.
I also replaced the2piece weaver with a 1 piece multi slot 20 moa picatinny. Hopefully the chinaman got his tea when he put it together. I'm waiting to hear back from the vortex rep as to when he can go over a few things with me.
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Old June 24, 2017, 01:39 PM   #24
RevLimiter
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Update: I finally got to the range today and got the rifle sighted in. Replacing the base seemed to do the trick. Don't think I moved the elevation more than 10 moa from center. Thanks for all the advice everybody!
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