Shifting Zero on Long Range Hunting Build

[flesher_2006]

So I'm new to long range hunting and this year I have dedicated a rifle build to do just that. I have a Christensen Arms Ridgeline chambered in 7mm Rem Mag. I have Vortex precision match rings mounted to a Talley 20 MOA 1 piece rail. I mounted a Vortex Viper PST Gen II 5-25 x 50 MOA rifle scope. Everything was torqued to spec and the rail was bedded to the action. I have a 5/8' sorbathane cheek riser from Gotta grip on the stock. Im shooting 162 gr Hornady Superformence (SST).

Yesterday I zero'd at 200 yards and got a sub MOA group. I dialed my optic to 3.75 MOA and was hitting a 4 inch steel target at 411 yards,. I was pretty pumped as it validated that I built a good shooting rifle. Well about 15 minutes later I shot at the same target and was hitting about 4 inches low. I then shot at a 200 yard steel target and was hitting around 3 inches low as well. I re-zero'd my rifle and dialed to 3.75 again and began hitting steel at 411 yards again and had no issues for the rest of the day (about 2 hours).

What do you think could cause this? Is there something that I should change or do you think it was from my inconsistencies as a shooter?
Any advice would help.

Thanks

Just to add one more thing to this. There are so many possibilities that it’s hard to narrow down exactly what was going on but I‘m willing to be it’s shooter related. If you were hitting that target consistently at 411 yards then stopped for a break, got back on the rifle and was impacting in a different spot, it was likely due to you breaking your shooting position and then getting back on the gun with a different cheek weld, eye relief, etc. If it was a mechanical issue, it would to have happened the last time you pulled the trigger for that first session which leads me to believe it’s shooter related.

 

[hereinaz]

Just to add one more thing to this. There are so many possibilities that it’s hard to narrow down exactly what was going on but I‘m willing to be it’s shooter related. If you were hitting that target consistently at 411 yards then stopped for a break, got back on the rifle and was impacting in a different spot, it was likely due to you breaking your shooting position and then getting back on the gun with a different cheek weld, eye relief, etc. If it was a mechanical issue, it would to have happened the last time you pulled the trigger for that first session which leads me to believe it’s shooter related.

Any ideas what he could have done to enduce such a zero shift?

I have played with different positions trying to shift zero just with position. I can't get one unless I change the suppot. Like from bipod to bag, but it hasn't been that big for me.

I am curious about what mechanisms would move a zero.

 

[SecretSpot]

Whether you think people hate on vortex too much or not the fact is it's still junk and you will need their warranty if you buy one. If that hurts your feelings you need to get your life on track cuz your scope probably doesnt

 

[WRO]

I will agree in part and disagree in part. I don't like generalizations.

It is a sliding scale. All scope companies with low end models have high failure rates for us LR hunters at the bottom tier. Rates are still unacceptable to some at the higher mid tier. As you increase cost and quality the rate of failure increases. Vortex highest lines don't fail any more than others.

NF won't make cheap scopes, so they don't have failures. Its why I recommend the SHV as the best budget scope.

I would never buy some Vortex because of high failure rate, but it isn't 100% on their PST II, nothing close to that. Among other things, the variables in a scope are likelihood of failure. You have to talk models.

If I was going to by a cheap scope to dial, it would be an SWFA, Nikon fx1000, Bushnell LRHSI/DMR if I was going to buy a good scope to dial it would be a NF/Kahles/ Swaro x5, Tangent, etc. At no point would I risk a hunt on a vortex or leupold I intended to dial..

 

[hereinaz]

A Nikon... but you won't buy any Vortex. OK.

 

[WRO]

A Nikon... but you won't buy any Vortex. OK.

Yep, FX1000 is a solid scope that can be easily purchased for less than 500.00. I've got 1000 rounds through mine repeatedly dialing with 0 issues. That being said, it's on a varmint rifle.

If I wanted to pay 40% more for a shit in a shoe box warranty I'd gladly purchase a vortex.

I've broke high end scopes, but not nearly at the failure rate I see Vortex's and Leopold's fail at when it comes to repeated dialing. About every other year we have a client with one that's failed their hunt..

 

[07yzryder]

I can tell you my brother and i were doing some load verification on his 30 weatherby mag. 4 shots is all it will allow. 4 shots in 3.5-4 inches at 400 yards 5th shot 6 inches low right WTF send one more, about touching the 5th.

wait until barrel is cool 2 shots in with group 1-4 then shots 4 and 5 in with group 5-6. only difference is temp. its repeatable and because its a hunting rifle and not a target gun we accepted 3 shots groups and wait until cool to the touch.

rifle is a 300 weatherby mag meat eater edition, zeiss conquest v4 3.5-14 (or close to that) in zeiss rings on some high end rail.

as far as shooter, i took my 338LM and put 6 rounds in a 2 inch group at 400 so shooter is familiar with recoil and is able to maintain decent accuracy.

 

[flesher_2006]

Any ideas what he could have done to enduce such a zero shift?

I have played with different positions trying to shift zero just with position. I can't get one unless I change the suppot. Like from bipod to bag, but it hasn't been that big for me.

I am curious about what mechanisms would move a zero.

In the realm of shooter error, Inducing “cant” in the rifle could more than explain a 4” error at 400 yards. Maybe I missed it but I didn’t read anything about the shooter having a level on his optic.


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[madcalfe]

In the realm of shooter error, Inducing “cant” in the rifle could more than explain a 4” error at 400 yards. Maybe I missed it but I didn’t read anything about the shooter having a level on his optic.


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rifle cant would be a left to right and low depending on which side its canted.... not just bang on but 4" low and there would be even less of a drop at 200 yards from a canted sight.

 

[LaHunter]

A scope that will not hold zero or not track true or consistent is a really frustrating problem. I have been there and done that. I chased my tail for too long thinking it was me or other things. Unless the scope just totally 'craps the bed', this can be a tough issue to pinpoint because many times the scope problem is not a consistent problem, which leads to tail chasing. I put a NF SHV on my rifle and that was the cure. The OPs problem could be lots of things, but his scope model has its fair share of 'documented' issues on the interwebs.

 

[wind gypsy]

I always figured Fx1000 and PST g2 were potato/potahto. Both made in phillipines and seen plenty of people claim issues with both.

 

[WRO]

I always figured Fx1000 and PST g2 were potato/potahto. Both made in phillipines and seen plenty of people claim issues with both.

Mine's been very reliable so far. Couple of my buddies have had nothing but success with them. Nikon runs a pretty high QC on even their OEM stuff..

 

[Wrench]

I have more invested in my nikon camera than my truck....but I wouldn't trust another nikon scope if ammo was at 1990 prices.

 

[hereinaz]

I always figured Fx1000 and PST g2 were potato/potahto. Both made in phillipines and seen plenty of people claim issues with both.

The idea that a Nikon is somehow in a different class than a PSTII is strange indeed.

Mine's been very reliable so far. Couple of my buddies have had nothing but success with them. Nikon runs a pretty high QC on even their OEM stuff..

And, this is what thousands of Vortex PST II owners say... can it be true for both of you?

Ultimately, Nikon is out of the rifle optics business anyhow.

 

[Ryan Avery]

If the OP is telling us the truth. It’s the scope!


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[Tumbleweed]

If the OP is telling us the truth. It’s the scope!


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Right? Why do some have to make it so complicated?


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[WRO]

The idea that a Nikon is somehow in a different class than a PSTII is strange indeed.


And, this is what thousands of Vortex PST II owners say... can it be true for both of you?

Ultimately, Nikon is out of the rifle optics business anyhow.

Nikon got out of the scope business because they were concerned it could negatively affect their camera business.

Engineering wise the nikon is ahead of the vortex, I'm not saying it's heads and shoulders better glass wise, but has proven to have more reliable turrets. Neither one I would take on an OIL hunt or even a good tag..

If I wanted a really cheap scope to dial the shit out of it'd be a SWFA.