Shifting Zero on new Long range hunting build

[FatboiZ]

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

 

[kcormack]

Welcome!

This post of yours is a F***king New Gun's question. Scroll down to Long Range Hunting and post it there.

This is the F***king New Guy's section. Easy to confuse the two.

Again, Welcome to Rokslide!

 

[PathFinder]

Buy a scope that isn't trash. So one that doesn't say Vortex on it. Both generations of that optic have so many documented issues it's embarrassing. Get you something mechanically reliable so you can enjoy the new rifle and forget all the issues.

Sent from my SM-G973U using Tapatalk

 

[Wrench]

Guns shoot where scopes tell them to go. You either have a busted mount....or another vortex victim.

 

[gexpro]

I had a vortex PST Gen II and i had major point of impact shifts after 4 shots.
long story short, i got rid of the vortex and went with a NF NX8 and never looked back. i can trust that NX8 with zero question in the back of my mind.

 

[Marbles]

I would have to burn a lot of ammo to trust that scope again, enough that it would be cheaper to get a new scope, send the Viper back to Vortex, then sell it.

If you are eligible for a mil/LE discount it might be worth giving a Vortex Razor a try. I have heard the Razor line is decent. Personally, the only Vortex product I own or have owned is a set of scope caps. The only Vortex product I would consider buying is the Razor 4000 rangefinder.

SWFA SS scopes have a good reputation if you cannot swing Nightforce or S&B money. There are other scopes that work, I just have not ever felt like taking the time and money in ammo to play with them and figure it is easier to stick with what others have learned rather than trying to earn the knowledge myself.

Of course, that makes what I say just an opinion about the opinions of others, so take it with a grain of salt.

 

[FatboiZ]

Well, it confirms what I was dreading and I agree that I would have to burn a lot of ammo to trust this optic again. Any recommendations on another optic?

 

[gexpro]

Well, it confirms what I was dreading and I agree that I would have to burn a lot of ammo to trust this optic again. Any recommendations on another optic?

i suggest alpha-top tier glass if you can afford it. I have been very happy with my Nightforce NX8