Rifle Scopes Loss of zero after hard impacts ?

[deersniper]

What causes rifle scope combos to lose zero after hard impacts ?

Was at a ice match a few weeks ago, one guy with a ZCO 527 on a generic PRS special lost his footing. Rifle ended up being .5 mil off on windage. I also fell at the end trying to carry too much crap. Bottom of rifle took impact. Was .3-.4 off on windage with a ZCO420 / atx.

 

[Mudflap621]

Mounts moving along rail or scope tube slipping seem like likely culprits.

 

[deersniper]

Spuhr mounts also.

 

[BLKWLFK9]

Shit happens. The zco is one of the best scopes in the world and can still be knocked out of zero. Im sure it will be by some but this should not be a "knock" on the quality/durability of the scope itself. This can happen to any scope. Tt, zco, Nf, s&b, etc. You should always check zero of any optic after it takes a tumble.

 

[Gohring65]

I had a LOW made weaver tactical take a hard fall, the turret had moved where the clicks were in between the hash marks, a few years later it took another hit and the turrets were knocked back to the hash marks.
If it happens again just slam it down again chances are it’ll fix it. Slam it hard though.

 

[Ksracer]

Was there a switchlug or similar quick change device on the barrel?

 

[smoothy8500]

I think it's a valid question. Is it scope/rings/mounts slipping? Or is it internally such as the erector slipping?

 

[Gohring65]

I think it's a valid question. Is it scope/rings/mounts slipping? Or is it internally such as the erector slipping?

Too many variables to pinpoint without a controlled test.
Could be one of those things, could be all of those things.

 

[deersniper]

Was there a switchlug or similar quick change device on the barrel?

The atx is quick change but I snug it tight with a wrench and the screw that clam shells the barrel threads gets 68 pounds

 

[Ksracer]

Did you try exercising the turrets to see if the erector tube would go back to the previously zero'd position?

I've completely disassembled rifles and had less shift than that on re-assembly. If it was mine, I would completely disassemble and retorque everything. Whatever got knocked around isn't in it's "home" position and is likely to shift back to where it is supposed to be the next match out.

 

[Reload10]

Action rail, scope mount, actual bending of optic.

@deersniper the best way to test would be like the nightforce protocol with collimation tube. Would eliminate all variables except for the optic, like you're asking.

 

[ma smith]

Side loading on rifle scopes seems to be the most difficult type of shock to retain zero on.

 

[Secant]

Internal movements within scope.
Scope movement relative to rings.
Ring movement relative to rail.
Rail movement relative to action.
Action movement relative to chassis.
Barrel relative to action.
Muzzle device movement
Chassis damage causing contact/stress.
Barrel damage
Combination of above.

On the internet it’s always the scope. Unless we’re talking about NF, then the person posting is a liar. Just kidding. Sort of.

 

[Basic user]

Dam, even vortex can take a hit and keep a zero lol

 

[NWnewguy]

It could also be shifting of the rifle in the stock. Especially if it's a chassis or stock with a bedding block.

 

[Lunchbox27]

I had a LOW made weaver tactical take a hard fall, the turret had moved where the clicks were in between the hash marks, a few years later it took another hit and the turrets were knocked back to the hash marks.
If it happens again just slam it down again chances are it’ll fix it. Slam it hard though.

Am I the only one who read this and thought of Christmas Vacation and the Ruby Sue “omg… her eyes aren’t crossed anymore”?

 

[Secant]

Am I the only one who read this and thought of Christmas Vacation and the Ruby Sue “omg… her eyes aren’t crossed anymore”?

Nope. I was gonna grab a YT clip of that and respond

 

[chevy_man]

Run the Scopes through a tracking test. Smack them on a phone book and test again.


Send them in for a check-up if you can spare it for the time.

 

[CSTactical]

What causes rifle scope combos to lose zero after hard impacts ?

Was at a ice match a few weeks ago, one guy with a ZCO 527 on a generic PRS special lost his footing. Rifle ended up being .5 mil off on windage. I also fell at the end trying to carry too much crap. Bottom of rifle took impact. Was .3-.4 off on windage with a ZCO420 / atx.

It is more than likely the ring/mount base interface and not anything internal to the scope. ZCO, TT and NTF does quite a bit of impact testing on their scopes. Have you done that kind of impact testing on your assembled rifle and tested it? I doubt anyone has or needs too. Regardless of it being a Spuhr or XYZ Alpha mount they are not meant to take impacts to them and hold zero which is why no manufacturer I know advertises such a thing.

 

[CSTactical]

Internal movements within scope.
Scope movement relative to rings.
Ring movement relative to rail.
Rail movement relative to action.
Action movement relative to chassis.
Barrel relative to action.
Muzzle device movement
Chassis damage causing contact/stress.
Barrel damage
Combination of above.

On the internet it’s always the scope. Unless we’re talking about NF, then the person posting is a liar. Just kidding. Sort of.

Exactly, there are so many variables, it's best to re-torque, re-zero and than see if things are not working consistently. Then narrow it down from there...

 

[silentwoods]

What causes rifle scope combos to lose zero after hard impacts ?

Was at a ice match a few weeks ago, one guy with a ZCO 527 on a generic PRS special lost his footing. Rifle ended up being .5 mil off on windage. I also fell at the end trying to carry too much crap. Bottom of rifle took impact. Was .3-.4 off on windage with a ZCO420 / atx.

I was crossing a running creek recently at night wearing nv goggles. Dual tubes so no excuse from me about depth perception.

MY DD mk18 smacked into large rocks, busted my knee, the metal one, but I went ahead with my hunt. Nothing to shoot that night.

The next day I checked zero, ACOG TA31H, it was off 1 click windage@50 yrds, elevation was fine.

I almost puked when I heard it hit.

Edited: typo