Chasing my tail with 100 yard zero

[Pdvdh]

Scope failure can be sudden/catastrophic, so that the problem is quickly apparent. Personally have had two of these.

The more insidious mode of scope failures cause less obvious, yet chronic problems. The scope continues to function well enough that it's not apparent the scope is sick/broken. The rifle can shift POI, yet turret adjustments are still functional enough to re-zero the rifle. And then the POI again drifts a little without warning. Good for a few more shots, and then the next time out the POI is again shifted. I've had several of these scopes. Each one deserved to burn in hell.

I offer this: if your rifle's proven accuracy begins to deteriorate, such as 3/4" groups begin averaging 1 1/2", in combination with slight changes in POI,... these were symptoms of my sick scopes. After eliminating loose screws, mounts, action screws, scope slippage in the rings, and everything else that comes to mind - if these symptoms persist, pull the scope are try another of proven quality.

 

[D.Camilleri]

Thanks guys,
I am going to take the VXIII 6.5-20 off of my 300 rum and put it on. I might also give sightron a call today. I can't find a single thing that is moving and the last thing I did to rule out movement was to bed the recoil lug. It is now tight, the pillar bed doesn't show any signs of movement either. Whatever this phantom problem is, it always seems to be 1 moa vertical movement from a know zero after dialing for a shot. My gut tells me the scope is at fault, but boy have I wasted a lot of time and money chasing this problem.

 

[Timber338]

I finally wrote up a thread on how I have been testing out my scopes. Doing something like this with your Sightron might reveal a problem. Although if the problem is in the scope, it might be from the mechanism shifting under recoil, which would not show up testing your scope this way. Either way you would accurately determine the correction coefficient for your scope turrets, and it might show that the turrets do not return to zero.

I would use your scopes current zero as the starting point for the test.

http://www.longrangehunting.com/forums/f18/scope-turret-reticle-performance-testing-167993/

 

[D.Camilleri]

Good idea! I have my Sightron boxed up and ready to be shipped back for them to check out. Recoil has to be the best idea I have heard mentioned. Maybe too many rounds fired using the lead sled......................If I get a chance tonight, I am going to put the leupold 6.5 to 20 on the 338 rum and see what happens.

 

[Timber338]

I think you are right that shooting from a lead sled can really punish a scope, and I believe that a muzzle brake is also very hard on a scope. I don't remember if you have a brake on your rifle or not. Good luck with figuring this all out, definitely curious to hear how it all pans out.

 

[bigngreen]

Leadsleds are hard on everything on a heavy hitting rifle, IMO their straight from the devil!!

 

[D.Camilleri]

Leadsleds are hard on everything on a heavy hitting rifle, IMO their straight from the devil!!

I would have to agree with you on that, but all of the sudden I have a fair amount of pain in my left shoulder so the lead sled is helping me not become unable to shoot. I don't use much weight on my lead sled, so it is able to move fairly easy across the plastic topped shooting bench, but I have been trying to remove as much of me from this equation also. As soon as this problem is figured out, I am back to non lead sled shooting.

Timber, I do have a brake on my gun, but I am not sure how that can effect a scope. My gun used to eat rings and bases for lunch before I put a brake on it.

 

[bigngreen]

Brakes are hard on optics, the sudden reverse recoil can really gutt them, the same recoil that was munching your gear without the brake could be doing the same just in the opposite direction now especially on lighter rifles with shorter barrels because you have better brake function. I haven't had a SIII go down on any of out bigger 338's but I have seen Leupolds eaten and spit out frequently.

 

[Pdvdh]

Brakes are hard on optics, the sudden reverse recoil can really gut them, the same recoil that was munching your gear without the brake could be doing the same just in the opposite direction now especially on lighter rifles with shorter barrels because you have better brake function. I haven't had a SIII go down on any of out bigger 338's but I have seen Leupolds eaten and spit out frequently.

Absolutely. Some scope designs handle tremendous recoil without a muzzle brake. However some will not tolerate reverse recoil that muzzle brakes cause, without coming unglued.

Piston driven air rifles, such as the RWS air rifles, eat scopes for lunch and dinner - if the scopes have not been designed to survive the reverse recoil caused by the sudden deceleration of the heavy piston. I once put a Bushnell ScopeChief IV on my RWS air rifle after it had been used with no problems on my .338 Win Mag. The ScopeChief IV was one of Bushnell's high-end scopes when I purchased it in the early 1970s. It lasted about 3 shots mounted on the RWS.

 

[D.Camilleri]

Brakes are hard on optics, the sudden reverse recoil can really gutt them, the same recoil that was munching your gear without the brake could be doing the same just in the opposite direction now especially on lighter rifles with shorter barrels because you have better brake function. I haven't had a SIII go down on any of out bigger 338's but I have seen Leupolds eaten and spit out frequently.

Now you have me worried how long my leupold will last on this gun. What are the symptoms that the leupolds exhibited when they went south?

I am going to try and slip out to the range in the morning and see how the gun shoots with the leupold. The big question will be dialing a shot, returning to zero and see if the zero stays on the next outing. I am truly hoping Sightron finds something wrong with the scope I sent in and fixes it. The turrets on that scope have always seemed to be to easy to move, maybe the springs are weak.

 

[bigngreen]

My buddies MK4 locks up in the turrets when it fails, it makes it most of a hunting season then he sends it back most every year, I lend him a Vortex when it dies, he was eyeballing my NF SHV the last time but I ain't lending that!!

 

[sp6x6]

My buddies MK4 locks up in the turrets when it fails, it makes it most of a hunting season then he sends it back most every year, I lend him a Vortex when it dies, he was eyeballing my NF SHV the last time but I ain't lending that!!

Whats he shooting? My Mark 4 has seen 100's of shoots on a braked 7-2oz 338 NM, have a old first tactical 3 they made been 10-15 yrs on a braked 340 wby no problems,also have one on a light 325wsm.

 

[Timber338]

So far my VX6 is holding up after about 400 rounds through my 7lb 14oz 338 RUM that has a 4-port muscle brake. And the vast majority of those rounds are shooting a 300 grain bullet... time will tell how durable this scope is.

 

[bigngreen]

I pretty much won't use any new Leupold optic, my buddies is on a lowly 300 WSM but they keep fixing it for free and he does not feel right about selling it so it stays. I've seen three VX6 scopes get sent back, fixed and then promptly sold in the last year, each one ended up at my shop because it was either I find the issue or install new barrels. I no longer have any Leupolds left which is sad IMO.