scope slipping

[Marshfly]

People need to get over this fear of lapping.

Yes. It’s a fear. It’s irrational. The receiver isn’t perfect. Things aren’t perfect. Even expensive things. You need to make them perfect if the imperfection they have causes an issue.

And they all have some imperfection.

 

[SDHNTR]

Just thought I’d put my experience out there as well. I have around 150 rounds down the barrel of my new 30 nosler and I just noticed the exact same thing as the OP. Very minimal movement, but forward movement nonetheless with a 4-32 NX8 and Hawkins ultralight tactical rings.

I had the scope indexed with paint pens and noticed one of the marks was inside the front ring ever so slightly. When I mounted it up I torqued the ring screws to 25 in/lbs and just like the op none of my bolts have moved (also indexed with paint pens) the scope has just slid forward. Everything was degreased before mounting. I just pulled the scope off with the intent of remounting at a higher torque spec and when I did I saw the impression from the rings on the scope as well as a small bare spot on the inside of the back ring and a matching bare spot on the scope tube.

Has anybody seen the bare spot on a tube or ring before?

OP whats your update on your situation with Hawkins?

Thanks for the help.

What is that adhesive you used? And why? Seems to be very little contact.

 

[Hooskerdrew]

What is that adhesive you used? And why? Seems to be very little contact.

I didn’t use any adhesive on it, just degreased the rings and scope tube and mounted per usual. Not sure why the markings are that color.

 

[mgray]

I had a scope slip on a .375 Ruger. It ended up damaging the power changing ring. I used rosin powder the next time and had no issues. I always felt like rosin was cheating, or taking the easy way out, but it’s worked for me.

 

[SDHNTR]

I didn’t use any adhesive on it, just degreased the rings and scope tube and mounted per usual. Not sure why the markings are that color.

Hmm. Something looks odd about those pics then.

 

[Hooskerdrew]

Hmm. Something looks odd about those pics then.

I’m right there with you. It’s my first NF scope, and the finish on it definitely seems pretty resistant to scratches or scuffs, so the coloration/marks has me curious as well. And I don’t know if that’s normal for the finish on them after mounting or not

 

[Hooskerdrew]

Hmm. Something looks odd about those pics then.

I forgot to mention it but while running my finger along the marks you can actually feel anything, like an indent or something of the like. It’s just visual

 

[RockAndSage]

Just thought I’d put my experience out there as well. I have around 150 rounds down the barrel of my new 30 nosler and I just noticed the exact same thing as the OP. Very minimal movement, but forward movement nonetheless with a 4-32 NX8 and Hawkins ultralight tactical rings.

I had the scope indexed with paint pens and noticed one of the marks was inside the front ring ever so slightly. When I mounted it up I torqued the ring screws to 25 in/lbs and just like the op none of my bolts have moved (also indexed with paint pens) the scope has just slid forward. Everything was degreased before mounting. I just pulled the scope off with the intent of remounting at a higher torque spec and when I did I saw the impression from the rings on the scope as well as a small bare spot on the inside of the back ring and a matching bare spot on the scope tube.

Has anybody seen the bare spot on a tube or ring before?

OP whats your update on your situation with Hawkins?

Thanks for the help.

This is exactly what can happen when scope rings are not lapped properly - what you are seeing is what happens when the contact points are not uniform between the rings and the scope. From the little that I can see from these photos, here's what I can offer:

- Indentations on scope tubes can and do occur when you have proper torque, when those pressures are put on a much smaller surface area than the rings are designed for, which is exactly what happens when rings are not lapped. The sides are just not perfectly parallel with the tube, and more pressure is applied to a smaller area. The effect is similar to how much more damage will be done to your foot if a woman steps on it in high heels vs flats.

- The rough surfaces of most scopes reduce overall surface contact, as there's just less of the scope tube in contact with the rings than if those tubes were smooth. Microscopically, it looks like a mountain range. It may feel like it has more 'friction' being rough, but those metal asperities (the peaks and valleys of the metal surface) are what have broken off in the photo. The peaks have literally been removed where the bare aluminum appears. This is minimized by maximum surface contact with the scope rings. But if rings are out of alignment it can enhance this wear through a type of friction wear called fretting (think vibratory rubbing and the wear it produces).

- The strange coloring that looks like adhesive is likely, at least partially, the result of rub-wear/fretting and the oxidized aluminum dust that wear produces.

- Look closely and you can also see pinpoint spots of greater wear, a couple of which almost look like pitting. That can be fretting on a high spot, but it can also be the result, possibly, of some of that oxidized aluminum being aluminum oxide, which is much harder than the aluminum substrate. When you scratch bare aluminum it oxidizes pretty quickly, but that aluminum oxide is very hard. With fretting, once it starts it can start accumulating and, essentially it turns into an abrasive. A couple of pieces of that grit in a fretting/vibrating situation can cause pitting.

- The strange wave-like patterns may also be an indicator of fretting, with the vibratory oscillations causing that wear pattern.

 

[SDHNTR]

What receiver is that? Does it have an integral rail or a removable one?

 

[Hooskerdrew]

This is exactly what can happen when scope rings are not lapped properly - what you are seeing is what happens when the contact points are not uniform between the rings and the scope. From the little that I can see from these photos, here's what I can offer:

- Indentations on scope tubes can and do occur when you have proper torque, when those pressures are put on a much smaller surface area than the rings are designed for, which is exactly what happens when rings are not lapped. The sides are just not perfectly parallel with the tube, and more pressure is applied to a smaller area. The effect is similar to how much more damage will be done to your foot if a woman steps on it in high heels vs flats.

- The rough surfaces of most scopes reduce overall surface contact, as there's just less of the scope tube in contact with the rings than if those tubes were smooth. Microscopically, it looks like a mountain range. It may feel like it has more 'friction' being rough, but those metal asperities (the peaks and valleys of the metal surface) are what have broken off in the photo. The peaks have literally been removed where the bare aluminum appears. This is minimized by maximum surface contact with the scope rings. But if rings are out of alignment it can enhance this wear through a type of friction wear called fretting (think vibratory rubbing and the wear it produces).

- The strange coloring that looks like adhesive is likely, at least partially, the result of rub-wear/fretting and the oxidized aluminum dust that wear produces.

- Look closely and you can also see pinpoint spots of greater wear, a couple of which almost look like pitting. That can be fretting on a high spot, but it can also be the result, possibly, of some of that oxidized aluminum being aluminum oxide, which is much harder than the aluminum substrate. When you scratch bare aluminum it oxidizes pretty quickly, but that aluminum oxide is very hard. With fretting, once it starts it can start accumulating and, essentially it turns into an abrasive. A couple of pieces of that grit in a fretting/vibrating situation can cause pitting.

- The strange wave-like patterns may also be an indicator of fretting, with the vibratory oscillations causing that wear pattern.

Copy that! That’s all great info. Thanks for the help.

 

[Hooskerdrew]

What receiver is that? Does it have an integral rail or a removable one?

Kelbly Nanook, its integral

 

[Mike D Texas]

I suspect your rings are the issue. I run a 5-25 ATACR on a 338 Norma Mag Improved shooting 300 grain bullets. It’s mounted with Nightforce Ultralight 4 screw rings and it’s never slipped once.


Sent from my iPad using Tapatalk Pro

 

[SDHNTR]

Kelbly Nanook, its integral

Odd. Highly unlikely the receiver isn’t true. I’d be chatting up Hawkins.

 

[Hooskerdrew]

I suspect your rings are the issue. I run a 5-25 ATACR on a 338 Norma Mag Improved shooting 300 grain bullets. It’s mounted with Nightforce Ultralight 4 screw rings and it’s never slipped once.


Sent from my iPad using Tapatalk Pro

Thanks for the help. I’m feeling the same way.

 

[Hooskerdrew]

Odd. Highly unlikely the receiver isn’t true. I’d be chatting up Hawkins.

I agree with you, my email is already in with them. Of course this stuff always happens on the weekend when they are closed.. haha.

 

[HawkinsPrecision]

Please note this is not a common issue we see and we are working with these folks to get their situations resolved. Our manufacturing process allows users to mount up their optics and run with them. So this is very uncommon.

 

[Hooskerdrew]

Please note this is not a common issue we see and we are working with these folks to get their situations resolved. Our manufacturing process allows users to mount up their optics and run with them. So this is very uncommon.

Thanks Nick! They are getting me taken care of.

 

[SloppyJ]

Please note this is not a common issue we see and we are working with these folks to get their situations resolved. Our manufacturing process allows users to mount up their optics and run with them. So this is very uncommon.

Legit response and way to get ahead of it. I run a set on my 300prc with a NX8 and so far so good with witness marks.

 

[burbank]

Any good videos out there on the lapping process?