Light rifles, big cartridges, and scope mounts - learned my lesson, now it's time to pass it on.

[codyadams]

I suspect that your problem was the frictionless fit between the scope and rings. Bedding the rings and polishing the scope tube reduced the friction between the two.

Most rifle chambers are finished to 16 line per inch smoothness so that cartridge case will stick to the chamber, any smoother and the bolt lugs will take a beating because the case will slip and put up to twice the amount of pressure on the lugs.

Before you make all of those changes try roughing the bedding a little and test a few rounds after reinstalling the scope. You won't need much roughness, make a slightly crosshatch pattern using a 600 grit wet dry Emory cloth.

I did clean all the shoe polish off the tube and got it down to the factory finish prior to reassembly, as well as cleaned up any remaining polish from the devcon itself, however your concept makes sense. But people like Ryan Pierce and other very smart rifle builders bed their rings religiously, and never have issues, so I figured that bedding the rings would be the ticket. I may reach out to him about his ring bedding process, if he would be willing to share. Bottom line, there wasn't enough grip. Something as simple as going 25 in-lbs vs 20 may have been enough to keep the scope in place, or roughing up the surface slightly, but on such an expensive optic, I didn't want to take the chance of possibly damaging it by over torquing, I do not know where the max is as it isn't openly stated in the manual, so I wanted to stay safe. If 20 in-lbs on that much surface area doesn't hold it, then I will simply increase the surface area.

I will also say that even though the devcon was slick, the grip it gave on the tube was outstanding. When I initially tightened it down, just using an Allen key and rolling it in my fingers to tighten the screws for all 8 screws, not even grabbing the short end and adding any torque, was enough to prevent me from being able to turn or push the optic forward or back. The screws had to nearly be loose to move the scope, the grip was so good. That is why I was so shocked it moved! I have used the Burris signature rings and their smooth poly inserts have almost as much grip, but like I said, I could push the scope down into the bases and nearly lift the rifle up without the ring top caps being installed, the fit was that good. I'm still blown away it wasn't enough, so my solution is maximum possible grip.

 

[hunterdan]

Tagging In. Good information thread. I wonder if something like the ARC m10 rings with the high torque value would have helped in a situation like this?

 

[bozoben]

You're making me think now... I've got an 11ish pound 338 rum with 1 piece tally ring/bases. Seamed to work just fine with my previous viper. However I just bought an nxs thats 10 oz heavier. Wonder if I should look into getting set up with a rail and heavier rings......

 

[codyadams]

You're making me think now... I've got an 11ish pound 338 rum with 1 piece tally ring/bases. Seamed to work just fine with my previous viper. However I just bought an nxs thats 10 oz heavier. Wonder if I should look into getting set up with a rail and heavier rings......

At a minimum, I would make some form of a reference mark so you could monitor it. You may not have any issues, but I would at least keep an eye on it.

 

[bozoben]

At a minimum, I would make some form of a reference mark so you could monitor it at a minimum. You may not have any issues, but I would at least keep an eye on it.

That's a good idea. Maybe I'll do that to begin with before I go drop $400 on heavy rings and a base.

 

[Northkill]

I've got double NF rings on my K525i on a 7 Allen Mag (Kirby built) - no issues so far. But this gun with his brake gives a recoil impulse with negative g's that would destroy a mediocre scope.

 

[Deleted member 48126]

I use seekins precision match rings. I just torque everything to spec. OP, That's a crazy amount of detail to make sure a scope doesn't move. You got me worried about my rifles now....

 

[codyadams]

I use seekins precision match rings. I just torque everything to spec. OP, That's a crazy amount of detail to make sure a scope doesn't move. You got me worried about my rifles now....

I p.m.'ed Kirby Allen earlier today, and his response makes me want to go through several of my lesser rifles and beef up their mounting situation! On a different note, he sure is an extremely generous man with his knowledge, if your reading this, thank you for your insight sir. Greatly appreciated!

 

[Deleted member 48126]

I p.m.'ed Kirby Allen earlier today, and his response makes me want to go through several of my lesser rifles and beef up their mounting situation! On a different note, he sure is an extremely generous man with his knowledge, if your reading this, thank you for your insight sir. Greatly appreciated!

Yeah I asked for help on a .338 LM build and he blew me away with his response. Wasn't expecting that dissertation. The man is absolutely awesome.

I only shoot .308 family and below cartridges bc I don't really have anywhere to go 1000+ yards. But regardless, I'm going to double check all my rifles. I have nice rings and bases on all them, but after reading what you do, I feel like my scopes are mounted with elmers glue and rubber bands!

 

[HARPERC]

I can't recall which one, but one of the tactical scope is marked to keep track of slippage. So not just us.

We used to be cautioned about scopes on air rifles, forward motion being different than recoil.

JE's video's have made me wonder what effect modern brakes have on the guts of our optics.

When we look at the forces involved, the advances in scope construction, and design its really amazing.

 

[HARPERC]

My first thought mounting my 5-25x ATACR solidly, was it looks like a plumbing project, but its travelled well, and shot well ever since. No bobbles.

 

[Wedgy]

We used to be cautioned about scopes on air rifles, forward motion being different than recoil.

Not air rifles but the break action piston driven ones, they have a small conventional recoil but when the piston hits the stop it then has a forward recoil, like a muzzle brake, that can destroy scopes not rated for this type of gun.

 

[codyadams]

Not air rifles but the break action piston driven ones, they have a small conventional recoil but when the piston hits the stop it then has a forward recoil, like a muzzle brake, that can destroy scopes not rated for this type of gun.

Absolutely, when I was a little tike shooting a Norinco .177 break barrel springer at starlings, I saw a reticle from a Walmart bushnell strait up snap, and another fell out of place. After that I got another cheapo scope, but was specifically designed for air rifles, and it held up. Now I avoid that issue, I just use pcp air rifles ha ha.

But to greatly summarize what Kirby said, what needs to be done on a firearm like this, is to use a full length rail, #8 or larger screws, pinned in place with 2-4 pins, and use at least 3, 4 being better, high quality scope rings, he prefers the Nightforce extreme duty rings, with two pushed forward against the rail lugs, and two pushed to the rear. I have #8 screws, and plan on doing everything else he advised. I'm thinking this should make a heck of a difference. Now I'm excited to see how my rifle performs once I get everything put together!!

 

[codyadams]

Yeah I asked for help on a .338 LM build and he blew me away with his response. Wasn't expecting that dissertation. The man is absolutely awesome.

I only shoot .308 family and below cartridges bc I don't really have anywhere to go 1000+ yards. But regardless, I'm going to double check all my rifles. I have nice rings and bases on all them, but after reading what you do, I feel like my scopes are mounted with elmers glue and rubber bands!

Ya, my 14 lb braked .260 AI has a bedded full length rail, then just two cheapish 6 screw rings on it torqued with blue lok-tite on all screws, and it is 100% consistent on that gun. Bedding the base on that rifle was more to ensure that there wasn't a bend in the rail induced by an imperfect Remington receiver, but I did not use release, they are easy to pop off even without, so it also added some strength to the system I'm sure. My son could shoot that rifle when he was 5 years old though, recoil is almost non existent. Even before I had the brake on, I could spot pretty much all my shots, unless I was in a really awkward position, so recoil is very modest. I think anything magnum status from here on out is gonna get the works on my rifles.....this sucks lol I'm just glad I didn't figure it out on my Wyoming mountain goat hunt coming up this fall.....