Question Regarding Pinned vs Unpinned Picatinny Rails

[ajmott1992]

I am running a Vortex SE 5-25x56 scope (2 lb scope) on a Tikka T3x chambered in 30-06. I'm using a picatinny rail as a scope base that is pinned with one 3mm stainless steel pin and four 6-42 screws. I have heard that heavy recoiling rifles running heavy scopes require a pinned picatinny rail, else your rail isn't secure. Is one 3mm pin enough for the recoil of a 30-06 rifle running a a 2 lb scope?

The Tikka T3x is drilled to accept two 3mm pins and one larger pin. I don't know why the mfr of my picatinny scope base designed the base for only one 3mm pin, unless that is enough to secure the picatinny rail. For reference, the Tikka T3x CTR uses a picatinny base with two 3mm pins.

 

[Macintosh]

If worried about it you could epoxy the rail too. Or, a set of UM rings pin directly to the action eliminating the rail entirely—thats probably the “most correct” answer from that perspective.

 

[ResearchinStuff]

i'd put an adhesive under the rail and not stress too much more about it. jb weld, loctite 380, etc.

 

[ajmott1992]

If worried about it you could epoxy the rail too. Or, a set of UM rings pin directly to the action eliminating the rail entirely—thats probably the “most correct” answer from that perspective.

The rail mfr recommended against bedding the rail with epoxy. I did use blue loctite as a film barrier. I want the 20 moa base for practicing out to longer ranges (1000 yards). I think the one pin would be fine under normal conditions, but in my case I'm running a heavy scope so I feel like I'm on the fence especially if I run hotter heavier loads.

 

[ajmott1992]

i'd put an adhesive under the rail and not stress too much more about it. jb weld, loctite 380, etc.

Thanks. Yeh I stress too much. I used a thin film of blue loctite between the rail and receiver.

 

[ResearchinStuff]

well, i wouldn't feel good about blue loctite in that application

 

[ajmott1992]

well, i wouldn't feel good about blue loctite in that application

well alrighty then.

 

[Macintosh]

Not sure what ammo you are shooting, but a quick plug into the hornady calculator for their 168 eldm match ammo says your 1000 yd elevation should be in the neighborhood of 10 mils. On a 32 mil scope you should have roughly half of that available—you’d have plenty of elevation travel to hit 1000 yards with a flat rail. Maybe not with some lower BC bullets, but at least it would be very realistic for some. You could plug in your preferred ammo and see where it leaves you, but you should have at least 13-14 mils or more of useable travel to play with before you need a elevated rail.

 

[ajmott1992]

Not sure what ammo you are shooting, but a quick plug into the hornady calculator for their 168 eldm match ammo says your 1000 yd elevation should be in the neighborhood of 10 mils. On a 32 mil scope you should have roughly half of that available—you’d have plenty of elevation travel to hit 1000 yards with a flat rail. Maybe not with some lower BC bullets, but at least it would be very realistic for some. You could plug in your preferred ammo and see where it leaves you, but you should have at least 13-14 mils or more of useable travel to play with before you need a elevated rail.

In hindsight maybe. I've taken the path of running a 20MOA rail with Mountain Tech rings and am not planning to switch. This setup allows me to take full advantage of my scope's potential and get a true back-to-zero for swapping my scope between picatinny rifles. A lot of this gear I got for a killer deal too. I appreciate your input tho.

 

[BLJ]

well, i wouldn't feel good about blue loctite in that application

Curious as to why? Thanks.

 

[ajmott1992]

Curious as to why? Thanks.

He's probably referring to blue loctite not being a strong adhesive between two flush metal surfaces. I consulted Loctite directly and their product is designed to double up as a film barrier between metal surfaces to keep moisture out and prevent corrosion. It may provide a little adhesion, but shouldn't be used as a primary adhesive in that use-case. A much better option would be to use actual epoxy or a surface-to-surface glue (loctite 380 is a real surface-to-surface glue). I was not using the loctite for adhesion, but rather to just film the mating surfaces to prevent corrosion.

 

[BLJ]

I’ve done the same thing before. Not a huge difference, but is noticeable when trying to remove the rail.
Can’t hurt for keeping moisture out as well. Thanks.

 

[SloppyJ]

Marinetex that bitch on there and then put your four screws in to make you feel better. She ain't coming off and now it's bedded.

 

[ResearchinStuff]

Curious as to why? Thanks.

https://dm.henkel-dam.com/is/content/henkel/TDS-209728-US-Loctite-Threadlocker-Blue-242-Carded-Tube-0.20-fl-oz-2018-04-09pdf

it's not a real adhesive. If you put jb weld in there, you can take the screws out and it will take some whacks with a hammer, or heating it up a couple hundred degrees to get it loose.

 

[BLJ]

https://dm.henkel-dam.com/is/content/henkel/TDS-209728-US-Loctite-Threadlocker-Blue-242-Carded-Tube-0.20-fl-oz-2018-04-09pdf

it's not a real adhesive. If you put jb weld in there, you can take the screws out and it will take some whacks with a hammer, or heating it up a couple hundred degrees to get it loose.

Thanks for the link. Interesting for sure.

I reread the original exchange between you and the OP and what I read and what made it to my brain were two different things.

 

[Shortschaf]

The shear strength of that pin is well north of 1000 pounds. If it's a tight fit it is more than sufficient to take load off the screws.

Bedding the rail is still a good practice and will only help the repeatability of your rifle

 

[ddowning]

https://dm.henkel-dam.com/is/content/henkel/TDS-209728-US-Loctite-Threadlocker-Blue-242-Carded-Tube-0.20-fl-oz-2018-04-09pdf

it's not a real adhesive. If you put jb weld in there, you can take the screws out and it will take some whacks with a hammer, or heating it up a couple hundred degrees to get it loose.

I used to call coyotes on an old farmers land that hunted with an old ithica 16 gauge slug gun. He had a pic rail on it to mount the scope. I asked him who did the work and he said he just jb welded the rail on there. It withstood the recoil for over 20 years before Iowa allowed straight walled cartridge rifles and he stopped using it. There are a bunch of stories (from others, not him) that he hardly ever missed a shot with that gun. There were zero screws. It must work pretty well.