How much clearance between the rail and the optic is needed?

[Jayne]

I'm always trying to mount optics as low as possible, and with this latest setup I think I've hit the lower bound. With the vortex rings the optic on this 300BLK is sitting damn near touching the rail:



I can break out some feeler gauges to know exactly how much clearance there is, but what's the lower bound? Does the pic rail flex during recoil or anything and would it smack into the base of the optic?

It at least looks pretty sharp on there, and with the stock pack with no padding it's a perfect fit for me in terms of elevation and eye box.



And yes @Sasquatch I'm trying 300BLK again. When I'm cranky with the sub-par subsonic accuracy of this one I'll let you know.

 

[Supermatch]

Unless your rings are shimmed with something flexible, you should not see any movement of the bell in relation to the receiver/rail unless your rings are absolute trash. Not with .300 blk, a shorter barrel with no whip, and two piece rings.

 

[Tim]

With GOOD quality mount/rings then as close as possible without touching is fine. If the mount/rings were questionable I’d throw them out go with a bit more clearance.

Vortex rings are good to go.

 

[Jayne]

With GOOD quality mount/rings then as close as possible without touching is fine. If the mount/rings were questionable I’d throw them out go with a bit more clearance.

Vortex rings are good to go.

They're the vortex 'hunter' rings and the base is the OEM unit from CVA.

 

[Jayne]

Unless your rings are shimmed with something flexible, you should not see any movement of the bell in relation to the receiver/rail unless your rings are absolute trash. Not with .300 blk, a shorter barrel with no whip, and two piece rings.

It's not the optic bell that's down there, that's the center of the optic where the adjustments are.

 

[Supermatch]

It's not the optic bell that's down there, that's the center of the optic where the adjustments are.

I'd have even less concern for that area, since that's the stiffest point in the chain (between rings, supported by rail and receiver). You have the most support there in a sinusoidal reaction.

 

[Gnash.Hyena]

I like to do the "paper test." If only one sheet of looseleaf printer paper can fit between the scope and rail, it's too close. If two sheets of paper can fit between the scope and rail, that's about right.

 

[Tim]

Id be more concerned about head position.

 

[Jayne]

Id be more concerned about head position.

Mine in relation to the optic?

 

[Tim]

Mine in relation to the optic?

Yup

But that’s a highly subjective personal preference thing.

 

[Jayne]

I like to do the "paper test." If only one sheet of looseleaf printer paper can fit between the scope and rail, it's too close. If two sheets of paper can fit between the scope and rail, that's about right.

gauges say 0.02" so with google saying paper is 0.004" I should be good per your test.

 

[Jayne]

Yup

But that’s a highly subjective personal preference thing.

It's in the right spot for me, pretty happy with it right there. It's a 1-8x so it's pretty forgiving. I've learned my lesson putting even 4-14x optics on 300BLK, it makes me think it's more accurate than it is.

 

[RR]

I like to do the "paper test." If only one sheet of looseleaf printer paper can fit between the scope and rail, it's too close. If two sheets of paper can fit between the scope and rail, that's about right.

I use a business card but same principle. Business card fits, we are good. Doesn't fit, we aren't.

 

[RR]

I'm always trying to mount optics as low as possible, and with this latest setup I think I've hit the lower bound. With the vortex rings the optic on this 300BLK is sitting damn near touching the rail:

View attachment 667681

I can break out some feeler gauges to know exactly how much clearance there is, but what's the lower bound? Does the pic rail flex during recoil or anything and would it smack into the base of the optic?

It at least looks pretty sharp on there, and with the stock pack with no padding it's a perfect fit for me in terms of elevation and eye box.

View attachment 667682

And yes @Sasquatch I'm trying 300BLK again. When I'm cranky with the sub-par subsonic accuracy of this one I'll let you know.

One of my absolute favorite rifles in the safe. I bought it for my youngest boy to use and he took his first deer with it two years ago. But on days he doesn't want to hunt I often "borrow" it.

 

[Jayne]

I use a business card but same principle. Business card fits, we are good. Doesn't fit, we aren't.

Standard business card is 0.014", so another test passed.

Guess I need to get some loads made up and just shoot it.

 

[Sasquatch]

And yes @Sasquatch I'm trying 300BLK again. When I'm cranky with the sub-par subsonic accuracy of this one I'll let you know.

Looks sweet- and yes, like 300 BLK!

I have some really nice subsonic loads using Sub-X. 12 grains of CFE BLK, 2.065 COAL.

I still can't get cheap coated stuff to group, though I can get speeds just about perfect.

 

[Get Off My Lawn]

It's in the right spot for me, pretty happy with it right there. It's a 1-8x so it's pretty forgiving. I've learned my lesson putting even 4-14x optics on 300BLK, it makes me think it's more accurate than it is.

After Billy & Michael458 went on about the 100g Raptors, I tried some. I was shocked how tight the 175 yrd group was. Hornady & Speers do not group that well.