UM TIKKA Scope Rings

[Dobermann]

@cueva: I don't have a pic handy, but my ZP5 with UM Tikka rings sits nice and high - not the kind of 'get the objective close to the barrel mount', but closer to 'upright head position'. Not sure if that's helpful; will see how I go for a photo later in the week ... it's a heck of a week, so nudge me if someone else doesn't post one.

 

[CD0311B4]

Where’s the 20moa mount? I’m in.

You beat me to it. I asked about it a couple of weeks ago… they didn’t confirm it for sure but they way I understood it it’s in the works.

I asked SPUHR last year about the 20moa tikka Hunter but he said no

 

[Lawnboi]

You beat me to it. I asked about it a couple of weeks ago… they didn’t confirm it for sure but they way I understood it it’s in the works.

I asked SPUHR last year about the 20moa tikka Hunter but he said no

Spuhr looks like it’s getting rid of all its tikka mounts, I wanted a tall 34mm and they are gone for good.

 

[sportsmans challenge]

@Ryan Avery

Whats your guesstimate on the 20moa tikka rings?

 

[plebe]

Thes are really really nice rings! Incorporating the pins is fantastic. Very well thought out and seem very solid.

Remounted my SWFA HD 3-9x40 and only took about 10 minutes using my laser.

View attachment 610392
View attachment 610393


Scope clearance with a Tikka T3X and McGowen Sporter size barrel. Rings are 30mm Lows. Wouldn’t mind seeing some “extra lows” in the future.

Agreed….

@Unknown Munitions, is there a plan for extra low mounts in 30mm in the future? Thanks.

 

[Oregon Bow Hiker]

Any idea when these will be back in stock in a 30mm low or med?

 

[2-Stix]

There on sale right now.

 

[HighUintas]

Do these return to zero if you take it off of the action and then put it back on? I think I've heard the um guys say it in a podcast, but I'd like to hear some reports of others confirming this

 

[2-Stix]

With a good shooting platform, barrel/action conection to the stock, a scope that holds zero, same weather and elevation, same ammo...it will be very close...if you take a scope mounted with those rings and have proved your zero... the scope and rings off together and put them back on. Not sure if you broke it all apart.

 

[Lawnboi]

Where’s the 20 moa mount?

 

[Oregon Bow Hiker]

Where’s the 20 moa mount?

Did they announce these are happening at some point?


Sent from my iPhone using Tapatalk

 

[Lawnboi]

Did they announce these are happening at some point?


Sent from my iPhone using Tapatalk

It was mentioned in a podcast

 

[HuntHarder]

@Unknown Munitions any idea on 30mm medium's back in stock date? Is the sale still going on?

 

[solarshooter]

Did some searching and haven't seen it asked or answered yet - what's the sensitivity on the UM Tikka Level? IE what does one tick mark correspond to in terms of degrees of cant? The reason I ask is I'm trying to determine how anal I need to be on getting perfectly level. For instance at 600yds, 1deg of cant produces sin(1deg)*3.5mils elevation = 0.06mils windage, so I probably wouldn't sweat being within 1deg. But 5deg produce 0.3mils of windage so I would care a lot about that. @Salmon River Solutions or @Unknown Munitions can you answer?

 

[khuber84]

Did some searching and haven't seen it asked or answered yet - what's the sensitivity on the UM Tikka Level? IE what does one tick mark correspond to in terms of degrees of cant? The reason I ask is I'm trying to determine how anal I need to be on getting perfectly level. For instance at 600yds, 1deg of cant produces sin(1deg)*3.5mils elevation = 0.06mils windage, so I probably wouldn't sweat being within 1deg. But 5deg produce 0.3mils of windage so I would care a lot about that. @Salmon River Solutions or @Unknown Munitions can you answer?

It's less about the windage influence of cant at center of cross hair, but elevation influenced by cant when holding wind with the reticle. The elevation error gets exponentially worse as you start holding more wind at the same value of cant angle.

 

[solarshooter]

Making sure I understand correctly - if I have 1deg of cant, and hold 1 mil wind on the crosshair, I develop sin(1deg)*1mil of elevation error? I don't think that's necessarily "exponential" error, it follows the sin function for cant and linearly scales with wind hold, but I see your point.

But again, in that particular example of 1deg of cant, my total wind hold would be 1mil +/- 0.06mils, and my total elevation hold would be 3.5mils +/- 0.02mils. So I would argue still very much within the noise. At 2 degrees, the errors would be +/-0.12mils on wind and +/-0.03mils on elevation. Obviously if the wind hold were greater, the "cant induced elevation error" would be greater, but 1mil of wind at 600yds is a ~10mph full value wind for my gun, which is pretty significant. So it seems to me that the "cant induced windage error" is still the biggest thing to worry about, since elevation adjustments are typically larger than windage adjustments.

All that being said, I'd still like to know what the hashes on the level correspond to.

 

[solarshooter]

Making sure I understand correctly - if I have 1deg of cant, and hold 1 mil wind on the crosshair, I develop sin(1deg)*1mil of elevation error? I don't think that's necessarily "exponential" error, it follows the sin function for cant and linearly scales with wind hold, but I see your point.

But again, in that particular example of 1deg of cant, my total wind hold would be 1mil +/- 0.06mils, and my total elevation hold would be 3.5mils +/- 0.02mils. So I would argue still very much within the noise. At 2 degrees, the errors would be +/-0.12mils on wind and +/-0.03mils on elevation. Obviously if the wind hold were greater, the "cant induced elevation error" would be greater, but 1mil of wind at 600yds is a ~10mph full value wind for my gun, which is pretty significant. So it seems to me that the "cant induced windage error" is still the biggest thing to worry about, since elevation adjustments are typically larger than windage adjustments.

All that being said, I'd still like to know what the hashes on the level correspond to.

Anyone have input to these questions?

 

[Shortschaf]

Anyone have input to these questions?

You are right.
SIN function will tell you the windage/elevation error caused by the corresponding elevation/windage holds/dials.
Increasing the cant angle increases the error trigonometrically
Increasing the hold/dial increases the error linearly

And yes, generally the elevation hold/dial is greater than the wind hold/dial, so its corresponding error is greater (error will be seen as a windage miss)


To measure the resolution of the bubble level graduations,

1. set the level on top of a straight edge of known length (like a 48" carpenter level for example. You are only using it as a straight edge though, don't worry about what the level's bubble shows. just watch the UM level.)
2. Shim the very outside edges of the straight edge until the UM level shows perfectly centered. This is now your starting point. Don't record the thickness of these shims.
3. Add shims (to either side, doesn't matter), until the UM's bubble is just touching the line. Record the thickness of ADDED shims.

Now the following calc will determine what angle it took to move the UM bubble to the line. Make sure your calculator is set to "degrees" if you want degrees:
TAN^-1(ADDED shim thickness / straight edge length)

A more precise way to do it would be to start with the bubble touching one line, then shim until it touches the other line. Do the same equation, and then divide by 2

 

[solarshooter]

You are right.
SIN function will tell you the windage/elevation error caused by the corresponding elevation/windage holds/dials.
Increasing the cant angle increases the error trigonometrically
Increasing the hold/dial increases the error linearly

And yes, generally the elevation hold/dial is greater than the wind hold/dial, so its corresponding error is greater (error will be seen as a windage miss)


To measure the resolution of the bubble level graduations,

1. set the level on top of a straight edge of known length (like a 48" carpenter level for example. You are only using it as a straight edge though, don't worry about what the level's bubble shows. just watch the UM level.)
2. Shim the very outside edges of the straight edge until the UM level shows perfectly centered. This is now your starting point. Don't record the thickness of these shims.
3. Add shims (to either side, doesn't matter), until the UM's bubble is just touching the line. Record the thickness of ADDED shims.

Now the following calc will determine what angle it took to move the UM bubble to the line. Make sure your calculator is set to "degrees" if you want degrees:
TAN^-1(ADDED shim thickness / straight edge length)

A more precise way to do it would be to start with the bubble touching one line, then shim until it touches the other line. Do the same equation, and then divide by 2

OK yeah good call, I can figure this out experimentally. I was hoping the designers had the numbers available but I'll try and figure it out myself.

 

[Salmon River Solutions]

the bubble level .

.480" OAL
.196" OD
the distance between the lines is .190"
the bubble is .120"

That should be what you need for the math

Ken