SM and UM Tikka rings

[dirtytough]

I threw a UM ring on a rail that had an SM ring already mounted to compare the height. I noticed the UM ring was offset from the SM ring. After a little testing it looks like the UM rings are machined off center.

I’m surprised it’s the UM ring and not the SM.

 

[FacePlant]

Yikes!

Design feature? Offset the scope far enough to the left and ejecting brass will clear SWFA windage knobs with ease!

Were these purchased recently? Any contact / response from UM on this? I need something taller than my TO84 rings and was considering their mediums but...

 

[dirtytough]

After talking to someone that talks to the actual manufacturer directly it sounds like something was off between what they thought the rail spec was and what it is. I did not hear that they actually corrected anything when they found out. Maybe they will in a future Gen?

These are used. I got them off here to test something.

I doubt the offset is enough to matter much. Might help with having to compensate for spindrift way out there? I didn’t think of helping to miss windage knobs but maybe that’s it? lol

Just surprised the SM which I view as a cheap but usable set of rings are a more proper fit than UM which I view as a premium ring.

I have a set of the SM HTO73 which are taller than the TO84 and haven’t had any issues so far.

 

[LongWayAround]

@Unknown Munitions

Is this a known issue? Limited number of rings affected?

I have one set of your rings and have planned to purchase more.

 

[Salmon River Solutions]

The offset is extremely minimal. The advertised tikka rail dimensions do not actually match what they manufacture, so the solid ring side was offset a very small amount to accommodate this. The rings are in line with each other, you just have to run the rings in a matching orientation (both clamps have to be on the same side)

Thaaaaaaanks Branden lol

Ken

 

[SDHNTR]

That explains why the set of UM rings I recently installed took up a lot more scope windage than I’m used to. Didn’t bother me much as I don’t dial for wind but it did make me scratch my head.

 

[Justin Crossley]

That explains why the set of UM rings I recently installed took up a lot more scope windage than I’m used to. Didn’t bother me much as I don’t dial for wind but it did make me scratch my head.

The rings being off center by .002" would not require a noticeable amount of windage correction. A large windage correction means something is angled in the system.

 

[BLJ]

The offset is extremely minimal. The advertised tikka rail dimensions do not actually match what they manufacture, so the solid ring side was offset a very small amount to accommodate this. The rings are in line with each other, you just have to run the rings in a matching orientation (both clamps have to be on the same side)

Thaaaaaaanks Branden lol

Ken

But not the Sportsmatch rings on the same rail?

 

[Shortschaf]

The rings being off center by .002" would not require a noticeable amount of windage correction. A large windage correction means something is angled in the system.

Nobody asked, but you are right.

Rings off center by 0.002" would cause an error of 0.002" at all ranges. Not important


Being collinear with eachother is of primary importance (no stress on scope tube)

Being also collinear with the bore is of secondary importance (zeroed windage close to mechanical center)

 

[FacePlant]

@Salmon River Solutions

So are currently manufactured rings now machined to fit the actual rail width or the previously assumed width?

 

[Marbles]

I don't see why this matters.

The UM rings work well. If they fit your needs, don't worry about it.

 

[SDHNTR]

The rings being off center by .002" would not require a noticeable amount of windage correction. A large windage correction means something is angled in the system.

That pic shows a lot more than .002”. 2 thou isn’t even discernible by eye.

 

[dirtytough]

The offset is extremely minimal. The advertised tikka rail dimensions do not actually match what they manufacture, so the solid ring side was offset a very small amount to accommodate this. The rings are in line with each other, you just have to run the rings in a matching orientation (both clamps have to be on the same side)

Thaaaaaaanks Branden lol

Ken

No problem I'm surprised it wasn't brought to the attention of the forum before. Heck they've been around a couple years I bet and I just got these last week. When did SRS/UM figure out they were machined off center? And did the machining spec get changed or did they continue to get machined with the same offset?

 

[Salmon River Solutions]

@Salmon River Solutions

So are currently manufactured rings now machined to fit the actual rail width or the previously assumed width?

No problem I'm surprised it wasn't brought to the attention of the forum before. Heck they've been around a couple years I bet and I just got these last week. When did SRS/UM figure out they were machined off center? And did the machining spec get changed or did they continue to get machined with the same offset?

The rings are manufactured to the correct width that the tikka rails are actually made to.

We've been aware of it for a while, and there's no functionality issue because of it. Your not going to notice your head is offset the small amount. We're literally splitting human hairs here lol.

We are working on a new clamp design and when we do this everything will be shifted to the center.

Ken

 

[FacePlant]

Thanks for the update, i appreciate you taking the time to interact with us overly analytical gear junkies!

 

[FacePlant]

I don't see why this matters.

As a very average shooter and sub 500 yard rifle hunter, it 100% doesn’t matter. As a machinist with a bit of OCD, it shouldn’t, but probably would.

 

[5811]

That pic shows a lot more than .002”. 2 thou isn’t even discernible by eye.

I agree. Are we all talking about the same thing? This looks more like 0.150"

 

[Marbles]

As a very average shooter and sub 500 yard rifle hunter, it 100% doesn’t matter. As a machinist with a bit of OCD, it shouldn’t, but probably would.

As someone with a touch of OCD myself, the concept of GETMO (good enough to move on) is life changing for the better.

I've wasted way too much energy perfecting things that don't matter and not focusing on the things that do already in life.

 

[Nine Banger]

OCD right handed shooters will need .002” thick moleskin when the change occurs.

 

[Justin Crossley]

View attachment 855284

I agree. Are we all talking about the same thing? This looks more like 0.150"

I mounted a set and measured. They are .015" from center or .030" offset from each other when you mount one reversed. As long as you don't do that, it's a non issue.