Scope ring height - moderator need advice.

[hillclimber]

Hi guys I just need some help before I order rings. I have a Sako Varmint laminated 22-250. I have a hausken moderator fitted. The scope is a pmii 34mm tube. My question is there a formula or guide to what ring height I need to get above moderator? Is the sight line in a scope the bottom of the tube? If that makes sense if bottom of 34mm tube is higher than top of moderator should I be ok? If I measure that height? Or do I need the bottom of the front lens above top of moderator? I was going to order online but I am not sure how to allow for moderator. Any help would be great thanks.

 

[Dalua]

I've never really thought that hard about this - my priority has always been keeping the scope as low as possible. The extent to which one is aware of the mod when looking through the scope will, I suspect, depend on magnification selected and barrel-length. I find low mag shows a lot of barrel/scope/foresight (depending on what's there to see), and with higher mag they become less obvious and/or 'disappear'.

Not sure a few mm extra on the mounts would make a huge difference; and certainly getting the bottom of the objective higher than the top of the mod would give a very high scope - manageable with an adjustable/slip-on comb, but desirable?

I'll be interested to know what other folk think!

 

[hillclimber]

I've never really thought that hard about this - my priority has always been keeping the scope as low as possible. The extent to which one is aware of the mod when looking through the scope will, I suspect, depend on magnification selected and barrel-length. I find low mag shows a lot of barrel/scope/foresight (depending on what's there to see), and with higher mag they become less obvious and/or 'disappear'.

Not sure a few mm extra on the mounts would make a huge difference; and certainly getting the bottom of the objective higher than the top of the mod would give a very high scope - manageable with an adjustable/slip-on comb, but desirable?

I'll be interested to know what other folk think!

Thanks you see I have been looking at those spuhr hunting mounts. They are threaded at top so I can fit a small rail to hold torch. From the measurements I believe they are about 7mm height + the sako base mounts. I'm not sure how thick they are. The scope has a pm11 5-25x56.

 

[Klenchblaize]

What’s a “moderator”?

Keep a scope LOW and unobtrusive!

K

 

[hillclimber]

Or maybe I don't need to worry about height??

 

[Malxwal]

I'd be more concerned with best cheek weld, purchasing mounts to suit that as opposed to being concerned with perhaps seeing a wee edge of moderator when zoomed out .

 

[malmick]

@Malxwal ditto, that's what I was going to say.

 

[hillclimber]

I've just read on web the end of barrel is not normally noticed unless you go under 3x mag does that make sense? I should be OK then?

 

[Rory]

I've just read on web the end of barrel is not normally noticed unless you go under 3x mag does that make sense? I should be OK then?

Yep, don't worry about the mod, keep the objective close to the barrel (allow for scope caps if you use them) to avoid a comb raiser.
Here's a handy calculator to get the right rings.

Scope Ring Height and Clearance Calculator

 

[hillclimber]

Yep, don't worry about the mod, keep the objective close to the barrel (allow for scope caps if you use them) to avoid a comb raiser.
Here's a handy calculator to get the right rings.

Scope Ring Height and Clearance Calculator

That's handy thanks.

 

[badbob]

In the old days when we mounted gun lights the reflective flare of the moderator could be a problem.
The scope should be as low as possible, most ballistic tables assume centre of scope 1.5 inches above the bore.

 

[Malxwal]

In the old days when we mounted gun lights the reflective flare of the moderator could be a problem.
The scope should be as low as possible, most ballistic tables assume centre of scope 1.5 inches above the bore.

1.5 pretty low really. I think Strelok defaults to 2".
I'm a bit obsessed with mounting scopes with only a day paper clearance, and 1.6 is good going.

 

[Alantoo]

I have always tried to get the scope as low as possible in order to get the line of sight to work better with the shallower curved, earlier part of the trajectory...air rifle thinking.

I haven't been able to see the moderator even at lowest magnification though.

Just experimented....If you wrap/lay your finger on top of the moderator you can just see a flesh coloured bloom in the top rim of the picture.

I find it really weird that the NV scopes like the Pard 008 appear to be mounted on stilts...anybody know why?

Alan

 

[bullet chucker]

A 56mm scope with a 34mm tube will determine your scope rings height, the moderator will fall into insignificance when all set up in my opinion.

BC.

 

[User00040]

Thanks you see I have been looking at those spuhr hunting mounts. They are threaded at top so I can fit a small rail to hold torch. From the measurements I believe they are about 7mm height + the sako base mounts. I'm not sure how thick they are. The scope has a pm11 5-25x56.

Good choice on the Sphur rings, but bear in mind that the PMII is a dial scope.

If you mount it too low with a moderator, the elevation dial will not be usable to it's full potential (you will have the moderator blocking most of the bottom half of the image).

Furthermore, an illuminated PMII has quite a narrow mounting surface, so ring spacing is critical. Unless you've invested in a proper picatinny rail and mount's, you could be in a bit of a bind with regards to eye relief, as the Sako dovetail (originally designed for long, lightweight fixed power scopes of 25.4 or 26mm tube diameter) is very limiting.

I'd ditch the Sako and get a Tikka T3 instead, problem solved by the integral dovetail rail (same as the Sako TRG minus a few extra recoil lug slots) and Spuhr's dedicated Tikka T3 mount.

 

[User00040]

Looking at the comments on here, I am puzzled by all the 'mount as low as possible' answers.

Clearly not factoring heat haze from the moderator and the fact that a dial scope actually needs more height over bore (or even better, an inclined/20MOA base).

 

[hillclimber]

Good choice on the Sphur rings, but bear in mind that the PMII is a dial scope.

If you mount it too low with a moderator, the elevation dial will not be usable to it's full potential (you will have the moderator blocking most of the bottom half of the image).

Furthermore, an illuminated PMII has quite a narrow mounting surface, so ring spacing is critical. Unless you've invested in a proper picatinny rail and mount's, you could be in a bit of a bind with regards to eye relief, as the Sako dovetail (originally designed for long, lightweight fixed power scopes of 25.4 or 26mm tube diameter) is very limiting.

I'd ditch the Sako and get a Tikka T3 instead, problem solved by the integral dovetail rail (same as the Sako TRG minus a few extra recoil lug slots) and Spuhr's dedicated Tikka T3 mount.

Thanks for the information that is very helpful. I've owed a Tikka varmint in 222 a very accurate reliable rifle. I just switched to the Sako varmint because I always wanted a Sako that's the only reason. It new a I fired a few unscoped though it so will be holding on to it now. Yes I have now found the problem with the S&B 34mm it's a pm11 5-25x56. And yes I do not have much room. I fitted the Sako bases but the middle tube is about 10mm to short to suit. I don't think I can get around the problem without a rail???! Or have you any ideas??? If I need a rail I was reading the Recknagel or Contessa??? Maybe the rail is the best option then I have a base for night vision also.

 

[Ttocs]

Are your Sako bases short or long action bases, the front base long action bases have the ring mount at the rear of the base the shorts at the front - difference between the two about 15mm.
On the subject of scope height, I always strive for a low mounted scope because it looks better and gives good cheek weld. However, if you’ve an adjustable stock, scope height can be manipulated to alter the length of your point blank range. For every caliber/bullet weight there is an optimum scope height that maximises point blank range. Have a play with a ballistic app, where you can change the scope height, and you’ll get an idea of the optimum height above the bore for your setup.
N

 

[Alantoo]

Looking at the comments on here, I am puzzled by all the 'mount as low as possible' answers.

Clearly not factoring heat haze from the moderator and the fact that a dial scope actually needs more height over bore (or even better, an inclined/20MOA base).

Heat shimmer goes upwards generally....another few millimetres of line of sight height above the bore is not really worth factoring is it? More important to reduce parallax issues with the trajectory?

If you are shooting lots of strings at a range then you can use a little fan to blow the heat haze away...I do now...but I developed the technique of blowing along the barrel just prior to pulling the trigger before I bought the fan....

Alan

 

[Brave Echo Niner]

Heat shimmer goes upwards generally....another few millimetres of line of sight height above the bore is not really worth factoring is it? More important to reduce parallax issues with the trajectory?

If you are shooting lots of strings at a range then you can use a little fan to blow the heat haze away...I do now...but I developed the technique of blowing along the barrel just prior to pulling the trigger before I bought the fan....

Alan

Or use a brake if you're at a range... The difference between a mod and a brake is night and day in terms of mirage!

It's one of the main reasons I run brakes for PRS as a pose to mods!

Ben