How Low Can You Go - modifying scope mounts

[Lol Moore]

So this little project was started by the need for some super low and narrow mounts for my new semi-pup Steyr before the bonfire pi##ers start with the "whats the point" there really isn't one other than I like cutting stuff up

The pup is incredibly comfortable and easy to shoot, problem is the scope is 50mm high and is unchangeable due to cheek weld on action constraints, so with 0.177" running legally this is a bit of a mare, it means the holdovers (I zero at 25 yards) are between 3.1 dots at 8 yards and 1.1 dots at 45 yards, so a lot of scope for error.

So now I am creating the semi-pup where my cheek will be just behind the action, where is the sweet spot for scope height, I suppose it depends what you want really, for me I like to have the spread of dots as small as possible and equal at 8 and 45 yards, this gives me less to remember during a comp - my weakness (apart from no time to shoot) is eyesight and falling apart under pressure

So 0.177" running at 11.4ftlb (all the below numbers off Chair Gun so not exact) this equates to a barrel to scope centre height of 32mm which would give a dot spread of 1.4-1.4, as the distance between the barrel centre line and the top of the action of a Steyr LG is 16mm and the scope is a 30mm tube (15mm radius) this means I would need mounts with a top of action to bottom of scope height of 1mm - not easy - so how low can you go

My current full length set up uses Rick Arden super lows, the mounts to judge all others against, the accuracy of machining is second to none. These are 7mm high, which means my scope is running on a centre height of 38mm which gives a dot spread of 1.9-1.3, pretty good and actually as good as it gets with this scope as the zoom ring is currently 0.5mm above the action - it will not go any lower

But with the semi-pup I think I can get the zoom ring over the breech cut-out so can go lower

So I bought some cheap mounts to cut up (thanks to Simmo for the idea), with the traditional match type mount and M4 clamp screws I think I can get down safely to 6mm, the constraint being the need to leave some material above the screws to flex, this is the weak area of this design so I have tried to improve on Ricks design a little by easing the stresses using a round hole not square corners, I can see some mileage in side cut outs too - like BKL do. I have left 2mm of material to flex. These are fine if you mount once and forget - if you take them on and off a lot they will probably fracture I got these down to 6mm so centre height of 37mm which gives a dot spread of 1.8-1.3, not much change as I struggle to differentiate between 0.1 and 0.2 dots anyway

https://goo.gl/photos/8GyMAL4vqVf4JwJL8

I also tried a set of Warne type mounts this time with M3 screws (but a lot of thread contact, almost 15mm long) and managed to get these down to 4mm so centre height of 37mm which gives a dot spread of 1.7-1.4, closer together but not the same

https://goo.gl/photos/6FYNcbAmtusHPqLy5

With the Steyr this is it I think, the only way to get lower is to get a rifle with a smaller distance between barrel and top of action, or to slow the pellet if I drop to 10.5ftlb the dot spread is 1.6-1.6 - more windage though

The mounts for comparison:

https://goo.gl/photos/DsSW9wkq9Z2k7zDu7


....watch this space for the semi-pup....

[Shed tuner]

tiger seal, and just glue the scope tube to the action ?

[Airsporter1st]

Wasn't there a scope with a partial circular cut out at the bottom of the objective lens, which would allowlower mounting (assuming you were able to lower the mounts still further)?

[Waisted]

A different method would be to cut the bottom mount vertically in half, fix one half to the scope and the other half is fixed to the rifle. Toss this idea around in your head see what you can come up with.

[MartynB]

Interesting little project. I have to say I prefer smaller objective scopes anyway, generally sticking to 4x32 or smaller if quality is good enough. I have some Hilver low steel rings with the Swarovski

[Gunfun]

Very impressive machining work on those scope mount bases and a good little problem.
The only way I can think of getting down to 1mm scope mount height is if you hang the mounts half off the ends of the rail (if the scope length allows) with the hanging off bit having more material depth/strength, might be easier to fasten a small plate to the end of the scope mount.
Other than that, the drastic measure might be machining 2 narrow slots across your scope rail say 3mm deep and 6mm wide, then machine a lug on the bottom of the mounts to suit and use several M3 bolts, counter sunk in the scope base to fasten it to the rail, just depends how much meat is on the rail/action.
As mentioned above Leupld make a 'low' series of scopes with a recessed objective lens to clear the barrel.
Have fun !

[RobF]

Why not mount onto the barrel?

[Lol Moore]

A different method would be to cut the bottom mount vertically in half, fix one half to the scope and the other half is fixed to the rifle. Toss this idea around in your head see what you can come up with.

Not sure exactly what you mean...but interested If you mean split the bottom half of the traditional mount vertically to do away with the small section of flexing aluminium essentially to create a three piece mount I thought about that but decided with different sizes dovetails (none seem to be the same??) it may create problems with lining up the horizontal area where the top clamp has to face up with the bottom section - would look neat though, and would gain a further 2mm

Very impressive machining work on those scope mount bases and a good little problem.
The only way I can think of getting down to 1mm scope mount height is if you hang the mounts half off the ends of the rail (if the scope length allows) with the hanging off bit having more material depth/strength, might be easier to fasten a small plate to the end of the scope mount.
Other than that, the drastic measure might be machining 2 narrow slots across your scope rail say 3mm deep and 6mm wide, then machine a lug on the bottom of the mounts to suit and use several M3 bolts, counter sunk in the scope base to fasten it to the rail, just depends how much meat is on the rail/action.
As mentioned above Leupld make a 'low' series of scopes with a recessed objective lens to clear the barrel.
Have fun !

I drew up my Steyr Bullpup in just that way originally with the mount slung between the front and rear dovetail sections but couldn't find a scope of the right dimensions (length diameter combination) to fit there Don't want to machine the rifle just yet but had thought about a WeaverTail system by as you say cutting slots across an existing dovetail so the mounting screws can sit in these slots - maybe if I find a cheap action I will have a go

Leupold do make recessed objective scopes but only with large objectives, I want 32mm or lower objective to give the required depth of field.

Why not mount onto the barrel?

Now then, would love to do that but its difficult with a Steyr, makes sense at the back end, does away with misalignment and some of the action/mount/barrel movement problems seen.

May play havoc with the combined barrel tuner/moderator/sleeve/shroud thing I am playing with - secret squirrel that one - but not as secret as the barrel mounted reactive stabiliser I have...ohh sugar, now I have told you I will have to kill you all

[RobF]

Now then, would love to do that but its difficult with a Steyr, makes sense at the back end, does away with misalignment and some of the action/mount/barrel movement problems seen.

How so? It's just a figure of 8, bottom one for the barrel, top cut after for the scope. Can slide the bottom one down the barrel. Guess it depends on where your scope sits back and forth but...

[Lol Moore]

How so? It's just a figure of 8, bottom one for the barrel, top cut after for the scope. Can slide the bottom one down the barrel. Guess it depends on where your scope sits back and forth but...

I have draw dozens of ideas up and it is almost always the ocular bell or zoom ring that hits something first, (with bigger objective scopes sometimes its the objective bell).

Getting the body of the scope low is only half the battle - like I say Steyrs are difficult there are plenty of rifles out there where the barrel is much closer to the top of the action/dovetail which makes life easier -but I like my LG's

[lensman57]

This is an interesting project but rather a futile exercise. There is really only one proper position for the scope and that is only determined by where the head's natural position relative to the cheek piece is. The scope will then have to be adjusted in height to come up to position for the eye. So I can't understand what you are trying to achieve here? It is interesting none the less.

Regards,


A.G

[copperjacket]

Interesting problem. Why not turn this around and fix a pair of inverted dovetails to the underside of the scope using loctite and then devise a slimline (dovetail to dovetail or diamond shaped) clamp to go between the two?

[Airsporter1st]

Have you thought about sticking the scope on the side of the gun - that way it can be aligned vertically with the barrel axis? I recall seeing scopes mounted like that in the old Westerns - and those guys could hit a gnat's bollock at half a mile.

[RobF]

This is an interesting project but rather a futile exercise. There is really only one proper position for the scope and that is only determined by where the head's natural position relative to the cheek piece is. The scope will then have to be adjusted in height to come up to position for the eye. So I can't understand what you are trying to achieve here? It is interesting none the less.

Regards,


A.G

Yes but the barrel can be where you like so eye to scope fine, then slam barrel to scope. It's just relative.

[Andrewjames]

Where can one acquire those Rick Arden mounts?