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Custom Machining Unertl Scope mount

Stray8

Gold $$ Contributor
I recently inherited a Unertl 24x target scope with POSA mounts. There are a few ready made options for this scope with a drilled and tapped barrel like Rem 40x, varmint special, rimfire, etc. However, I have a savage PTA in 6BR that i would like to mount it on. There are people that make adapters for POSA to picatinny and other adapters like Steve Earle, but none appear to be exactly what I need. The main problem with the target scopes is the mounting distance should be 7.2" or more optimally, and this is difficult to achieve without a mount over or on the barrel.

So, my options for a home for this scope are buy a new rifle, have my rifle drilled (don't want to do that), or a custom mount. I plan to do a custom mount so I can have a unique setup on a rifle I already have.

First step was to design the mount, I based it off of a regular savage round back scope rail. Tried to keep it simple to be easier to machine/print. My current design has a full 60 degree dovetail and mounting slots for 2 different 7.2" spacing spots or 1 9" spacing. May end up making it less tall overall. I could always add more mounting slots in the future if desired.

savageunertl.jpeg

The initial plan was to buy a mill and machine it myself, but that would be more money than getting it machined or printed. Now the plan will be to have someone do it for me. There are several online based companies that will machine or 3d print your design in metal now, so I got some quotes.

Macined from aluminum
USA based - ~$400
Foreign - ~ $200

3D printed from Aluminum
~ $1000

Looks like the foreign based machining will be the most economical option. If anyone has gone through this process before, I am open to any tips.
 
Are the mounts much different than Redfield blocks?
I believe the original unertl and redfield blocks were the same. The posa mounts have a 1/8” deep half cylinder machined out instead of a small circle cut.
 
I recently inherited a Unertl 24x target scope with POSA mounts. There are a few ready made options for this scope with a drilled and tapped barrel like Rem 40x, varmint special, rimfire, etc. However, I have a savage PTA in 6BR that i would like to mount it on. There are people that make adapters for POSA to picatinny and other adapters like Steve Earle, but none appear to be exactly what I need. The main problem with the target scopes is the mounting distance should be 7.2" or more optimally, and this is difficult to achieve without a mount over or on the barrel.

So, my options for a home for this scope are buy a new rifle, have my rifle drilled (don't want to do that), or a custom mount. I plan to do a custom mount so I can have a unique setup on a rifle I already have.

First step was to design the mount, I based it off of a regular savage round back scope rail. Tried to keep it simple to be easier to machine/print. My current design has a full 60 degree dovetail and mounting slots for 2 different 7.2" spacing spots or 1 9" spacing. May end up making it less tall overall. I could always add more mounting slots in the future if desired.

View attachment 1355474

The initial plan was to buy a mill and machine it myself, but that would be more money than getting it machined or printed. Now the plan will be to have someone do it for me. There are several online based companies that will machine or 3d print your design in metal now, so I got some quotes.

Macined from aluminum
USA based - ~$400
Foreign - ~ $200

3D printed from Aluminum
~ $1000

Looks like the foreign based machining will be the most economical option. If anyone has gone through this process before, I am open to any tips.
What's wrong with drilling the barrell? $30-40. I have a Unertl Ultra Varmint 15X that I have put on 3 barrels. Now it's on a Rem 700 6BR Kreiger barrel. Shoots well under 1/2" with good bullets. Great rifle for GH. Sell your scope and buy something practical.
 
That is essentially a Davidson type rail with 4 shallow end mill cuts after turning it on its side 90 degrees with holes drilled for a Savage action. Same dovetail that's either made onto or screwed onto the top of many custom target actions. Surely someone has these available in a long length and the holes and end mill cuts can be made fairly quickly. Long bases cantilevered over the barrel were used on early BR actions when the only true target scopes were the long ones like Unertl, Lyman and Fecker.
 
What's wrong with drilling the barrell? $30-40. I have a Unertl Ultra Varmint 15X that I have put on 3 barrels. Now it's on a Rem 700 6BR Kreiger barrel. Shoots well under 1/2" with good bullets. Great rifle for GH. Sell your scope and buy something practical.
I have multiple savages and could put it on any of them and gives me the option to change barrels easy still. Also, my 6BR barrel shoots light and heavy bullets into the high 1s low 2s at 100yrs. I don’t really want to mess with the barrel.
 
That is essentially a Davidson type rail with 4 shallow end mill cuts after turning it on its side 90 degrees with holes drilled for a Savage action. Same dovetail that's either made onto or screwed onto the top of many custom target actions. Surely someone has these available in a long length and the holes and end mill cuts can be made fairly quickly. Long bases cantilevered over the barrel were used on early BR actions when the only true target scopes were the long ones like Unertl, Lyman and Fecker.
You are correct, the specs are the same for a 1/2 Davidson dovetail mount. I have been unable to find anything except 12” blanks for the 3/8. Could also do a long picatinny rail with the adapters, but it would be even uglier. Most picatinny blanks have flat bottoms that would need to be radiused too.
 
Perhaps one of the dealers who makes 2 piece bases would cut you a long blank to your length. I would think that they must get them in long blanks. I have bought Weaver/picatinny long blanks, 18" as I recall.
 
I think youd need to stick with the seperate base for the barrel not a 1 piece mount. Or trade that scope for something a bit more modern
 
What's wrong with drilling the barrell? $30-40. I have a Unertl Ultra Varmint 15X that I have put on 3 barrels. Now it's on a Rem 700 6BR Kreiger barrel. Shoots well under 1/2" with good bullets. Great rifle for GH. Sell your scope and buy something practical.
Pardon my stupidity, but what is GH???
 
Perhaps one of the dealers who makes 2 piece bases would cut you a long blank to your length. I would think that they must get them in long blanks. I have bought Weaver/picatinny long blanks, 18" as I recall.
I have a 36” unslotted picatinny base but the bottom is flat. Steve earle lists on his website that they do not have or sell blanks unfortunately. I emailed him about this a while back and he didn’t seem interested in the project.

I think youd need to stick with the seperate base for the barrel not a 1 piece mount. Or trade that scope for something a bit more modern

Your advice is sound, but the scope is pristine, functional, and has sentimental value. This is about making a square peg fit a round hole for fun mostly.
 
Your advice is sound, but the scope is pristine, functional, and has sentimental value. This is about making a square peg fit a round hole for fun mostly.
Keep looking till YOU get what YOU want. Someone out there has or will make what YOU want. ;) ;)
 
How does this work when attaching the mount to the barrel? does it not wreck havoc with the harmonics of the barrel?
 
What is your current center to center mount hole spacing? and screw hole spacing?

The original bolt action mounts extended over the barrel about 1 1/4”

The other option was to use 5.4” spacing. This basically gave you a MIL adjustment at 3 clicks per inch instead of 4.

Undrilled mount blanks are readily available and brownells used to sell 1/2” 60 degree bulk rail, but all I see now is 3/8”.

In a pinch there are copies of the base chart that would allow you to get an idea of what to look for that might work online.

There is also a Unerl forum.
 
A 24x Unertl is a fair amount of weight to put on a long cantilevered base for a CF application. I would definitely go with the steel vs aluminum for material strength considerations.

I would start mocking up how high the final centerline of the scope would be once you stack up the rail w/ the Posa mounts. You will need to add to the cheekpiece height (pending how you plan to shoot the rifle - i.e. benchrest, prone, etc.)

Another random thought is to bounce this project off of Jim Kelbly. He might have some good input and might be able to make the base for a reasonable price - and you will NOT have to worry about the quality.

Good luck on the plan and keep us updated.
Regards,
Ken
 
What is your current center to center mount hole spacing? and screw hole spacing?

The original bolt action mounts extended over the barrel about 1 1/4”

The other option was to use 5.4” spacing. This basically gave you a MIL adjustment at 3 clicks per inch instead of 4.

Undrilled mount blanks are readily available and brownells used to sell 1/2” 60 degree bulk rail, but all I see now is 3/8”.

In a pinch there are copies of the base chart that would allow you to get an idea of what to look for that might work online.

There is also a Unerl forum.

I have made some modifications to try to get the mount shorter. I should be able to keep it to 10" total. The COG of the scope will be around the front mount.

savageunertldrawing.png

A 24x Unertl is a fair amount of weight to put on a long cantilevered base for a CF application. I would definitely go with the steel vs aluminum for material strength considerations.

I would start mocking up how high the final centerline of the scope would be once you stack up the rail w/ the Posa mounts. You will need to add to the cheekpiece height (pending how you plan to shoot the rifle - i.e. benchrest, prone, etc.)

Another random thought is to bounce this project off of Jim Kelbly. He might have some good input and might be able to make the base for a reasonable price - and you will NOT have to worry about the quality.

Good luck on the plan and keep us updated.
Regards,
Ken
It will pretty much be a free recoil BR rifle when done. I think the height of the scope should be about right for this application.
 
If you can get the shorter version to work for proper eye relief, you could join 2 of the 7" blank Davidson bases together by milling the height of each where the ends meet (lapped one on top of the other at the front base screws). Bruno's has 2 in stock; you would still have to radius the bottom side. These are 3/8" high; he also shows 1/2" high in stock. Don't see any mention of the 3/4" high base, which was also available when Sinclair stocked them. https://www.brunoshooters.com/mm5/merchant.mvc?Screen=PROD&Product_Code=20229
 
If you can get the shorter version to work for proper eye relief, you could join 2 of the 7" blank Davidson bases together by milling the height of each where the ends meet (lapped one on top of the other at the front base screws). Bruno's has 2 in stock; you would still have to radius the bottom side. These are 3/8" high; he also shows 1/2" high in stock. Don't see any mention of the 3/4" high base, which was also available when Sinclair stocked them. https://www.brunoshooters.com/mm5/merchant.mvc?Screen=PROD&Product_Code=20229

Forgive my ignorance in this, but I thought 3/8 and 1/2 dovetail described the dovetail dimensions not the height?

Also, 2 7” would be good if I had the equipment, surely someone else could make it out of a single piece of metal with a dovetail cutter. If I could find a 1/2 dovetail with a radiused bottom the rest could be done with a drill press.
 

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