Scout Rifle Integral Pillar Bases

[ThomD]

I have a project rifle I would like to mount scout scope integral bases on. I really want the scope to be low and normally this requires custom bases rather than the various approaches that have been tried on stock rifles like the savage and Ruger, or even the Steyr. My thought is to partially machine the bases, then silver solder them to the barrel, then machine the dovetail for the rings. If it didn't work I could pop the bases off, and try again when I have my stuff together.

None of this particularly puzzles me, except getting the bases to be a perfect fit for the barrel at the point of contact. Most barrels are tapered, and some are convex tapered, at least where the rear base sits. Other than roughing it on the grinder by eye, then scraping it to a perfect fit, I can't think of a way to do it. I mean, sure, purpose cut reamers for every external barrel dimension in creation, but that is not going to work for me.

I am after this kind of look/function:

Is it possible to mill a flat for the rear ring, not sure I would want to do that on a 375.

Any ideas on how to do the install? There are a bunch of kludges and after-market bolt-ons that could be discussed, but in my case it has to be an "integral" solution. No I am not milling them in to a raw barrel blank, but short of that soldering is as integral as it gets. It isn't simply about getting a scope mounted, I want to know how to do this specific job.

 

[Paul Tummers]

I have a project rifle I would like to mount scout scope integral bases on. I really want the scope to be low and normally this requires custom bases rather than the various approaches that have been tried on stock rifles like the savage and Ruger, or even the Steyr. My thought is to partially machine the bases, then silver solder them to the barrel, then machine the dovetail for the rings. If it didn't work I could pop the bases off, and try again when I have my stuff together.

None of this particularly puzzles me, except getting the bases to be a perfect fit for the barrel at the point of contact. Most barrels are tapered, and some are convex tapered, at least where the rear base sits. Other than roughing it on the grinder by eye, then scraping it to a perfect fit, I can't think of a way to do it. I mean, sure, purpose cut reamers for every external barrel dimension in creation, but that is not going to work for me.

I am after this kind of look/function:

Is it possible to mill a flat for the rear ring, not sure I would want to do that on a 375.

Any ideas on how to do the install? There are a bunch of kludges and after-market bolt-ons that could be discussed, but in my case it has to be an "integral" solution. No I am not milling them in to a raw barrel blank, but short of that soldering is as integral as it gets. It isn't simply about getting a scope mounted, I want to know how to do this specific job.

I am not used to this kind of scope mounting which is the reason for asking; what is going to happen when the barrel heats up/ expands and there comes tension on the scope ? Does it cause the POI ro change much?
I have EAW detatchable mounts on my rifles and they are constructed in such a way that there is room for barrel expansion or - shrinking, depending on the temperature of the rifle.

 

[FredC]

ThomD,
For a underbarrel laser mount I did on my son's rifle, I made a crude single flute reamer out of semi hard stainless. Used the set over on the tail stock to match the taper on the round blank then milled the straight single flute, then hand filed the relief.
If you could incorporate a complete band into your bases Loctite or other aneorobic adhesives might give you enough strength for what you are planning. It worked fine on my son's laser mount.
If you stay with the single pillar style can you build a fixture to hold each one then bore them using a taper attachment? Or bore an appropraite sized block of steel then cut out the segment you need? If you have access to a CNC lathe cutting the taper is a lot easier than setting up a taper attachment.

 

[ahall]

If you are dealing with a simple taper on the barrel, then bore a ring on the lathe.
A base is short enough that the compound should bore it. No need to set up a taper attachment.

Its simple enough to lay out where the base goes, measure the diameters and calculate the taper.
If you have no sights, you can slip the barrel through the bored hole and check the fit prior to removing it from the lathe.

 

[ThomD]

I am not used to this kind of scope mounting which is the reason for asking; what is going to happen when the barrel heats up/ expands and there comes tension on the scope ? Does it cause the POI ro change much?
I have EAW detatchable mounts on my rifles and they are constructed in such a way that there is room for barrel expansion or - shrinking, depending on the temperature of the rifle.

That seems like a fair question to me and may explain some of the reasons for the approaches taken on say the Ruger, where there is a definite tactical niche. The original scout was seen as an all purpose weapon, which included, in Jeff Cooper's mind, military applications, but not ones all that likely to really heat things up. Today those applications would be fanciful for this kind of bolt action rifle. The main uses are general rifle uses outside the burgeoning high rate of fire uses, like hunting. That said, some of the courses of fire, such as at Gunsite would certainly have heated the barrel up a little, and I have never seen the POI change mentioned as a problem. However, practical accuracy, an issue I once corresponded with Cooper on, was not in his mind overly demanding. He was not arguing over 1/10 minute amouints. The steyr uses an approach more like an AR with a full length Picatiny, in that the barrel and mounts are not unified.

 

[ThomD]

If you are dealing with a simple taper on the barrel, then bore a ring on the lathe.
A base is short enough that the compound should bore it. No need to set up a taper attachment.

Its simple enough to lay out where the base goes, measure the diameters and calculate the taper.
If you have no sights, you can slip the barrel through the bored hole and check the fit prior to removing it from the lathe.

You are correct, it could be bored as a taper. I have often done that, but as an weekend kind of guy that never occurred to me for this. Thanks for the whack to the side of the head, to get me pointed in the right direction.

 

[ThomD]

ThomD,
For a underbarrel laser mount I did on my son's rifle, I made a crude single flute reamer out of semi hard stainless. Used the set over on the tail stock to match the taper on the round blank then milled the straight single flute, then hand filed the relief.
If you could incorporate a complete band into your bases Loctite or other aneorobic adhesives might give you enough strength for what you are planning. It worked fine on my son's laser mount.
If you stay with the single pillar style can you build a fixture to hold each one then bore them using a taper attachment? Or bore an appropraite sized block of steel then cut out the segment you need? If you have access to a CNC lathe cutting the taper is a lot easier than setting up a taper attachment.

I am pretty much all manual. I have a KO Lee that I guess I could use to cut some sort of reamer. I really haven't spent time with it yet. But it is possible, I was dismissing reamers just because I hoped the was a simpler solution, though it would be a learning thing. Thanks for the ideas

 

[ThomD]

So I dismissed the idea of milling a flat for the rear base. It almost looks like that is what was done. What do you all think about that approach? Part of it would be how the heck to determine how far one can go with particular gun and cartridge. I am thinking of the 375 ruger version of the Savage Brush gun I could write Savage, but I can't imagine they would answer in a positive vein. What would be their defence if anyone sued them for whatever random variation a customer had in mind.

 

[ulav8r]

The front third of the barrel could be cut down to .10-.125 wall thickness safely. In the chamber area .19 thickness would probably be ok bit I would prefer .25 as a minimum thickness.