Bought a bubba'd 1917 action. Pictures show the bubba work, and the obvious reason I bought it anyway.

I'd like to mill the hacksawed area to a faceted contour, similar to an octagon barrel. Kind of a rib effect. My intent is to build a peep sight to go into the duck pond. Back of the pond will probably be milled out, as will the left side of the action to get an Ed Lapour 3 position safety shroud.

What would you all use to line up the action to mill the contour, particularly since a peep sight will be centered on it? Not much to true to on the action anywhere.

My thought is that the peep ought to be aligned with the barrel bore. Presuming the barrel is threaded square with the bore, a true mandrel would suffice if the action wasn't barrelled yet. Or, could wait until the barrel is on it, and make sure that the outside of the barrel is concentric with the bore to indicate from.

I'd prefer to have a longer radius to indicate from than trying to align with the receiver threads. Any error there would multiply several times extended back to the rear of the action. The barrel full length would minimize any error.

Another thought is assume and check that the duck pond and screw hole is centered. Would give one indication if my measurements are right.

Any other ideas?

dave

quote:

My thought is that the peep ought to be aligned with the barrel bore.

I don't recommend centering on anything but the receiver's axis, or bolt bore. In fact all machining operations should be based on the bolt bore.

Like Malm said, use the centerline. Make a manndrel to hold it between centers and reference the centerline.

IMO it depends on how far you want to go in ensuring a perfect alignment. There are 2 kinds of mandrels for this purpose, receiver mandrels and thread mandrels.

Anyone smithing any of the common actions should make a sort of universal receiver mandrel, with threaded holes at appropriate locations for affixing it to the various receivers. This was one of the first projects required at Trinidad. A snug fit here will ensure that you are indexing upon the bolt bore C/L (but not necessarily the receiver's thread bore C/L). This is the mandrel to use if you plan to rethread the receiver for ultimate accuracy.

A thread mandrel OTOH uses a main shaft diameter small enough to clear the bolt bore while the threaded portion is left as large as possible, to better center it in the threaded portion of the front ring. This is the mandrel to use if you don't plan to rethread the receiver to match the bolt bore.

If the threads aren't concentric then the duck pond may not be aligned with the bore and so the rear sight may be off-center within the pond. OTOH if you move the side of the duck pond to ensure a centered sight, then the pond won't be centered within the sides of the rear bridge.

IIWY I'd ensure the pond LOOKS centered within the rear bridge, IOW I'd shape the sides of the rear bridge to look concentric with the pond unless the pond was noticably off-center.

This will never be a bug-holer anyway so IMO a lot of accuracy machining would be largely wasted. Make the pond look centered and cut off as much of the bridge as possible, and don't forget to also reduce the front and rear of the bridge, there's LOTS of unneeded and awkward-looking steel there.

There are several ways to reshape the rear of the ejector box spring, and NONE of the more attractive ones involve leaving that big honkin' round insert knob at the rear.
Regards, Joe

Well, what you all are suggesting is the line of least resistance, anyway. Since I'll not be rethreading the receiver to align with the bolt raceway, I'll turn a mandrel to thread into the action threads, and extend through the bolt raceway. I can use that to mount the action on my barrel octagonning jig, and then indexing and milling the rear bridge will be simplistic. Can use that mandrel to simultaneously square the action face.

I'll use some judgement, check the mandrel against the bolt raceway alignment and the alignment against the duck pond to make sure it all looks good when I'm done.

Joe, I'm planning to take a lot of metal off of the front and rear of the bridge. The way it is now, it's cut to knife edges and will have to be cut way back to square it all up and make it look good anyway. And, the Model 70 style safety shroud requires quite a bit to be removed.

Thanks for the ideas!

dave

quote:

Originally posted by J.D.Steele:
This will never be a bug-holer anyway so IMO a lot of accuracy machining would be largely wasted.

What does that matter? "Accuracy" machining dictates that ALL critical surfaces be square. From those that launch the bullet to those that support the sights.

quote:

Originally posted by Westpac:

quote:

Originally posted by J.D.Steele:
This will never be a bug-holer anyway so IMO a lot of accuracy machining would be largely wasted.

What does that matter? "Accuracy" machining dictates that ALL critical surfaces be square. From those that launch the bullet to those that support the sights.

How much do you charge your customers to barrel a 98 Mauser? According to you, that would involve recutting not only the threads but also the front faces of both the internal and external rings, lapping the lugs and shimming the bolt body among other things.

Have you ever tried to chase internal SQUARE threads?

I don't believe you do all of that to the Mausers you rebarrel or else you have some VERY strange clients.

Or else you just wanta be contrary.

Dave, I can visualize a folding peep that appears out of the pond with a spring-loaded detent of several possible types. Windage adjustment would be a snap but I haven't figured out a good way to do the elevation yet, needs to be a very sturdy & foolproof way.
Regards, Joe

quote:

Dave, I can visualize a folding peep that appears out of the pond with a spring-loaded detent of several possible types. Windage adjustment would be a snap but I haven't figured out a good way to do the elevation yet, needs to be a very sturdy & foolproof way.
Regards, Joe

I'm not sure how to do the sight yet. Might be pop up, or might just be fixed. Windage is easy, but as you say, elevation is more intricate. I might just use shims under the the entire sight and regulate it to my load. I'll probably use a tab forward of the main part of the sight base and utilize the existing screw hole to hold the sight in.

Another way to handle elevation is to use one of the variable elevation front sights. I think NECG has a nice one.

dave

quote:

Originally posted by J.D.Steele:
How much do you charge your customers to barrel a 98 Mauser? According to you, that would involve recutting not only the threads but also the front faces of both the internal and external rings, lapping the lugs and shimming the bolt body among other things.

Have you ever tried to chase internal SQUARE threads?

I don't believe you do all of that to the Mausers you rebarrel or else you have some VERY strange clients.

Or else you just wanta be contrary.

The guy is talking about setting the action up for sights. What I'm saying is, it doesn't matter what the intended use of the gun is, or it's expected capability, if you are going to the effort to shape, profile and set up the receiver for sights, or fit a barrel for that matter, then it is important that it is done "accurately". He can address the rest of the machine work as he see's fit. But for now, the sights need to be as square as possible.

Guys, I'm not a smith, so maybe this is way off, but isn't the bridge there more for bolt guidance than strength? And the enfields don't have guide ribs on the bolt (though you could add one) so...

couldn't the bridge be cut off, a new one made with the peep, therefore not having to work around (or within as the case may be) the pond, then braze it back on? Maybe less work in the end with a better result?

Just wondering, even though I don't do these things I am always very curious as to HOW they are done.

Red

Good point, Red. Yes, it's doable but is a lot of work when compared to just cutting things away. Would require a conceptual design and then the actual fabrication and then (perhaps the most difficult part) the proper and attractive installation. The odd-shaped lumps on the Enfield's rear will usually cause warpage when heated for brazing or welding so this would be ticklish. However many Enfield conversions also entail welding up the rear tang for a higher wrist line, so any added work for bridge warpage would be absorbed in that operation. Food for thought.
Regards, Joe

Ok, since Bubba is already at work, bow about using the FR-8 rear sight which is a disk with a V-notch for 100 yards and peeps on the rest of the sight at various heights for further distances. Just a thought. Yes, I know Bubba.

I've seen the rear bridge removed and one milled with the bolt guide welded back in place. It was shaped like a single square bridge Mauser. Bolt rib was added to the bolt body like the later Model 30's or 720's. Was a very impressive piece of gunsmithing and avoided the pond, sight spring hole and the ugly amateur shaping of the bridge.

Larry,

I had no idea that sight existed, did a google search and it comes up. That would be an interesting approach. Wouldn't be hard to make one, and it could be made a lot better looking. Make one that rotates like a Hadley eye cup, could have a couple of different V notches. Unfortunately, to make it work right, the disc would have to be rather large to have the peep sight come out as high or higher than the V notches. I was thinking a very low, very strong, foolproof peep sight. A base, a drilled hole, a screw in eye disc to change apertures. No frills, all workhorse.

dave

dave, that is exactly why I thought about that sight. It does rotate with the V in the first position and different height peeps as you rotate it around. The best part is that it is just soldered on.

It certainly could be made better looking. I like the idea of a single solidly attached base with different solidly mounted aperatures.