Gunplummer
New member
Been busy. I would check the angle on the dovetails. Europeans have a weird metric angle standard (Mauser sights, Russian extractors, ect.) It may be a standard American angle, but you never know.
Receiver Opinions Please
- Thread starter CowTowner
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Dixie Gunsmithing
Moderator Emeritus
tobnpr,
I'd say you could, easily, since that extra steel making the dovetails really does nothing for the receiver's strength. I don't know if it would hurt it's value though. To me, I would rather have it so standard mounts would work.
I'd say you could, easily, since that extra steel making the dovetails really does nothing for the receiver's strength. I don't know if it would hurt it's value though. To me, I would rather have it so standard mounts would work.
Dixie Gunsmithing
Moderator Emeritus
I don't think they ever did use things like our standard Jacobs and Morse tapers, etc. They did on machinery, as they had to sell it here, but on guns, they made up a lot of their own. On this rifle, they would want a locking but releasable taper, similar to a Morse. If it's Morse, it will turn out to be about 5/8" per foot. By the photos, it looked less than a Jacobs steeper taper. A Jarno is at 0.6" per foot, and it could be it too. It looks a little more splayed than a B&S at 1/2" per foot. They were bad to stick.
The basic Morse taper was what made the old LC Smiths shoot well, they had an extra long choke bore created by standard Morse taper reamers. I have my old Elsie locked in my gun safe, ready to go at a moments notice. It's been one of the best guns I ever laid to my shoulder.
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Clark, I know you're hunting and won't see this for a while, but...
I'm new to the machining game, so please forgive the ignorance...I'm self-teaching on a Sieg X2 and a mini-lathe for now.
If the bases are not available in the U.S.-given that you're a machinist- would you try to mill your own bases to fit the dovetails? Given that the odds of finding a dovetail cutter with the correct angle would be slim and none, can it even be done?
Can't help but wonder, why even have them (the dovetails) in the first place? Do you think they add any stability to a mount, as opposed to just mounting a flat base on top of them?
I'm new to the machining game, so please forgive the ignorance...I'm self-teaching on a Sieg X2 and a mini-lathe for now.
If the bases are not available in the U.S.-given that you're a machinist- would you try to mill your own bases to fit the dovetails? Given that the odds of finding a dovetail cutter with the correct angle would be slim and none, can it even be done?
Can't help but wonder, why even have them (the dovetails) in the first place? Do you think they add any stability to a mount, as opposed to just mounting a flat base on top of them?
Dixie Gunsmithing
Moderator Emeritus
I wont be able to do it until tomorrow, but I'll plug those numbers into my CAD program, and see what taper they really are. I'm hoping it's just a standard angle, however if not, you could have a cutter ground, though that would be pricey.
Edit: Using a calculator, the angle on a side came up to 18 1/2 degrees, or a 37 degree cutter. That is an oddball. I'll check it with CAD tomorrow, but it should be the same.
I could have sworn those dovetails were tapered, too, so I must have looked at something else and thought that. After looking again, they were straight, so my bad
Cutter Ang by matneyw, on Flickr
Edit: Using a calculator, the angle on a side came up to 18 1/2 degrees, or a 37 degree cutter. That is an oddball. I'll check it with CAD tomorrow, but it should be the same.
I could have sworn those dovetails were tapered, too, so I must have looked at something else and thought that. After looking again, they were straight, so my bad
Cutter Ang by matneyw, on Flickr
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My current plan A is to use dovetails and 6-48 screws. I have been using dovetails as sight bases for several decades now, they used to be very common as scope bases back in the day when scopes were long and placed out on the barrel.
Bases generally had hole spacing’s of 0.860” and 0.562”. These don’t convert to nice round mm dimensions so I have no idea where this crazy convention started or why. The front holes on the square bridge are 0.860” apart, but the back holes are 0.500 from each other. At least that is my best guess for the back holes. Dovetails with half inch hole spacing are rare, I don't know a current source.
This is a source for scope bases:
Champion's Choice Single Step Bases
http://www.champchoice.com/store/Main.aspx?p=ItemDetailOptions&item=A175
My standard Warne rimfire rings and B-Square rimfire rings will fit on these dovetails. The dovetails in the picture are 0.175 high, but until I have a barrel mounted, I won’t know what height of dovetail will allow the scope objective will clear the barrel. On my Anschutz rifles, I am using a 0.225” dovetail with my Redfield 3200 scopes. An Anschutz barrel has little to no taper.
Since the rear holes are spaced 0.500” I can take a 0.860”dovetail and drill a hole up a half an inch from one hole and that should work. If I go this route, I will epoxy the dovetails to the receiver and attach with screws.
While this approach will work, will cost less than a $400.00 set of rings, I think a flat aluminum Picatinny rail, something I could drill properly spaced holes, would be a better way to go. I do see that flat picatinny rails are available, but these are pre drilled.
http://www.rakuten.com/prod/picatin...r&adid=29963&gclid=CLjalM-Vq8ECFSgS7AodxUYAOA
The picture looks nice, but I have no idea if the rail is flat or contoured on the bottom nor how long it is.
http://www.opticsplanet.com/evolution-gun-works-browning-bar-rifle-picatinny-rail-scope-mount.html
I would prefer the Picatinny as I could use Weaver scope bases. I like Weavers, they lock inbetween the slots and the bases won’t move under recoil.
Bases generally had hole spacing’s of 0.860” and 0.562”. These don’t convert to nice round mm dimensions so I have no idea where this crazy convention started or why. The front holes on the square bridge are 0.860” apart, but the back holes are 0.500 from each other. At least that is my best guess for the back holes. Dovetails with half inch hole spacing are rare, I don't know a current source.
This is a source for scope bases:
Champion's Choice Single Step Bases
http://www.champchoice.com/store/Main.aspx?p=ItemDetailOptions&item=A175
My standard Warne rimfire rings and B-Square rimfire rings will fit on these dovetails. The dovetails in the picture are 0.175 high, but until I have a barrel mounted, I won’t know what height of dovetail will allow the scope objective will clear the barrel. On my Anschutz rifles, I am using a 0.225” dovetail with my Redfield 3200 scopes. An Anschutz barrel has little to no taper.
Since the rear holes are spaced 0.500” I can take a 0.860”dovetail and drill a hole up a half an inch from one hole and that should work. If I go this route, I will epoxy the dovetails to the receiver and attach with screws.
While this approach will work, will cost less than a $400.00 set of rings, I think a flat aluminum Picatinny rail, something I could drill properly spaced holes, would be a better way to go. I do see that flat picatinny rails are available, but these are pre drilled.
http://www.rakuten.com/prod/picatin...r&adid=29963&gclid=CLjalM-Vq8ECFSgS7AodxUYAOA
The picture looks nice, but I have no idea if the rail is flat or contoured on the bottom nor how long it is.
http://www.opticsplanet.com/evolution-gun-works-browning-bar-rifle-picatinny-rail-scope-mount.html
I would prefer the Picatinny as I could use Weaver scope bases. I like Weavers, they lock inbetween the slots and the bases won’t move under recoil.
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Gunplummer
New member
If you have no access to machinery, Brownell's used to sell blank lengths of Weaver base material.
Perhaps something like this?
http://www.brownells.com/optics-mou...ifle-bases/picatinny-base-stock-prod1651.aspx
Or perhaps something more like this?
http://www.brownells.com/optics-mou...ses/blank-scope-ring-base-stock-prod9851.aspx
http://www.brownells.com/optics-mou...ifle-bases/picatinny-base-stock-prod1651.aspx
Or perhaps something more like this?
http://www.brownells.com/optics-mou...ses/blank-scope-ring-base-stock-prod9851.aspx
Oh, c'mon! Picatinny rails look like a toothache. A real rifle deserves real scope bases and rings. You can buy blank bases (like these) and cut dovetails in them. Or Leupold QD mounts, if you'd rather. Or Leupold QRW bases and rings, if you just gotta have simple.
This looks to be an even better option, for the Dumoulin receiver: IR-RU-22 Ironsighter bases. These bases fit the Ruger 10/22, the hole spacing is 0.862” and 0.500” and they will work with Weaver rings. They are aluminum so I can easily remove the slight Ruger receiver arc from the bottom.
Turns out a one piece Weaver base for the Marlin 336 is workable, as long as you are willing to cut it into two sections. It is flat bottomed, the back has a 0.500” hole spacing, the front holes have almost a 0.862”, but with oval head screws, it tightened down on my Dumoulin receiver.
Turns out a one piece Weaver base for the Marlin 336 is workable, as long as you are willing to cut it into two sections. It is flat bottomed, the back has a 0.500” hole spacing, the front holes have almost a 0.862”, but with oval head screws, it tightened down on my Dumoulin receiver.
I have taken the bases off, but it is not much. I was thinking of using the flat side of my grinding disc, maybe a file. I am going to take it slow and make sure that both bases are going down the same amount. I plan to epoxy the bases onto the top of the receiver.
I looked at a set of FN Mauser Redfield type bases. Huge curvature, way too much material to remove. However, the hole spacing was correct for front and back.
There may be a better solution that has not been found yet. There may be a set, or a combination of front and back bases from two sets, that would work better. The basic problem I have is I need an actual physical specimen to determine hole spacing and base curvature. I have not found this information on the web, all manufacturer's will tell you is what guns their bases fit.
I looked at a set of FN Mauser Redfield type bases. Huge curvature, way too much material to remove. However, the hole spacing was correct for front and back.
There may be a better solution that has not been found yet. There may be a set, or a combination of front and back bases from two sets, that would work better. The basic problem I have is I need an actual physical specimen to determine hole spacing and base curvature. I have not found this information on the web, all manufacturer's will tell you is what guns their bases fit.
I would just thread in correct dia/thread pitch screws, measure out/out with calipers, and deduct the shank dia. of the screws- same as you would measure groupings on a target.
Or, you could buy one of these:
http://www.use-enco.com/CGI/INSRIT?PARTPG=INLMKD&PMPXNO=946264&PMAKA=613-5903
As far as the matching the dia. of the receiver to the base, I don't think it's critical as you're going to bed it- but IMO, it would be important to remove material equally on both sides of the centerline so that the base will have equal contact to the receiver on both sides. If you don't have access to a mill, it might be better to just leave the base flat. My concern is that whacking at it with a grinder, and then torquing it down might tend to force the base off the centerline.
Honestly, I would only do a job like this on my mill. Aside from the curvature of the base, getting the screws precisely spaced, as well as centered on the rail would be very difficult otherwise. The rail could end up being off the centerline of the bore. Small deviations might be resolved with a windage adjustable base, but I think it's best done right.
JMO...machinists/gunsmiths chime in...
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I measured the cut, and it is 60 degrees.
Looking at curved top Mauser bases for modification:
Weaver S45 [steel rear 0.504" hole space 0.395" thick, 0.050" curve on bottom, 0.285" deep countersink 0.207" with 0.146" clearance hole] and Weaver S46 [steel rear 0.860" hole spacing, 0.220" thick, 0.069" curve on bottom, 0.110" deep countersink]
Too boring... will have to make a sketch.
I have some V blocks I have modified for holding Weaver mounts upside down for milling. I could easily mill the bottoms flat. But the mounts need to end up being the same thickness, and the Weaver #45 is too thick and the countersink is too deep. I would be milling up into the countersink.
Things that come to mind to do in addition to milling the bottoms flat:
1) Drill and tap the rear of the Mauser for 8-40 threads, and make a bigger diameter countersink and clearance hole in the #45 steel Weaver.
2) Make a bigger diameter countersink in the #45 steel Weaver and put a washer under the 6-48 screw head.
3) Search for other thinner steel scope bases with 0.504" hole spacing.
4) Consider Aluminum scope base options.
5) Just use two S46 front bases and drill and countersink another hole at .504". Cut the length down to 0.815" to get rid of the unused hole.
6) An S25 is a .504" space hole that is .248" thick. That is only 0.026" thicker than an S46 at 0.222" thick. An S25 in the rear, an S46 in the front, it just might work.
Looking at curved top Mauser bases for modification:
Weaver S45 [steel rear 0.504" hole space 0.395" thick, 0.050" curve on bottom, 0.285" deep countersink 0.207" with 0.146" clearance hole] and Weaver S46 [steel rear 0.860" hole spacing, 0.220" thick, 0.069" curve on bottom, 0.110" deep countersink]
Too boring... will have to make a sketch.
I have some V blocks I have modified for holding Weaver mounts upside down for milling. I could easily mill the bottoms flat. But the mounts need to end up being the same thickness, and the Weaver #45 is too thick and the countersink is too deep. I would be milling up into the countersink.
Things that come to mind to do in addition to milling the bottoms flat:
1) Drill and tap the rear of the Mauser for 8-40 threads, and make a bigger diameter countersink and clearance hole in the #45 steel Weaver.
2) Make a bigger diameter countersink in the #45 steel Weaver and put a washer under the 6-48 screw head.
3) Search for other thinner steel scope bases with 0.504" hole spacing.
4) Consider Aluminum scope base options.
5) Just use two S46 front bases and drill and countersink another hole at .504". Cut the length down to 0.815" to get rid of the unused hole.
6) An S25 is a .504" space hole that is .248" thick. That is only 0.026" thicker than an S46 at 0.222" thick. An S25 in the rear, an S46 in the front, it just might work.
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I'm into this thread a bit late.
The typical Mausers were made of low carbon steel ,like a 1020 which was carburized. Normally OK but wartime ones might be a problem. My '43 Oberndorf had spotty hardness on the receliver so I had it recarburized and hardened. I asked about their method and it was OK .You first made sure both locking lugs made contact and other necessary details.
After the war there was a big movement to use 4140 an excellent steel for many things . If you want better than that use 4340 as some have done.
The typical Mausers were made of low carbon steel ,like a 1020 which was carburized. Normally OK but wartime ones might be a problem. My '43 Oberndorf had spotty hardness on the receliver so I had it recarburized and hardened. I asked about their method and it was OK .You first made sure both locking lugs made contact and other necessary details.
After the war there was a big movement to use 4140 an excellent steel for many things . If you want better than that use 4340 as some have done.
Gunplummer
New member
If you want better than that buy an Arisaka, which is already 4140.