Pistolero
Well-Known Member
I turned out an aperture for the peep sight on my project .22 rifle. I got this Marlin 80G rifle, a magazine fed bolt
action on GB for $50. It had a missing rear sight, broken firing pin and missing butt plate, and no magazine. Once it
got here, the cartridge guide at the top of the chamber, a piece of flat spring steel was also broken off. This model
will feed shorts, longs and long rifles from the magazine, and needs this guide above the chamber to keep the shorter
rounds from going up too steeply during feeding.
I made a new firing pin on the lathe, a bit of a challenge because the fat part is maybe 3/16" and the long nose is about
0.090 or so, about 1 1/2 inch long, IIRC. I turned down the first 1/2 to diameter, then the next 1/2 inch and then the final bit,
so that I was never cutting on an overhang of over about 1/2 inch, and even then I had to take several 'spring cuts' at the
end to let it finally cut to true diameter, or pretty darned close. So, got it shooting.
Now, Numrich had the cartridge guide, but it is trapped between the barrel and the action.....got to pull the barrel. A big
pin is driven across to locate it, got it out, but then the barrel was still very tight. Heat and a special aluminum driving
bar let me tap it out of the action - not threaded. Replaced the cartridge guide and put the bbl back on and repinned it.
I started looking on eBay for a rear sight, but ran across a factory optional peep, and my action was drilled for it. The only
problem is that they are apparently fairly rare and prices were in the $100 to 200 range for complete units in top shape. I
finally found one missing the aperture and turning a bit brownish, but still not bad for $50.....doubling the price of the rifle
right there! I also found a proper Marlin new butt plate for the Model 80, and it fit well, just a hair oversized, so could grind
to a perfect fit.
I shot it for a bit with the aperture mounting hole like a ghost ring, but the front sight was way too low. I ordered a Williams
fire sight fiber optic replacement the correct calculated height and installed it in place of the original brass bead. Now it was
hitting where the sights were (adjustable) looking. I got a filler for the original back sight dovetail, and the final piece was
the screw in aperture.
I started with a piece of 1/2 OD 4140, turned to .490 as a knurling diameter and put a light knurl on the first 1/2 inch of the
bar. Then I cut it down to diameter to thread it. The thread is a non-standard size, a #10-40. Standard threads are 10-24 and
10-32, but with a lathe, it wasn't too hard....except that the snout is VERY short. My threading cutter wouldn't really work, just
too big and fat to cut threads close to the disk like I needed. So, I got a piece of 3/16 tool steel stock, ground it a bit narrower
and then ground a 60 degree thread cutting tip on it. I set it up with a larger tool cutter as a shim, then squared it up and centered
it. Now I can cut threads. After getting the threading done, I drilled the center hole all the way thru, then counterbored it
on both ends to prevent glint off the edge of the aperture.
Finally, heated it red hot and dunked in oil which hardens it and also puts a nice black oxide finish on it. I will not easily be
damaged.
Here are some pix of the aperture disk and the sight. It is kinda fussy work single pointing just a few fine threads next to a shoulder
like that, but I got it done. Still learning but having fun with it. It is a bit amazing at the roughness that these super closeup
pix show. I though it looked pretty nice..... don't us high magnification on your machining
projects.
Kinda fun to save an old rifle like this, and it is very accurate, feeds reliably. Just a nice old .22.
I'll pass it on to a grand nephew eventually.
Bill
action on GB for $50. It had a missing rear sight, broken firing pin and missing butt plate, and no magazine. Once it
got here, the cartridge guide at the top of the chamber, a piece of flat spring steel was also broken off. This model
will feed shorts, longs and long rifles from the magazine, and needs this guide above the chamber to keep the shorter
rounds from going up too steeply during feeding.
I made a new firing pin on the lathe, a bit of a challenge because the fat part is maybe 3/16" and the long nose is about
0.090 or so, about 1 1/2 inch long, IIRC. I turned down the first 1/2 to diameter, then the next 1/2 inch and then the final bit,
so that I was never cutting on an overhang of over about 1/2 inch, and even then I had to take several 'spring cuts' at the
end to let it finally cut to true diameter, or pretty darned close. So, got it shooting.
Now, Numrich had the cartridge guide, but it is trapped between the barrel and the action.....got to pull the barrel. A big
pin is driven across to locate it, got it out, but then the barrel was still very tight. Heat and a special aluminum driving
bar let me tap it out of the action - not threaded. Replaced the cartridge guide and put the bbl back on and repinned it.
I started looking on eBay for a rear sight, but ran across a factory optional peep, and my action was drilled for it. The only
problem is that they are apparently fairly rare and prices were in the $100 to 200 range for complete units in top shape. I
finally found one missing the aperture and turning a bit brownish, but still not bad for $50.....doubling the price of the rifle
right there! I also found a proper Marlin new butt plate for the Model 80, and it fit well, just a hair oversized, so could grind
to a perfect fit.
I shot it for a bit with the aperture mounting hole like a ghost ring, but the front sight was way too low. I ordered a Williams
fire sight fiber optic replacement the correct calculated height and installed it in place of the original brass bead. Now it was
hitting where the sights were (adjustable) looking. I got a filler for the original back sight dovetail, and the final piece was
the screw in aperture.
I started with a piece of 1/2 OD 4140, turned to .490 as a knurling diameter and put a light knurl on the first 1/2 inch of the
bar. Then I cut it down to diameter to thread it. The thread is a non-standard size, a #10-40. Standard threads are 10-24 and
10-32, but with a lathe, it wasn't too hard....except that the snout is VERY short. My threading cutter wouldn't really work, just
too big and fat to cut threads close to the disk like I needed. So, I got a piece of 3/16 tool steel stock, ground it a bit narrower
and then ground a 60 degree thread cutting tip on it. I set it up with a larger tool cutter as a shim, then squared it up and centered
it. Now I can cut threads. After getting the threading done, I drilled the center hole all the way thru, then counterbored it
on both ends to prevent glint off the edge of the aperture.
Finally, heated it red hot and dunked in oil which hardens it and also puts a nice black oxide finish on it. I will not easily be
damaged.
Here are some pix of the aperture disk and the sight. It is kinda fussy work single pointing just a few fine threads next to a shoulder
like that, but I got it done. Still learning but having fun with it. It is a bit amazing at the roughness that these super closeup
pix show. I though it looked pretty nice..... don't us high magnification on your machining
projects.
Kinda fun to save an old rifle like this, and it is very accurate, feeds reliably. Just a nice old .22.
I'll pass it on to a grand nephew eventually.
Bill
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