OK, well my latest AR180B arrived with the original mount removed and someone had attached a low profile aluminum rail to the receiver. It was "OK", but not the best.
The gunsmith who did the work, IMHO, was sloppy. The fasteners were tapped all the way through the rail (ugly) and black anodized rails look awful on a parked receiver. It was also way too low. Even using extra-high Leupold MkIV rings, I couldn't get the bell to clear the rear sight. I think it must have been set up to use an eotech with quasi-co-witness which is exactly not what I want in a varmint gun / paper puncher.
Here's the "before". The gunsmith used a mill, got the holes exactly 1.00" apart and milled the bottom of some rail from a round receiver to a flat profile to make this. Suffice it to say, my standards are higher than this, though the idea was basically sound.
So I started with a 10" chunk of Nightforce 1913 rail in steel from TSE. I shortened it in the mill to fit the receiver and milled down the height so that the rear sight channel allows the rear sight to be used, but keeps the mount high enough so that MkIV extra-high rings can place a Leupold rear scope bell just above the rear sight assembly as I didn't want to remove the iron sights. I also had to correct a cant in the mount - it had 40 thou of runout, presumably for making a 20MOA offset base, though this seems odd as it is supposed to be a raw gunsmithing blank. Anyhow, I reset it to zero in the mill since I won't need to shoot past 400 yards.
I drilled mounting holes in the mill using the DRO to place the holes exactly 1.00" apart to mate with the existing receiver holes. The mount was still very heavy so I hogged out a bunch of hollows in the mill spaced evenly between the mounting holes. This reduced weight by about 35%.
I also planed down a bunch of 8-32NC screws and cut new slots. These need to be low-profile to not interfere with the bolt and I made the front two smaller still to not interfere with the gas piston's movement. They work great now, whereas before the gas piston was contacting these front two fasteners.
And here it is mocked up:
The mount is at my buddies for glass bead blasting and maybe tomorrow I will parkerize it and install for good
Tinkering is fun and this will blow away the standard mount or the Stormwerks mounts which aren't nearly as stable as a rigidly attached solution made of steel.
The gunsmith who did the work, IMHO, was sloppy. The fasteners were tapped all the way through the rail (ugly) and black anodized rails look awful on a parked receiver. It was also way too low. Even using extra-high Leupold MkIV rings, I couldn't get the bell to clear the rear sight. I think it must have been set up to use an eotech with quasi-co-witness which is exactly not what I want in a varmint gun / paper puncher.
Here's the "before". The gunsmith used a mill, got the holes exactly 1.00" apart and milled the bottom of some rail from a round receiver to a flat profile to make this. Suffice it to say, my standards are higher than this, though the idea was basically sound.
So I started with a 10" chunk of Nightforce 1913 rail in steel from TSE. I shortened it in the mill to fit the receiver and milled down the height so that the rear sight channel allows the rear sight to be used, but keeps the mount high enough so that MkIV extra-high rings can place a Leupold rear scope bell just above the rear sight assembly as I didn't want to remove the iron sights. I also had to correct a cant in the mount - it had 40 thou of runout, presumably for making a 20MOA offset base, though this seems odd as it is supposed to be a raw gunsmithing blank. Anyhow, I reset it to zero in the mill since I won't need to shoot past 400 yards.
I drilled mounting holes in the mill using the DRO to place the holes exactly 1.00" apart to mate with the existing receiver holes. The mount was still very heavy so I hogged out a bunch of hollows in the mill spaced evenly between the mounting holes. This reduced weight by about 35%.
I also planed down a bunch of 8-32NC screws and cut new slots. These need to be low-profile to not interfere with the bolt and I made the front two smaller still to not interfere with the gas piston's movement. They work great now, whereas before the gas piston was contacting these front two fasteners.
And here it is mocked up:
The mount is at my buddies for glass bead blasting and maybe tomorrow I will parkerize it and install for good
Tinkering is fun and this will blow away the standard mount or the Stormwerks mounts which aren't nearly as stable as a rigidly attached solution made of steel.
