I would start looking at Numrich Gun Parts Corp.They may be found on the web.Also check Brownells Gunsmithing catalog.
Start with gunpartscorp.com then eBay and auctionarms.com
The front sight is mounted on a "dove tail", you just tap it out of the notch in the ramp with a hammer and a punch or drift pin. The ramp is welded on, you cant take it off.
The standard mod 70 had a Winchester bead front sight on a ramp base with a sight cover. The standard rear sight was a Winchester 22G open sight. The rifles chambered for .375 H&H Mag had the Lyman 6W folding rear sight. Model 70 National Match (chambered for .30-06 only) had a Lyman No. 77 front sight on a forged ramp sight base and a Lyman No. 48WH rear sight. All receivers were tapped and drilled for popular scope and iron sights. The Model 70 Super Grade had a Redfield full gold bead front sight on a ramp with sight cover and a Winchester 22G open rear sight. (with acknowledgement to The Gun Digest, seventh edition, 1953)
No. sales@countrygunsmith.net
Only 1 screw is visible, there are 2. Remove front sight hood, drive dove tail blade out from left to right. The other screw is visible now. Remove both screws and the ramp comes off.
Try e-gunparts.com
Winchester buckhorns often came with hoods. Look at the sides of the front sight ramp.Are there slots cut into the sides of the ramp? If there are, the sight originally came with a hood.
You must hire a contractor to measure and build a wheelchair ramp in front of your house.
The "P" designates peep rear sight & ramp front sight, not sure of the "G" designation.
1. Remove the screw to the rear of the front sight ramp.2. Remove the "blade" from the front sight ramp.3. Remove the screw from the front of the front sight ramp (which was formerly seated under the "blade").
If your rifle is new in the box condition(never fired)and you have the box and hang tags still with it.The minimum price is 600 dollars.Some Winchester collectors are paying in excess of 1,000 dollars for this model in the condition you have described.
Ramp/live model.