Frozen screw...

[Scout Sniper]

Yes the Pyropen is gas fired, cool little tool. It has the power to get the heat in quick enough if you ramp the power up!

It does sound like a small jet engine and with a quick nozzle change is also a blow torch!

[M1 Thompson]

I'd like to see some photos of exactly what we are talking about here. It may help work out the best way to deal with this screw.

Here's the culprit.

[RobD]

I'd get out my impact driver...

[Roger Payne]

If it's really that tight I'd consider whether it was absolutely essential to remove it in the first place. However, if so, it might be worth making a rudimentary tool akin to the striker disassembly tool to grip the two semi-circular recesses either side of the threaded stem on the volley sight range plate. This will at least help to stop it twisting & potentially ripping the woodwork if it does move if you really have to give the screw some serious wellie.

Before doing that, as you've been advised above, a little local heat (obviously with care because of the proximity of the wood), combined with a little clutch/steering system fluid. I was recommended this years ago as a better alternative to most commercially available penetrating oils. Even so, you need to be patient, putting on several applications, & leaving it for a couple of days to soak in. It has worked well for me in getting many rusted in screws in SMLE's, & also the tiny 8 BA screws in rusted up No32's. It's also cheap & readily available as you can use old discarded stuff - it doesn't need to be new.

[M1 Thompson]

I'm not concerned with the stock. It's been cut down and sanded to the point of being useless except as a source of patch material. A set of reproduction handguards overhang the stock by 1/8". Here's an overall shot of the rifle as I purchased it. Luckily, the barrel wasn't cut down. I still cannot understand why someone would take a rare rifle and cut it down. Whatever the reason, they took a rifle worth maybe $1,000, at the time, and turned it into $100.

[Roger Payne]

If the stock is truly scrap then you could always cut round the plate & screw removing them from the wood completely. You'd then be able to get at the screw threads much better. The penetrating oil & heat would go straight to where they are needed. It might sound drastic, but if that forend is just firewood.....

In fact, you could hold the screw shank in a small vise & try rotating the plate to unscrew it (after a good soaking with a penetrant).

[30Three]

Is there any chance of finding a replacement screw? Seeing as these have been sanded and damaged. If so I'd just drill the head of the rear side and punch out the screw.
If you are scraping the wood, then do as Roger says; destroy the wood to save the part.

[M1 Thompson]

Is there any chance of finding a replacement screw? Seeing as these have been sanded and damaged. If so I'd just drill the head of the rear side and punch out the screw.
If you are scraping the wood, then do as Roger says; destroy the wood to save the part.

I haven't seen one yet. The other alternative is to have one made. If I had a tap and die, I could make one myself. But, I understand that the threads are proprietary.

[Patrick Chadwick]

If the info in Stratton is correct, then an 8-36 thread, possibly thinned down a few 1/1000", ought to be close enough to be eased in. My experience is that ordinary steel screws can often be reformed a touch by the (usually) much harder gun parts into which they have to be fitted.

(Later)
I think the dimensions in Stratton are rounded up. The (no longer available) Enfield Apprentices site had a table that showed 0.1656" x 37 tpi.
8-36 is 0.164" x 36 tpi. So no need to thin the thread, just grease it well and use the method "In until it sticks, then screw it out. In a little further, then out again..." etc. and it should be reformed by the dial sight thread, especially as the length of thread is quite short.

The most important piece of equipment here is your patience!

P.S: Have you tried the counter-intuitive method of first trying to TIGHTEN the screw as hard as you dare!
This can sometimes break the bond that is causing the screw to stick.

[Scout Sniper]

100% would come out with automatic centre punch!!