Anthony,
The extra hardening probably will help, to what extend I don't know. My logic tells me that if Ivan can break his sear under 150 kg of force, the problem lies with the metal not the hardening. As far as I know hardening makes the metal more brittle and not actualy much stronger, a bit maybe. Why not machine a completely new trigger sears, at the most there will be only two. One for ur finger and one for the shaft end sear. The other point to notice is that a wider or thicker sear will last longer cause it has more surface area to bear the load. I don't know RA trigger sears but my non- XHD JBL uses about 2mm thick trigger sears. The XHD version has extra surface added/welded which is made of Tungsten Carbide, perhaps some 4mm thick. The Rife sears are 4-5mm thick.
If u can get ur hand on Monel, it will be best. Use 304 instead of 316 SS. Stay away from SS with L rating which means low carbon. This is highly corossion resistance but strength wise not good. 17-4 SS is another possibility, shaft is made of this, I heard.
The next weak link are the trigger pins which hold the 2 trigger sears. If the pins can handle the load, next watch out for the pistol grip. If it is made of plastic, it has to bear the load of the pins. 150 kg relying on small pins that exert pressure on the plastic pin holder ( in pistol grip ) is downright dangerous. Imagine the typical pin size is about 2-3mm diameter. When the gun is loaded with 150kg of force, 2 ends of the pin which hold the sear for the shaft will be handling the load. Since the load is going towards the muzzle, the effective load area for the pin holder is not the total circumference, but 1/2 of it only.
If you can ever make both trigger sears thicker and thus stronger, you need to worry most of the pin holder in that plastic pistol grip, later worry about the pins. The older JBL Woody uses plastic pistol grip ( brown color ), the failure is at that pin holder, cause it is made of plastic.
The other factor to consider is that, is RA trigger sear design good enough to sweet release 150kg of force ? Some trigger will become super hard ( if not jammed up ) one it reach the threshold limit. Non XHD JBL is one of them, that is why the XHD one is different. Riffe trigger is unique. U can use 2 or 5 bands and the release is almost the same, a hallmark of a good trigger. The way it is installed on the gun is another strong point. It comes in a unit including its own housing. Just drop it in , secure it and use it, unlike the JBL that you need to dismantle the pistol grip and can access the trigger sears one by one. The beauty of this trigger assy is that, since it has its own housing, the housing bear the load plus two big bolts that secure it. The load is then transfered to the recess cut out in the teak barrel and the two bolts. Wood is strongest when you press it againts its grain, and it sure can take a lot of pressure.
The Metal Tech Riffe is another trigger mounting genius design. It is assembled as such, the load is beared by both the plastic butt end and two bolts that goes thru the thick aluminum barrel. Can't explain properly with out photo.
I fear one thing most, ur RA pin holder in the pistol grip. The best tigger sears and pins design and material is useless if it eventualy break that pin holder.
Why don't you get Omer pistol grip and modify it somehow. I heard it can take 2 x 20mm safely. Confirm with Omer on that kind of pressure.
Becareful,
IYA
