I am also building a DE gun, it is about 80% complete I would guess. I am down to the bolts and firing components. Having read everything I could find about the gun I became very worried when I read of all the misfires, extractor breakages, hard to crank, breaking off the soldered in bosses for the crank etc. I also did not find a single gun that would fire repeatably. So, this new thread and addressing the known issues is a welcome find. I have not worked on my gun in about a year or so because I got sidetracked on home cnc retrofits but am going back to the gun very soon.
In my research here are the issues I found on the DE gun and ideas I have to correct them. Firstly, I noticed the RG&G gun seems to fire reliably so I looked at their plans for ideas and the possibilities of incorporating them into the DE gun internals.
Extractors: The DE ones have no room for error, dirt etc. and are commonly broken off during firing. First choice would
be a standard spring loaded extractor finger like the RG one, if it could be worked into the DE design.
Nearly every commercial built gun out there uses a spring loaded finger method, for a reason no doubt.
Second possibility would be a spring steel extractor that clips around the bolt, sort of like a pocket clip on a
point pen, Marlin did this on many of their 22\'s. I bought a Marlin part to look over for ideas.
Hard Cranking: This is closely related to firing pin spring pressure which is widely known. I put a 3 piece ball thrust
bearing recessed into the bolt carrier along with a ball bearing for the mainshaft in the cocking ring. More
bearings are a possibility but harder to retrofit into a already built gun.
Have not looked closely at this yet but it appears the RG gun cam profiles are a LOT different than the DE
profiles. The angles that the bolt lug is pulled up along with the transition into that angle would probably
effect cranking effort a lot I would think. Perhaps, just perhaps a reshaping of the cam profiles would
make for a smoother running, easier to crank gun? Look at the RG homepage, there is a cam image there.
The bolt lug on the DE design runs into a sharp turn up the angle on the cam, the RG cam is much more
gradual, any wonder the DE gun cranks hard!
Firing Pins: For reliable firing with the least spring pressure, non rotating pins with a properly shaped point are a must.
There is a lot of info out there on the proper shape of the point, basically it should be shaped like a
exclamation point and tapered slightly. Proper firing pin geometry will allow lighter springs which is highly
desireable.
Breaking off the Crank Bosses: I have read several reports of people breaking off the silver soldered round bosses which t
the crank slides through. This is no real surprise, its a pretty weak area and a lot of force can be applied.
Again, a idea from the RG gun. I am going to look into bolting on a brass piece to the cocking ring, bored
for the crankshaft to pass through and clearanced for the gear. This would be a huge gain in support.
Lastly, Would it be possible to stuff the RG gun internals into the DE gun housing? Being able to disengage the firing pins would be a big plus. The RG gun housing is larger in diameter but maybe with some redesign could be stuffed into the DE housing?
? That would be the best of both worlds.... the scale looks of the DE gun and the firing reliability of the RG gun. Nobody ever tried this from what I have found looking around.
I\'m anxious to get back working on my gun and hope to brainstorm with others to get a reliable firing gun.
George
