Looking for Rail Gun Advice

J

Joe Woosman

Member
I'm trying to set up an indoor test range and I think a rail would be the most practical setup. I don't know much about rails. I wouldn't think I'd need anything too fancy, just functionally accurate. The best I can see from pictures, the tracking mechanisms look very similar. Older rails appear to have a thick plate as the top frame and the newer ones look like they use an I-beam design. How important is the design on these? Any input appreciated.
 
It is very important for a rail gun to truly return POA everytime precisely. Otherwise it's not worth the trouble. Movement on the bench is often a problem. Slop in any part of the adjustments as well as torque reversal can be tough to correct as well. Gun handling can also be an issue on light designs. Vibrations in the gun will need to be addressed. That really shows up with a rimfire with its triple barrel time. Other important factors in the design are more specific to the user, such as control layout and function. Go to a large unlimited match and you will see a lot of variations, though the sliding V rail part is pretty much the best and universal to all good rails.
 
When you make an adjustment to a particular aiming point, reversing the travel direction of the last adjustment made and fire the gun, quite often the new point of aim will settle in, being somewhat different from where you put it. The best way I personally have come up with to reduce this, is to use thrust bearings and pull(rarely copied) the spring into compression rather than push(commonly used) it. It is mostly a windage problem since most elevation adjustments employ gravity rather than a spring to maintain the position.
 
When Jerry Hensler shows up at a Benchrest Match ,that I attend. I make it over to his Loading spot to see what new designs/gadgets he's come up with. Its like attending a Benchrest science exhibit. I listen intently to his explanations about how his innovations work. I don't always understand all the tech talk,but at the end of the Match his targets prove that his ideas work. A true Benchrest Guru. Like Butch says...Lissen to Jerry.



Glenn
 
I won’t pretend to know anything about rails but I do have a fair amount of experience with mechanical design and harmonics. I would imagine the purpose of the spring and thrust bearing is to take up slack in the threads of the windage assembly. An elimination of the spring variable might be possible by eliminating the need for the spring. I can envision a threaded shaft under tension via thrust bearings and a precision half nut that would ride on one side of the threaded shaft, also under tension towards the shaft. The engagement of V threads under tension would eliminate any slop in the assembly and the large contact area of the half nut combined with the tensioned assembly should allow harmonics to pass through rather than resonate. Just a thought. Not sure if it addresses any real problems.
 
I have never tried the halfnut approach. Keep in mind that windage, elevation, and stepper cam adjustments need to work seperately on a common point mount without affecting each others position.
 

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Wow. You've got a lot going on there Jerry. Much different than the other rails I've seen. I like it! Thanks for sharing the pics. Makes me want to build one instead of buying one. If only there were more time in a day....
 
The busy look is because the gun is my old CF rig converted to RF which is a score format with 25 record bulls. In making this transition, a lot of things showed up that didn't appear in CF. The steppers can accommadate a 5 x 7 matrix of aiming points. If you look carefully, you can see a lot of small differences as compared to traditional rail designs.
 
That answers a few questions. I wasn't sure why so many adjustment screws. I never thought of a matrix of aiming points like you described. I do see a lot of differences from others I've been looking at. I like your no lock nut design. Is that damper design used in CF at all?
 
No, the damper is for RF. The skinny barrel with a tuner on the end vibrates for a long time compared to a CF. The damper is a close fit piston/cylinder design that uses air compression/vacuum to kill it. The gun is a single shot with no magazine, but 25 record shots can be fired in about 2-3 minutes. This allows one the luxury of running a condition in spurts rather than constantly guessing the hold over in the 20 minute time allotted. Without the damper, that is not possble with any expectation of accuracy.
 
I have not fired a CF round since the Nationals in Midland. I sold most of my surplus CF BR stuff that year. I kept enough to field a SP or a rail, should I want to at some point in the future, which is not likely. 27 years was enough for me. I did have a pretty good first year with ARA. With the current economic outlook, I probably won't do any shooting at all this year.
 
Jerry H said:
I have not fired a CF round since the Nationals in Midland. I sold most of my surplus CF BR stuff that year. I kept enough to field a SP or a rail, should I want to at some point in the future, which is not likely. 27 years was enough for me. I did have a pretty good first year with ARA. With the current economic outlook, I probably won't do any shooting at all this year.
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Sorry to hear about your decision to move on to something else. 27 years is a long time to do anything. You might as well write a book about all your ideas/inventions that added to the objectives Of the Sport.

Good Luck at ARA.



Glenn
 
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