measurement help of your BR rifle rest

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plastikosmd

Guest
I am in the process of fabbing up my own front rest. I have only seen pictures of the fancy rest you guys own. I have searched the net and only seen reference to changes at 100yards regarding elevation. Could i get a range of measurements for overall height adjustment in inches/cm whatever. I am making the main elevation screw and need to figure out how much 'elevation' should be present. I would like to use one of your rests (sinclair, farley, whatever) for reference. This will be for precision shooting at 100yrd and some sigificant distance stuff. thank you
 
plastikosmd

The amount of elevation adjustment you need in a front rest really has nothing to do with distance you are shooting. There is less than one degree of angle required to change your point of aim from 100 yards to 1000 yards. So, what you need the flexibility for is to accomodate different benches and terrain. For that you want as much as you can build into a rest. Even then you'll still be making adjustments in the rear bag or rest, and the feet and speed screw, to get even more elevation or depression.

Many of us build our front rest to have two different elevation adjustments. A primary adjustment in a base column and a secondary adjustment in a center post. On mine, the primary is 2.5" and the secondary is 3.5" for a total of 6". You may think that you can get by with only a secondary post but if you make it long enough to handle extreme conditions, then you won't be able to screw it down far enough to use its total length.

Bottom line - build as much elevation into the rest as is physically possible. And I'll guarantee you, the time will come when you'll need more.

JMHO

Ray
 
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The worst case situation, on the low side, is when you are shooting slightly downhill, using a rifle that is very short from the toe of the butt stock to the bore CL. This is the situation that I find myself in shooting my 6PPC at Visalia. In order to give myself a little more room, so that I was not so close to bottomed out, I had my rest modified so that the plate that the bag sits on will go as low as 4.5". This is with a windage top. The base is a Hart, with the double rise feature, and I have not run out of adjustment when shooting on a range that is uphill from bench to target. Although going taller would not be as hard as going shorter, simply because one can fit spacers at the leveling points. Some time back I had a Wichita that was low enough for Visalia, but a little short for the Fresno range. I made some offset spacers out of aluminum and solved the problem.
 
thanks guys, you read my question and phrased it in a much more atriculate manner. This is really what I was looking for. As far as lowest height, this maybe a problem for me also. I think I will be limited to about 6" min off top of the table, maybe a bit more. I need a bit more help understanding the primary and secondary height controls. What I have now is a large keyed acme screw that could easily elevate 8" or so. The cost of this is the overall shaft length thus affecting a minimum setting. My plan was to have about 3-4 inches of 'screw' or fine adjustment. This screw rides in a sleeve that then is clamped to the base. By loosening this clamp the entire mechanism could be moved up and down, maybe over 2-3 inches, giving me a 'rough' adjustment. Is this similar to how the professional ones are made? Of course I will also have a bit more adjustment in the 3 feet, maybe 0.5-1.5 inches or so. I know this is also a loaded question, but what is the average height, off the table that the bottom of the windage top sits at? 8" +/-2? 10" +/-2 etc. This would give me some range to work in. thank you!
 
As Boyd said, be more concerned with getting it as low as possible. My coaxial rest top is 5" from the table to the top of the bag plate. I can remove the mariner wheel and get it to 4.5". I think 6" would be a very maximum height when fully extended. I would like to be as low as 4". Remember you can use a shorter rear bag to get more elevation and a taller one for shooting lower. I would definitely not use an acme thread. Too much movement per turn. Not enough fine adjustment.
Butch
 
A few hints-

Screw the feet as low as they will go. Then measure from the bench to the top of your "sleeve". That is the maximum length you can make your screw without bottoming out.

Make the sleeve as large a diameter as you can, and as long as you can. That will make it more stable.

Install some bearings between the sleeve and mariners wheel.

Try to design the two adjustments so that they lock with just one handle.

Ray
 
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thx for advice. well the acme is done/made along with sleeve. Bearings are also done. I have have a brass shim to try instead of my current bearing spacer to save space. RE- acme, If it is too much gain per twist I will try something else but what I have is adapted from another item. Those measurements help. When I get to assembly I will post pics. I am leaning toward flat triangular plate for base over 3 legs (with 3 threaded feet). I will add/customize a store bought windage top instead of fabbing one. no need to reinvent the wheel there
 
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