Front rest and rear bag technique to keep on target for 6.5X47L

[BoydAllen]

You have come to the right place. Since I was heavily involved in building a range that has 42 benches that do not move, trying to learn more about bench design and construction has become a hobby. While others look at the shooters in pictures taken at the firing lines of benchrest matches, I am also eying the benches to see if I can discover their construction details. Check your PMs

 

[artbosco]

Boyd - I've got a friend with some ranch land nearby (Austin outskirts area) that wants to convert it to a training range. He hasn't got the capital to do that yet, but he said I can shoot there whenever I want. This would allow me to tune my rifle without the "ceasefire" interuptions I experience at the public range I go to. However, to use my friends ranch for tuning, I would need to set up a benchrest to fire on. Any suggestions how I might build one.

Here is an excellent article on materials, design, top shapes, pictures, etc., etc., :

A Short Study Of Benchrest Benches

www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CDEQFjAA&url=http%3A%2F%2Fbenchrest.com%2Farticles%2Fbenches.pdf&ei=-CcaVPqbGMed8gGAzIGIBA&usg=AFQjCNFycC3muI8fBZFb82rNXmcPmrZfwQ&bvm=bv.75097201,d.b2U

 

[Cassidy]

Great ideas for benches.

 

[Cassidy]

I talked with Bill Shahane today about how to add weight to the end of his ST-1000 Tracker stock butt (my rifle discussed above). He said to drill a 1" diameter hole (start drilling as low on the butt end as I can without ending up drilling through the side of the stock) and place enough lead in the 1" hole to balance the rifle. So now, since we need 1 pound 6.8 oz of weight (which is 1.425 lbs) on the end of the butt to balance the rifle, the question is how long a piece of 1" cylinder of lead will provide this weight, meaning how deep should I drill the 1" hole to get this 1 pound 6.8oz lead weight once the 1" lead cylinder is placed into the 1"diametr hole. I thought some of you might enjoy conjuring up high school geometry to figure this out. See if I screwed up the following calculation (some of you physics types are going to have more to say). The specific gravity of lead is 707.9 lbs/ft3, so the volume of lead needed to get 1.425 pounds is: 1.425 lbs divided by 707.9 lbs/ft3 = 0.0020 ft3 of lead. So I need 0.0029 cubic feet of lead to get 1.425 lbs of lead. Next is to determine the length of a 1" diameter lead cylinder to get 1.425 lbs. Unless the web steered me wrong, the equation to figure out the volume of a cylinder is pi times radius2 times the height of the cylinder. This means that the height of the cylinder is equal to the volume of the cylinder divided by (pi times radius2); this is 0.0020ft3 divided by (3.1416 times 0.0467 ft2); the 0.0477 is the 0.5 inch cylinder radius stated in feet. The result is 0.2919ft, which is 3.503 inches. If this is correct I need to drill the 1" diameter hole slightly more than 3.5 inches deep to get 1.425 pounds of lead into the butt of the rifle. See if I screwed up.

I want to correct my calculation above. The 0.5 inch radius equals 0.04167 feet, not 0.0467 or 0.0477 feet as stated above. Using this corrected value, the 1" hole needs to be drilled 0.367 ft which is 4.40 inches or about 4 and 3/8" deep. My typo.

 

[Phil]

You should also figure in the size of the hole and the lead plug....

If both are at 1" you will, most likely, have some difficulty getting the lead in and possibly stressing the wood stock.

The hole either needs to be a smidge oversized or the lead needs to be that smidge undersized and longer to compensate for the reduction in diameter...

The lead plug can be epoxied in to prevent movement.

Sorry for mucking up your math, just trying to help avoid a potential problem...

Phil.

 

[BoydAllen]

It won't be as dense as solid lead, but you can always pour in a lead shot and epoxy mixture.

 

[Cassidy]

No problem, Phil. Thanks Phil and Boyd for the feedback. Am still working the rifle weight problem since adding the lead will bring total rifle weight to over 17 pounds; now trying to figure out how to deal with it. If I add lead to a 1" drilled hole, I can get 1" diameter lead rods from the web inexpensively and turn them down slightly to fit into the drilled hole. Not going to do this yet until I figure out a reasonable way to get to 17 lbs overall rifle weight and also balance the weight on the front and rear rests.

 

[johara1]

I would balance it between the front of the receiver to about 2" out the barrel for a starting point. just tape a bag to the rear but on the side of the stock and start filling it with lead shot when it balances and melt it in a 1" copper piece of pipe. now either cut the pipe off and bore a hole to fit or leave the pipe on and bore a hole to fit. fine tune with your fore end stop ……… jim

 

[expiper]

Cassidy,,,,no matter what you do you will have to re-aim the rifle after each shot,,,and this thread has morphed into a question about lead weight,,,as suggested ,,I use #9 lead shot (the finest that I culd find spur of the moment,,) just weigh it on your handy scales and weigh the epoxy then mix up the mud and smear it in the hole,,,(put lead in dry to be shure you can get it all in there and drill a deeper hole if necessary,,,this mixture can be drilled out easily if your next bbl or scope is heavier and puts your rifle over the limit,,,,and allow a cupla oz for scale error and common sense,,,,,Roger

 

[johara1]

If you get them balanced then you will go on to how to make them track……. One that is tracking properly does not have to be adjusted on every shot but it will come back in the box on every shot…. The reason i use pure lead you can get more weight to the rear for balance and it doesn't take up so much room like adding shot to epoxy…… jim