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Post by zimmerstutzen on Sept 26, 2007 16:37:14 GMT -4
There's been alot of discussion about what caliber etc. The following table may be useful for understanding the difference on a target (animal) of various calibers.
Ball Size Sq. Inch hole
.310 .0754 .350 .0962 .390 .1195 .440 .1520 .490 .1885 .530 .2206 .570 .2552 .610 .2922 .740 .4300
A .490 ball punches a hole twice the size of a .390 cal ball A .530 ball makes a hole that is about 15% larger than a .490 ball. a .570 ball makes a hole nearly 30% larger than a .490 ball.
In addition, the larger the round ball the better it retains energy out to 100 yds.
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Post by bob1961 on Sept 27, 2007 9:01:55 GMT -4
here's some drill bit sizes fer ball blocks fer the different calibers too....................bob
.32 = 21/64" .36 = 3/8" .40 = 27/64" .45 = 29/64" .50 = 1/2" .54 = 35/64" .58 = 19/32" .62 = 5/8" 69 = 11/16" * .75 = 3/4" * (needs to be filed after drilling to fit)
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Post by zimmerstutzen on Sept 27, 2007 15:24:59 GMT -4
If you want to make a bullet board, drilling the cleanest edge holes can be a challenge with a regular drill bit or spade bit. Use a forstner bit. They cut extremely clean holes right through, but use a piece of scrap wood under your stock.
Also use the hardest densest wood you can find for a bullet board. Rock maple is good, osage orange, oak is ok, but rather open grained. Avoid pines, poplars, and other soft woods.
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Post by ralphi on Sept 28, 2007 16:58:27 GMT -4
I agree on using the forstner bits my question to all is how thick should the ball board be 1 inch 3/4 inch 1/2 inch 3/8 inch or what ?
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Post by bob1961 on Sept 28, 2007 23:20:43 GMT -4
right now my .50 block is 3/8" thick, so that when the PRB is pretty much flush with the top and sticks out the bottom by a little more than a 1/16" to center it on the muzzle before poking it with a short starter.................bob
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