Different books

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OldRanger
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Different books

Post by OldRanger »

So what do you do when different books give really different data? For instance the sierra book says 43.5 is the max Varget to use with a 168 gr smk. But the Hodgdon website say 46 is the max. And both claim the velocity will be similar (2700 for the sierra book, 2731 for the Hodgdon). I don't have a chrono yet to verify either. I started lower and worked up to 46.5 with no signs of high pressure at all. My best ladder groupings came in right at 46. So would you shoot loads 2.5 grains over what one book says is max? Again, no primer flow, no primers pushed out, no cracks, no brass flow into the ejector groove, no flattened primers and no difficulty extracting.

Oh, and the Hornady book says 45.5 max. *sigh*
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Jerry G
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Re: Different books

Post by Jerry G »

Any rifle you are going to shoot in competition should not be shooting max loads unless you have a pickup full of rifle barrels. $400 to buy one and then the cost to have it reamed and head-spaced is something I don't like to pay for every couple years.

I would start with a low range load and work up to a velocity and energy needed to take down a ram. I am convinced that any bullet around 140 gr and up does not need to go much faster than 2650 fps. I also believe you should shoot a lighter bullet at about 2650 to 2700 fps for the close 3 animals.
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Re: Different books

Post by OldRanger »

I'm shooting 150's with 43 grains of 4064 for the closer 3, and 168's at the rams.

But my question is more about the book differences. What if one had 40 grains for a low end, and another had 43? For the same powder bullet combo. I know I'm going to work up from a floor, and possibly down below it a bit, but what number would you use?

After I get to actually see my rounds hitting steel, and then get a chrono, I can adjust. I'm just going in an accuracy band for now.

But how do you determine which book or starting value you use?
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Re: Different books

Post by yankee »

Different numbers because: Different barrels, different chambers, different actions, different barrel lengths, different ways of measuring pressure, different cases, different primers. I would start with the low numbers less 10% and work up. To get a rough idea of your velocity. Shoot a group at 200 then move out to 500. How many minutes did you come up and put that into the reloading tables for the bullet in hand and you should have a rough velocity. Shoot what the rifle likes and is accurate. Remember you have to hit them before you knock them down.
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Re: Different books

Post by OldRanger »

Good idea with the minutes from 200 to 500 to determine velocity. Thanks.
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Re: Different books

Post by Jerry G »

That only works if you are shooting the same load for all animals. However, I suppose you still get a 200m zero with your ram load and check it at all the distances. You can back into a velocity with a good ballistic program and 4 data points.

I have found that if I use the different BCs for slower velocities I can print out a sheet that is real close to what my rifle does. Sierra does give several BCs for varying velocities as your bullet moves down range.
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Re: Different books

Post by OldRanger »

Or I could just buy a chrono. But not this year, I just bought the gun and a full reloading bench.
I buy all my guns from t-rex. He's a small arms dealer.
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