I shot a ladder test for my STW

remingtonman_25_06

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Joined
Jun 4, 2003
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Location
Hermiston, Oregon
I need to know how to post pics. I took them from a Nikon digital camera. Its loaded on the computer. Do you click on image on the instant ubb code? What do you do from there. Any help is appreciated. I need some experts to look at this ladder test. I got about 4 seperate groups at 300 yards.
 
Go to photobucket.com and set up a free account. Upload your pics, highlight and copy the bottom line under your photo (it will start and end w/
 
I went out yesterday to do a ladder test for my new 7mm STW. I aquired it in a trade from a friend for my 7mm Rem Mag in a black shadow. He did not want the weight or bulk of the bigger STW, so he offered to trade since he knows I like the upper end of the velocity scales. Anyways, the rifle is a Win mdl 70 Classic. It has had the trigger worked on and it wears leupold 2 piece base and a vari x2 3-9x50 with fine duplex. I am ordering another set of tactical bases for this rifle, as I might end up putting that new MK4 I just bought for my RUM on my STW. Anyways, I have always liked the 140g for deer so I started there. I had H-1000 and a little IMR-7828. I used Fed 215, Rem cases, and the OAL was 3.6" for all tested. I only tested a few rounds at first. 78g and 79g of IMR-7828 gave me 2 shots within 1/2" but with a flyer of 1 inch on the 3rd shot. I loaded 80g and 81g of H-1000 and found the same results. The first 2 are touching with a big 3rd flyer. Usually around 1.5" for H-1000. I am testing in the desert basically, I am thinking barrel heat is causing these. I am letting my barrel cool 3-4 minutes and still after the 2nd shot, the barrel on the STW and RUM are HOT. It is 98 degrees here in Hermiston. I tested velocity and IMR-7828 produced 3400 and 3450. H-1000 was running 3175 and 3250. I did not really know what to do, so I loaded up a ladder test with H-1000. I started at 78.5g and went to 83g. Here is the target. By the way, I loaded up 5 rounds to "foul" the barrel and shot 4 of them at 300 to zero the rounds. It put 3 into 1.9" and then flew the 4th about 3 inches high and right. This was using 79g of H-1000. I like the 3 shots though.
8xj5lf.jpg
 
to shoot the ladder and get any meaningful information it requires a chrono to spot the nodes and to go up in about .2-.4 increments on the powder. I like to use .3 increments.

harmonic nodes will be spotted by both groupings of bullets and the MV will tend to group. For example they might be 10fps apart for say three rounds and then jump to 20-25 on the 4th shot and it should impact away from the previous group.

Each ladder can only work one component for variation. Most tend to know what case to use, what primer and what bullet. The variable is powder charge, seating depth and neck tension.

I start with the bullet jammed in the lands for the ladder. That way I know I am looking at max pressure curves when shooting the ladder.

BH
 
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