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Help with a 7WSM load

shotgun 01

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I have a Winchester Model 70 in 7WSM that I have had for years. It has always shoot decent groups with the Winchester MaxBond bullets, but decided to see what it would do with hand loads. The original stock has been replaced with a B&C stock, and had a "tune up" done by Bennett Custom Works.

I decided to work up a load using the 140 grain Nosler Accubonds. I used 64 grains of IMR4350, with a CCI magnum primer. OAL was 2.850. These loads shot okay, but weren't quite a good as the factory rounds. I tried stretching out the OAL to 2.950, which still fit nicely into the mag well, and was safely off the lands. Again, I didn't see any great improvement over the factory rounds. I am shooting about a 1 1/2" to 2" groups at 100 yards, using a shooting rest (very well supported). I feel like this gun should be shooting 1/2" groups, easily.

So, does anybody have a suggestion? I know every gun has a magic combination of powder and bullet, but I just wonder what my next step should be. I was thinking of backing off on the powder charge by a grain or two, or possibly a different powder.

Just curious to know what you more experienced loaders would try.
 
Out of the 4 reloading manuals i use 60.5 gr of IMR4350 is the max charge for a 140 gr bullet , I have had great results with Accubonds being very accurate , Personally all i use for hunting now are Berger VLDs, thats the most accurate bullet i have shot and had great success with them on deer and hogs
 
Thanks for the info. Nosler recommends 64 grains of IMR4350 as the most accurate load, so that is what I have tried. Also, it gives me the exact fps as the factory Winchester rounds. I think I will try a lighter charge and see what happens.
 
Shoot me a PM and I'll share some magic with you when I get to my lap top at the house. Do you have any cronograph data, and what is your barrel length?


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Here's the issue, the 2 closest OBT's for your 24" barrel are 1.228 & 1.102

At the lower node you would be at around 59.5gn ~ 2960fps. safe to 95* powder temp. But at that low of charge your at 87% case fill which may give high extreme spreads.

To get to the next faster node... You should use 64.5gn ~ 3177fps, but that puts you just in the red zone for pressure. To hot, 64743psi SAMMI Max is 63817.

uploads.tapatalk_cdn.com_20160818_bf49c697dedbea06057a1c5d0f10a9de.jpg


In other words this isn't the optimal powder for this bullet barrel length combo. I would look at the next slower powder to get to the top node with a little less pressure.


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IMR 4831 (if available)gets you to the lower node with a faster MV and a higher case fill (which helps keep ES low)

2.950, 60.5gn 3012fps at 95* powder temp.

uploads.tapatalk_cdn.com_20160818_483bb2dfea37685ddd623d219fb1bd57.jpg


let me know what powders you have if you want me to run any other powders.


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I'm shooting 180 grain Berger's with 64.2 grains of Reloder 26 and CCI BR2 primers. I have a 24 inch barrel so I'm only getting 2900 chrono'd speeds.

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