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nw07heavy

Anyone know case water capacities for different .270 Win brass?

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On 4/15/2018 at 7:47 AM, nw07heavy said:

I was wondering if any reloaders here have the case capacities of current different brands of .270 Win brass, or has QL data that has these case capacities. I just picked up a .270 Win and have Winchester brass, but would like to have the capacity numbers before working up loads with different makes. Thanks in advance for any help.

Weigh your own cases with water. Decap the case and clean the primer pocket. Then add wax or modeling clay to the primer pocket. Weigh the case after doing this then make note of weight. Add water to the top of neck and weigh again. Subtract the empty weight from the water filled weight and you have your water capacity. Your NECO program will be much more accurate with this unit of measure. If you can weigh at least 5 cases and get an average. Weighing cases with primers spent or live can easily throw this off as spent or live primers will vary greatly in weight. Also it's best to resize the case as water capacity will change on sized cases as well. It's best to use an eye dropper and fill the case from the bottom up as you might get an air bubble that can throw measurement off. NECO QL's accuracy is only as accurate as the info you feed into it!

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On 4/17/2018 at 9:13 AM, nw07heavy said:

Thanks for all your observations. Looks like Winchester brass really needs to be scrutinized.

Yesterday I tried a box of Winchester 130 grain Power Point factory ammo and chrono'd four rounds in a 24" barrel. Interestingly, velocities came in, and adjusted for meteorological conditions, I recorded 3,037 fps, 3,166 fps, 3,151 fps, and 3,114 fps, which is quite a variation, since the box indicated 3,060, but no barrel length.

The first shot out of a cold or clean barrel will always be quite different. Was that 3037 your first shot? If you go to those last three shots that's an extreme spread of 52 which is about as good as it gets with factory ammo. You can cut that ES in half with reloaded ammo. 

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