Compressed WC680

[farmerjim]

I am working up loads for my 357 maximum Handi rifle with WC680 using AA1680 load data. The Western powders load tables show 20.9 to 23.2 grains for a 200 grain lead boolit (RCBS 35-200). These all work fine.
The 357 Maximum-T/C table shows from 27 to 30 grains of AA1680 . The Handi should be fine with the pressures created by these loads (35,810), BUT above about 25 grains the load becomes compressed. Is there any problem with compressed loads of WC688?

[Goatwhiskers]

Jim, as you know my load is 28gr. of A1680 which is supposed to be the same powder, definitely a compressed load. I had originally started with loads in the low 20's which was in line with the data available at the time. Got my info on increased loads from 357Maximum.com which no longer exists, but the old boy had gotten some loads pressure tested by Western Powders and they were not as high as you show. As I approached this level the soot started to go away and the groups started to tighten up. Apparently this powder requires a certain amount of pressure to burn properly--ain't interior ballistics fun? By the way, I doubt the pressure behind a cast bullet is going that high.

[farmerjim]

The tables for the 1680 did not show that it was a compressed load, so I was reluctant to use a WC680 compressed load. I will start working up from 25 in 1/2 grain increments to the 30 max. I may have to stop at 28 because I will not be able to compress the powder enough to chamber the round.

[Goatwhiskers]

At 28 you can feel the charge being compressed as you seat the boolit. Never went past this, tho some do up to 30, so can't comment on that. Besides, it was optimum in my rifle so I quit there. GW

[9w1911]

Any of you guys work with Thunderbird T680, I was gifted a keg but have done littel research and no loading yet, I want to use it for 223.

[farmerjim]

It should be the same as a1680, but I can't find any use in 223 in any of my numerous load tables.

[Moonie]

I remember W680 loads for my 445 supermag being compressed slightly.

[Goatwhiskers]

I hate it when someone tacks their own trade name on something like powder. Did a little digging on that Thunderbird, seems to be at least much like A1680, if it's not the same thng. Follow the usual rules, start low and work up slowly, probably will be OK. You have probably noticed in these times of shortage that folks have tried and succeeded with powders that ordinarily aren't listed in the manuals. One must be super careful tho, for example some powders have been found to give pressure spikes when over or under loaded. GW

[9w1911]

Agree, why not just call it what it is.