Uh Oh dumb question time

[336A]

Ok folks please don't beat me over the head here, this question just might get a "here's your sign". I was sitting on the fence for some time over getting some WIN 231. Yesterday I finally gave in a purchsed some. When I got home I was referencing my Lyman pistol and revolver handbook, whatever the newest one is that is in print now the version escapes me.

Anyway I was looking at the loads for WIN 231 with the #358156 & #358311. Lyman shows a max load of 5.0gr with the lighter 358156 (155gr) & IIRC 5.2gr with the heavier 358311 (160gr). So my dumb question is why do they list a lighter charge with the lighter bullet? Is it due to the 358156 having a gas check? The datat for Unique on the other hand is a Max load of 5.4gr with the 358156 & 5.3gr with the heavier 358311. So why is it flip flopped with the 231? could this be a typo?

[HeavyMetal]

Bearing surface, alloy hardness, lube type these and many other things have a lot to do with pressure in any given load.

The 358156 is a SWC design while the 358311 is a roundnose.

My experience with the 358311 is the front driving band is usually under sized, it was in the two molds that fell into my hands anyway, so they have much less contact area than the 358156 which has alway had full diameter driving bands, again in the molds I have handled.

Because of this pressures can be higher for the 358156 over the 358311 despite the payload difference.

I will also note that boolit weight in the 358156 molds, four seperate single cavity molds, has been much higher than the "suggested" 155 grains Lyman says they should weigh! each mold hovered around 165 grains until HP'd at which point the did indeed become 155 grain boolits!

The 358156 in plain or HP worked OK for me but the gas check was alway a hassle and the mold got traded off at some point. I now have a 358429 HP and I am estatic with it's perfomance in my Contender! I also have a 358477 which will be HP'd shortly for my buddies 357.

Because of these "discripency's" I long ago cast and then weighed my boolits and then chose a powder based on as cast weight and intended use.

I've found this much more reliable than just picking a load from a manual based on what manufacturers say it should weigh.

I also load a little on the light side and then work up with either a new boolit or a new gun.

[336A]

So should I use the data for the #358156 for commercial cast SWCBB & RNFBB bullets as well. Or should I use the data for the #358311 since the commerecial bullets don't have gas checks?

[HeavyMetal]

First I'd compare the actual bearing surface of your commercial boolits to the pictures in the Lyman manual.

Then I'd use the start data for the closest match. I'd also ignore the gas check, at least as an increaser of pressure, I would consider it in the bearing suface comparision.

I would also weigh those store boughts as well as check the diameter! I've seen a lot of different quality out there and checking keeps you safe.