Winchester Super Target?

[ORCA]

For .40 I've been using 5.3 grains of WST with a Berry's 180 grain buller with a OAL of 1.20. In side by side comparisons with VV-320 I can't tell a difference in the recoil or accuracy.

[Joe]

You can add me to the list of satisfied WST users.  My scale is off some but it reads 4.4 grains of WST with a Target Barn 230gr LRN, WLP primer and various case's averages 750fps out of my 4¼" Commander bbl.

Joe

[Duane Thomas]

Had an EXTREMELY interesting conversation with Allan Jones at Speer today. For those of you who don't know, Allan Jones is the editor of the Speer Rifle & Pistol Reloading Manual, and wrote more than a little of it. Allan is an honest to God ballistician, compared to a kitchen table reloader like, for instance, me.

He had very good things to say about Titegroup. I mentioned the idea I've heard from several people that TG is "dirty" which I've always found hard to believe. I mean, I fire mostly Titegroup through my gun and I clean it every 2,000 to 3,000 rounds - not that it needs it, I just start feeling guilty.

Allan didn't buy that "Titegroup is a dirty powder" thing at all. Apparently Speer has been using a non-cannister version of Titegroup for some of their factory 9mm. According to Allan it didn't work that great for 147s, worked okay for 124s, and was absolutely superb for 115s. Anyway, one of the ways they evaluate powder at Speer is for clean burning, by doing what's called an "ejecta test." ("Ejecta" is actually a geological term - the stuff that comes out of a volcano is ejecta.) What they want to determine is how much powder is unburned inside the casing by measuring how much unburned powder exits the muzzle during firing.

To start with they totally clean the firing range. They put the gun in a mount so it doesn't move during firing, so every shot is consistent, and fire 100 rounds of ammo with a particular powder. On the range floor they've spread a piece of butcher paper. When they're through firing they carefully pick up the butcher paper, gather the powder, weigh it, and compare that measurement to the combined charge weight of all the rounds fired. This gives them the percentage of unburned powder ejected from the gun - which is also a pretty good indicator of how much is staying inside the gun to gunk it up. Obviously some of the weight, a minor amount, is going to be primer fragments, and jacket/lead residue, but they assume that's going to be negligible, and in any event consistent from powder to powder.

The typical powder will put out residue in the 12 to 13 percent range. Titegroup is the only powder Speer has ever tested that puts out residue in the 6 to 7 percent range. When you start talking a powder that is twice as clean burning, this is a major drop, especially considering that every other powder they've ever tested was within about one percentage point of each other.

We also discussed the idea of WST being "reverse temperature sensitive" or somesuch, i.e. its pressures get higher the colder it gets. According to Allan, just about all powders will do that to a certain extent. The most egregrious offenders are those that are heavily double based; what happens is the nytroglicerine in the powder actually freezes, then when it ignites it literally blasts the powder apart and its burn rate goes WAY up, with correspondingly more velocity and pressure. BUT this doesn't start to happen until the powder actually freezes, and that doesn't happen until temperatures of about 40 degrees below zero Fahrenheit. So temperature was probably not the explanation for increased velocities reported by one Enosverse correspondent.

(Edited by Duane Thomas at 8:13 pm on Aug. 20, 2002)

[Steve Anderson]

So the old heat = velocity may not be an absolute?

Or does extreme heat = pressure?

It's all Voodoo!

SA

[George D]

Duane,

I thought you may be interested in some results that I have in relation to the temperature sensitivity of WST.

I chronographed my 38 special load (138gr BNWC, 3.8 WST) in early spring (temp approx 70F) and got 886 fps, SD 9.0. I repeated the exercise yesterday - hot summer day (low 90's) - and got 866fps SD 5.8.

Not a large variation, but enough to change the required PF120 from pass to fail, and enough to indicate that the inverse temperature sensitivity may not be confined to very cold temperatures. I wonder if the same phenomena extends to 231?