WSF - Reverse Temp Sensitivity Question

[rdtompki]

We've sent 20K+ rounds of WSF behind our 147gr Bayou bullets. These are soft loads for steel challenge, currently 3.3gr @ 1.11" OAL. During the Spring most of our shooting is around 50 degrees, but recently we've hit some early afternoon temps 85+. Not unexpectedly the 3.3gr went from cycling reliably to not locking the slide back and not always clearing the last case.

Actually, this isn't a problem in steel challenge, but I'm moving up to 3.4gr which I'd estimate is similar to the 3.3gr at the previous lower temps. I haven't had time to chrono the 3.3 under the warm conditions; 850fps as I recall when cooler. Has anyone chron'ed a 9mm WSF load over a range of temperatures?

 

[LiveLife]

WSF is reverse temp sensitive and you may need to use much more than .1 gr to reliably cycle and lock the slide back.

I use WSF mainly for full power loads. Try upping the powder charge.

BTW, are you using shorter 1.110" because your barrel won't allow longer length?

FWIW, for lighter loads (especially lighter than published start charges), I would suggest faster burn rate than W231/HP-38 powders.

 

[Blue68f100]

I have not found WSF to be reverse temp sensitive. WST Yes.

 

[rdtompki]

BTW, are you using shorter 1.110" because your barrel won't allow longer length?

FWIW, for lighter loads (especially lighter than published start charges), I would suggest faster burn rate than W231/HP-38 powders.

I can drop about any OAL into the SA 9mm 1911 chamber, but the shorter OAL gives me (actually my wife) a softer load that will still cycle. The side benefit is that the rounds are cleaner than 3.7gr WSF @ 1.15".

When I started reloading some 5 months ago WSF was all I could get my hands on and since we're shooting 4K/month I need a fair amount of powder on hand. I do have HP-38 which I'll test at some point. Also have N340 and a bit of HS-6 to try as well.

 

[ddc]

...my wife...
...since we're shooting 4K/month I need a fair amount of powder on hand...

LOL, you've got the same problem I have although I'm not quite as bad off at about 2.5K/3k/month....

My wife started tagging along with me to the range and then after a while to IDPA matches. Now she's going off on her own to practice several times a week without me!

All of a sudden my powder requirements went from "well I guess it's not all that bad; maybe I can cut back some place else" to "holy crap batman, whose got powder and how can we afford it..."

All in all a nice problem to have but it reminds me of the saying "be careful what you wish for because it may come true."

Good luck.

 

[Hondo 60]

ddc - all in all it's a nice problem to have.
My ex hated guns and anything to do with them.
That's why she's an ex - well not the only reason, but it was a big one.

 

[LiveLife]

WSF - Reverse Temp Sensitivity Question

WSF ... 147gr Bayou bullets. These are soft loads for steel challenge, currently 3.3gr @ 1.11" OAL. During the Spring most of our shooting is around 50 degrees, but recently we've hit some early afternoon temps 85+. Not unexpectedly the 3.3gr went from cycling reliably to not locking the slide back and not always clearing the last case.

I'm moving up to 3.4gr which I'd estimate is similar to the 3.3gr at the previous lower temps. I haven't had time to chrono the 3.3 under the warm conditions; 850fps as I recall when cooler.

WSF is reverse temp sensitive and you may need to use much more than .1 gr to reliably cycle and lock the slide back.

I use WSF mainly for full power loads. Try upping the powder charge.

I have not found WSF to be reverse temp sensitive. WST Yes.

I think at higher powder charges, the effects of reverse temperature sensitivity may not be obvious. OP is using lower charges (may be below published start charge even with shorter 1.110") which could be potentiating the reverse temperature sensitivity.

BTW, are you using shorter 1.110" because your barrel won't allow longer length?

FWIW, for lighter loads (especially lighter than published start charges), I would suggest faster burn rate than W231/HP-38 powders.

I can drop about any OAL into the SA 9mm 1911 chamber, but the shorter OAL gives me (actually my wife) a softer load that will still cycle. The side benefit is that the rounds are cleaner than 3.7gr WSF @ 1.15".

When I started reloading some 5 months ago WSF was all I could get my hands on and since we're shooting 4K/month I need a fair amount of powder on hand. I do have HP-38 which I'll test at some point.

You might want to use longest working OAL that will reliably feed/chamber from the magazine for less high pressure gas leakage.

W231/HP-38 is temperature sensitive so warm summer load that will barely reliably cycle the slide may require higher powder charge on cold winter days.

If you are looking for softer loads, I did a comparison test on this thread using W231/HP-38, Bullseye, Red Dot/Promo, Titegroup that produced very light recoil yet accuracy - http://www.thehighroad.org/showthread.php?t=748940