Silhouette temperature sensitivity

[zzt]

In mid-Summer I loaded 3000 rounds with Silhouette to 170PF, because I could not get WAC at the time.  At the last shoot the temps were in the low 40s and I had a lot of stovepipe jams.   The same gun ran perfectly with the same loads in the match the day before (70s).  So I'm guessing there was power loss due to the cold.

 

Does anyone know how temp sensitive Silhouette is, and to what degree?

[JMike]

 

[caspian guy]

  your millage may vary,  based on gun or oal or.   But I always found it to be inverse temperature sensitive to enough extent that a load hot enough to trust across a match chrono in the summer  was hotter than i wanted in cool weather.

 

I think i was bumping up and down like .2-.3 grains.

 

The other thing i have noticed is that silhouette varries from lot to lot enough to have to pay attention to it.

[zzt]

Thanks guys.  Inverse was not what I was expecting.  I only have 500-600 left, so I'll put in a lighter recoil spring and shoot them up in practice.

[zzt]

I took the same gun, mags and ammo to the range today and fired off a quick 40 rounds.  No issues.  The only difference was the temp was 70 instead of low 40s.  So inverse sensitivity does not seem to be the case.

[adamge]

I have always read that it is inverse sensitive on the internet.  Never tested that myself though.  And it's hard to measure a few % change when I chrono with ES of like 90fps.

[zzt]

Yeah.  When I switch back to loading Open rounds, I'll put aside 100 and use them for chronoing.  Five strings of 20 at various temps from 35 to 90 should do the trick.

[Don_B]

Perhaps it is your gun lube that does not like the cold temp?

[zzt]

Don, I use SuperLube synthetic oil with PTFE.  I has the same viscosity from freezing to 95 degrees. Actually more than that, but that is the range I shoot in.  It is definitely not the lube.