45r wrote:I read something on another site that lil gun has around 4 or 5 thou higher pressure in cold weather due to it's higher nitro content or something like that.Is that why the pressure is often lower for top loads on data sheets compared to H-110/296.
45r-
There are two parts to your interesting question.
[1]
I recall reading the same rumor somewhere. I think it's not true. Like Hoot, I've not observed any increase in Lil'Gun pressures at low temperatures. (We don't get quite the temperature extremes here in MI's U.P. that he gets in MN.)
I'd really like to know where the data for a 4-5K psi increase originated. For this level of detail, somebody must have had a pressure measuring device. Because the claim runs counter to the usual understanding of how powders work, I'll be sceptical until somebody produces the set of data showing this, with a description of how it was collected.
Hodgdon claims that their line of Extreme powders show decreased temp sensitivity, but Lil'Gun is not one of these powders.
I'd bet that "nitro content" is not the reason for the claimed behavior. Nitroglycerin has been a component of smokeless powders for about 124 years. The original British cordite was more than 50 percent nitroglycerin, and it was notoriously temperature sensitive, with the highest pressures occurring at high temps. The double-based nitro-containing powders distributed by Alliant all show the usual decrease in pressure when fired at lower temps.
According to some gun writers that seem to know what they're talking about, the ball powders from Ramshot/Western (like the Enforcer powder that does pretty well with light bullets in the 450B) are a lot less temperature sensitive than the majority of other powders. They attribute this to some remarkable additives developed within the last 20 years in Europe. However, the powders do not show an increase in pressure at low temps, but rather a comparative lesser decline in pressure at low temps.
Hodgdon doesn't reply to emails very promptly, but it still might be worthwhile to send them this question and seek their opinion.
[2]
Could you further explain your question about data sheets showing pressures at top loads for Lil'Gun vs H110/296?
Has Hornady published pressures for 450B reloading data? To which data sheets are you referring? I'd really like to know for some of my own efforts with this cartridge.
Thanks.
--Bob