Do you reload?

[dbHunterNY]

I've been told that the fps change from sub freezing to near 100* F doesn't shift much. This is from someone that shoots competition at 1500 yards with 338 LM. I think he said under 30 fps difference.

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I've seen a guy shoot rounds loaded with H4350.  same loads just some sitting in the summer heat and others in a cooler with ice.  he got differences of 80-100 fps.  when I figure that into my 30-06 it's probably about a 4" difference at 400 yards with air temp ballistics and change in velocity from difference in powder temp.  it's something I could work with for deer hunting but not making me feel all warm and fuzzy.  lately much of my shots on deer are around 300 yards.  if that difference was with my 223 shooting chucks that'd be not good.

 

...that's just change in ballistics.  doesn't account for any change in accuracy/group size that 100 fps would do.  maybe that's one of the most unstable? idk.

Edited March 21, 2016 by dbHunterNY

[shawnhu]

I've seen a guy shoot rounds loaded with H4350. same loads just some sitting in the summer heat and others in a cooler with ice. he got differences of 80-100 fps. when I figure that into my 30-06 it's probably about a 4" difference at 400 yards with air temp ballistics and change in velocity from difference in powder temp. it's something I could work with for deer hunting but not making me feel all warm and fuzzy. lately much of my shots on deer are around 300 yards. if that difference was with my 223 shooting chucks that'd be not good.

...that's just change in ballistics. doesn't account for any change in accuracy/group size that 100 fps would do. maybe that's one of the most unstable? idk.

H4350 is an extreme powder, and should be as stable as it gets, provided all other factors are taken out, such as the reloader's technique.

If you're deep into an accuracy node, your group size should not be affected too much, but POI would surely not be where you'd expect it to be if there's a 100fps difference and target is 400 yards.

Typically, shooters that shoot at those distances would create a table for temperature compensation and just reference it to adjust.

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[wildcat junkie]

I've seen a guy shoot rounds loaded with H4350.  same loads just some sitting in the summer heat and others in a cooler with ice.  he got differences of 80-100 fps.  when I figure that into my 30-06 it's probably about a 4" difference at 400 yards with air temp ballistics and change in velocity from difference in powder temp.  it's something I could work with for deer hunting but not making me feel all warm and fuzzy.  lately much of my shots on deer are around 300 yards.  if that difference was with my 223 shooting chucks that'd be not good.

 

...that's just change in ballistics.  doesn't account for any change in accuracy/group size that 100 fps would do.  maybe that's one of the most unstable? idk.

The main concern W/temperature sensitivity in powders has more to do W/chamber pressure than Mv. When cycling the bolt of a DGR in the African heat, a spike in chamber pressure that results in a sticky bolt lift could prove detrimental to ones health when a quick follow-up shot on a charging Cape Buffalo is the situation that needs immediate attention.

 

This is one of the reasons why African PHs prefer double rifles or, in the case of bolt actions, the 375 H&H. The sharp taper of the H&H case promotes easier extraction regardless of what  chamber pressure has done to the brass.

Edited March 21, 2016 by wildcat junkie

[shawnhu]

Just got back from the range,

Haven't had time to organize and crunch the data, have dinner to prepare,

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