Load development 50 degrees

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Ragin_cajun

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Minuteman
Dec 31, 2011
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#1
So i recently picked up a 6gt and need to work up a load for it but it’s 50degrees. My question is (using h4350) can I do the work up and when I find a node just load some and warm them up before shooting to verify no pressure issues in warmer weather? I can wrap them in a heat pad to bring the temp up to 90 degrees pretty easily. Is this a fairly safe indicator of pressure in warmer months?
Hornady brass
H4350
Cci450
Berger 105
 
#2
Not sure why ... but somehow, the thought of wrapping loaded cartridges in a heating pad just seems dangerous to me. I have no empirical or factual or experiential basis for that feeling, but nonetheless, I wouldn't do it myself and would look to using temperature insensitive powders instead. But that's just me.
 
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#3
When I develop a load I always check it no matter what time of year, I put a few rounds in a plastic bag put them in the freezer over night then put them in a cooler on ice on the way to the range. To get a few rounds hot I put them in a baggie on the defroster in my truck on the way to the range and when I get there I crank the heater up on defrost only.

Shoot the cold ones first by the time your ready to shoot the ones on the defroster they will be 100+...I have checked rounds with a heat gun after being on the defroster for 15-20mins and have been up to 110deg.
 
#4
Since you don't list where you live or where you shoot , just use the hottest day's Temp. you will shoot in , and use what ever source of heat, car heater or engine, of if your range has an available power source , get an accurate thermometer and take a heat source, heat gun, a hair dryer, and a pair of gloves , metal at 90* , well you will learn
 
#5
I live in NW Florida (luckily) 30min from Altus or element 😁. These rounds will be normally shot in local prs matches starting February 1. I’ve got 5 rounds loaded light 33.5 gr to warm up the barrel and gun before I start doing the test to warm up the barrel. I appreciate the feedback guys
 
#7
spife7980 said:
It’ll be close enough, I certainly would not wait until spring to shoot them
Click to expand...
Thank you.....with 6.5 CM and H4350, there ain't much of a difference in MV in my limited experience.

at 42.1 g I've seen about a 10-15 fps from Maryland in July (didn't record the temp like an idiot) where the temps this summer were pretty much all in the high 90's vs 55F.

Powder seems very stable to me.
 
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#8
I’m current;y doing some work on a couple of new barrels, and it’s in the 40s. My solution is to load the mags in advance and keep them warm in my pockets until ready to shoot. Not a perfect solution, but at least the rounds aren’t chilled to ambient temp.
 
#9
The FCSA 50 caliber guys shoot a lot of VV20N29 which is a notoriously temperature sensitive powder, and they run heating pads on their shells to keep them at some temperature. I think it’s 100° or more.

So there’s certainly no danger in doing that contrary to what was suggested above
 
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#10
H4350 is quite stable so as long as you're not pushing max you should be fine.

Most of my experience is with 6.5cm and I plan on testing some in the morning at 0*. I have data from 20 or so up to 90, curious to see what it does tomorrow.
 
#11
Ragin_cajun said:
Is this a fairly safe indicator of pressure in warmer months?
Click to expand...

Go download Gordon's Reloading Tool and play with the starting temperature to get an idea of how the pressure profile changes. You can then also play with slightly different powder charges to see what it takes to match.

But to answer your question, if the powder starts at the same temp, then it will essentially fire the same. Where you will get variance will be in the first handful of shots where the barrel will be cooler in 50 degree weather than it will in, say, 90 degree weather. Unfortunately, the basic cartridge simulators we have access to do not simulate the energy absorbed by the barrel. Of course, after a couple shots, the barrel will be warmed regardless.
 
#12
Ragin_cajun said:
So i recently picked up a 6gt and need to work up a load for it but it’s 50degrees. My question is (using h4350) can I do the work up and when I find a node just load some and warm them up before shooting to verify no pressure issues in warmer weather? I can wrap them in a heat pad to bring the temp up to 90 degrees pretty easily. Is this a fairly safe indicator of pressure in warmer months?
Hornady brass
H4350
Cci450
Berger 105
Click to expand...
I've load dev at 10-20F in Jan and ran the same load until Sept at 100-105F

Drop the heating pad idea and keep all the ammo at the ambient temp you're doing the load dev. Record the data for the temp you shot the ammo at and be consistent with the dope check as the temp climbs.

Stay under the book max for the bullet class (which is nowhere near real max) and you ll be safe during the hotter months if you are really concerned. If you load develop close to max pressure at 50F most likely youll have issues at 20F and also at 80F so avoid that.

6GT is pretty efficient and H4350 is pretty stable. You should have no problem finding loads around the 2800 mark without pressure issues using a 105 and 22-26 inches of barrel.
 
#13
I've tried running artificially heated rounds in the Winter to mimic Summer temps and it just doesn't work. I was fine with pressures in the cold, then popped primers when the ambient temps were hot. I went to great lengths to keep the ammo hot, hair drier, truck heater vent, and then kept in an inside pocket of insulated coveralls before firing. Even firing out of the warm truck cab. So, I gave that silly shit up and load Winter and Summer rounds, and because the harmonics change from Winter to Summer as well.
 
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#14
I usually just log the temp during the testing. I'll also test at the opposite end of the temperature spectrum (ie: if load development occurs in January, I'll retest in July). However, usually by summer I've shot that load multiple times in progressively warmer weather.

Really the only 'caution' occurs when you load your ammo close to max pressure initially in the winter. Some powders are pretty sensitive. H4350 generally isn't.
 
#15
Well I started at 34 gr and was getting bad results so I just kept climbing and settled at
36.9 gr getting 2935 with 5 sd and 5 shot 1/2 moa groups out to 600. All in all im very pleased
 
#16
Ragin_cajun said:
So i recently picked up a 6gt and need to work up a load for it but it’s 50degrees. My question is (using h4350) can I do the work up and when I find a node just load some and warm them up before shooting to verify no pressure issues in warmer weather? I can wrap them in a heat pad to bring the temp up to 90 degrees pretty easily. Is this a fairly safe indicator of pressure in warmer months?
Hornady brass
H4350
Cci450
Berger 105
Click to expand...

Years back when I lived in CT I worked up loads with H4350 in the teens and then took it to south TX for a match that was in the 80-90 degree temps and there was no issue. You are fine at 50 degrees with H4350.
 
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#17
With H4350, you are fine at 50 for any temp you might shoot in, assuming you aren’t way over loaded to begin with. The various sources out there suggest a velocity change of somewhere around .2 fps per degree for h4350 so between fifty and 90 you would expect to see less than 10 fps change. Related to pressure, how much powder would cause a 10 fps change? Perhaps .2 grains? Can your load withstand a .2 grain increase without being over pressure? I hope so.

Point being. Go nuts at 50* and don’t look back.
 
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