outside temperature vs 308W load

mveniot

mveniot

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Tomorrow is the last day of the gun season for deer. I have been hunting in temperatures from -14 to -30 C. I am using H4895 powder for a 150 grain bullet. Anyone know how these temperatures are affecting my load? Maybe I should be using a different powder for these temps.:)
 
What temperature did you test the load in ?

Being an "Extreme" series Powder you should not loose too much velocity but I cant imagine the velocity being the same with a big temperature shift.

As for a better powder for shifting temps, Ive heard that Varget is very stable.
 
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mveniot said:
Tomorrow is the last day of the gun season for deer. I have been hunting in temperatures from -14 to -30 C. I am using H4895 powder for a 150 grain bullet. Anyone know how these temperatures are affecting my load? Maybe I should be using a different powder for these temps.:)
Click to expand...

The only issue you will have at that temperature is the increased air density at lower temperature. In my experience the bullet drops 1/2 to 1 inch at 100 yards compared to a summer zero. The acutal drop depends on the bullet BC. But for deer this should not present much of a problem
 
Velocity will drop 100 to 300 fps. Not a big deal, unless you are at longer range.


Two things you can do to make "all-weather" ammo. Use Varget. It has the least temperature shift. For winter ammo, use a magnum primer with same powder charge. This will get velocity back to about "normal". Don't make a lot of it because it might be too hot for summer use.

The bigger issue is your rifle. In cold wx the firing pin can slow down if it has any cold lube on it. Most reliable is to swish it out in some kerosene or Varsol and shoot bolt and trigger dry.

Good luck.
 
cold weather powder

I agree with the comments on Varget being suitable for cold weather. Minus 28C here today, mercifully with no wind chill factor.

I've read that Varget is like 4064 'short cut'. Could be. I was at the range recently with a fine Springfield '03 and shot a 1 1/4" three shot group at 100 yds with a load consisting of 50 grs 4064 and the Sierra 155 gr Palma Match.

This is good performance from this 'as issue' rifle.
 
4895 and 4064 share the same formulation, with 4895 being smaller extrusions. They have nothing in common with Varget. Varget comes from Australia (Mulwax 2208??) and IMR4895 comes from Canada.
 
In sevre cold weather the really only thing you have to think about is the rifle action, ie, the firing pin. If it is in oil or grease, it won't fire the cartridge. Take the bolt apart and thoroughly clean it with something like kerosene and let it run dry.
Forget about any difference in velocity and just shoot the animal. Away back in depression time when all homesteaders in the bush lived on wild meat, they hunted and shot game in weather as cold as 40 below F. They had their rifles properly free of any oil and the old CIL Dominion 30-30 shells killed the moose just as dead as on a warm day.
 
Thanks for the info. Last day of the season and I did get my buck. He had already dropped his antlers. The receipt worked great, wind chill -39C but I was disappointed in the bullet. I was using a 150 grain SST. The deer was standing broadside to wards me. When it entered it hit a rib and the bullet went all to pieces. There are two exit holes, one on the opposite side of course (quite small) and the other was back from the entry hole to wards the hind end, about 14 inches (very large). When I gutted the deer, it didn't have anything left in the chest area, all mush. The one front quarter opposite the entry hole is gone. Made me a little nervous. What if I had hit a leg bone or square on the front quarters.
What is everyone else using.:)
 
I had a similar expereince with a 150. Spoiled a lot of meat. Our hunt camp all decided (as we were skinning this deer) to switch to much heavier bullets.

This way our deer and moose ammo could be the same. Would not blow up and destroy meat. Would not be defeated by big bones.
 
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GANDERITE said:
4895 and 4064 share the same formulation, with 4895 being smaller extrusions. They have nothing in common with Varget. Varget comes from Australia (Mulwax 2208??) and IMR4895 comes from Canada.
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Varget is ADI 2208 (used to called Mulwex, doesn't seem to be called that any more).

H4895 as of late is ADI 2206 (i.e. its Varget's one-step-quicker next door neighbour).

(ADI = Australia Defence Industries).

Good advice on solvent-rinsing the interior of the bolt (firing spring etc) for cold weather shooting, but even for cold weather shooting, he should make sure that he still lubes his bolt lugs with grease, and also a small dab of grease on the cocking piece cam surface (being careful not to allow the grease to get in at the spring). If these rubbing surfaces are completely clean and grease-free, the metal can gall.
 
Thanks for all your comments. I am going to do a couple of things.
First I am going to use the 150 grain "SST" on the range.
Secondly I am going to see what the receipt shoots like at -30C.
Third I am going to use the 150 grain "Interbond" bullet for deer and possible moose.
 
mveniot said:
Tomorrow is the last day of the gun season for deer. I have been hunting in temperatures from -14 to -30 C. I am using H4895 powder for a 150 grain bullet. Anyone know how these temperatures are affecting my load? Maybe I should be using a different powder for these temps.:)
Click to expand...

There's probably going to be a slight drop in velocity using H4895 but not enough to worry about. Go for it.
 
I think the bonded core bullets are best of all worlds,hold together,widest range of impact velocities resulting in reliable expansion and Accubonds are very accurate.
 
In a standard caliber and load a reasonable rule of thumb is about 1 fps loss per degree F away from the temp the ammo was loaded at and about 65 psi pressure reduction. As posted, the issue is the hardware, the firing pin, that needs to be lube free or dry lubed - mica, graphite, something along that line.
 
I just tried this out for my own learning curve with varget yesterday. The last time the gun was shot was on a match on Aug long weekend, and it was hot, 25-27 deg, yesterday I took the gun out left the ammo outside for 1 hour on the bench it was -24 with the wind chill.

Results were 1 inch high at 100 yards for 5 shots.

Put the some ammo in my pocket went inside for 15 mins and warmed them up to room tem.

Results same POI as in Aug X rings.

so about 50 deg temp change only resulted in 1 inch elevation change high, makes perfect sence to me, as the pressure should be lower.

I tried this in the summer as well, as I had a hot gun and left the bullet in the chamber to build heat, almost the same result but not as much, half inch low

Even the Extreme powders change a bit, but not as much as the other pwders
 
Temperature stable powders seem to be a hot weather rather than a cold weather fix. Last winter when chronographing ammo loaded with H-4350 Extreme at -32, and allowing both the rifles and the ammo to get cold, indicated a significant drop in velocity (125-150 fps) from what would have been expected in warm weather. Best bet is to verify your zero throughout the year.

Hybrid 100V is said to be a cold weather stable powder, but I haven't chronographed any of these loads yet to confirm that. When St.Marks Powder developed this stuff, prior to selling it to Hodgdon, they measured the over pressure of a large airburst at -40, so I don't know if that necessarily translates to cold weather stability when used as a propellant. -36 right now, but I don't have the urge to go shooting for some reason. Getting soft I guess.
 
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