I've never had this happen...

[Bob 964]

My "pet" load is a .308 Hornady 208 Amax, seated at or near the lands, using 48.0 grains of Power Pro 2000 MR. This load generates 2600+ FPS. Unable to find any Power Pro 2000 MR powder, I picked up a pound of Varget. Since I had no experience shooting the 208 Amax using Varget, I loaded an OCW test to try to find the optimal powder charge weight and seating depth.

Based upon advice from Hornady and Hodgdon technicians, powder charge weights ranged from 39.6 grains to 41.7 grains, in increments of 0.3 grains. When I fired the first fouler/sighter, I reached over to pick up the ejected case and it was cool (almost air temperature) to the touch. I don't ever recall picking up a recently ejected case that wasn't like picking up a "hot potato." This persisted throughout the first round robin. Ammo temperatures were constant at 80-82F, and the barrel temperatures ranged from 80-92F. Muzzle velocities ranged from 2212 FPS to 2377 FPS. I stopped after the first round robin because I could neither understand nor explain why these "fire-formed" cases weren't burning my fingertips when I picked them up.

Any thoughts as to why these cases were so cool to the touch?

 

[former naval person]

Rifle? Bolt cases are cooler than semi's.

 

[Bob 964]

Rifle? Bolt cases are cooler than semi's.

It's A Savage 110FP, long action. I've shot this rifle for more than a year, shooting both factory ammo and ammo I have handloaded. This was the first and only time I have experienced this problem. After a couple of times, I would slowly pull the bolt back so I could extract the case with my fingers and the case was still not hot to the touch. I am perplexed!

 

[rduckwor]

Early in the string, before I heat the barrel and action up too much, mine are typically cooler than expected. I'm guess that a lot of the heat generated by the Varget burning is transferred rapidly to the cooler chamber and action.

Later on, the action is much hotter and the ejected brass gets pretty warm too.

 

[stranded]

My guess, is the heat sink factor of the barrel is able to handle the lower charge/ heat better and the cases are comming out cool.(barrel temp) I just was trying a new barrel on my 22-250. Old loaded rounds are way too fast(bolt raises hard) No barrel warm up after 20 rounds. Went to a slower powder but bigger charge. H4895 to H4350, 34.5gr to 39.0grs. Speed went from 3600+(each shot was faster to 3800+ when I quit) to 3555. With the slower powder the barrel heats up to the touch after 2nd firing ,but the speed is constant. I am trying to say dwell time is the answer. If not, see my sig line.

 

[armorpl8chikn]

Yep seen this before. I experienced it in an AR of all things. Look at your velocity. I would assume that the pressure spike is much smoother on this particular load thus generating less heat. I can run IMR4320 with 80gr SMK's in my NM upper and it takes forever for the barrel to heat up. Just like you are seeing though, the velocity was not barn burning, but they were hell accurate...which is really all that matters. When you find a load like this, that quite litterally is using a less than optimum powder for maximum velocity, you will experience cooler barrel temps and brass temps. I am not a physics dude so I can't explain it scientistically' but I know it happens and there is no harm in it if you are happy with the velocity and the accuracy.

 

[Bob 964]

Thanks Chikn.