308 Load Question

[joustin]

I have a general question about a load I have been using. The data checks out but it seems weird. I have some 147gr surplus 308 bullets that I am loading behind CFE223. The only question I have is that after I fire the round, the brass comes out clean, a little soot on the neck but it is getting a good seal. The question / problem is that when I fire .223, 45ACP etc the brass comes out hotter than hellfire, in the 308 load below the brass is not very hot at all, room temperature at best. Is this normal or powder related?

Load data
147gr FMJ
1.99 Length (The brass all came short, it is virgin LC brass)
2.786 COL
48.4-48.6gr CFE223

 

[rodregier]

Same action type for .308, .223 and .45?

Cartridges fired in a "standing breech" rifle (bolt, lever, pump, single-shot) have a lot more time to transfer heat to the chamber compared to a semi-auto.

 

[joustin]

223 is in an AR, 45 ACP is in a Springfield XD. 444 is a lever action and it seems much warmer. It could be that the bolt 308 is cooler and transfers the heat better, it seemed cool after 10+ back to back shots.

 

[rodregier]

amount and kind of propellant burned has an effect on how much the barrelled receiver heats up too.

 

[joustin]

It is in a Savage Hog Hunter, it is rather beefy and may have something to do with it.

 

[Slamfire]

My 308 brass is very hot when ejected from my M1a's. Brass ejected from a 30-06 Garand will burn you. Used to be that all the shooters wore Campaign Hats on the firing line, Garands fling brass in all directions and the wide brim protected your neck. It is my recollection that brass from a Garand next to me went down (or up) my shooting coat one match, during rapid fire prone, and even though I flopped like a fish between rounds, I was unable to dislodge the case till the string was finished. I had a three inch burn mark when I got home.

Those where the days!

 

[rodregier]

Hot brass is why pro instructors for semi-auto pistol instruction want their students to wear:

- Brimed ball caps (with brim forward)
- Eye protection
- Long sleeved shirts with closed collars

 

[medalguy]

I was shooting with a group many years ago consisting of both sexes. There was one very lovely young thing with a low-cut top shooting with the pistol group. Someone recommended she put on a button-up shirt but she didn't want to due to the heat.

Well, sure enough, a piece of brass went down the front of her top, and she almost came out of that top. It was........interesting.

Brass can get pretty hot in a semiautomatic. I would guess maybe your load is not really hot ballistically speaking,but that's only a guess since I don't use CFE223 and it's not in my manuals.

 

[gamestalker]

I've noticed similar effects too, but I've never been able to explain it completely.

I mean you would think a full tilt 7mm RM load using RL22 would produce a rather warm piece of brass when extracted, but it doesn't. I can pull a cartridge straight from the chamber of any of my 7 mags. and it is barely room temperature. On the other hand, a case from a 22 lr, 9mm, .40, or magnum wheel gun is always scorching hot.

Don't get it, but it's the nature of the beast I suppose.

GS

 

[Swampman]

I've also noticed vast differences in the temperatures of just fired brass, even in the same calibers, but I've never made any notes of exactly which powders were "cool" and which were "hot".
Maybe it's time to put a new box on my reloading data sheets...

 

[Grumulkin]

I believe you will find that if you were to shoot a 223 round out of a bolt action gun and another out of a semiauto, the one shot out of the semiauto would be hotter. I think the reason for this is that the action starts to open slightly before the bullet exits the bore and lets hot gas come back. Some of the hottest cartridge cases will come from lower pressure loads where there is not a good seal and gas comes back and really heats the case.

 

[mahansm]

Brass from a semiauto will be much hotter than from a manually operated action. The reason is simple.

The brass from a manually operated action spends more time in the chamber, in contact with the chamber walls, and transfers most of the heat it picked up from the burning powder charge to the chamber walls. Brass from a semiauto is extracted/ejected very quickly after firing and before there's time for significant heat transfer to the chamber.

Other than this, different powders have different pressure curves and different combustion temperatures. I've noticed, for example, that my larger revolvers get noticeably hotter firing loads with 'Lil Gun than with 296 or 2400.