Not exactly a reloading question, but maybe tangentially...

I have a couple of M760 pumps in .30-06 and .270 that I shoot occasionally, and which are good hunting guns but aren't really accurate enough to trouble with handloading for. When shooting plain vanilla Remington core-lokt factory ammo in either gun, the brass comes out too hot to touch.

I've been handloading for decades, all kinds of combinations in many calibers including both of those. Brass from my handloads, no matter the powder or velocity, always come out barely warm to the touch.

Anybody here know why the difference? Are factory propellants really that different?

Powder choice is the key. With rifles that are shot in semi automatic rifles the factory loaded rounds are with powders that are typically "hot natured" as I call it. This is a question I have mulled for thiry years now; If the brass is that hot on some powders ( such as IMR-4350 ) are almost cool to the touch; then what difference is happening inside the barrel? I would like some of the "Powder Experts" to enlighten us if possible?

It has something to do with how long the brass sits in the chamber after firing to transfer heat to the chamber walls. if it is jerked right out and thrown on the ground by a semi-auto, it can't transfer as much heat. This also applies to semiauto handguns. Did you ever get a .45 ACP empty down your shirt neck??!! Hurts, don't it!!

I have seen the same thing. Some brass comes out hot enough to blister your skin while other brass is barely warm. It doesn't have much to do with the action type, either.
I am assuming that faster powders would heat the brass more because more of the burning is occuring inside the case instead of in the barrel.

The "HOT" brass has everything to do with the time spent in the chamber after firing!
I have never racked an empty out of any of my bolt actions that I couldn't hold on to! But, on the other hand, I have seen brass come out of the auto's that I had to let cool before I could pick them up!
Why do you think that the brass from an auto that lands in the snow after firing will almost always be discolored?

because the chamber is overized, which is why you have to use smallbase reloading dies on them.

i have the same thing happen with 1891 MN 7.62x54r rifles, and tokarov rifles... and m14s.. brass HOT HOT HOT...

22's do the same thing, in a ruger 10/22 (or anything else) and abolt gun....

jeffe

I think some of you guys are nuts!
I have shot everything from 375 H&H Magnum and 458 Win Mag and all the way down to .22 Shorts in bolt action rifles and I have NEVER had a hot piece of brass come out of my chamber.
Fireform said he was shooting a Rem. M-760 (pump)! Sometimes when firing a pump, the action gets opened during recoil, which means that the brass is out of the chamber almost as fast as an autoloader, and deffinately faster than a bolt.
Hot brass doesn't have anything at all to do with an oversized chamber either!
Come on guys, tell it like it really is!
Chuck

[ 07-28-2003, 23:08: Message edited by: Chuck White ]

The temperature of the brass is mostly a function of how long the brass stays in contact with the chamber after firing, which almost directly correlates with how much heat is transfered to the barrel prior to the brass being ejected (although pressure, burning temperature, and duration of burning may make an extremely small difference.)

It is almost impossible to eject brass from a bolt rifle fast enough for the brass not to cool a bit. By the same token, most brass ejected from any kind of autoloader will be very hot to the touch. For this phenomenon to show up in a pump, the action would have to be cycled very quickly.

[ 07-28-2003, 23:35: Message edited by: Stonecreek ]

Was driving with my wife one Saturday afternoon. She was wearing a blouse that had the first two buttons unbuttoned. I stopped to shoot a crow with my 10/22. The ejected case bounced off the winshield into her shirt and bra and came to rest on her lovely right nipple. You could smell the flesh burning. Don't tell me brass from a .22 is not hot to the touch, 'cause my wife has the scar to prove it.

Fireform --- eldeguello, Stonecreek and Chuck White are all correct in their reasoning. I shot Browning BAR's for years, with my brother-in-law shooting a Rem pumpgun, all exibited hot brass. You may see some brass "warmer to the touch" than other with the bolt actions, but no way near a "hot" as the autos and pumps. Try picking up brass from a machine gun, or fully auto anything, and you will get the picture. Good shooting.

Fellas--

Thanks for all the replies, but I'm having a hard time sorting them out. Some of you seem to be saying that the faster the brass comes out, the hotter it will be. Others that the longer it stays in contact with the chamber, the hotter it will be. Can't both be the case (pun intended)!

For what it's worth, these pumpguns are being shot off a bench and they are not being rapid fired or cycled immediately. I eject the brass from the pumps and handloads from the boltguns about the same length of time after firing (3-5 sec). And while the brass from the boltgun is practically cool right out of the chamber, factory loaded brass from the pumpguns is hot for a long time--too hot to pick up for maybe 20 seconds, and hotter than the handloaded brass ever was for at least a minute after firing. So, I'm not convinced by the cycling theory.

And crowrifle, I hope by all that's holy that you kissed it and made it feel better .

Fireform;
Generally speaking, the longer the fired case is left in the chamber, the "COOLER" it will be! A few seconds makes a big difference!

I'll bet that if you stood off to the side when someone was firing, say... a 30-06 and you cought the empty (bare handed) when it came out of the chamber, you "WOULD" put it down, real quick!

When I shoot my bolt action rifles and rack out an empty, it almost never touches the ground, it is usually in my left hand as the bolt opens. That is of course, unless I'm in a hurry to get off a second shot!
Hope this clears things up for you!
Chuck

Wow, I can't believe some of these answers.

Unfortunately Stonecreek, it was. I almost had to wrestle the gun away as she was trying to return the favor.

I performed a search to find this thread again. When I first read it I didn't think much about it. Until yesterday. I was shooting at the range sighting in for deer season. I shoot a bolt 30-06 and a mod 100 in 284Win. I was using the same powder in both guns, old H4831. The 06 load was 56.5g w/Sierra 180, the mod 100 got a Hornady 139 w/55g. The 06 brass comes out almost cool to the touch while the 284 literally burned my fingers. I cant seem to decipher the previous answers, can someone please tell me what's really up???

Yes, red! The longer a fired case stays iun the chamber, the more time there is for the thick, steel chamber walls, acting as a "heat sink", to absorb heat from the brass cartridge case, rendering it cooler than if it is ripped right out of the chamber by an automatic action like the M100 you have. The shorter the time there is to transfer heat to the chamber, the hotter the ejected case is going to be.

how about an expiriment.

take and semi auto and fill with factory loads.

pop off three shots, equal time between shots.

grab the third case and use an infrared temp gun to get temp on it say after 5 seconds (allowing time to locate and read temp.

next allow gun barrel to cool to "normal" (checked with thermometer) and repeat with diffrent powerders in handload (loaded to about the same velocity).

I am sure there is a diffrence in temp depending on powder type.

now back to what old and slow asked. is there a advantage over "hot" powder or "cool" powder? is there a diffrence in barrel life? in accuracy? anyone want to try this?

Auto Loaders seem to do this. It must have to do with the exhaust gases that recycle the bolt in them. Aren't the 760 sort of like a " manual transmission' version of the 740s?

It should not have anything to do with unsafe pressures, etc, as the same factory ammo is used in a bolt gun.

It should not be a concern, except maybe Crow's wife does have a legitimate beef about it.

[ 10-02-2003, 06:19: Message edited by: seafire/ B17G ]