Are some powders "cooler" than others

I would use IMR 4350 with that bullet, it will probably give you the best velocity for a light bullet. Another I like is RL19.

No matter what you use the barrel will heat, can't be helped when you burn that much powder.

I used 4064 and cfe223 were my two favorites for light bullet 270 loads.
CFE was fast.
As far as cool, can you use a battery powered air compressor where you shoot?
Coleman makes the air mattress inflation ones that take D cell batteries.

How much of the barrel heat is due to the burning powder compared to the heat produced from friction of the bullet going down the barrel? I have always attributed most of the barrel heat up to the friction. Not sure if that is due to something I read, heard or just assumed.

I have a CFE load for my Thirty Aught Six and one hundred ten grain V-Maxs. So nice.

I have a few small inflators. Good thing everyone is wearing muffs. They get annoying fast. I throw a jacket over mine when I'm not alone. I have a rubber hose that suffs tight in the chamber, it makes it much easier to use.

I'm still looking for the perfect fan. Without purchasing the "Chamber Cooler", obviously. Because that's no fun...

I, too, am interested in the temperature of powders, but for an AR. Great question.

The barrel heats up from the super hot gases that's behind the bullet. Yes some bullet friction will add heat but most all it is from the gases. As for which ones run cooler, I do not known when it comes to rifle powders. But in pistol powders with high nitro run hotter. So may have to look at the composition of the powder. Or attach a temp sensor to your barrel and fire some rounds and see how fast a particular powder heats up the barrel.

All the cool powders sit in the back of the bus....

Demi-human said:

I have a CFE load for my Thirty Aught Six and one hundred ten grain V-Maxs. So nice.

I have a few small inflators. Good thing everyone is wearing muffs. They get annoying fast. I throw a jacket over mine when I'm not alone. I have a rubber hose that suffs tight in the chamber, it makes it much easier to use.

I'm still looking for the perfect fan. Without purchasing the "Chamber Cooler", obviously. Because that's no fun...

I, too, am interested in the temperature of powders, but for an AR. Great question.

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Watch out on those inflators. They have a bad habit of spitting out water if it's humid out.

It's easy to calculate the amount of heat that friction generates. It takes about 150 pounds of force to push a bullet down a barrel. 150 pounds over 2 feet is 300 foot pounds, converted to heat. (In this case, work is numerically equal to energy.)

► In the most general terms, "fast powders" are hotter, "slow powders" are cooler.

► The main heating is caused by the burning powder. And the powders that heat the barrel the most are the ones with the highest percentage of nitroglycerin added. The ones with zero nitroglycerin added are called "single-base" powders. There's not many single-base powders around, but they can be found. At one time all the IMR powders were single-base; not so much in the last few years.

It will take a small amount of work, but the percentage of Nitro is stated in the powder MSD sheet (aka MSDS), which anyone can get from the powder manufacturer's web site.

For more info, look under the section "Chemical Formulations" when you Click Here

The 270 Win is a big cartridge (relatively) and takes a lot of gunpowder. In my opinion there is nothing you can do, by changing powders, that will do anything to reduce the heat output of the cartridge significantly. Unless you down load the cartridge way, way down. And then you are defeating the purpose.

For a time there was a very vocal reloader by the name of Seafire. Seafire championed the use of Blue Dot in many cartridges. Charges of Blue Dot gave good velocity with low heat output. With the exception for all the blown up rifles, it appeared to be a great solution. But the blowups were a problem. Alliant told me that small changes in anything would cause the Blue Dot pressure curve to spike. Alas, nothing is finished, nothing is complete, and nothing is perfect.

I nominate Trail Boss. Each grain looks like a tiny little bagel. How cool is that?

Just a unscientific opinion but I doubt the slight difference is rifle powder burn rate would make a measurable difference in barrel heat.

Fire 10 rounds of powder,x y and z with time for the barrel to cool down in between..

Measure barrel heat with a laser thermometer.

Debate

This is my .270 Win Pet Load for Varmints

It is extremely accurate, and devastating.

Lee Q. Loader said:

What would your powder choice be for this bullet? Keeping in mind that I will be shooting quite a few rounds and I need to keep the barrel from overheating. So are there powders that don't heat the barrel as much as others? To me this hardly seems possible.

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I've had FAR better luck loading bullets on the light side in .270 Win than I ever did with .308 Win.

In both cases, however, the faster powders shoot more accurately with these light bullets.

In terms of barrel wear, with such an overbore cartridge, the faster powders, to my thinking, will be kinder to your barrel...as well as more accurate.

You will burn less powder with the faster powders. It is the hot gas that burns the throat. Which do you think would produce more throat erosion? 49.2 Gr of RL-15, or 60 Gr of 4350? (60 Gr of 4350 will give you maybe 200 fps more though...but a fast miss is a miss.) That RL-15 load is still a 90 Gr HP at 3420 fps...

Another $.02:

Worry more about heat from a short interval between shots.

The .270 will make for spectacular hits, and some longer shots.

The downside for prairie dogs are:
- How much louder a .270 win is than a .223 (it will keep the dogs down more).
- The recoil, although reduced by a lighter than normal .270 bullet, will be greater...preventing a good view of a hit through the scope.
- The cost. Decent .224 bullets are cheaper...you use more powder.

It's the flame temperature of the gases that can cause damage quickly. The latent heat in the barrel remaining after the burn is a much lower temperature. Allowing the barrel to cool between shots is not going to reduce the flame temperature at all. It is only going to lower the latent heat of the barrel slightly and that temperature is not likely to be very high to begin with. A 200 deg. F barrel that burns your hand and you can fry an egg on is not the cause of damage. It's the 3300 F flame temperature of the powder. Theoretically, ball powders have a slightly lower flame temperature than extruded, but the difference probably isn't enough to produce a meaningful effect. In practical terms, smokeless powders all have about the same flame temperature. Burn rate is not correlated to flame temperature. So the two most significant factors I can think of that affect powder erosiveness would be: 1, the chemical composition of the gas because some chemicals cause greater damage to the heat affected zone. 2, the mass of the powder being burned -- there is a strong correlation between mass of powder burned and barrel life. This is simple enough to understand: more powder mass produces more hot gas to erode barrel. One rule of thumb is a barrel will last for about 20 pounds of powder. But of course people have different criteria for when a barrel is "shot out."

Use the tool you was born with, your hand.

If you can't grab the barrel and hold on, stop shooting until you can.

Yes powder heat can be used to calculate expected barrel life. In my 300 Win Mag RL26 which is very high heat can produce very high velocities is otherwise safe pressure levels at the expense of barrel life. Even when loaded down to same velocity H1000 will give an expected 50-100% increase in barrel life. The high heat gives a very broad long pressure spike vs a cooler powder such as H1000. Makes R26 a superb hunting powder. Target rifles such as PRS and other long strings of fire, it will be very hard on rifles leading to throat errossion.

Hodgdon Powder has a reduced load recipe for its H4895 powder. https://imrpowder.com/wp-content/uploads/2016/11/h4895-reduced-rifle-loads.pdf Not super high-velocity rounds, but I imagine perfectly adequate for ground squirrels at reasonable ranges. For that matter, any accurate scoped .22 LR would be adequate, and not as expen$ive, or hard on your shoulder. That's why a lot of guys don't use the 30-36 or 270 for varnints much anymore.