Cold temp affecting terminal performance of plastic tipped bullets

[HARPERC]

..Perhaps it's wise to consider animal physiology as a variable with temperature too......

I think so.

 

[WildRose]

Actually the eldx is one of the bullets Ive noticed do this along with vmaxs, amaxs, and nosler ballistic tips. There performance is fine when it really cold, but much more like a monolithic hunting bullet that expands and punches through. But if it's warm, they seem to 'detonate' and do a lot more damage.
Yeah, I was wondering about super heating of bullet as it's fired, but taking a frozen bullet, and its under heat for only moment, how much heat could it uptake? Then I was wondering what is the wind chill effect at Mach 2 and it's -20 is?

Sorry but that just doesn't make sense. The more likely culprit is powder temperature sensitivity causing your loads to run considerably slower in cold weather.

The temperature of the bullet at impact isn't going to vary enough to make any difference because the heat from the igniting powder and friction combine to give your bullet a very consistent temperature in flight.

The other likely culprit is range. Higher impact velocities will give you more explosive impacts and much more violent expansion than slower speed impacts.

 

[WildRose]

Actually the eldx is one of the bullets Ive noticed do this along with vmaxs, amaxs, and nosler ballistic tips. There performance is fine when it really cold, but much more like a monolithic hunting bullet that expands and punches through. But if it's warm, they seem to 'detonate' and do a lot more damage.
Yeah, I was wondering about super heating of bullet as it's fired, but taking a frozen bullet, and its under heat for only moment, how much heat could it uptake? Then I was wondering what is the wind chill effect at Mach 2 and it's -20 is?

Friction is going to be the greater component in the heating of the bullet. Remember when we first tried to make the transition from subsonic to supersonic aircraft and missiles we had to come up with a whole new discipline, material science, to come up with materials that did not soften to the point of failure or flat out melt in flight due to the heat of friction once we started pushing them beyond about mach 1.5.

The friction of the bullet interacting with the barrel and then the friction of it interacting with the air I think would have to completely eliminate any effect of the temperature of the bullet sitting in the chamber.

 

[WildRose]

You didn't even read the thread did you, just assumed it was about a bullet you don't like so you recommend the very bullets the thread is about!!

Go bark at someone else.

 

[Hand Skills]

The friction of the bullet interacting with the barrel and then the friction of it interacting with the air I think would have to completely eliminate any effect of the temperature of the bullet sitting in the chamber.

Possibly in the case of monolithic copper bullets, but with lead in the mix i wouldn't count on it, not in the ~1s timeframe that would apply to our example. Keep in mind copper has a melting point of 1085C. 40deg delta T is pretty small, as a percent.

Lead melts at 330C - 40deg delta T is a lot more significant (12%), especially considering I have SEEN exposed lead at the base of a bullet melt as a result of firing. The more I think about this, the more I am thinking about how close to a phase change that core really is upon impact.

Just the thoughts of a carpenter...

 

[WildRose]

Possibly in the case of monolithic copper bullets, but with lead in the mix i wouldn't count on it, not in the ~1s timeframe that would apply to our example. Keep in mind copper has a melting point of 1085C. 40deg delta T is pretty small, as a percent.

Lead melts at 330C - 40deg delta T is a lot more significant (12%), especially considering I have SEEN exposed lead at the base of a bullet melt as a result of firing. The more I think about this, the more I am thinking about how close to a phase change that core really is upon impact.

Just the thoughts of a carpenter...

I get all that. We're only talking about a maximum difference though of a few degrees because the body of the bullet is getting the bulk of it's heating from friction both in the barrel and in flight.

The most likely culprit here is powder temp rather than bullet temp.

 

[Hand Skills]

For the IMR powders, each change of temperature of one degree Farenheit changes the muzzle velocity by 1.7 fps in the same direction. Thus, and increase in the temperature of the powder amounting to 20 Farenheit could be expected to increase theMV by 34 fps.

Ok, so let's go big, and suppose 100deg F delta T;

That's 170FPS

Let's go slow, and suppose MV of 3000FPS ~ 5%

I would put that in the 'contributing factors' category.

 

[Canhunter35]

Interesting reading everyone's thoughts, but I guess no one else has really made that observation which is interesting. Not sure powder temp would affect it. I've shot a lot of deer with my 115 nosler ballistic tips at 3280 fps with imr 7828. It was cold when I shot my mule deer at 50 feet, minus 200 fps is still over 3k mv, yet the bullet punched making about 1.5" channel of damage. All the other deer I've hit it's like a bomb went off in the internals with 3-4" of damage in a channel. Lots of them over 200 yds. I don't think it's a velocity difference but hand skills may be on something about the physiology of the deer being different when it's really cold. I've also noticed this a lot on coyotes. Cold, nice little exit wound, hot, they have big old holes in them.

 

[WildRose]

For the IMR powders, each change of temperature of one degree Farenheit changes the muzzle velocity by 1.7 fps in the same direction. Thus, and increase in the temperature of the powder amounting to 20 Farenheit could be expected to increase theMV by 34 fps.

Ok, so let's go big, and suppose 100deg F delta T;

That's 170FPS

Let's go slow, and suppose MV of 3000FPS ~ 5%

I would put that in the 'contributing factors' category.

I'll refer you back to this. In addition to the heat from the chamber and friction while riding down the barrel the tip of the bullet is heating to 600-800F in flight.

https://www.longrangehunting.com/th...f-plastic-tipped-bullets.194366/#post-1364011

There's just not much way the cold is going to be able to affect the bullet.

Now one thing I did see many years back in sub 20F weather was that sometimes the tips on Nosler BT's would get brittle enough to break off when loading them into the magazine or when chambering one as it contacted the feed ramp.

From what he's written I don't see that to be the case here. If anything from his last post the problem may have more to do with excessive impact velocity causing them to essentially turn inside out which is something I have seen in a lot of the BT's and one of the main reasons I quit shooting them as they tended just to punch pretty much a caliber sized hole all the way through doing very little damage or go off like a bomb causing too much meat loss to suit me.

Hornady has their tried and true Interbond back in production and if I were going to go back to shooting a traditional bonded bullet I wouldn't fool with anything else. There are higher BC bullets out there but I've never had an Interbond fail me in any way on literally hundreds of animals.

 

[Canhunter35]

I'll refer you back to this. In addition to the heat from the chamber and friction while riding down the barrel the tip of the bullet is heating to 600-800F in flight.

https://www.longrangehunting.com/th...f-plastic-tipped-bullets.194366/#post-1364011

There's just not much way the cold is going to be able to affect the bullet.

Now one thing I did see many years back in sub 20F weather was that sometimes the tips on Nosler BT's would get brittle enough to break off when loading them into the magazine or when chambering one as it contacted the feed ramp.

From what he's written I don't see that to be the case here. If anything from his last post the problem may have more to do with excessive impact velocity causing them to essentially turn inside out which is something I have seen in a lot of the BT's and one of the main reasons I quit shooting them as they tended just to punch pretty much a caliber sized hole all the way through doing very little damage or go off like a bomb causing too much meat loss to suit me.

Hornady has their tried and true Interbond back in production and if I were going to go back to shooting a traditional bonded bullet I wouldn't fool with anything else. There are higher BC bullets out there but I've never had an Interbond fail me in any way on literally hundreds of animals.

Makes sense about the bullet turning inside out. Although failure is too strong of word. When I initially got my 257 it liked hornady 90gr gmx factory loads and they basically performed similar to the ballistic tips performance every time with a 1.5" channel. I usually shoot behind the front leg so I like the bullet to detonate. Lol

 

[WildRose]

Makes sense about the bullet turning inside out.

I had dozens of them do it and was lucky enough to recover quite a few of them from big hogs and a few deer.

They are a decent, cheap bullet to shoot at varmints and predators but I quit using them on game animals for those reasons.

Admittedly I'm probably the pickiest person I've even know when it comes to terminal performance so I've been through quite a few bullets over the years.

Until I started shooting the Peregrines my "go to" bullet for the last couple of decades was the Hornady Interbond and the Nosler Accubond was not too far behind.

I'm a nut for consistent, predictable, controlled expansion in a broad range of velocities because I never know if my next shot will be at 40 yards, 400, or 750yds and with my "go to" calibers being 7mm STW and 300 Rum with the 300wm close behind impact velocities can be anywhere from 3200-2000fps from shot to shot.

I hate caliber sized hole punchers and hate explosive bullets just as much or more so I'm not exactly easy to please. The only thing that bothers me worse that unnecessary wasted meat is for a wounded animal to run off.

 

[Pdvdh]

Admittedly I'm probably the pickiest person I've even know when it comes to terminal performance so I've been through quite a few bullets over the years.

I'm a nut for consistent, predictable, controlled expansion in a broad range of velocities...

Ever shot the Swift A-Frame? Or Trophy Bonded Bear Claw?

 

[WildRose]

Ever shot the Swift A-Frame? Or Trophy Bonded Bear Claw?

Shot both actually. Was unimpressed with the A-Frame's accuracy beyond 100yds. Never had a problem with the Trophy Bonded Bear Claw terminally but there are numerous bullets that have better accuracy. I find the latter very similar to the Nosler Partition.

 

[Pdvdh]

Yeah,
I use them at closer ranges (under 400yds) so tack driving accuracy isn't critical.
Terminal performance has pleased me.