Temp effect on pressure

27 January 2004, 16:07

CCM Doc

I was at the range yesterday - the weather a balmy 6 degrees F - testing some new loads I had worked up for my 416 Weatherby Magnum using RL 22. After the 35th round, I realized that my efforts might be for naught if there was a significant effect on what a "maximum" laod might mean at this temp vs. at 100F.
What have your experiences been, especially with Reloder 22, in large calibers?
Thaks in advance,
Paul

27 January 2004, 16:39

RMiller

I had some trouble with IMR4198 and 600 grain barnes in a 458 win mag.

I worked up a load at 15* F which worked fine. But at 40*+ they were a little hot. The primers fell out while ejecting the fired cases. < !--color-->

This has been the only problem I have run into.

27 January 2004, 16:44

CCM Doc

Did you re-work up the loads at the higher temp? If so, how much did you have to back off of the original load to get back to a safe level.
(Have to admit, I chuckled when I first read about your primers. Thank God for safely built rifles).
Thanks,
Paul

27 January 2004, 16:47

470 Mbogo

Hi CCM Doc,
I looked in the A-Square manual and their test powder was RL15 with the end result being a 0.9fps increase per degree F plus a 66psi pressure increase per degree. I haven't read anything that says RL 22 is temperature stable but The Winchester Ball powders are as well as the Hodgdon SC series of powders. I've found velocity differences with temp for both RL15 and RL19.
Hope this helps,
Dave

27 January 2004, 16:51

CCM Doc

That was very helpful indeed. I will have to pick up that manual (and hear my wife ask again "Don't you have enough of these?).
Thanks again,
Paul

27 January 2004, 17:37

RMiller

I never did work up another load for those bullets.

I have a few rounds left and keep thinking that I'll shoot them up when its cold out. It was 30 below zero this morning

. I'll probably just get a bullet puller and try another load when its warmer.

27 January 2004, 17:38

ALF

.

27 January 2004, 17:53

500grains

Why would you hunt with max loads in a 416 weatherby? That cartridge pushes 400 grain bullets a full 300 fps faster than they were ever intended to go, so I would work on reduced loads that achieve 2400 fps.

27 January 2004, 19:55

Atkinson

This is something that should never be an issue for a proper handloader....I never hunt with max loads, I find max then cut back a couple of grains...You will find once you reach a point in velocity that additional grains of powder simply drive up pressure not velocity....

28 January 2004, 10:23

GeorgeS

I never do any load development in cold weather in belted or other high-pressure rounds. That is saved for the spring and summer.

In winter, I shoot moderate loads in new guns, and my already-developed loads in my other guns.

George

28 January 2004, 17:14

CCM Doc

Quote:

Why would you hunt with max loads in a 416 weatherby? That cartridge pushes 400 grain bullets a full 300 fps faster than they were ever intended to go, so I would work on reduced loads that achieve 2400 fps.

Didn't really address the question, unfortunately. As far as your statement, I decided rather than interject my own opinion, I would get that of the bullet engineers from the companies that I regularly use.
Awaiting Swift and Hornady responses but Norfork and Barnes thought your statement was "curious" "incorrect" and "silly". Each gave lengthy, professional and rational explanations with specific examples of both media and in-game results at speeds of 2700fps and stated that their bullets are, in fact, designed to operate at such velocities. I await responses from Swift and Hornady reps, but I expect similar statements, to be honest with you. Perhaps I am wrong, but I do not believe that it was some mareting person responding for Barnes and Mike, from Northfork, certainly knows of what he speaks.

In response to Mr. Atkinson, your method is precisely the same as my own. The question in my mind is whether backing off 1-2gr from a max found at 6*F provides enough safety cusion when the temperature is significantly higher.

I am sure you are right, GeorgeS, to paraphrase: "Work up the loads in similar conditions to those expected in the field." Perhaps the best advice.

I enjoyed the education from experienced, intelligent and interesting folk. Nothing wrong with sending those 400s out at 2300fps (per 500gr), but certainly is fun spitting them out a bit faster too.
Thanks one and all,
Paul

29 January 2004, 04:07

GeorgeS

Paul,

I recall an article Ross Seyfried wrote, reviewing the .416 Wby. He liked its horsepower (of course

), and at the time stated that the factory-loaded Swift A-Frame was the only soft he'd use on Cape buffalo with that gun.

George