IMR-4350 Temperature Sensitivity?

[Rmitch223]

How temp sensitive is this powder?

I'm doing my first load development process with this powder currently and I'm curious if I need to back down my charge weight when the temperatures increases?

How much would I need to back it down if at all?

Would it be worth it to just switch to H4350 and start my load development over?

 

[ksthomas]

Re: IMR-4350 Temperature Sensitivity?

Normal temperature sensitivity for the IMR series of single based extruded powders is on the order of 1.7 fps per degree. Lots of factors go into this, so this is nothing more than a ballpark figure. This, incidentally, is from a standard temp of 70 degrees, with pressures and velocities going up as the temp increases, and down as it decreases. Pretty standard stuff.

If temp sensitivity is an issue, you might want to look at one of Hodgdon's "extreme" series of powders.

 

[Rmitch223]

Re: IMR-4350 Temperature Sensitivity?

Here in Oklahoma are temp varies pretty drastically through the year from 100+ degrees in the summer months to as low at 20 degrees in the winter.

I currently do not have a chronograph as I am new handloader.


Basically I'm just curious as to the loads I'm developing now in winter months are going to be dangerous when the temps start going up in the spring.

 

[ksthomas]

Re: IMR-4350 Temperature Sensitivity?

Not if they're reasonable loads to begin with, but many I see, aren't. Don't firewall your loads, and leave some room for those hot days in the bright sun. The few added fps that comes with such hot loads is nowhere near worth the risk, to your gun, or you eyes and fingers. Issued a limited set of these,no substitution or replacements, so you really want to keep them intact.

 

[former naval person]

Re: IMR-4350 Temperature Sensitivity?

I suggest doing your initial load development with magnum primers. The slower powders get a little resistant to ignition when it is very cold. I ran into that in Montana years ago with 4831. The magnum primers solved that. Standard Winchester primers are made to work with heavily coated ball powders, so are higher flame temperature also.

 

[Greg Langelius *]

Re: IMR-4350 Temperature Sensitivity?

Kevin makes a key point. After several decades of individual load development, I will simply say that I firmly believe there is no long term advantage to hot loading or working in the max range of loads, and that there can easily be short and long term disadvantages, up to and including catastrophic hazard. If you think you need more propellant, what you really need is a larger case capacity.

Hot loading, just don't do it...

Greg

 

[Greg Langelius *]

Re: IMR-4350 Temperature Sensitivity?

Some will want to work with IMR-4350. I see little advantage when the same entity, Hodgdon, markets both IMR- and H- powders. The H-4350 is an Extreme Powder, and is also an SC (Short Cut) product, so it already employs measures to alleviate temperature sensitivity, and to improve powder flow in measures. To me, it's a no-brainer.

 

[jfseaman]

Re: IMR-4350 Temperature Sensitivity?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Greg Langelius *</div><div class="ubbcode-body">Some will want to work with IMR-4350. I see little advantage when the same entity, Hodgdon, markets both IMR- and H- powders. The H-4350 is an Extreme Powder, and is also an SC (Short Cut) product, so it already employs measures to alleviate temperature sensitivity, and to improve powder flow in measures. To me, it's a no-brainer. </div></div>Yup

 

[Rmitch223]

Re: IMR-4350 Temperature Sensitivity?

Ive worked up from 37gn to 40gn and the rifle is shooting very accurately with 40gn. I'm not sure I will push it anymore. I may try 40.5 and 41gn in the future but right now I'm pretty happy. Shooting 1/2" groups at 100yrds now and 1" groups at 200yrds. I'm very curious as to what velocity I'm getting with this load. Gonna have to get a chronograph asap.

Do you guys think I will have any issues with this 40gn load come summertime?