Load development and ambient temperature

[FingerBlaster]

Should ammo temperature come into play when you do load development? You want to pick the middle charge on your node, my understanding is so that temperature fluctuations will not make you shoot high/low at different times of year, is this correct? In that case, if you are shooting on one of the hottest days of the year, would you not want to move towards the a higher charge in the a node? Vice Versa if shooting on a colder day would you not want to skew towards the lower end of the node?

 

[Deleted member 10043]

Nodes are like unicorns, which gallop and fly based on almost anything and don't really exist unless you're an eight year old girl. Use good judgement and known safety practices when working up a load taking your current temp under consideration. Personally, I go for equivalent factory velocity and about 100 fps higher if practical. Or just go balls to the wall and creep up to max stress velocity and then back off .5 grains if want to squeeze as much speed as you safely can. You need to be comfortably aware on the second method. No fucking around.

 

[Deleted member 113831]

Should ammo temperature come into play when you do load development? You want to pick the middle charge on your node, my understanding is so that temperature fluctuations will not make you shoot high/low at different times of year, is this correct? In that case, if you are shooting on one of the hottest days of the year, would you not want to move towards the a higher charge in the a node? Vice Versa if shooting on a colder day would you not want to skew towards the lower end of the node?

Yes, if you are working up a load in 90* weather, you will use the top end of the node you found. That way you might be less likely to fall out the bottom of it in the winter. Vice Versa in winter, you would use the bottom to allow for heat in summer.I'v e done this a lot in the past, it works with varying degrees of success depending on the cartridge and temp sensitivity of the powder.

Something I've realized in the last couple of years is just how much effect small differences in seating depth affects loads. Tweaking seating depth is kind of like tweaking MV in your ballistic solver, a little makes a big difference. These days I just pick a load that is 2% off of actual maximum load in my rifle. This is the pressure window I want to be in anyway. Then I play with seating depth to find a good spot. If a suitable combination doesn't show up within about .040" of max length, I try another combination. I don't have a lot of time to screw around load developement these days, and this has worked for me enough times that it has become my routine.

 

[FingerBlaster]

Below the number to the right of the type powder is the fps change for each degree of temp change.

What do you mean below and right of what?

 

[Deleted member 10043]

Where is the VR, Uncle?