Lever and Temps?

[KMW 1954]

Just this fall I started with a 6ARC Bolt rifle and as was suggested and proved true I found LeveRevolution as the most productive with all the 105gr bullets I have tried.

I have developed a very nice wide load and have been shooting this at temps between 60* to 40* and it has held up. Now the temps have really dropped, currently 25* and this is the temps I will be dealing with for our winter rifle league. Guessing between now and the middle of March we will be experiencing temps between 0* to 35*..

As of late I have been being told that LeveRevolution is not very temperature friendly. How much so? Just in general. I have experienced this in the 223 with TAC. Had what I thought was a great load, developed at about 40*, until the temps skyrocketed into the 80's. Pressure spiked and the load fell apart.

 

[Oso]

I this has been periodically discussed for various powders. I haven't seen a chart of powders and their specific temp sensitivity / velocity change. However, this detail is captured in data used for ballistic apps to determine velocity and corresponding drops at different temperatures. Probably best starting point.

 

[Jager]

You're probably going to be losing about ~40 fps at 25F, from a load developed at 50F, with LeveRevolution. A lotta tunes go sideways when that kind of velocity variance enters the picture.

One of the great things about the new micro-sized doppler chronographs like the Garmin Xero, the AndiScan A2 and A3, and the LabRadar LX is that they're so easy to use that they give us instant insight into situations like this.

 

[KMW 1954]

Thanks. These loads are relatively new and so far have only been shooting small samples of which I haven't chrono'd yet. Still using a MagnetoSpeed.

Sadly the range I work and shoot at just reduced to winter hours and now only open 3 days per week. So that will also limit my testing.

 

[jmkasza]

I’d be interested in seeing your results if you post them. I did rather quick load development last fall, but didn’t end up hunting with my 6 Arc this year. Life got busy and I didn’t shoot as much this year as I’d like. 95gr Berger CH… can’t remember the charge of Lever off hand. A little below max, but not by much. It’s been a fun round so far.

Always curious about velocity fluctuation with the wide range of temps here in north central Idaho. Could be 10* for a deer hunt or 90* while out for coyotes in the summer.

 

[chromatica]

LeveRevolution and CFE223 are known to give the highest velocities for 6ARC bolt, but are also known to be temperature dependent. I have experimented with RL-16, N540, Varget, H4895, and N140. N140 is giving me the best SDs with average speeds between 2725 and 2800. I am hearing that N140 is being used successfully in competition with the 6mm variants, so I think that means it is temperature stable.

 

[KMW 1954]

Just got back from the range. Temp today was 20* lower than last I shot Wednesday. Groups opened up a good bit. Shot 3 loads and all showed the same. Did not chrono anything. So right right now not certain if it was the weather or me. I just never did seem to find a comfortable position and the cheek weld didn't feel right. Now I will have to wait until Friday before I can shoot again.

 

[EdHarley]

That happens when your cheek freezes to the stock.
Brrr.

 

[KMW 1954]

That happens when your cheek freezes to the stock.
Brrr.

Though the reality is that this is the weather we choose to shoot in from Jan to March. No need to worry about a barrel heating up!

 

[SeabeeKen]

My son and I started working with Lever not long after it came out. In his 6.5 grendel it was a tack driver. He did discover that in the hot summers it was quite temp sensitive and changed powders. I dont recall him mentioning issues during deer season.

 

[KMW 1954]

My son and I started working with Lever not long after it came out. In his 6.5 grendel it was a tack driver. He did discover that in the hot summers it was quite temp sensitive and changed powders. I dont recall him mentioning issues during deer season.

I found last night another thread on a different forum pertaining to this same subject. It was from a few years ago but the poster did run chrono tests at different temps and seemed to find that below 60* it became pretty stable. They did post numbers.