Velocity falls off after the max load?

[Bradley Walker]

So if you are exploring the upper node of your load (the tuned spot before the max pressure). Let's say the temperature goes up, will you see the velocities drop?

That appears to be what I saw.

On my round robing test yesterday the first 18 shots the sweet spot of 30 grains of R15 was at 2785. It was shooting bug holes.

The later in the day at the hottest part of the day, the same load produced 2740. It still shot tight but the POI had changed. I would have taken more powder to achieve that same velocity later in the day. Is that right?

 

[jamesh]

I don't use RE 15 but that would seem to fall in line with Hodgdon data for RE 15.

http://www.hodgdon.com/smokeless/extreme/page3.php#308win

James

 

[Josh11]

If your poi is lower, then its not the chronograph. It's your load. I have heard that rl15 is temp sensitive but it shouldn't be that much. I just changed from rl15 to varget. What Scale are you loading them with? Could it be a drift in the scale?

 

[RDavies]

I have found in my particular 284 that once I start compressing the load, the velocity goes down and I have recently found the same with a 308. Some guns seem to go the other way and start getting pressure spikes with heavier load. ( as I found in my 308 with a different powder/bullet combo)

 

[Jim See]

less shoulder pressure on the stock in the second session could cause a loss of velocity.