Watch your temp.

[DavidV]

Shot in a match in Tulsa, Ok this last Saturday.
10 at 300 =100 8X
10 at 500 =100 7X
20 at 600 =200 11X
20 at 600 *%$*&@#$%
I was doing great until the last string of 600.
After my two sighters I fired the next 8 rounds into the x ring.
During those round I noticed that my bolt was getting hard to lift and on the 8th round I could not get it to open. After banging on the bolt with my hand I proceeded to break the bolt handle off.
As the day got hotter and the barrel warmed up even more the pressures must have skyrocketed.

I was shooting 32.9 grains of RL15 in my 6Dasher. I developed the load in much lower temps and it did fine.
Moral WATCH THE TEMP.
Bad end to an otherwise great day.
Now to send the bolt to Kelbly's

God Bless
Good shooting
Watch the temp!!!!
DavidV.

 

[Cheechako]

David

By coincidence there's a post about ammo temp on another Forum, right now. An old long-range benchrester's trick - take a cooler with ice to the line with you. When that starts happening you can save the day by cooling your ammo. Best to run some tests before hand to see what the effects are but I've done it myself and it works.

Ray

 

[Forum Boss]

Yep,

You might be shocked what 15-20 minutes in direct sunlight can do to the pressure.

This from May 20, 2005 Blog:

RELOADING TIP--Monitoring Ammo Temperatures: Keeping your loaded cases at a controlled temperature is vital for maintaining good ES and case life. At a recent varmint match we observed pressure signs with cases that had been sitting in direct sunlight for about 15 minutes. As we were running a "moderate" Norma 203B load, the pressure indications were surprising. Testing over a chronograph, cases that had been sitting in direct sunlight showed velocities up to 70 fps higher than those that had been kept in the shade. Using QuickLoad's temperature function, we calculated from the rise in velocities that case pressures had increased by over 4,000 psi--just from 15-20 minutes in direct sunlight!

We will now keep a temp strip in our ammo boxes at all times. Neconos.com offers Bar-L Benchrest temp strips that visually display heat readings from 86 to 140 degrees,our cases got warm to the touch so they were probably about 110-120° F). Think of these strips as compact, unbreakable thermometers. With adhesive backing, they can also be used to monitor barrel heating. Put a strip on the side of the barrel and the barrel's temp will be indicated by a stripe that changes from black to green. There is also a "general purpose" strip that reads to 196 degrees,bottom row). The Benchrest strip is in the middle.