Hot Load

[Gman]

My 6BR shoots bugholes with 31.6 gr. of RL15, Berger 105 BT,,just touching the lands) Lapua brass, CCI 450 primer. When the temp. gets above 70 degrees, I get very heavy bolt lift. How much less powder should I load to get the same accuracy ? My average velocity is 2916 fps with the above load. Is there a certain amount "tenths of a grain" I should decrease, and still get the same accuracy?

 

[NorCalMikie]

If it was me, I'de back down to 30.0 and go up in 1/10 steps. You don't care about speed as long as they're,bullets) going in the same hole. A little slower is easier on the barrel and brass. But I'am not into speed! I like bug holes!
You might have good accuracy at a slower speed. Don't know till you try. Good excuse for more trigger time.

 

[expiper]

Listen to Lynn...he shoots in lots of very hot weather...I usually back down one number on my powder measure ...which is aprox 5-6 tenths of a grain...I shoot a BR a lot....if the cal is bigger and uses more powder...then adjust to suit...Roger

 

[Gman]

So 31.0 grains of RL15 is a good place to try. If I'm not getting the accuracy at 31.0, then I guess I should drop down maybe 1 tenth of a grain and see how they group ? Oh, Thanks for the replies!

 

[HPMike800]

Gman:
Your load sounds very hot. I was shooting 30.0gr of RL-15 in Norma cases with naked Berger 108's and during a long 600yd match it got up 100 deg or so and I ended up wiping out all the primer pockets in the brass I shot that day. If your shooting naked bullets in the summer, I would think 29.0-29.5grs is a max load for the 105-108gr bullets. I see shooters producing good groups at 600yds with velocities in the 2775-2800fps range.

I switched to Varget. My $0.02 worth.

 

[Gman]

Thanks for the heads up. When the temp stays under 70 degrees, I get absolutely no signs of pressure with 31.6 gr. RL15. I got a brand new keg of RL15 so I'm gonna' start at 30.0 and work up. Thanks for the replies!

 

[Forum Boss]

Every barrel is different. Some guys are maxing at 30.3 grains of RL15 while others are topping out at 31.3. Your throat length and whether you jam or jump will also make a difference.

I can shoot 30.7 RL15 in the morning when its under 60 degrees. If the temp goes no higher than about 70 I'll shoot 30.5. If I know it's going to be 85 degrees or so, I'll load 30.3.

Be sure to keep your ammo cool before it goes in the gun! And don't let it sit cooking in your chamber for a long time before you shoot.

Even with Varget it's very important to keep the loaded ammo out of direct sunlight. In 15 minutes, Bright sun can cause the cases to heat up to 110 degrees even if it's only 80 degrees air temp.