Reloader 15 temperature/velocity change questions.

[gunsnjeeps]

Does anyone have data on adjusting Reloader 15 for temperature? While chronographing .308 loads over the weekend I have about a 100 fps change from the mid 60's to the low 90's. Loads were fired in a .308 Match Garand and Savage 112. I also have about the same change in issued M118LR.

As an aside 43.1 grains of Reloader 15 is not equivalent to M118LR. 43.1 gave me stiff bolt lift and extraction problems in the Savage, M118LR fired fine.

 

[BC 6.8]

I'm not sure about 308, but I have been working on some loads for my .223/5.56. At 55° F my 24.5 gr Re15/75 gr HPBT load was running 2690 fps. The other day (70°F) I shot 24.4 gr and 24.5 gr loads that averaged 2709 and 2715 fps respectively. I have some rounds loaded at 24.1 gr and 24.3 gr to test this weekend. I want to get the velocity back down to the 2690 fps range because that was where the best accuracy was. I will probably end up with a summer load and a winter load.

My advice for .308 would be to back off at least .5 gr and probably need 1 gr less to get the same velocity as you were before it warmed up.

 

[j-dubya]

Try 42.5gr for your M118LR-like loads.

 

[Boogaloo]

43.1 grains of RL-15 @ 65*F shows (for my settings) 2640 FPS
43.1 grains of RL-15 @ 90*F shows (for my settings) 2672 FPS

That's a 32 FPS spread due to temperature, which almost (but not quite) equates to 1 FPS per degree rise in temp.

I used Quickload to get the data in case you were wondering.

 

[M40_A1]

I found 42.8 gr. RL-15 in full length sized Lapua brass to match 175 gr. FGMM (about 2585 at 65 F).
Are M118LR and 175 FGMM equivalent?

 

[700sendero]

I shoot 42.8 gr rl 15 in lc lr 07 f/l sized for 2625 @ 87degrees 22" shilen 1/10 rebarreled 700 ltr...I read somewhere the velo for fps is like 1.2 fps for every degree in temp change ..can't confirm haven't been back out with crono on a cooler day....

 

[gunsnjeeps]

Sorry I didn't post velocities the other night I was on my tablet and didn't have them.

For the M118LR, on April 9th I had an average velocity of 2658, on May 30th I got 2720. Both functioned fine in my Savage. The 43.1 grain RL15 load ran 2735 and gave me hard bolt lift an I had to forcibly extract the cases.

My 150 grain ball equivalent load (44.6 RL15) ran 127 fps faster in my Garand than when I worked it up.

 

[gunsnjeeps]

Deleted double post.

 

[leadbullet]

A friend of mine found out the expensive way that his 45 degree weather lapua brass 6MM dasher blows primers out at 80 degrees. Shoots great but all his brass is toast after the out of state match.
he is going back to varget, as having a summer and winter load is just too silly for him. I am still having a good laugh though.

 

[gunsnjeeps]

I have about 7 pounds of RL15 to use. I think I'm going to load it in 150 grain loads Ball equivalent load) and work up varget for the 175's. I shoot Varget in my AR year round with the same sight dope out to 600 yards.

 

[M40_A1]

Try both. My rifle prefers RL-15 over Varget by a hair with 175 SMK.

 

[40xs]

Be carefull shooting a winter time load in the summer (especially if it's close to max.) with RE powder. I had a good summer load for horn. 208 and shot a match in the winter and the impact was 4 moa lower at 1000yds.. This was not , however RE15, but RE 17, but I feel that the results would be similar. I wonder what I would have experienced if the temperatures had been reversed. I went back to varg.

 

[gunsnjeeps]

Our problem in Virginia is we can have a mild week and a hot week the next, for example May 25th was 67 degrees (my guess was off by 2 degrees) and May 31st and Jun 1st were 90 degrees. Once the temps go up we stay in the 80's and 90's until October.

Just noticed you are in NC, so you get about the same thing.