annealing velocity change???

[stvnbrg]

Hi. I have a .223 and previously at 700 with non annealed brass I'm consistently dialing for 21.25 minutes. I annealed my brass this last time and my drop is now 21.75 ! All other variables the same, is this loss of velocity due to annealing??

 

[Derek M.]

Several factors could contribute, like temperature, a different lot # of primers, powder, etc. One thing I noticed was a drop in velocity going from new brass to once fired in my 280 Remington with Norma brass. I went from 57.5 grains of powder for virgin brass to 57.7 in once fired just to maintain the same velocity.

I do not know honestly but would think annealing would be closer to the bottom of causes for what you are seeing.

 

[Joe King]

just a change in barometric pressure and humidity can cause that much of a change in trajectory.

 

[stvnbrg]

Normally I would agree however I have been using , with outstanding accuracy thus far, the Applied Ballistics app from Bryan litz which has inputs for those values and which have never been wrong before. Information on this is tough to find! One theory I found was less neck tension due to softer brass makes for lower pressure and reduced velocity. Thoughts?

 

[Greyfox]

I have found annealing to tighten velocity spreads, but not effect average velocity to the degree that you describe. But that's just my experience.

 

[Derek M.]

I have gone back and forth over the years on it mostly depending on time and laziness but I think I'm going back to annealing after every shot just for consistency. I doesn't take long to do it in small batches.

 

[elkaholic]

The only difference I have seen is lower es/better accuracy (especially vertical).....Rich

 

[Joe King]

Normally I would agree however I have been using , with outstanding accuracy thus far, the Applied Ballistics app from Bryan litz which has inputs for those values and which have never been wrong before. Information on this is tough to find! One theory I found was less neck tension due to softer brass makes for lower pressure and reduced velocity. Thoughts?

Run the calc leave the pressure alone for the 1st drop table, run it again and change the pressure by a value 1.0 (1st 29.92, 2nd 28.92) and see what happens, it'll change your trajectory by 1/2moa at the distance you stated, same thing shows up on my shooter app as well. you can also just make up a drop table for the average and go with it, in theory that will keep you within 1/4 moa. that is in theory.

 

[Coyboy]

The quick and dirty answer is yes, you can see a slight velocity decrease with newly annealed brass, from it's pre-annealed state. I have seen it with my f-class loads often enough that I normally bump up the powder charge .2-.3 grains on the first loading after annealing.

I guess you could say I seen it enough that before the PRS finally which was Dec 1 and 2nd, I annealed all my 6xc brass ( about 400 pcs). Then I loaded it for the biggest match of the year with an extra .2 grains with-out ever testing it. My velocity was within 3 fps of the brass pre-annealing. This allowed me to use all my currrent accumulated data, saving me a bunch of test time.