Load development - Interesting brass find.

[SpencerC]

So I finally got out for the first time this year and was able to start my load development in my new .223 barrel. I was using fully prepped, virgin Lapua brass, Berger 90VLD's and N150 lit by CCI BR4 primers. I was amazed at the consistency and was very pleased with my results overall.

Now, for the interesting part. For a couple/few groups I had a couple flyers so I marked the brass for inspection later when I got home, and I noticed that this brass did not grow in length at all. Every other piece used grew between .003" and .005". These were all the same length, at 1.750", to start and the only pieces of brass that did not grow in length, produced flyers.

For my next outing I will load these few pieces of brass again and see if they produced a flyer a second time. Just a little something interesting I thought I would share and see if anyone else has noticed the same.

 

[Heavies]

Nice. I would like to see what happens on your next firing!

Next time I need to break out the new brass I am going to look for that.

 

[bozo699]

SpencerC,
That is very interesting, thanks for sharing. Please keep us updated on your findings
Wayne.

 

[1000yardstare]

Is it possible that the cases that "did not grow" were actually shorter than the other cases to begin with before firing?

Could be that all cases grew in length by the roughly the same amount but the initially shorter cases would still be shorter after firing.

 

[SpencerC]

All of the brand new, blue box Lapua brass was 1.752" from factory, I FL sized them, trimmed them all to 1.750" and neck turned. No cases were below 1.750" to start. Weird, no?

 

[jonbearman]

Not so weird,all metal no matter how blended has hidden variances and can be of different hardness slightly.They will grow slightly different due to being sized and springback being alittle different every time. I have noticed this especially with .223 and wildly with 22-250 especially through the years.After a couple firings they settle down and grow slower and dont require as much trimming.