Previously I posted a question about fire forming brass. I wanted to minimize case stretching in the process, especially in the head region. I good explanation of what happens is detailed at the Hornady web site (good read). This is the load I ended up with.

Fire forming load for my 25-06 Ruger M77 Varmint
Hornady 117grn btsp .257 20 thousands into lands
cci 250 LRM primer
54.5grn Ramshot Magnum powder. starting load for safety

By seating the bullet into the lands I hoped to eliminate movement of the brass forward buy the firing pin.

Pic1 is of brass from my old barrel. The ring on the brass is large enough to be felt as well as seen. This is why it was sent back to Ruger. It actually left a micro ridge around the head region. I am unsure whether it was due to a slightly large chamber or slightly large headspace. I figured I would let them figure it out. Of note: when I cut open the brass no thinning was evident.

Pic2 is from the new barrel with factory ammo. Notice I still have a ring but no noticeable ridge. I have been told the shiny ring is from the brass stretch in that region.

Pic3 is from my fire form loads. NO ring is visible or measured!






Results: It worked. Of special consideration is brass length of the fire formed loads. In all previous loads (hand or factory) I have had to trim after the first firing. The brass length actually shrank in the forming load. From starting at 2.489 trimmed it ended up at any where from 2.487 to 2.480 with an average of 2.484. Factory round’s brass ended up at 2.492. This was a surprise to say the least and leads me to believe that the case formed to the chamber without positive stretching along its axis. I expect this to give me a better more consistent case with a longer life, but only time will tell.

mello