Had a rifle dropped off to me that I've previously loaded for with a 90 gn Barnes projectiles to a load just above the recommended book max. In this gun it was fine with reasonable velocities and no pressure signs. I'd run out of these so got some of the 90 grain Nosler E-Tips to try out.
In the packet there was a warning note to start off at starting loads and not to exceed mid loads.
In light of this and of hearing that the E Tips copper alloy was slightly harder than other lead free projectiles I did as recommended. I loaded up for a ladder test with one load each of 45, 46, 47, 48 and 49 gns of AR2213SC. I realise the last three are above mid loads but thought I'd take them with me to the range in case the factory warning was simply the manufacturer being fearful of being sued.
So first shot with the starting load from the ADI manual resulted in a pretty flat primer and slightly sticky bolt lift. Velocity was 3122fps! The ADI manual states their velocity through a 24 inch test gun as 3020fps for this load. This raised my eyebrows somewhat.
I decided I'd give the next one a whirl. This was 1gn above the book starting load. This gave a velocity of 3197fps!
This same rifle with the same batch of powder didn't achieve this with 48gns behind the same weight Barnes solid copper projectile. With 48gns it achieved 3150fps, the E-Tips got 50fps past this with just 46gns.
Here's the problem, it was not a safe load! The bolt took a herculean effort to open and when I managed to extract the case the primer pocket had opened up big time and the primer fell out during extraction.
You don't need to be too familiar with measuring casehead expansion to know you've got an issue there!
The photo below is of an unfired case beside the 46gn load. It measures .207" inside the primer pocket. The 46gm load expanded this out to .221". Thats .014" expansion at the strongest end of the case!
This next photo is the buggered case with a new primer in it. You can see the gap around it showing how much the numbers above look like in reality.
It wasn't a hard decision to stop firing at that point. I went home, pulled the remaining loads and started again at 43gns with 43.5 and 44gn loads also. 43gns ended up being a decent load with the others still too warm.
So a word of warning if your intending to load with E-Tips. They're good projectiles but definitely start low and don't do what a lot of us experienced reloaders do and start above the book starting load because we're used to these being ultra conservative. With these projectiles they aren't.
Bookmarks