Lesson on twist rates ( and copper solids )

[PigButtons]

So I bought some copper solid bullets, 45gr .224. I didn't much think about anything other than price, they were cheap and available. I wanted them for fire forming my 22K Hornet cases and figured they'd be fine. The fastest twist rate that I have in a 22K Hornet is 1:12 and shooting these bullets from that rifle I couldn't reliably hit a 2'x3' steel plate at 25 yards, and the bullets when they did hit were hitting sideways to the plate instead of head on. The bullets sat on my shelf for several months. One other thing is when I tried to pull the bullets with a kinetic puller they would snap off just above the neck instead of coming out of the case neck. They appear to be compressed powder with some sort of bonding agent or maybe just compressed under high pressure.
Well last week I decided to try them in an AR that I have with 1:8 barrel and with some load development they will shoot 1/2 MOA out to 50 and I have not yet tried them to 100 yet. The other bullet in the picture is a 55gr soft point .224 and you can see the difference in length and weight distribution. The 55gr bullets do just fine in even 1:14 barrels.

 

[Park ranger]

It looks like a frangible bullet, not solid copper. Shooting steel up close

 

[PigButtons]

It looks like a frangible bullet, not solid copper. Shooting steel up close

Thank you for helping clarify the term. Also good to know because I like shooting steel at 50 and sometimes worry about the ricochet.

 

[sawcarver]

+1 on frangables. Not solid

 

[divingin]

It looks like a frangible bullet, not solid copper. Shooting steel up close

I think the term is sintered. Compressed (possibly bonded) copper powder. Frangible would refer to the fact that it falls apart or deforms on impact.

Copper bullets tend to be longer for a given weight, hence the need for a faster twist rate.

There are reports that you need to clean *all* the copper from jacketed lead bullets out before trying the all-coppers (and vice versa, I'd assume.) I don't really know as I don't hunt, so never tried the coppers.

 

[PigButtons]

I think the term is sintered. Compressed (possibly bonded) copper powder. Frangible would refer to the fact that it falls apart or deforms on impact.

Copper bullets tend to be longer for a given weight, hence the need for a faster twist rate.

There are reports that you need to clean *all* the copper from jacketed lead bullets out before trying the all-coppers (and vice versa, I'd assume.) I don't really know as I don't hunt, so never tried the coppers.

I think there's a lot of cross talk around copper projectiles. Part of it is because marketing departments are in charge of the messaging around the products. Solid copper as I originally meant it above was that it is all copper all the way through. And even the "solid copper" projectile products that are machined from copper bar stock and that are not the frangible sintered units refer to them as " monolithic" solid copper. Actually neither of them are "pure" copper in a chemistry sort of way but are alloyed with other metals. So really it's just a word salad and we're just the tail trying to wag the dog sometimes.

Thanks for the tip on cleaning. But it doesn't seem to matter in the one rifle I'm using, at least for the little that I shoot them together.

 

[Mulligan]

Your post reminded of these bullets from Barnes
CW