An interesting thing happened to me at the range this AM. I have a 6.5-06 Ackley with a 1-8 twist. Velocity with 120 gr Speer Hot Cor was around 3150 fps. In 15 shots, this happened twice: The bullet did not hit my 2x3 target stand, but there was a very small roughly rectangular hole (2mmx3mm) thru both the paper and the corrigated plastic behind it. They grouped wild, too, varying as much as 8" vertically. They must be coming apart in midair due to the twist. That's the only thing I can think of. They were replaced immediately with 120 Gr Rem Corelocks (3/4 to 1" grps) Ever see this????

If it's hot core ,the core should be bonded to the case and shouldn't come apart even with a tight twist. Talk to Speer .

The Hot Core is not considered a bonded bullet. The core is poured into the jacket in a molten state. This is supposedly to keep oxidation from happening between the core and the jacket that does happen in standard cup and core bullets.

I've never heard of any of the larger caliber Hot Cores coming apart but I have dissentigrated a few of the Hornady SX's trying to push them to fast. I wouldn't give up on them too quick, they are pretty good bullets for not being comsidered a premium.

I thought some sort of flux was put into the cup b4 the core was poured???????

A Clue!!!

In 1966 I rechambered a 6.5 Arasaka to a 6.5X.284. At the time the only bullets that would not fly apart in the air were Hornady and Norma 160grainers and a number of Barnes' originals and Jack Whitworth's 156 grain psp. That was a 30" barrel with a supposed 1-8.5 twist. Anyway it was a fast twist. It really was a one shot show stopper; Fantastic, dramatic kills roger

I've used many of the Speer 120s at the same velocity range and with a 1:8 twist and have never, ever experienced anything like that. The twist is not too fast for that bullet at 3150 fps -- that's for certain.

Please don't take offense to this question, but are you certain you have not loaded .25 caliber, 120 grainers by mistake? Or if fireforming, coould you have grabbed standard 25-06 ammo inadvertently? That would definitely cause the situation you describe.

How many rounds do you have through the barrel?

Sounds like maybe a batch of deffective bullets. I've shot a number of those bullets in a 1 in 9 .264 at 3350+ fps and never had a problem......

The only bullets I've personally had come apart were lightweights fiured iun a .220 Swift. Obviously, these were loaded too fast!

The Speer Hotcores do NOT have bonded cores. I wish they did!

Here's some more particulars...I don't own a 25 cal rifle, so don't have any bullets. Seating felt the same for all of them, so it doesn't seem like Speer tossed a few in there just for fun
The barrel has about 100 to 150 rounds thru it, if that. I also clean the barrel religiously after every session.
It sounds like the bullets are flaky. That's OK, they'll work just fine for fireforming new brass.