What impact speed is needed for reliable expansion of X bullets?

Barnes claims only 1600 fps, but their BC numbers look suspicious. Some tests of expansion in wet paper suggest 1800 fps is plenty in dense tissue, but what about in less dense tissue such as the lungs?

Hey asdf, Try this: www.seahook.com/bestbullet.jpg and be patient while it loads cause it is worth the time.

asdf,



You have a point that just some hide and hair and then delicate lung tissue is not much to expand a bullet on. Also keep in mind that X bullets don't expand to as large a diameter as other bullets. Some other bullets when expanded also have very sharp edges to the remaining jacket. Coreloks are one that do that.



I called Sierra and asked what bullets to use on coyotes at very long range. The answer was to choose a bullet that would be going at least 2300 fps at the target. This is due to the small size of the coyote and who knows where you will hit one at long range. I see some analogy to low velocity lung shots on game as well.



On the other hand the 30-30 has been working at less velocity but it takes a lot of energy to expand a bullet and round and soft nosed bullets have to be easier to expand. Bullets like the ETP copper X's are not as soft as lead. They also have small meplats. You just can't trust something like that at low velocity.



It's not all that hard to get an X bullet going really fast however as most select lighter weights with monolithic bullets.



As far as ballistic coeficients go I don't trust most of the data out there. There is a copy of actual testing from a magazine on the net. I hope someone will find it and link us to it.



From what I read I would not shoot an animal in the lungs with an X bullet. On the other hand if you hit some bone with it then it's a different story. Matching the bullet to the game is the plan. I just don't see whitetails and X's as on the same page if one wants to be optimum.

I've shot a lot of game with X bullets in different calibers. I've had one that failed to expand at all, which I would guess was traveling around 1850 when it punched through the heart of an elk. It was found against the broken leg on the off side. I think they punch through deer too easily, and I stick with Hornadies or Partitions for deer size animals.

asdf,

1600fps was what Barnes quoted to me too. It's not likely I'll impact below even 1800fps in my .45-70. But I did not get info on impact velocities for the muzzleloading/handgun X bullets; did you? These would quite easily dip below 1600fps at impact, especially the handgun. The mouth of the cavity on these bullets is quite large though.



Note that hardness is not the only critical issue in expansion as the interior of the cavity in X bullets is deeply scored, hence the name. It is designed of course to accomplish what the insert tip is also, namely expansion initiation.

Beartrack: I wasn't aware handgun hunters were trying the spitzer X bullets. A fine testimonial indeed.

steve_y: I was told 1600 fps for the spitzers, 1600 for the discontinued (sigh) .348 XFN, and 1000 for the .45-70 XFN.

I believe both the cavity size and the thickness of the "petals" can be varied to give them whatever opening impact speed they choose. My concern is with the spitzers, but judging by the wet newsprint tests I've seen, 1800 looks to be safe, and 2000 is likely a sure bet. I read of one set of tests claiming 2400 fps is the ideal launch speed for typical African bush hunting, and that suggests 2000 fps is also plenty. I was simply hoping to get more "real world" data on these.