Midway Dogtown RPM Limits

So I ordered the 500 pack jumbo case of .223" 55Gr SP Dogtowns from Midway.
I started loading and found a load that seemed to group well. The Chrono shows that it is flying at about 3350FPS. So I went out with a box to do my final sighting in this morning.
When what did I spy with my little eye??? Lead vapor following the bullets!! I re-Chrono'd and the velocity was the same.
I called Midway to ask what the RPM limit was, and the answer was the published "Keep them under 4000" So I asked him with what twist barrel, Since my FP has a 1-9 twist.
He had no answer, but gave me a Sierra tech number. Said they were "Familiar with our products" Which I think means they make them for them. In any case, I think that the Dogtowns are essentially the Blitz's, NOT BLITZKINGS. IF that is so, they have a rough RPM limit of around 240,000. This means that I'd have to slow to about 3000FPS.
Anyone else have a similar experience, or know about what the Rotational limit is??

Vapor trail is just moisture in the air.

I push the 55's above 3600 with a 1:9 twist 223 AI. I fireformed a few through "super duece" - a 1:8 twist 222 mag ai.

Suppose, if boredom sets in, I could see how fast or when they explode from my 22/6mm AI with a 1:8 twist. That should push them past the 4200/4300 mark.

Do know, at 223 AI velocities....36xx, these bullet come apart rather nicely as they pass through a prairie dog.

What do the targets look like? If the bullets were starting to vaporize there would most likely be those little "comet tails" around the holes.

uj

Sorry no targets. Was shooting at some steel targets at a range. But you could see a Grey "aura" around them, the whole way to the target. I had 5 rounds that were Hornady SP's and they didn't do it, so I don't think that it is a condensation issue.

Only times I have seen bullets come apart from excessive rotation they just made a "puff" and didn't reach the target. Never seen them leave a trail (other than condensation/vapor as was said).

+1

Well, this is what it looks like:

http://www.thehighroad.org/attachmen...8&d=1059792338

uj

So I talked with a gentleman named Wade, from Sierra a moment ago.
Here is what he told me. The .223" 55Gr SP Dogtowns should have a RPM ceiling of about 260,000RPM. Of course depending upon bore smoothness, etc...