Just ordered a Rock Creek barrel

Fifty,

I apologize if this has been asked before, but what kind of velocities are you expecting to achieve in top pressure loads in the 300 Allen Express with the WC 265g and 290g, for instance.

Thank you.
 
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John A,
What sort of velocity difference have you seen between the 265 ULD RBBT and the 290 ULD RBBT?

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Figure about 150 fps more for the 265 at the same pressures. I shot them both yesterday and they averaged 138 fps faster but the 290 load seemed just a bit hotter. Also the new 265's I'll try next will be shorter.

Here were the loads:

265 RBBT Bonded, 98 gr US869, Fed 215, Nos Brass, 3.6" OAL: 2827 fps

290 RBBT, 95 gr US 869, Fed 215, Nos Brass, 3.6" OAL: 2689 fps

Again, that's from a 26.7" long standard 300 RUM. Temp, 43 degrees.

In addition to the extra length, these weren't quite as slippery as the flat base 290's I tested earlier. There was slight extraction resistance on a couple of shots with each bullet indicating those loads need to be backed down a couple of grains. I'd expect a 30" barrel to give a good 100 fps more than mine at least.

The other news is these bullets turned out to be too long for my 1:9 twist. The 265's built on the shorter jacket should work for me so I'll try them next. I would expect a 1:8.3 to work fine for the 290's, but my 1:9 just can't handle them.
 
Life got in the way. Wife got pregnant during the long wait for the barrel. Spoke to Mike and they hadn't started making the barrel yet so I cancelled. Eventually ended up with a LH Rem 700 300 RUM for less than what I had in the action I was going to use for the custom. I'm launching 200 gr Accubonds at 3200 fps under an inch at 100 yds, made my longest kill to date last fall. Broke both shoulders on an elk at 589 yds.

I still would love to have one of Kirby's creations but dang that kid goes through some diapers!
 
Congrats on the baby and putting your priorities in order. I have a 5r rock BBL in 22-250AI and it took forever to get it. But its mighty fine. Was it worth the wait? Next BBL will be from Lawton 6 grove cut rifled for my 6x284. Maybe Bartlien for the 22-250AI . Dang who knows what the economy will be like in the coming months.
 
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