I have a 7mm Ultra that is set up as a target rifle. Recoil is very comfortable & the ballistics are superb. It is very likely going to be a world class throat eroder. [img]images/icons/frown.gif[/img]
I'm getting 3,300-3,400 fps out of a 30" Kreiger 1:9" barrel with 180gr JLKs. 130 Sierras went out at 3,671. It is much less 'efficient' than the STW for the amount of powder it uses. I only have @ 150 rounds through it trying to find a load/powder it likes.
Some interesting finds so far:
* It only requires @17 MOA from 100-1,000 in elevation. [img]images/icons/shocked.gif[/img]
* It takes @ 1/4 the wind drift as a 308 at 1,000. [img]images/icons/grin.gif[/img]
* The time of flight at 1,000 is almost exactly 1/2 that of a 308. :razz:
* Where a 308 will just tip over a 12" T1 steel plate at 1,000, the 7mm RUM will flatten it & make do backflips. [img]images/icons/smile.gif[/img]
It's too soon to tell much else.
All 'standard' powders I've tried so far leave 1/4 - 5/16" of the case unfilled below the shoulder. I'm messing with BMG powders (H50BMG, WC860, & 5010) lately & am seeing some improvements. The longtime longranger is right: a l-o-n-g barrel is advised due to the serious overbore.
The good part is, a 180gr VLD or similar should give downrange (not necessarily terminal) performance out to 1,000 approaching a big 338 WITHOUT the recoil a whopper 338 projectile will give ya! It also has impressive sectional density to help it on target. The ballistics programs I've run the numbers on show that the 180 should still be doing @ 2,200 at 1,000 & @ 1,500 @ one mile. It is a shame the throats probably won't last.
I do want to try some of Warren's 162 LRBTs. I shot a group in a tricky fishtailing wind last week at 500 yards that could be covered with a fist. Not bad for a preliminary load. That was with a 156gr Cauterucio.
I wish I had more to offer, but I hope this helps you a little.
I ordered tham direct from Bob Cauterucio. He was a little hard to find, but what a nice fella! His address is:
482 Comerwood Ct.
S. San Francisco, CA 94080-4205
He shipped direct to my house in a reasonable time. I bought one box each of his 156s & 176s. Both have BCs near or above .700, according to Bob.
Unfortunately, from everyone I've spoke to, the STW and the 7RUM will be throat toasters, when loaded regularly to max. I haven't split a case neck yet, but I'm only getting 4-5 loadings each before the primers can be seated with your thumb! [img]images/icons/frown.gif[/img]
I've been checking erosion regularly, my 7 RUM had 3/1000s eaten off the throat in the 1st 60 rounds (as measured with a comparator). If it gets 800 rounds through it before re-set, I'll be VERY surprised. I did spec the barrel to allow an extra long non-tapered area ahead of the receiver to give the possibility of at least two re-sets.
The problems created by overbore on the .284 & smaller caliber magnums is a major one not easily overcome.
Check out the 7mm Dakota. It is of course, the 404 case but shortened. Shoots less powder than the STW, 7-300W, and Ultra with basically the same results. My uncle shoots this cartridge and can push the 160's over 3,200 fps. Besides, a game animal doesn't care what velocity you hit him with as long as it is enough to get the job done, which is far less than many think.
To be honest, I have never shot one and am not intimately familiar with them. There are people on this board that do shoot them however. My uncle shoots one in a 16 pound bench rifle that is very accurate and an impressive performer. He can push the 180 berger over 3,000 fps easily with a 29 inch barrel. It is the 404 case just like the Ultra but it is shortened. He gets the brass from Dakota and I don't know how many shots he gets per piece. It must be decent quality as he shoots 5 shot groups well under 10 inches at 1,000 yards. Just post a message saying you need info on the 7mm Dakota and you'll probably get a bunch.
Tell me more about the Cauterucio bullets. How are they constructed? Meant to be a target or hunting bullet? I am always interested in trying high BC bullets in 7mm. What is the BC number according to Bob?