I finally got a chance to do some loading and shooting and have found my new “do everything load” for my 300 RUM. I know some out there are looking for results/experience with these components, so here you go:
My rifle isn’t some big heavy bench gun or expensive custom gun. It’s just your average run-of-the-mill A-Bolt Composite Stalker. [img]images/icons/wink.gif[/img] It has the factory original (pencil thin) 26” barrel with well over 1,000 rounds through it. About ¾ of those were from when it was a 300 Win Mag before I had it rechambered to RUM. The only accuracy mods I’ve done to it are a Moyer’s trigger, and relieving some more material from the barrel channel of the much-too-flexible composite stock to make sure the free-floated barrel stays free-floated (it must have been something to do with the increase in recoil of the RUM, but right after I got it rechambered it wouldn’t shoot worth a damn—-the barrel contacting the stock was the problem). The scope is a Leopold 3.5-10X50mm with Stoney Point Target Knobs.
200 Accubond , 95 grains of Retumbo, brand new completely un-prepped Remington cases, Federal 215 primers loaded to 3.60” OAL, 3177 fps.
I started out with H870 because I had a bunch I wanted to shoot up and I thought I could get some good velocities. I was easily able to beat the above velocity with it. I didn’t get a pressure sign (in my rifle the first sign is an ejector mark) until a round clocked 3311. Backing off quite a bit still put me at 3246, but the load just wouldn’t shoot. I think it’s because I was in too big a hurry to pack all that powder in the case properly so I was compressing it so much the seating depth varied widely. Anyway, it wouldn’t shoot and H870 is dead. Enough about that.
96 grains of Retumbo yielded 3208 and no pressure signs. I didn’t clock 97 grains but I’d expect it would have gone around 3240. I got a slight ejector mark with that one. Extraction was unchanged—still a finger-tip affair.
So I backed off to 95 grains. What this powder lacked in velocity, it made up for with consistency. Three randomly picked rounds went 3171, 3183 and 3179. I know it’s only three rounds but I’ve never had an extreme spread of 12 and a standard deviation of 5 before even with only three rounds. This is with “as thrown” powder charges, no less. I knew right there this load would be more accurate.
Disclaimer: I feel this load is safe in my rifle but if you try it in yours you will die, guaranteed. Don’t try it. You will die!!!
OK, now that that’s out of the way, I can tell you that my rifle has a rather sloppy chamber and with rounds seated to 3.60” to fit in the magazine it basically has a free-bore as well. So you really might
run into pressure signs before I did. This is backed up by Brent Moffit’s data—at 90 grains he was at 3082 fps while I was only at 2977 fps. At 92 grains I was still only at 3062 fps. So really, work your way up to this slowly guys—especially given the tales of Retumbo acting completely differently for different people. Be safe.
I now realize I forgot to take a pic of the bullets before firing. Oops. Sorry. You all know what they look like anyway.
I have been waiting for a very long time for somebody to make a heavy, high BC 30 bullet with reliable terminal performance. I was actually close to setting myself up to swage my own bullets so I could make what I want. Well, Nosler came through. It seems so far they did it well enough I might not have to get into the swaging business. Don’t get me wrong, there is nothing “earth-shattering” about the terminal performance of these bullets. Some bullets will do some things better. Other bullets will do other things better. But this bullet lived up to my expectations (as far as I could test it). It seems like a very good all around bullet for my purposes.
I apologize for my lack of photography skills and/or equipment. Damn I need a digital camera! Anyway, these pics were the best I could do. I hope they’re good enough for you guys:
The bullets from left to right are the 180 Scirocco, 180 XLC, and 200 AccuBond. The bullet of each type on the left is a simulation of a long range impact with minimal resistance. Each on the right is a simulation of a normal range (like 250 yard) impact.
The “long range” Scrirocco retained 88.7%, the “normal range” retained 78.2%. Great weight retention but they didn’t penetrate very far—as one would expect with them opened to such a huge diameter.
Both XLC’s retained 99%, of course. The “normal range” XLC is what I’m used to seeing from my tests and the reason I used X bullets exclusively for so long. Absolutely perfect! It’s the “long range” one that’s disturbing. It hardly opened up. The wound channel was tiny. As you can see the shank is slightly bent. This is the only bullet that didn’t penetrate straight. About ¾ of the way in it took a 45 degree turn to the left. I could attempt to explain why with some Euler column buckling equations but I won’t. [img]images/icons/shocked.gif[/img] I’ll just show you what happened.
The AccuBonds retained 76% and 64%.
They don’t look all that impressive. Much the same as a Partition doesn’t look all that impressive compared with some of the “pretty” mushrooms some of the custom bonded bullets give. But Partitions always get the job done. If this bullet mimics their performance, I’ll be more than happy.
In an impact where the XLC hardly opens up and doesn’t penetrate straight, these open up just fine and go straight. In an impact where the Scirocco is nearly turned inside-out, these hold together and penetrate farther. A pretty good compromise between the two.