DarkStar,
Gee, I guess I stepped on some toes here!
I explained exactly why I came to the conclusion that the "magic" velocity gains with RL-17 were mostly an Interent myth in a fairly recent RIFLE magazine article titled "Designed Powders," about the history of improvements in smokeless powders. Sorry so many people apparently missed it. I'll quote some pertinent info from that article:
"The main reason for all the RL-17 excitement is a report on the website
www.6mmbr.com. Two very knowledgeable handloaders, German Salazar and Bob Jensen, ran some pressure tests with RL-17 in the 6XC case, using an Oehler 43 strain-gauge system, obtaining velocities up to 200 fps faster than those achieved with any other powder. They reported their results in an on-line article with headings such as �State-of-the-Art Powder Delivers Amazing Velocities� and �Paradigm Shift In Powder Performance.�
"There�s no doubt that their results are valid, but the 6XC is a specialized wildcat, developed by well-known high-power target shooter David Tubb. It�s typical of modern target rounds, with a short, fat case and long neck, and normally loaded with very sleek 6mm target bullets in the 107-115 grain range.
"Internet chat rooms suddenly buzzed with this information, and soon almost every handloader on the planet expected an extra 200 fps from ANY cartridge loaded with the new Wonder Powder. Thus they started stuffing cases with RL-17 until they got as much speed as possible, once again judging pressures by whether or not the case came apart. Not so amazingly, some guys did coax an extra 200 fps out of their .30-06!
"But if we examine Alliant�s pressure-tested data (see sidebar) we find that while RL-17 does provide a velocity advantage in some cartridge/bullet combinations, the gain rarely reaches 100 fps, and in many cartridges other powders provide more velocity. The �paradigm shift� found in the 6XC case is not due to a magic powder, but the fact that only a few powders are suitable for a very specialized cartridge. Reloder 17 just happens to be the perfect match for the 6XC.
"In Alliant�s data RL-17 also appears to be the perfect match for the .25 WSSM, another very specialized round. In more common cartridges, such as the .30-06, there are already dozens of appropriate powders, and RL-17 faces tougher competition. One example is Alliant�s new Power Pro series. Alliant�s website even states that �Each Power Pro powder is engineered for a specific use��and Power Pro 4000MR is among the powders that beats RL-17 in some cartridges, including the .30-06."
I can't reproduce the side-bar, because for some reason the data comes out scrambled, but it compares Reloder 17 data with the top velocities from other powders, using Alliants PRESSUE-TESTED DATA. But here are a fw main points:
The biggest gain over other powders is in the .25 WSSM with 120-grain bullets, which shows a top velocity 127 fps higher with RL-17 than any other Alliant powder.
It also shows gains over RL-19 with some bullets the .300 WSM, 104 fps with 165's and 82 fps with 180's. But the RL-17 data was shot with Speer boattails, and the RL-19 shot with Speer flat-bases, which develop more pressure, so all that data isn't really comparable.
The next highest gain is 78 fps with 100-grain bullets in the .243 Winchester. The third highest is 60 fps with 200-grain bullets in the .325 WSM. And that's ONLY comparing it to other Alliant powders, not all powders on the market.
In some combinations RL-17 is slower than other powders. With 200-grain bullets in the .30-06 the top RL-17 speed is 2552 fps, not particularly exciting and also 43 fps SLOWER than with Alliant's new 4000-MR. In the 6.5x55 with 140's it's 147 fps SLOWER than any other powder listed, and in the .338 Winchester with 225's it's 113 fps behind.
Please note there there are no 150-200 fps gains anywhere in Alliant's pressure-tested data. Instead there's a fairly normal mix of 75-100 fps gains a few cartridge/bullet combinations. This can occur with about any new powder, not because of any "paradigm change" but (as with the 6XC) the powder matches up well. But in most cartridges RL-17 shows just about what we'd expect from a powder in it's burning-rate range.
Now, let's look at some of the loads mentioned so far in this thread:
Somebody mentioned getting 2900 fps with the 6.5 Creedmoor and 140-grain bullets. There is no Alliant data for the 6.5 Creedmoor, so he has no idea about what pressure his handload might be getting.
Somebody mentioned getting fantastic velocities with the 200-grain AccuBond in the .30-06. Alliant's data (as mentioned above) lists a maximum load producing 2552 fps, 43 fps slower than listed with 4000MR.
SU35 got great velocities with 180-grain boattails in the .300 WSM--by starting with Alliant's maximum load and working up. This makes me suspect that his loads are in the 70,000 psi range.
Similarly, Keith is getting 3550 fps with 110-grain TSX's in the .270 Winchester. There is NO Rl-17 data for that bullet listed by either Alliant or Barnes, so my guess (again) is that pressures are probably right up there.
I've tested RL-17 in a number of rifles and cartridges. It's a fine powder, and does produce 50-100 fps more in a few cartridge/bullet combinations--just as many powders do, thanks to matching up well. But Hodgdon Hybrid 100V is capable of much higher gains in certain cartridges, yet there hasn't been any huge excitement over it,
due to two factors:
1) No website proclaimed it a "paradigm shift."
2) Hodgdon released a bunch of pressure-tested data along with the powder, so handloaders didn't have as much chance to "work up" loads the old-fashioned way, by looking signs of case distress. As I've mentioned many times in various articles over the years, these often don't show up until pressures reach 70,000 psi or thereabouts. ANY powder will result in pretty zippy muzzle velocities at 70,000 psi.
