Like many medium burn rate powders, RL17 will cover a wide spectrum of cartridges for which it will work. Whether it will be the best powder choice is subject to a number of other factors. With a 40 grain BT, for instance, it looks as if it would be a possible powder for the 22-250. With a 180 grain AB, I would guess that there are better powders available. Data is coming online fairly swiftly, but there will always be some questions as loads are developed. Alliant's list of cartridges tested seems to be expanding (http://www.alliantpowder.com/reloaders/Powder.aspx?powderid=25), ranging from the 223 WSSM to the 338 WM. My reaction is that there are generally better powders for the larger capacity cases with a long powder column. RL17 was developed with the short mags in view, and it fits that niche quite well.
I get the impression that RL17 will be best in calibers that are a little underbore and where you would like to gain a little more velocity. Take a case like the 30-06; it will drive a 180 gr bullet to only 2800 fps because you run out of powder space before you can stuff enough slow powder (RL22) in there to get you going faster and the faster powders (IMR4350) build up too much pressure to get there either. RL17 seems to be a faster powder that doesn't build up pressure.
Hard to explain but I would think it would be most useful in calibers like:
257 Roberts
6.5x284
6.5 Creedmoor
260 Remington
7-08
280 Remington
308
30-06
30-06AI
338-06
338 Win Mag
350 Rem Mag
375 H & H
375 Ruger
To name a few. IOW, calibers where you would like to get a little more velocity. Certainly the powder may work in overbores like the 257 Weatherby, but why do you need it? You have plenty of room for powder as does the 7 mag and 300 win mag.
Right now I'm looking to load it mainly in my 30-06 and the 375 Ruger I have coming. Everything else I am getting enough velocity to satisfy my needs.
Well the WSM's are a short action case which means powder capacity and the encroachment of the bullet will be a problem. IOW you would have a hard time using a slow powder like RL22 and getting enough in there to get velocity up.
Like the 300 WSM with a 200 gr bullet. Could get more velocity if you could just get more of a slow burner like RL22 in there without a serious compression problem. The RL17 would allow enough powder to hit a decent velocity without pressure problems.
The big question everyone has is; Is it temperature sensitive?
Woods, I use R-17 in my 270WSM hunted with it last year from 1st week in Oct thru last week in Nov here in Colorado. I'm been shooting it also during the winter not much has changed since last year during the summer when I started using R-17. I've also started using it in the 300WSM take me a few more months before I decide.
I've also tried it in the 30-06 and 7x57 was pretty slow in the 30-06 with 180gr bullets compared to the load I use gave me nothing extra in the 7x57 over my existing load.
I'm going to try it in the 6RemAI and 243AI and I just fireform some brass for the 280AI and if weather get alittle better next week will try some in that.
Were starting to see the powder supply ease up here so time to start burning some. I'd sure like to see R-17 used more than just for the WSM calibers over on 6br having luck with 6.5x284 and 284 so we''ll see.