Hi. I have a newly barreled 270win that I've been working loads on, and this is the first time I've played with a 150gr bullet in a 270. It'll shot most 130s quite accurately. It did very well with the 140btsp hornadys I was able to try in it. It does decent with some of the stubby 150s I've played with, but not great. A friend who bought some 150SSTs on accident gave me some to play with. About the best I can get them to do is roughly 1.5" and that load won't print consistently.

I went to Berger's stability calculator and it says that the 150SST is marginal in a 1-10" twist(which is what I have), and even at a 270wsm velocity it's barely stable. If I take my load and put it in at a 1-9 twist it's barely stable.

It's interesting to note that none of the current Hornady factory loads have the 150SST, but Fiocchi does load it in one 270win load. That Foicchi load is marginal in stability according to the Berger calculator.

So, in short, what have been your experience with the 150s in a 270win, and if you can comment specifically on the 150SST? Is my so-so accuracy due to stability issues?

Could be, but I doubt it. The SST's just aren't that long. If your barrel really is a true 1:10, and you are up near the top, I can guestimate (without the length in front of me) that you may not have a stability of 1.5, but nothing that would cause abnormal accuracy. I doubt the issue is a lack of stability. Some barrels don't like some bullets, for a score of little reasons that are hard to nail down.

I've not heard of problems stabilizing 150gr bullets in the 270.

My 270's do well with any of the 150 gr Nosler offerings. I trialled SST's a few years ago with discouraging results.
Can't really comment on the stability thing, but the SSTs would not group well at 100 yds with any of the combinations I put together, so I never bothered to work with them at longer ranges.

I would also add that I have found if difficult to find combinaations that didn't shoot reasonably well out my 270's. The SST was one of the odd ones. The Interlocks, on the other hand, have been easy to get along with.

I had a good load with the 140sst in my last 270, and it was easy to find. The 150sst are not a must have, as there are many good options.

Thanks for the input guys.

I have often thought a 1-9 twist would be better for the 270.

NTG, I've worked up loads for the 130 and 140 SST's, and that rifle had a preference for the 130's, clustering them into half an inch. The 140's hovered about 7/8". Either was more than good enough. I haven't worked with the 150 SSTs. Still, for most hunting, I'd be happy packing a 1.5" shooter. My first 270 wouldn't do that at 50 yds...

I hear you on the 1.5" group not being that big of a deal, but I can't get that consistently. About 1 in 3 will do that the rest are 2-2.75". I'd think there's a problem with the nut behind the trigger but other loads are consistent.

I'd chit can them and load some 150gr. partitions up and be done with it... Hint...

I imagine the 150 partitions would do fine...I don't see anything but mule deer in it's future and a partition is more than is needed for muleys IMO. I'll probably just get a pile of the hornady 140btsp when I'm done playing with other bullets. They've always worked and should be fine if shooting more than mule deer some day.

I've had very good results using the 150 gr. Sierra Game Kings regarding accuracy. When my supply ran out last year and I couldn't find any I just switched to the 150 gr. Nosler Partition, no change in powder charge nor the seating die. Accuracy was just as good. Never did care very much for the 130 gr. bullets as I get they were a bit rough on eating meat. Talked to the father of one of my hunting partners and he steered me to the 150 gr. Game King. Frankly, I never used the .270 much over the years, got my first one in 1973 but always had good results with the Sierra GK. Last game animal shot with the GK was a nice representative antelope on a ranch hunt in New Mexico. On my elk hunt two years ago, I took the .270 on the first day, a .280 Rem. the second and on the third and last day my lucky .35 Whelen. Dropped a nice fat cow elk at 350 yards laser measured. Just a simple cow elk cull hunt on a ranch.
I have four rifles in .270 and all but one are sub-MOA with eh GK. I haven't tried the Nosler load in the other three yet and tke one not sub-moa holds right at an inch or a slight hair more. It's a Ruger #1 with a very long throat. With your problem bullet, try playing with the seating depth.
Paul B.