With the snow melting, I'm finally going to get back into gel tests and all that, so first thing this spring was Sierra's 158 JHC in 357 Magnum. Contacted Sierra, they suggested 2400, and I prefer 2400 and Aliant and all, but I wanted to go full power, so i tested with 17.0 H110 and CCI 550's. My gel test ended up with a standard deviation of 5fps and some extremely consistent expansion and penetration:


Some questions for those who load more with H110 and also those who have loaded, and maybe hunted, with the bullet in question: my M27 usually shoots quite strong velocity wise against book data, and in this case the average velocity was quite a bit lower than listed, what are anyone else's chronos reading with this or similar load? Is it sane to push any more than 17.0 with a jacketed 158? Is this kind of low standard deviation normal with this powder and range of load? And, for those who have hunted with this bullet, how has it performed in the field?

I appreciate any help I can get.

Since Hodgdon give 16.7gr of H110/WW296 as max, I'd not push it any farther than you already have. My M28 starts to get sticky ejection at 16.5gr.

You didn't tell us what velocity you got or what manual you got your reference velocity from?

If you got it from Hodgdon's, they use a 10" barrel for their tests.

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Waiting for the break of day

I'm 16.5 gr of H110 and the Berry's 158 fmj rnfp for my Ruger GP100 6" . Shot a 2.78" 6 shot group at 50' off a nice sturdy rest. I'm at about 1455 fps.

Quiet sorry about that, didn't take the time to post the details like i usually do, but as follows:

Velocities:
1295 fps
1290
1299
1295
1285
Average: 1292.8 fps Standard Deviation 5.0, 586 ft. lbs. energy

The 17.0 load was suggested by Lyman's 49th for the XTP, which also listed the same maximum load for 2400 that Sierra advised me to use, so i used this as equivalent data. I saw to other suggested maximum loads, both from Hogdon's website and also from an old NRA Reloading handbook that took a load from the old Speer super hot book of 17.8 grains! So I went with Lyman, who tests a 4 inch barrel, 1309 fps average listed, and a maximum average pressure of 38,400 CUP So, knowing the old MAP of 357 Magnum is 46,000 CUP, I was only testing a few loads for gel and curiosity, and the strength of a 2000's manufactured N frame, i did the most reckless reloading decision of my life, actually using a maximum listed load for a cartridge hand weighing every charge to .1 of a grain.



Cases extracted easy.

Primers didn't look too bad, but I'll take anyone's take on the looks of those as well. My tight new manufacture barrel was doing under the average of Lyman's 4 inch barrel test, but there are enough factors to explain that, too, I suppose, different bullet, lot of powder, primer, and the fact I don't crimp my cases like a gorilla, leading to perhaps less than high end performance.

Incidentally, I accidentally found my father's old Sierra handbook I thought was lost looking for more information this morning, which also lists 16.3 grains H110, 1,200 FPS out of a 6 inch Colt Trooper Mk III.

Looks like I'll be toning them down in the future. Still have a gel test I plan on doing using the Magtech SJHP, but I suppose no need to hot rod em.

Duckford, one thing I've found with 296/H110 is that it really likes a hard crimp. But from your small SD I would say that the crimp you were using was very adequate. As for your lower velocities, they aren't that much lower than what your book showed; well within results gathered with different pistols. It might all come down to the different barrel gap between the test pistol and your pistol. Testing like this is where something that has a non-vented barrel would be nice to have on hand. Something such as my Coonan Classic or a Contender with a 357 barrel.

Tried H110 with the Speer SWCHP 158 grain and the magic of close standard deviation of velocities suddenly went away.

Velocities:
1259 fps
1250
1224
1265
1313
1262.2 fps average 29.00 standard deviation 559 ft. lbs.

Same cases and primers, H110 at 15.3 grain load. The Speer swage bullets seemed hard for swage, and their lube did well for the pressure and velocity, there was some minor leading, the tiny fragments instead of big slivers. Cases fell out with hitting the extractor, so I'm not worried about pressures on this one at all. I guess the SWCHP also doesn't like to be thrown at gel at 1250+ fps. Likes to fragment pretty hard, with core separating from the expanded mushroom head. Also will penetrate pretty deep either way.

Might try H110 with other lead bullets that are more suitable to high end loads, but interesting to learn none the less.