Anyone have any load data for 357 Magnum? I tested 15.0, 15.5, 16.0 and 17.0 grains of H110 in a Smith and Wesson 686 Pro Series 4 inch barrel and groups were all over the place. Hornady 158 grain XTP's were used along with CCI small pistol magnum primers. Crimp die was snugged down when it touched the case mouth and turned an additional 1/4 of a turn.

I use 16 grains with 158gr bullets.

My 686 loves 13.5gr of 2400 with 158gr XTP, CCI 500 (non magnum) small pistol primers and I crimp it fairly heavy.

That sounds like a pretty light crimp for H110, although I guess that depends on the die and how much flare you had, which would affect when it "touched the die." I've only used the stuff a little, but the conventional wisdom with H110 is to crimp heavily.

Can you post a photo of the crimp?

Can you judge neck tension? Try seating without crimping, note the bullet position, then push pretty hard on the bottom of the case with your thumb and see if it drives the bullet in. Minimizing your expansion and flare might also help with giving tighter bullet pull for better ignition. Last ammo I loaded was .38 Special with Lee dies. I flared all the cases comfortably in case I wanted to use cast bullets with any. Wound up using only Xtreme plated and Nosler JHP. The Xtremes seated normally (can't be started by hand past the flare). The Noslers would slip all the way to the canalleur with firm finger pressure! I was using HP38, so I hoped they would not be a problem, and accuracy seemed fine, but I'd have been sorry about that die setting if I'd been planning to use a slow powder. I will have to try much less flare the next time I plan to load those bullets.

If you're using a Hornady bullet, are you also using a Hornady load manual? if not, that would be the place to start. Hodgdon manual also has data for the bullet mentioned.

Crimp just enough for good ignition and burn and to to keep the bullet from moving under recoil. Any more can distort the bullet which does nothing for accuracy. A lot of people seem to like extra heavy crimps that are not needed.

This all requires a bit of experimentation and some group shooting from a benchrest.

I am currently working up some loads from the speer manual starting with 13.9 grains, 14.3 grains, 14.6 grains 15.0 grains of H110 etc.. The COL will be 1.575 and I will be using small pistol magnum primers with Hornady 158 grain xtp's.

I will post some pictures of the crimp in an hour or so.

I've used 16.3gr of WW296 (same powder) with 158gr bullets since 1974. I've always used a heavy crimp per instructions in the old WW manuals.

Hodgdon recommends 15.0 grains as a starting load. I'm thinking 13.9 and 14.3 grains might prove to be erratic.

Are you using a separate crimp die or the seating die to crimp your bullets in the case? If you are using a separate crimp die such as a Lee FC or Redding profile crimp die, that crimp sounds to me like you are on the light side of a good crimp on H110/296 powders. When I used a Lee FC die, I would go 1/2-3/4 turn from when it started touching the case. I presently use the Redding profile crimp die and have it adjusted to where it gives a hard crimp with jacketed bullets with a cannelure usch as the Hornady XTP bullets or my present choice of Zero 158 JHP bullets.

The one on the left has no crimp, one in middle has 1/4 turn and one on right has 1/2 turn of the die

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Some of these loads you guys mentioned here are kinda stout for general plinking/shootin'. I only load 357 magnum to full power if used for a specific task, like hunting. For all other times I load more in the middle upper ranges. But that's me.

Two loads that I like thru my 4" 686 are:

Either Hornady 158gr XTP or Berry's 158gr plated JFP bullets.

11.9gr H110
Winchester WSPM primer or CCI 550 (magnum primers)
COL 1.590"
(warm, but not scalding hot)

9.8gr Blue Dot
Winchester WSPM or CCI 550 primers
COL 1.575"

(Note. This load is more than warm, but not warm enough to loosen your crowns on your teeth, but close, real close)

158gr Hornady lead SWC
3.8gr titegroup
Winchester WSPM or CCI 550 primer
COL .590"
(very tame load, 38 special kind of recoil)

(If you want to shoot a load that can potentially loosen a filling on your tooth, then bump up the Blue Dot to the max of 10.2 grains and stick in a mouthguard like the ones we used to wear for football and clamp down on it and let it fly)

The RCBS carbide die set that I have has the roll crimp and seating die built in together and I seat and crimp in separate steps.

I also use a RCBS 3 piece die set however I get a more uniform and consistent crimp by setting the RCBS bullet seater crimp by inserting a sized case into the shell holder and lowering the handle. Adjust the bullet seater die until it just touches the case mouth, back off a hair then tighten down the lock ring. Seat the bullet, set aside.... when ready I change dies and use a Dillon crimp die. I adjust the crimp die just enough to put a small shiney ring around the case mouth and then just a hair more. Just enough crimp to barely notice a slight indentation of the case mouth into the bullet. Out of thousands of rounds, I never not once had a bullet creep on me from recoil with this setting.

Well, yeah, I expect there are a few .357 Magnum loads out there. ;-)

You've got a fine revolver. And those CCI Small Magnum primers ought to work just dandy with H110 and those XTP bullets for making up some stout, accurate loads.

As a general rule, you ought to be start with load data from the manufacturer of your bullet. Sure, you can use data from a different manufacturer, using a similar bullet, but you need to be careful. If you're going to do that, the recommendation is to extrapolate from several sources... what you're looking for then is a general consensus. Using a single one-off load source that's not from your bullet maker is kinda out on the limb.

Hornady's #9 manual lists H110 loads for your 158gr. XTP starting at 12.7gr. and ending at 15.6gr. So your pressure series started near the maximum, and then quickly went well beyond it.

Any particular reason you jumped the last load in your pressure series a full grain, after advancing in half-grain steps before that? That's a dangerous practice. You want to be extra careful as you approach max load, not less.

The second pressure series you're working up sounds much more reasonable.

As others have mentioned, your original crimp sounded light. The third picture you posted looks about right.

And, finally, and please don't take this the wrong way... but asking for load data from your pals - that would be us - is kinda like asking the fellow next to you at the range if it's safe for you to shoot. You own what you put in that cartridge case, just like you own where that bullet goes... so do your own due diligence.

Good luck!

How are you accuracy testing? Are you using sandbags from a bench or something similar? I have fooled myself before thinking I had poor loads when it really was my poor techniques in bench testing not to mention my worsening eyesight as I age.

Shooting at 20 yards from my rear bag that I use on my FTR Rifle.

For a 158 grain bullet, you might want to experiment with using around 7 to 7.5 grains of Unique.

I use a Heavy crimp with Lead bullets..........
and a medium to med. light crimp with jacket bullets.

A light crimp on a jacket bullet might work for target loads but
a "Good" crimp is needed for maximum fps with jacket bullets.

If you can't see the case bending into the bullets crimp band, you
need to adjust your die a little more.

As for your poor accuracy, the weapon must not like the bullet or the powder.
I would try a different powder.

Good luck.

I like 14.5 grains of 2400 under a 158 JHP. It looks like this out of a 6" Model 19:



When I don't want the pretty light show, I'm pretty happy with Universal and Longshot.

Universal works like Unique when you don't need top velocity. I just prefer it since its purplish grains prevent any confusion between it and other powders. (I follow the "only one powder out in the work area at any time" rule, so that *shouldn't* be a problem, but it's nice to have an extra level of assurance.)

Longshot works great in the automatic pistol cartridges, so if you load those too, it's convenient. It isn't too far behind 2400 in velocity, with a lot more rounds per pound, if you care about that. (Both of them lag behind H110 quite a bit, of course). I've mostly had good results with it in revolvers. The only exception was that in .43 Mag with RMR plated HPs, I was getting keyholes with max charges of Longshot and good results with max IMR4227. All other combinations, including RMR .357s and Xtreme .43s, worked fine. Weird.

People call it "Loudshot," but any max load in the .357 is pretty loud, IMHO. It would probably sound mild compared to your H110 rounds.

I use 15.3gr under my cast 358156 gas checked which comes up to 166gr.I've chronoed it at 1304fps out of a 6'' bbl.I shoot it in my M28,my 586,Dan Wesson and my Blackhawk.Just a little too stout for my 4'' model 13.The brass almost falls out of the chambers(exept for the mod 13).
Accurate in all my guns.My crimp is similar to yours.
Maybe try another bullet would help you solve your accuracy problem.If not,guess you'll have to change powder.

15.4 grains H110 under a 358156 SWC, 161 grains checked and lubed. CCI SPM primer, Starline brass.
1235fps in a 6.5" Blackhawk. 1.5" 25yds rested groups.

I use ear plugs and muffs when shooting these. I have 150 loaded up, they will last me for years. Most of my 357 Mag shooting is much more mild.

Variations can cause variations in crimp, which isn't good for 110 in .357s.

Also, 110 is good for HEAVY loads. If you are getting some erratic burning I'd try using one of the 'lighter' magnum powders like 2400 or Acc 9 that are more amenable to downloading as well as having more of a full load to get the velocities you are after, which is more conducive to better burning.

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Like said, you will want a good stiff crimp when using a hard to ignite ball powder like H110/W296.

Under a 158gr XTP bullet my most accurate load is between 16.5gr and 16.7gr W296 with a CCI-550 primer depending on the gun.

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Please note post #3;
My 686 likes 13.7gr of 2400 under Hornady XTP, nets 1235fps across the chronograph. Be aware that quickload says this is over max load even though the powder manufacturer list 14.8gr as max with 158gr golddot. Lyman 49 says the max load is 15.5gr. I just wanted something above 1200fps.

My Lyman list a maximum of 2400 powder at 14.9 at 41,800 CUP. With the 357 158gr bullet.

Just a heads up.

At the link below it has light, medium and heavy .357 cast bullet loads.

My Friend, The .357
by Skeeter Skelton

Shooting Times Magazine
June 1988

My Friend, The .357

Below Cowboy Action loads.