Load Request - .357 Magnum 170gr LSWC "Keith"

I'm looking for load data for a 4" S&W using a 170gr Keith style 170gr LSWC.

I don't have and 'Magnum' powder yet but have been looking at purchasing some 2400, H110, or Lil Gun for this load.

I would like to start somewhat below max load and work up from there...so H110 concerns me a little.

Thanks,

Jake

Don't have a manual handy for any charge weights, but I'd think this would be a good job for SR-4756. I think you may be right in moving away from H110, but not because of the "reduced load" issue, which has been overblown, especially on the internet. The 170gr. Keith is going to take up quite a bit of case volume, so I'd think a somewhat faster powder might be in order. If 4756 turned out to be too fast, I'd think 2400 would be a good choice. (Worked for Elmer!)

IMO 2400 will work well for a lead bullet in that Magnum round.

Lyman's 3rd Edition (1980) Cast Bullet Handbook lists this data:
168gr Lyman #358429
2400 9.7gr to 13.5gr
H110 11.8gr to 15.7gr
IMR4227 9.8gr to 14.5gr
SR4759 9.8gr to 13.5gr

The current Lyman 49th Edition lists this data:
170gr Lyman #358429
2400 9.7gr to 13.5gr (same as 1980 data)
H110 14.4gr to 15.0gr (changed from 1980 data)
IMR4227 9.8gr to 14.5gr (same as 1980 data)

Hope this helps a little...

__________________
Freedom is never free!!
SWCA #3437

I'll 2nd 2400. My 1970's Lyman manual shows 13.5 grs MAX and my new manual shows 13.0 grs of 2400 as MAX. 2400 has become a bit faster burning lately.

I used to use the 13.5 gr load as thats what EK used. Then pretty quickly throttled back to 12.5 grs. And that was only for N frame guns.

Used to load the #358429 168 Keith slug in .38 Spcl cases, std primer and 5.0 of UNIQUE...by the THOUSANDS. My original circa 1972 or so M-66 4" has digested that load without a burp. Accurate and powerful.

I just don't shoot .357 mags like I used to. The last mags I loaded were with the 12.5 gr load and older 2400. It's a stout load for sure.

Personally I'd try 12.0 grs and go from there.

FN in MT

All above excellent advice. I particularly like 2400.

Because the cylinder is so short, you can't chamber a .357 round with this bullet (I know) in a Model 27 or Model 28. You have to use .38 Special cases and .38-44 loads.
(Technically, you can chamber them. You just can't close the cylinder).

__________________
and what his trumpet saith

I seated my Lyman 358429, which is the bullet he's asking about, almost to the top of the driving band on top of 15.0 gr of Alliant 2400 (2004 vintage) and clocked 1420 fps MV out of a 6" M28-2. However, that isn't a load I would recommend as a starting load.

If every fired round was supposed to just drop out of the cylinder they wouldn't have put ejectors on the guns.

THANK YOU EVERYONE!

I found my best accuracy with the Lyman 358429 was was with a stiff load of Herco in the 357. If you look at the older Lyman manuals it list loads with Herco that rival just about any other powder power wise. With my 6" Model 28 I get over 1200 fps with a bullet that drops 173 grains from my mould and # 2 alloy. Shoots with great accuracy in all of my 357's and has taken a few deer also. I crimp on the top driving band so lenght is no problem in my 28's.

No leading and clean burning, Herco is a powder that most overlook.

Kirmdog

Very overlooked maybe but most, I'm not sure. HS-6 is overlooked a lot too, they might be tied.

__________________
Freedom is never free!!
SWCA #3437

Herco and HS6/HS7 are on my lists of powders to experiment with. Soon. Soon I will get to them.

__________________
SWCA 1646

OK I should have wrote "Herco is a powder that most people overlook", guess I get a D- for grammer. I never was any good in English class. LOL

I buy Herco in 8# cans and use it all the time for 38 Special, 357, 45 ACP and 45 Colt. I never tried HS-6 so I guess that I'm "overlooking" that powder. I'll have to give it a try.

Kirmdog

Forgot about Herco, and with no good excuse. When I loaded lots of 9x19, it was my go-to powder. Just scooped up a case-full (approximately) and topped it off with a 115gr. JHP.

What length are you all loading these to in .357 brass? My notes say just forward of the front driving band...

Does anyone have a pic of one loaded I can use as a reference?

Really interesting how the N frame cylinder is shorter than the L frame.

You'd think it would be the reverse.

I can load the 357429 regularly for the L frame, but for the N frame I have to crimp in front of the front driving band.

My go-to load for that bullet is 15g W296/H110 and a WSP, but I worked up to it - you should too.

I still have some old 2400 and occasionally use it @ 14.5g.

H110 is fine for full-house loads. Don't worry about having to start at the high end--it just doesn't burn properly in reduced loads.

Also, if you plan to use this ammo in an N-frame, remember that a Keith bullet will stick out of the cylinder if you use 357 Magnum cases and crimp the bullet in the crimping groove. I learned that lesson the hard way...


Okie John

The infamous THE LOAD will also work in this situation. It's loaded in .38 Special brass, so the length will work in M28s and M27s (it may not work in a King Cobra that has an even shorter cylinder).

As you can see here, 5.5 gr of Unique wasn't even close to the results from either lot of SR 4756.