.357 Magnum SNS 158grn SWC info.

I too handload for the GP100. Awesome revolver once you lighten up the trigger pull !

Some of my data :

My full bang load is 16.5 gr of H110 with a cast 158 gr SWC. I'm at about 1260 fps. Your not going to squeeze much more velocity out of this combo as lack of more case capacity will be the issue.

My lighter load is 13 gr of 2400 with the same cast 158 SWC and that shoots about 1110 fps. If you really want to load up higher velocities you can do this with 2400, but use prudent discretion.

H110 is a ball magnum powder that needs to be loaded to near max case capacity or you could experience incomplete burns. I also suggest magnum primers.

2400 is an awesome versatile magnum powder that can be easily downloaded to suit your needs. Good luck, the GP100 is a rugged and very accurate shooter. LOVE mine !
 
Road clam,

I have the identical load using sierra jsp's. It's superbly accurate. I did experience what you were describing with lesser charges of this powder. Groups went bad and i was getting so much unburnt powder that whenever I'd eject my brass it would leave some under the ejector star and near lock up the cylinder when I'd close it if I didn't remember to check. What bullets do you use(self cast or storebought)? Any problems with leading?
 
Kwik2010 said:
Road clam,

I have the identical load using sierra jsp's. It's superbly accurate. I did experience what you were describing with lesser charges of this powder. Groups went bad and i was getting so much unburnt powder that whenever I'd eject my brass it would leave some under the ejector star and near lock up the cylinder when I'd close it if I didn't remember to check. What bullets do you use(self cast or storebought)? Any problems with leading?
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I like Missouri Bullets. Use them in many calibers. Awesome bullets and good prices. No leading issues at all. Leading usually stems from improper bullet dia for your barrel. With hard cast a snug fit is better than loose. Gas blow by from improper bullet expansion and sealing melts the lead and sticks to your barrel. leading can also occur from not using any lube. I'm no cast expert but this is what's been explained to me.

Here's my .357's :
http://missouribullet.com/details.php?prodId=41&category=5&secondary=10&keywords=
 
Kwik2010,

A couple of resources you should be aware of:

One is the Cast Boolits board where you will find mountains of detailed information.

Another is the Los Angeles Silhouette Club site, which also has a lot of cast bullet information and, in particular, has a free download of Glenn Fryxell's book available.

Kwik2010 said:
You also mentioned that you shoot jacketed after lead. That helps with the cleaning afterward? It just helps scrape it out or what dya mean?
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As Nick mentioned, this is not considered good practice. There are two reasons: One is that a heavy layer of lead fouling will raise pressure and some instances of barrel bulging have been noted. The other, and this from someone who gave up the practice, is that it didn't actually seem to clean the barrel. Rather it just ironed a lot of the lead flat and burnished it into the bore surface rather than shooting it out. I could push a few patches through afterward and the bore would look smooth and shiny, but if I then ran a brush through I would see all these dull patches all over where the brush had scruffed up the surface of the patch-polished lead.

An experiment I keep meaning to try is to turn off a jacketed bullet ogive and give the end of the bearing surface a negative sharp edged cup profile and to shoot that through a leaded bore and capture it to see if the edge chisels any of the lead off. But a rounded bullet ogive seems mainly just to burnish lead into the bore surface.

A good lead cleaner for me has been the Wipe Out No-Lead. You wet the bore and chambers with it and let it sit for an hour and the lead turns dark and crumbly and then just patches out easily.
 
Noted. I'll get some lead cleaner. Went and shot a few loads tonight. 4.7 grains of unique seemedto be the most accurate but I was also shooting from a tailgate in the wind so I'm gonna load up the same batches and try again this weekend when I can get some more control on the environment. But they were definitely pleasant to shoot. I could shoot all day with any of them loads and still be begging to pull the trigger again. Even if I don't get comfortable enough to load up some hardcast screamers I'm definitely going to keep a bunch of lead on hand for some good old tin can fun. Thank you all for the info you've given me.
 
As Nick mentioned, this ("clearing" lead by following w/ jacketed) is not considered good practice.
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That's why I only share my experience and stop short of recommending it. I'm just an old guy with old habits - and not necessarily good. The practice seems to work for me and my guns will likely be in fine working condition during my funeral service. I rather stopped investing time in trying to mitigate lead buildup in my guns.

What I really should be doing is looking for a local-ish gunsmith who specializes in slugging barrels and correcting cylinder throat diameters for optimization with lead bullets. The irony is that I don't even ask much from my lead ammo. None of my lead recipes that I still use exceed 950 f/s; and most are in the 750-ish range. If my guns were optimized for lead (I strongly suspect the culprit is the cylinder throats); with proper bullet diameter and hardness, I should be able to shoot extensively with next to no leading.
 
Oh we've all got habits. I never take everything on the internet as gospel but it gives me somewhere to start and research. I appreciate it all regardless.
 
Not sure if anyone mentioned this before, but the load manuals you mentioned have data for their own swaged lead bullets. Swaged Lead Bullets are soft. This is why you don't see load data in these manuals pushing these bullets over 1,000 FPS.

If you are using Hardcast Bullets they can be pushed faster, up to 1,500 FPS, with no leading issues.

I use the same SNS 158 gr SWC Hardcast Bullets you have and use data in the Hodgdon or Lyman Manuals for load data with these bullets. Works great.
 
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