357 Magnum Max Loads

[Me239]

Hey everyone! So I've been dabbling with max loads in my 4" GP100 with both 125 and 158 grain bullets with H110. With a charge of 17 grains of H110, my 158 grain bullets get around 1240 fps, a modest 70 fps higher than my old 38/44 loads, and 40 fps slower than a 155 grain 40 S&W from a G23. Does this seem a little under-powered to you guys?

With loads from boutique manufactures like Buffalo Bore and Underwood, 158 grain bullets are getting 1400+ fps. How can this be safely replicated? I've heard that companies like BB use proprietary blends of powder to get these levels of performance, but I'm sure some of you guys have found a way to best commercial ammo. What's the secret to getting the mythical 1300+ fps with a 158 grain bullet from a 4" tube?

 

[505Gibbs]

In a sense you have answered your own question. They DO have non-commercially available powders unless they use H110/WW296 for example.
Also, check the bbl. length used for the boutique ammo mnfgs.
Ruger's are tough but why blow one up potentially in the pursuit of fps.

 

[rockquarry]

I no longer load .357, but if your books say those are safe loads, fine. If you mentioned jacketed or cast , I missed it. If you're shooting jacketed, you won't get as high a velocity as you can with cast of the same weight and style bullet, BUT, charge weights may or may not be the same. Check the books. Looks to me like your getting very good speeds for jacketed bullet loads.

 

[Sevens]

I can’t tell you what Buffalo Bore is doing but before the discussion goes too deep, I’ve got to know if you are reading advertising material and/or box end labels from Buffalo Bore or if you have purchased, fired and chrono’d these loads yourself from your same 4” GP-100?

Before worrying if your loads are falling short, need to know if the bar is actually where you think it is.

In my opinion, 1240fps average for a 158gr from a 4-inch barrel is pretty darn good.

 

[Me239]

Sorry for lack of info, bullet is a 158 grain hardcast SWC. And from YouTube videos and BB’s published velocity from real handguns, they seem to be legitimate. I’ve tried their 380 hardcast loads and can attest to those at least. Just sort of shocking 40 S&W can best a 357 magnum from similar barrel lengths.

Also, my GP100 is a beat up, old police trade in DAO that I got for a steal. It’s not the end of the world if it blows up, but I’d like to keep it (And my eyes/face) as it’s my only full sized 357 revolver.

 

[LoboGunLeather]

I have been reloading ammunition for 48 years now, and casting bullets for 46 years or so. I used to dream about the ultimate levels of velocity, energy, penetration, bullet expansion, and all the other related stuff.

I have never blown up a firearm. I have damaged the extractor in a rifle sufficiently to require replacement. I have had to use a dowel pin and mallet to extract fired cases from revolver cylinders.

Over the decades I have become pretty conservative in my approach. If I really believe that I need more than my usual .357 magnum loads I start thinking about using a bigger gun and caliber!

YMMV. Your guns. Your reloads. Your consequences.

Best regards.

 

[Sevens]

Unless the GP-100 has some serious metal flaw or an obstruction, 158gr bullets and heavy doses of H-110 aren’t going to blow anything up. Knock it around, flame cut it, rattle it in every direction sure... but nothing that will cause a catastrophic failure.

To do that requires high-energy ultra-fast burning powders. Stick with H-110 and try and kill ‘er slowly over time. Nothing here is gonna “blow up” and chasing velocity and learning about guns & loads does NOT require any heavier caliber or deep philosophical questions.

For whatever reason (popularity, I guess), there exists no internet conversation about .357 Magnum and handload velocities without someone suggesting moving to a heavier caliber.

Moving to a .44 Mag has never/will never get anyone anywhere when it comes to enjoying and experimenting with .357 Magnum.

 

[38SPL HV]

Personally, I never have a need to push 158 gr cast SWC with more than 13.5 grs of 2400 in 357 Magnums. Currently, I usually “quit” upping charges for my 158 gr cast 357 Magnum loads once I obtain 1,200 FPS with them in 6 inch revolver. I find that this velocity level using 158 gr cast SWC and 2400 powder gives me darn good accuracy and adequate power. If I need more throttle, I would opt for a 41 Magnum or 44 Magnum.

 

[Me239]

I have a 44 with a 9.5” barrel if I want velocity and power. I just was frustrated trying to get 357 magnum up to it’s full potential with published data. I guess 40 S&W and 10mm can 357 magnum these days.

 

[alwslate]

You're not going to blow up your Ruger with any published loads with 296
or 2400 and 158 gr bullets. Getting 1300 + fps out of a 4" barrel is easy
with a 158 gr cast bullet but is pretty hard to do with a jacketed bullet.
In general high velocity out of a 4" .357 Magnum is much easier with
2400 than 296. Try the older .357 data that was listed in some manuals
as being for heavy frame revolvers only after the mod 19 came out.
Try 15.5 grs of 2400 with a magnum primer with a 158 gr jacketed
bullet and you just might see your 1300 fps. Realize that full power .357
factory ammo is pretty hot and runs at higher pressure than just
about any loads listed in manuals. You will run out of case capacity
with 158 gr bullets and slow powders available to handloaders before
you will ever even come close to blowing up heavy frame .357s.

 

[Nevada Ed]

First, I am hoping that you are shooting jacket bullets at those speeds and not lead bullets.

While maximum loads can be used in ay revolver, I try to find a load below maximum that is
accurate and easier on the weapon.

My 6" 686 does better with a 158gr XTP at 90fps lower than a maximum loading.

 

[Eddietruett]

I'm not sure why you would want to get more velocity than you age getting now. 1250fps is plenty fast to do anything a 4" Barrel Revolver was designed for. If you are hunting or long range shooting, you should opt for a 6 or 8" Barrel and that would pick up the velocity some as well as long range accuracy.

 

[Schnyd112]

I run 18g w296 under 140 xtp’s and it is obnoxious from my 4” 586. I can’t imagine wanting any more but it’s a camp gun and those are loads for anything that doesn’t want to leave. We also shoot a 14”x14” gong with them, and back up a couple steps each time to make it harder. Like playing horse.

1300fps seems super hot for a 155 from a 40sw but I never owned one. Being as they are dangerous and blow glocks to pieces. (This is a joke, please treat it as such)

 

[shocker]

What's the secret to getting the mythical 1300+ fps with a 158 grain bullet from a 4" tube?

Western Powders says you should get close with AA 7 or 9 and an XTP. Also realize there are "fast" and "slow" guns as described in the Speer manual. Same make and model but significant differences in measured velocities with the same load.

 

[bmcgilvray]

I've obtained higher velocities with 158 grian bullets with max loads of 2400 than I have with max loads of H110 or any other powder I tried. In the .41 Magnum and .44 Magnum H110's been speed champ.

Older Lyman manuals or the 1978 Sierra manual will get a person to 1400 plus fps with 158 grain bullets. Use good once-fired brass and work up loads carefully.

I'm like Sevens. Experimentation can be fun. I went to the Elmer Keith School of Hand loading. I actually used a "delicate" Smith & Wesson Model 19 4-inch for some "experimental performance" hand loading when I was young and nothing came loose or cracked. I'd never heard or read of Model 19s being delicate back then.

Highest velocities were obtained in a 6-inch Model 27. I tried that 15.5 grains of 2400 under a 158 grain bullet that alwslate mentions which was a maximum published charge weight in a manual or two of the 1970s. The Model 27 flattened primers. 15.2 was more well-mannered and I settled on 1500 fps for 1406 fps as a heavy hunting load.

Recreated it a few years back and took a whitetail deer with the Model 27. Worked a treat.

 

[slickracer]

Personally, I never have a need to push 158 gr cast SWC with more than 13.5 grs of 2400 in 357 Magnums. Currently, I usually “quit” upping charges for my 158 gr cast 357 Magnum loads once I obtain 1,200 FPS with them in 6 inch revolver. I find that this velocity level using 158 gr cast SWC and 2400 powder gives me darn good accuracy and adequate power. If I need more throttle, I would opt for a 41 Magnum or 44 Magnum.

Hard to beat that load. If you need more than that, it's time to move up to a .41 or a .44

 

[rockquarry]

When I loaded the .357 Magnum, I used the Hensley & Gibbs #51 mould to cast the original .357 Magnum bullet designed by Phil Sharpe, a 158 grain plain base SWC. I never found a better bullet for this cartridge though the Lyman gas checked #358156 SWC at about the same weight would probably equal the #51 in terms of accuracy. Guess I should do a side-by-side comparison to verify my suspicions but probably won't.

I used 12 grains #2400 powder and a standard CCI primer. Muzzle velocity in a 6" Python was about 1100 fps, maybe a little more. 14 grains of H110 / Win. 296 with either a standard or magnum CCI primer would provide about the same velocity and accuracy, but with the attendant fireball muzzle flash and more noise that is common with this ball powder. Some prefer the added flash and noise but I liked the more pleasant-to-shoot #2400 load.

1100 fps may seem sedate by some shooters' standards, but it's easy on both gun and shooter and will likely perform as well as a bullet traveling 150 fps faster unless one is shooting beyond a hundred yards or so.

 

[BigMuddy]

The original.357 Magnum cartridges were loaded with 2400, and it is still my favorite. As others have mentioned it will get more velocity than H110/296 in my experience.

You don’t need a “reason”. Replicating the original.357 Mag loads in heavy enough guns can be fun. Stay safe and enjoy.

Dan

 

[mikld]

FWIW; When I got my first Magnum revolvers, a 4" 357 and a 629, I had a raging case of "Magnumitis". Every load was at or near max with all available bullet weights and designs. One time I had to pound out the empties from my Taurus 357 when I "inadvertently" used a charge .3 gr over max. and I actually had to send my 629 back to S&W for repairs from too many too hot handloads. I didn't hunt with my Magnums, I just wanted "ugh, more power, ugh, ugh!". I didn't have a chrony at the time but in my estimation I was driving a 160 gr. cast Lachmiller SWC to roughly 1,200(+) fps in my 357. My 44 Magnums loads were pretty hot too. But perhaps when age, maturity set in I realized the only need for the extra 200-300 fps I was getting was for my ego...

 

[HorizontalMike]

I get ~1370fps out of N105 in my 4in 686ND using a 158xtp with Vihtavuori load data/chart. Rather stout, and not as much fun as they used to be...