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]

Originally Posted by Me239

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]

Originally Posted by 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.

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...

[biku324]

18.0 grains of Lil Gun will get all you can safely get out of 158 lead bullets. Not a load I would use in a worn revolver. And no, after 12 years of using Lil Gun, I have NOT suffered flame-cutting of top-straps, erosion of forcing cones, etc., and use it in S&W and Ruger revolvers and both a Ruger 77/357 and a Marlin 1894c. Just lucky my firearms can't read internet posts, I guess.

[Me239]

I don’t necessarily need the extra velocity, but I’m more frustrated that max loads of H110 don’t even come to factory velocities. I’ll be trying 2400 soon to see if that gets better results. A lot of these will be leaving a 20” barrel, so breaking 2000 fps would be neat.

As for the 40 155 grain, I load my 40’s with Longshot under a 180 grain XTP and get around 1120 fps from my G23.

As an aside, I’ve also tried 7.5 grains of Unique under a 240 grain plated bullet in my 3” 44 special and clocked it at 660 fps... 9.5” barrel got 690 fps. Not sure what’s up with that.

[fredj338]

Originally Posted by 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?

Many will say the boutique ammo exceed most saami pressure specs.. Also all guns produce diff vel with identical loads especially revos. I can hit 1300fos with 158gr in some of my 4" guns but not all. Reallity, not much diff between 1300 vs 1400fps in the field Imo.
Btw, there isnt really a ballistic comparison btwn 40/155 & 357/158. Vel may be sim but SD is much higher with 357/158. If you used a 357/135gr, you would easily reach 1300fps+ with sim penetration. Also a lead bullet will typically get you another 50fps with the same charge. I like 2400, but always get higher vel with h110 & mag primers.

[Sevens]

Originally Posted by fredj338

Many will say the boutique ammo exceed most saami pressure specs..

Buffalo Bore in particular has shown a complete disregard for SAAMI in some of their products. I have no idea about the .357 Magnum ammo that is in the opening post of this discussion, but Buffalo Bore has disregarded SAAMI before and continues to do so.

[stansdds]

My load data is now very old, from the early 1990's, but when working up maximum loads in 357 Magnum with 125 and 158 grain JHP bullets, these were my results, all with Remington nickel plated 357 Magnum brass and CCI-550 primers. I did consider these to be the maximum safe loads in the two revolvers I was using at the time. These loads may not be safe in any other firearms other than the two I used, so approach with caution.

Powder..Charge...Bullet..........Weight..Type...Velocity..Test weapon
AA#9....17.5gr....Winchester....125gr....JHP....1580......GP-100 6"
AA#9....17.5gr....Winchester....125gr....JHP....1634......Dan Wesson 8"

H-110...21.0gr....Winchester....125gr....JHP....1661......Dan Wesson 8"

H-110...17.0gr....Winchester....158gr....JHP....1406......Dan Wesson 8"

H-110...17.0gr....Nosler...........158gr....JHP....1377......Dan Wesson 8"

Factory Remington 158gr JHP velocity:
GP-100 6 inch = 1401 fps
Dan Wesson 8 inch = 1442 fps

I would expect a 4 inch barrel would give significantly lower velocity with H-110/W-296 as it is a very slow burning pistol powder. Even with a 6 inch barrel, the fireball is significant. It is my opinion that H-110/W-296 is best reserved for revolvers with barrel lengths of 6 inches or greater.

[Groo01]

Groo here
Sounds like you need to find a copy of Speer #8 manual ...[can't have mine]
Remember that the hot loads for the original 357 were done with cast lead bullets.
If you want similar use gascheck or "coated"[not plated]
In hunting loads you get about 100fps more speed.
I chased the speed demon too and stuck my shar of cases.
Some modern powders will get hot loads at lower pressures.
If you try this, use at least an "L" frame or GP100 or better yet an "N" frame.

[Qc Pistolero]

My load is 15.3gr H110 under my own cast 166gr 358156 with GC.the load,while being shot almost exclusively in my 4'' 28 is safe in all my .357s even though I admit that it is the max my model 13 will take.No problem with all my others.
I've chronoed it at 1304fps from a 6'' bbl so I guess it must be doing around 1225-1250 in my 4'' tubes.
If your 158gr bullet is with the J word,you are in the ballpark.

[fredj338]

Originally Posted by stansdds

Factory Remington 158gr JHP velocity:
GP-100 6 inch = 1401 fps
Dan Wesson 8 inch = 1442 fps

I would expect a 4 inch barrel would give significantly lower velocity with H-110/W-296 as it is a very slow burning pistol powder. Even with a 6 inch barrel, the fireball is significant. It is my opinion that H-110/W-296 is best reserved for revolvers with barrel lengths of 6 inches or greater.

Yes slower powders do better in longer bbls but you will always get highest vel in any bbl length. It may not be much more & the blast will be impressive but vel will always be higher at max loads.

[Greenjoytj]

Originally Posted by Me239

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

Don’t forget the pressure standard for the 357 Magnum, 44 Magnum and 22 Hornet were all lowered buy SAAMI many years ago.
To get the mythical MV of the original 357 Mag loads would exceed today’s current SAAMI pressures.

Old reloading manuals would have the load data but then the rule for reloading is to use current published load data which would max out pressure at the current (lower) levels.

[cowboy4evr]

I don't buy current / latest load manuals . My older manuals load data has never harmed any of my revolvers , and yes that includes occasional use of the infamous " Speer #8 " . If I want data for a more current powder I just go their website . I agree that 13.5-14.0 grs of 2400 using a 158-173 gr cast bullet gives me the best accuracy . If I want more power I use H110-W296 using older load data . Regards Paul

[stansdds]

Originally Posted by Greenjoytj

Don’t forget the pressure standard for the 357 Magnum, 44 Magnum and 22 Hornet were all lowered but SAAMI many years ago.
To get the mythical MV of the original 357 Mag loads would exceed today’s current SAAMI pressures.

Old reloading manuals would have the load data but then the rule for reloading is to use current published load data which would max out pressure at the current (lower) levels.

SAAMI did not lower the pressure standards, they changed the way pressure is measured.

The old measuring system used a copper disk that was crushed when the cartridge was fired. For 357 Magnum, the pressure was rated at 45,000 CUP.

When SAAMI started using the far more accurate electronic piezo tranducer system to measure pressure, the 357 Magnum was rated at 35,000 PSI.

There is no mathematical formula to convert CUP to PSI.

[muddocktor]

OK, first of all, comparing the velocities of your loads to published loads by Buffalo Bore are like comparing apples to grapes. The only way you can compare them together is for you to buy a box of that expensive ammo and chrono them across your chronograph with your own pistol. Once you do that, then you are comparing apples to apples. Because now you are comparing them in the same weapon, which in a revolver makes quite a difference. You say your GP100 is a gun that's had a lot of rounds through it, so your barrel/cylinder gap and barrel erosion is liable to be larger than BB's test gun that they chronoed their ammo through. BTW, I also think like Sevens and think that some of that BB ammo is probably loaded hotter than SAAMI pressure. They might be loading to CIP pressure rating instead of SAAMI pressure values. CIP in 357 Magnum is 8,000 psi higher than SAAMI specs (43,511 psi vs 35,000 psi).


And just to give you an idea of how much velocity you gain with a longer barrel, I have some chrono data for some Accurate #9 shot out of my 4" 28-2 and my 20" barreled Rossi 92 SRC on the same day over the same chronograph and out of the same box of reloads. The load was 13.6 grains of Accurate #9, CCI 550 primers and Zero brand 158 grain JHP bullets. Out of the 28-2, these averaged 1130 ft/sec. Out of the Rossi, they averaged 1700 ft/sec. So as you can see, barrel length and vented vs non vented barrel makes a large difference. With H110, which is a bit slower powder than A #9, the difference might even be more between those 2 guns of mine.

[Greenjoytj]

The copper crushed method for recording pressure, cross references the degree of length reduction in inches to a look up table that accompanies the sample of copper slugs. The copper slugs are tested and calibrated to a known PSI pressure. Every few thousands of slug length shrinkage equals a known PSI pressure value.

The crusher method of sensing pressure has at its core PSI pressure.

The SAAMI testing method samples the pressure at the center of the cartridge case. CIP method takes the pressure at the case mouth as the bullet exits the cartridge case the internal volume has increased by the volume of space created by the absence of the bullet shank. The higher CIP pressure values are to take into account the greater internal case volume at the moment the pressure sample is taken.

The unit CUP assigned to pressures measured with the copper crusher method informs the reader of the method used to acquire the pressure value. Likewise pressure values measured in units PSI inform the reader that a piezoelectric sensor was used to take the pressure sample.

Another way of proving that the 375 Mag max pressure was down graded, is to see current published loaded recipes that can’t make the cartridge perform at the historically high MV that this cartridge was famous for.

It my understanding that S&W ask SAAMI to lower the pressure standards for this cartridge.