H&G 6 cavity #503

[FISH4BUGS]

Some time back I lamented here the fact that I just paid stupid money for a new in the box, unused 6 cavity #503 with handles.
It was the "cry once, enjoy it for a lifetime" post.
Well, I just finished a run of 1500 .44 bullets in 3 sessions.
I cannot tell you what a pleasure it is to cast with one of those moulds.
The mould guide on the Lee 20 lb pot takes the weight off the mould and your arms.
Running the pot at about 650 degrees seems to the be sweet spot.
Pre heating the mould is an absolute must. Once up to temp, the bullets drop out with a tap from the neoprene mallet.
The only hold back is the mould temp. Too hot, the bullets get frosty. My next session, I'll experiment with the "...Bruce B speed casting" method.
I like a bit of a frost on them but sometimes it goes too far.
The pain of paying stupid money for the mould has gone away, and I will enjoy it for the rest of my days.
I can only marvel at the machine work skills these guys had - don't forget - it was pre-CNC days and they did them on good old fashioned Bridgeport lathes....by hand....with calipers.
Those days are gone sad to say.

[Ozark mike]

Glad ya like it. Never touched a cnc anything but like me a good ole southbend mechanical wonder. Dro does make it a lil easier though

[Don Purcell]

FISH4BUGS, I have an original 8 cavity H&G 503 that is 32 years old and also have a matched pair of 6 cavity Ballisticast 1503 molds that were made around 1999. Even with the age difference I can switch a cast bullet between the molds and the molds nearly close to just bigger than a hairline. Running all three molds at the same time makes a couple of piles of Keith bullets pretty quick. Glad you have yours and are enjoying them. Crack on!

[FISH4BUGS]

FISH4BUGS, I have an original 8 cavity H&G 503 that is 32 years old and also have a matched pair of 6 cavity Ballisticast 1503 molds that were made around 1999. Even with the age difference I can switch a cast bullet between the molds and the molds nearly close to just bigger than a hairline. Running all three molds at the same time makes a couple of piles of Keith bullets pretty quick. Glad you have yours and are enjoying them. Crack on!

I have rounded out my collection of H&G moulds to do every pistol caliber I shoot. The only jacketed i buy are 147 plated 9mm for suppressed, 223 and 308. The rest are all cast.
I have a 10 cavity S55 (.380 bullet) that can also produce a pile of bullets in short order. These are shot in the Mac 380 subgun.
I guess I have become a Hensley & Gibbs casting snob.
It sure does make life easier to use good equipment.

[44MAG#1]

I have rounded out my collection of H&G moulds to do every pistol caliber I shoot. The only jacketed i buy are 147 plated 9mm for suppressed, 223 and 308. The rest are all cast.
I have a 10 cavity S55 (.380 bullet) that can also produce a pile of bullets in short order. These are shot in the Mac 380 subgun.
I guess I have become a Hensley & Gibbs casting snob.
It sure does make life easier to use good equipment.

Which #503 did you get I have two different designs. One with the narrow front drive band and the wider base band than the middle drive band. And one with the equal length bands.

[FISH4BUGS]

Which #503 did you get I have two different designs. One with the narrow front drive band and the wider base band than the middle drive band. And one with the equal length bands.

I'll have to take a look.
I wonder which is considered the "original" Keith design?
The #503 is said by most to be the true Keith designed bullet.
Interesting question.

[Don Purcell]

My very first #503 H&G had the narrow front band, a little wider middle band, big grease groove and then wide base band. That was in 1979. By 1988 the design was like what Elmer wanted with three equal bands and had a meplat of .300.

[FISH4BUGS]

I'll have to take a look.
I wonder which is considered the "original" Keith design?
The #503 is said by most to be the true Keith designed bullet.
Interesting question.
I just lubed and sized a bunch on the Star Sizer.
These #503's have a narrower front band above the crimp groove and what appears to be equal size bands above and below the wide lube groove.
I might put some calipers to it if you need better measurements.
The serial number is in the 6000's so I would suspect it is a later mould?
My understanding was that the serial number is equal to the invoice number when they sold it.
I just sent an email to Tom Dugas, the resident expert on Hensley & Gibbs and asked for his input as to the possible variations on the #503. He is in the middle of a remodeling project so he may not get right back to me.
I sent the link to this discussion so hopefully he will weigh in.

[Don Purcell]

FISH4BUGS, the crazy thing is as much as Elmer complained about mold makers ruining his design by cutting down the width of the front driving band that first H&G #503 that I mentioned shot really well. I remember once shooting my 8 3/8" and my dad's 8 3/8" at 100 yards setting down across my knees with that bullet and his load of 18 grains of 2400 shooting three groups that are the type you will always fondly remember. Have fun.

[Petrol & Powder]

The great thing about crying once and moving on is that the crying part is relatively short compared to the moving on part.

[FISH4BUGS]

FISH4BUGS, the crazy thing is as much as Elmer complained about mold makers ruining his design by cutting down the width of the front driving band that first H&G #503 that I mentioned shot really well. I remember once shooting my 8 3/8" and my dad's 8 3/8" at 100 yards setting down across my knees with that bullet and his load of 18 grains of 2400 shooting three groups that are the type you will always fondly remember. Have fun.

My 3 screw Ruger Super Blackhawk and the 5 screw pre-29 can hit a 24" steel at 200 yards with iron sights from a rest.....amazing when you think these tired old eyes can hit, on a normal day, 1 out of 6, and on a GOOD day, 2 out of 6.
These are the #503 with 9 gr WW231. Not full house loads but very accurate.

[FISH4BUGS]

The great thing about crying once and moving on is that the crying part is relatively short compared to the moving on part.

I have forgotten the pain of paying through the nose for the # 503.
You are right....moving on and I am now enjoying it.
My go to 44 mag/spl bullet.

[Mal Paso]

This is the drawing for the MP 503, the bands are all .1".

[44MAG#1]

267151

[Gamsek]

MP copy of H&G#503, 6cav aluminium
https://uploads.tapatalk-cdn.com/20200903/8b557dd40b896428ba05db08a8c7db6e.jpg
also marked as MP 432-256


https://www.mp-molds.com/product/mp-432-256-pb-hp-4-cav/

[44MAG#1]

Wonder how Mr Keith would have done at 600 yards with that MP 432-256? Good looking bullet.

[derek45]

My ARSENAL #503
https://i.imgur.com/nQGypmJ.jpg

https://i.imgur.com/z1oEwmp.jpg

[Mal Paso]

I have that Arsenal 5 cavity 503, great mold! I got it when I had alignment pin problems with my 6 cavity MP 503. I think the hotplate was too warm and tapping on the hinge bolt to loosen the bullets caused the alignment pins to move out. Suddenly I had huge fins on the bullets. I have since reset the alignment pins and cross pinned them. I was told the new molds are all cross pinned now.

[FISH4BUGS]

I checked my H&G #503. It DEFINITELY has a narrower top drive band. No question.
I tried to measure the drive band but the plastic RCBS Case length Calipers just are not up to the task.
So....I wonder just WHO is the true Keith design?
Minor variations here and there between manufacturers, but someone must have been the true Keith design.
My bet goes with H&G.....

[Gamsek]

Wonder how Mr Keith would have done at 600 yards with that MP 432-256? Good looking bullet.

“Later, in the early 1960s, Elmer Keith was frustrated with the changes that Lyman had made to his SWC designs, so he turned to H&G and commissioned them to reproduce his original SWC designs. The results were the H&G #503 (.44 SWC), the #501 (.45 SWC) and the newly designed #258 (.41 SWC) for the brand new .41 Magnum.”

Link:

http://www.lasc.us/Fryxell44SWC.htm

MP 432-256 is allegedly true copy of HG#503. (??)

[44MAG#1]

“Later, in the early 1960s, Elmer Keith was frustrated with the changes that Lyman had made to his SWC designs, so he turned to H&G and commissioned them to reproduce his original SWC designs. The results were the H&G #503 (.44 SWC), the #501 (.45 SWC) and the newly designed #258 (.41 SWC) for the brand new .41 Magnum.”

Link:

http://www.lasc.us/Fryxell44SWC.htm

MP 432-256 is allegedly true copy of HG#503. (??)

Which #503 is the one he commissioned ?

[lightman]

H&G made a really nice mold. All of mine cast like a dream.

[FISH4BUGS]

Which #503 is the one he commissioned ?

OK....so let's see what we have to date:
The #503 IS the Keith designed bullet.
Different manufacturers of moulds may have made some minor changes to the design over time.
It would appear that H&G is the TRUE bullet design but it may have changed a bit over time.
Different manufacturers do different things to designs which apparently pissed off Keith.
Not that it really matters in the big picture but staying within the H&G design, are they all the same with the slightly narrower front drive band?
Or...are there variations on the #503 within H&G?

[Don Purcell]

Look at my earlier post and it tells of the two different styles of the H&G #503's that I have from the late 70's to late 80's to the Ballisticast #1503 from around 2000. My later H&G and Ballisticast are more true to Keith's wishes than my first H&G even though it shoots very well regardless.

[44MAG#1]

OK....so let's see what we have to date:
The #503 IS the Keith designed bullet.
Different manufacturers of moulds may have made some minor changes to the design over time.
It would appear that H&G is the TRUE bullet design but it may have changed a bit over time.
Different manufacturers do different things to designs which apparently pissed off Keith.
Not that it really matters in the big picture but staying within the H&G design, are they all the same with the slightly narrower front drive band?
Or...are there variations on the #503 within H&G?

As I have said several times on this site that I have two different designs of the H&G #503 molds myself. So with Don Purcell saying there were two and Me saying there were two we know there was at least two different #503 H&G molds.

[mattw]

I would love to get my hands on the 41 mag version, but I can't justify the cost and I have to many great performing 41's already. The Saeco 411 being my favorite so far.

[Mal Paso]

OK....so let's see what we have to date:
The #503 IS the Keith designed bullet.
Different manufacturers of moulds may have made some minor changes to the design over time.
It would appear that H&G is the TRUE bullet design but it may have changed a bit over time.
Different manufacturers do different things to designs which apparently pissed off Keith.
Not that it really matters in the big picture but staying within the H&G design, are they all the same with the slightly narrower front drive band?
Or...are there variations on the #503 within H&G?

The MP 503 clone was copied from a H&G 503 mold that Dale53 supplied. The original MP run was a group buy right here.

Elmer designed the 503 for 44 Mag and the 429421 for 44 Special as 44 Mag did not exist yet.

Lyman reduced the forward band to reduce chambering issues which had an effect on accuracy. I like the forward band just inside the throats.

Elmer used tin/lead alloys and sized .429". Most of us use antimony/tin/lead alloys and .430-.431" seems to work better but tight throats could result in more chambering issues. So forward bands get reduced and chambers made longer. Fit is King. LOL

[44MAG#1]

"The MP 503 clone was copied from a H&G 503 mold that Dale53 supplied. The original MP run was a group buy right here.

"Elmer designed the 503 for 44 Mag and the 429421 for 44 Special as 44 Mag did not exist yet."
Lyman reduced the forward band to reduce chambering issues which had an effect on accuracy. I like the forward band just inside the throats.

Elmer used tin/lead alloys and sized .429". Most of us use antimony/tin/lead alloys and .430-.431" seems to work better but tight throats could result in more chambering issues. So forward bands get reduced and chambers made longer. Fit is King. LOL"




When was the #503 H&G designed for the 44 Mag by Mr. Keith?

[Mal Paso]

"The MP 503 clone was copied from a H&G 503 mold that Dale53 supplied. The original MP run was a group buy right here.

"Elmer designed the 503 for 44 Mag and the 429421 for 44 Special as 44 Mag did not exist yet."
Lyman reduced the forward band to reduce chambering issues which had an effect on accuracy. I like the forward band just inside the throats.

Elmer used tin/lead alloys and sized .429". Most of us use antimony/tin/lead alloys and .430-.431" seems to work better but tight throats could result in more chambering issues. So forward bands get reduced and chambers made longer. Fit is King. LOL"




When was the #503 H&G designed for the 44 Mag by Mr. Keith?

You would ask that. I'm up to early 1969 and he's still touting the 429421, all 3 versions so it would be after that. His H&G 41 Mag bullet was already in production then as was his connection to H&G. The article: Elmer Keith picks his favorite loads for handguns. I have everything I ever found on Elmer archived it's just finding the right piece.

The 503 is in the 1975 H&G catalogue, still looking.

The 1990 H&G catalogue shows a wider front drive band than previous drawings and claims to be an Original Keith Design. The illustrations are all hand drawn sketches though.

[44MAG#1]

You would ask that. I'm up to early 1969 and he's still touting the 429421, all 3 versions so it would be after that. His H&G 41 Mag bullet was already in production then as was his connection to H&G. The article: Elmer Keith picks his favorite loads for handguns. I have everything I ever found on Elmer archived it's just finding the right piece.

So going that he is up to 1969 and he is still touting the 429421 then the 44 mag had been out since 1956, I believe. So he evidentially worked up the "Keith Load" with the 429421.
I wonder which one of the 429421 bullets he used? How many versions of the 429421 had there been up to the 44 Mag introduction?

[Mal Paso]

The Keith Load is mentioned in the 1969 article written by Keith. He was absolutely right! Magic happens at 22g. I've has ESs of 10 fps across 2 6 shot strings at 1500 fps! It's also above max pressure for 44 Mag. He also says the wide full front band was to reduce skidding as the bullet engages the rifling and spins up.

[44MAG#1]

The Keith Load is mentioned in the 1969 article written by Keith.

Since around 13 years the 44 Magnum had been in existence in 1969 the "Keith Load" must have been developed shortly after 1956. I don't know the exact date but the "Keith Load" had been in existence for several years. I still wonder about the birthdate of the H&G 503 bullet.

He was absolutely right! Magic happens at 22g.

I wonder how he worked up the "Keith Load". On paper then at distance shooting at objects etc. to confirm his load?


I've has ESs of 10 fps across 2 6 shot strings at 1500 fps!

That is a screaming load. What barrel length? Have you tried different "lots" of powder just to see the differences? Did you use standard primers?


It's also above max pressure for 44 Mag.

If it is should a person use it? There are others that say that it isn't over maximum . We know, according to Mr. Keith his load ran around 1400 fps with 34,000 CUP pressure when tested by H.P. Whites labs.

He also says the wide full front band was to reduce skidding as the bullet engages the rifling and spins up.

Mr. Keith used an alloy that was 1-16 tin and lead (around a 10.5 BHN alloy) to work up the "Keith Load" which by todays standards is a soft alloy. If one is using a 15 or 18 BHN alloy would a more narrow front band control "skid" just as well? If not, has anyone done an accuracy comparison of a narrow front band bullet and the wider front band bullet?

Some of my questions have been injected in the quoted feature.
In all of this my main question still is: When was the H&G 503 bullet added to the H&G lineup? Did Mr. Keith ever use the narrow front band H&G 503 bullet or were the bullets he used all the "normal" wider front band?
What did the first Ideal 429421 bullet look like and what year did they change the design for the first time? How much did they change it? What version did Mr. Keith use in working up the "Keith Load"?
I find all this interesting.

[Mal Paso]

6 inch, 4 inch about 100fps slower. There is lot to lot variation in 2400 and I have recorded faster.

Your pics.

[44MAG#1]

6 inch, 4 inch about 100fps slower. There is lot to lot variation in 2400 and I have recorded faster.

Your pics.

Do you have the mold on the left? The "Keith Bullet" in the center photo what variation is it?

[Don Purcell]

I have on old Gun Digest from the early 60's that in the back list many manufacturers. I remember a listing of cast bullets from the old Markell Cast Bullets and the show the 250 grain Keith listing it as "a man's bullet" and it looks like the Keith with all wide bands and squared grease groove but I don't remember if they list which mold company. I will try to find it and see.

[derek45]

EDITED -- The Blue bullet is an OHAUS, not an IDEAL, I was mixing it up with my 368477

Here's an old OHAUS 44-250-K, compared to my ARSENAL #503

In my mind, the 503 is what Keith described, and the OHAUS has deviations from the Keith design.

smaller crimp groove
smaller front band
smaller rounded lube groove.

both shoot well, but I sold the OHAUS 2 cavity, as I wanted more production.

I think the ARSENAL 503 is just right.

( IDEAL is blue, 503 is clear coated)
https://i.imgur.com/HclYOTi.jpg

https://i.imgur.com/bgPMqWn.jpg

[44MAG#1]

What about the bullet in my #14 post?

[derek45]

another pic of a naked ARSENAL 503 pushed thru a sizer

you can see the front band is getting resized also

https://i.imgur.com/HnWRpJV.jpg

[derek45]

267151

Looks like
3 equal full diameter bands
big crimp groove
big squared off lube groove

..just what the doctor ordered

:drinks:

[Texasflyboy]

There is a previous thread on this subject from 5-8 years ago. Username: "GLL" took incredible photos of all the different 503's he owned and posted them here to Cast Boolits. After a long back and forth what I recall was we all agreed that in the time before ISO 9000/9001 standards, there was significant variation in "official" projectile designs from *everyone* including Hensley & Gibbs. Wayne Gibbs told me their "design ledger" was a piece of plywood with the actual bullets of each design sitting in shelves. When they needed a new cherry, they took the bullet down from the board and cut the cherry....by hand.

Here is a photo of the Hensley & Gibbs Bullet design board:

267568

I have 503's from the 50's to the late 90's. And the only ones that appear to be true to the "three equal driving bands" were the ones from the late 80's to business closure (1999). All were made by Wayne Gibbs.

This mould is from the early 1990's, best I can tell. And the front driving band is the thicker style.

267566

Here is the link to the mould photo:

https://www.hensleygibbs.com/TCD/hollowpointarticles/Design503_files/image005.jpg

This is a early 60's mould. Regard the thin front driving band:

267569

[Mal Paso]

Great Post! Thank You!

Just got lost for a while on https://www.hensleygibbs.com/

[FISH4BUGS]

Many thanks Tom!
Lots of good info.

[bushytail man]

Back when I was a teen, I wrote to Elmer Keith concerning the #503 vs the Lyman 429421. His return letter (which I still have) states he thought the #503 H&G was the truest to his design.

[44MAG#1]

Back when I was a teen, I wrote to Elmer Keith concerning the #503 vs the Lyman 429421. His return letter (which I still have) states he thought the #503 H&G was the truest to his design.

Which 503?

[MT Chambers]

I have read about what Elmer liked and wanted and concur on most things except that load of 22 or more grains of 2400, I drop it to 21 or less for my hand's sake. I bet many Smiths have loosened up with that 22 gr. load. If I need more speed I go to H110 or better still Mp300 ( I think that's what it's called).

[Mal Paso]

Which 503?

We know he was around for the early 503 with the narrow front drive band. The wide front drive band appeared about the time Elmer passed. Elmer's last wish or now he's gone, we'll fix it? I like the late #503 and choose to look at it as an evolving bullet style.

[Mal Paso]

Here are the hand drawn catalogue pictures from the indicated years.

[cowboy4evr]

I have H&G 503 , all 3 driving bands are the same size . I have always been under the impression that was one of Elmers beefs with Lyman , that they shrunk down the size of the front driving band . I personally am not aware of EK's designs having a smaller front driving band . I have H&G 258 for my 41 magnum , another EK design and it has the wide front driving band and that bullet was designed about 1964-5 . So even back then he wanted a large front driving band . Regards Paul

[curioushooter]

I have two Keith-type SWC 44 molds and two Ray Thompson-type SWC 44 molds

H&G 503 MP Molds clone in brass

Lyman 429421 Arsenal Molds clone in Al

Lyman 429244 MP Molds clone in brass (also, a hollow point mold)

Lyman 429215 Ohaus molds clone in Fe\

The front driving band varies widely in these, with the 503 having a very wide driving band. I size everything .431 as both my Blackhawk and S&W624 have .431 throats. Using starline brass (which seems on the short side of spec) none of these designs has had trouble chambering, though I am pretty sure that the 503 is actually pushing into the throat a little. So the stuff about one being for 44 special and one magnum seems sort of moot to me. What seems to matter is throat diameter.

The best accuracy for me has been obtained from the 503, but all seem to work well. Much better than I can deliver.

I suppose if I could pick just one it would be the 503 as it casts so well and is so simple and easy to work with. My least favorite is the 429421. The grease groove is enormous and it uses about 2-3x the grease of the others. It also seats deepest into the case of the 4. I use load ata for the 429421 for all of these, even the 429215, and it has worked well.

[Mal Paso]

My least favorite is the 429421. The grease groove is enormous and it uses about 2-3x the grease of the others.

I always thought it was designed to sell more Lyman Lube.

[Dragonheart]

When someone sounds praise for H&G, I am right there with you because as far as I am concerned H&G is second to none. H&G is for more than a lifetime, so you have an investment that will continue to pay dividends.

I am 72 and I have H&G molds older than me and they cast just as well as the day they went out the door. I have mostly 4 cavity molds, but a few 6 & 10 cavity and I have to say it takes a better man than me to pour & tap those big molds all day long. Even with a mold shelf to take the weight the opening a 6 and especially a 10 cavity is a chore. I finally had to have help so I built "Ram Tapper" and open the mold with a push of a button. Now my problem is feeding the 10 cavities a 20 pound Pro Melt pot goes down really fast.
273839

[curioushooter]

Very cool device Dragonheart


I always thought it was designed to sell more Lyman Lube.

I thought the same thing, though Keith seemed to like lots of grease. Another explanation I have is that in Keiths days of experimentation (the interwar period) bullet lube was probably any available grease that would remotely work. Tallow, parrafin, petroleum jelly, straight beeswax, and a lot of other things were probably used and I think they tried to make up for lack of performance with extra quantity. With our carefully formulated lubes today it seems you don't need as much. I can say for certain that I find lube deposits on the muzzle from even the 429215 (which has narrow half-circle grooves). The 429421 is simply excessive and since I recover virtually all my bullets in a sand trap I see that about 80-90% of that lube on the 421 ends up in the sand.

[curioushooter]

I have read about what Elmer liked and wanted and concur on most things except that load of 22 or more grains of 2400, I drop it to 21 or less for my hand's sake. I bet many Smiths have loosened up with that 22 gr. load. If I need more speed I go to H110 or better still Mp300 ( I think that's what it's called).

I think Keith's original Heavy 44 Special load (the 429421 cast of ~20:1 w/ 17 gr 2400 in solid head brass) is more than is really needed. I prefer the load with the H&G503 to the 429421 (which affords more case volume and weighs slightly more since it puts more wight in the front driving band and nose and has a wider meplat). It clocks 1250 FPS from my 5.5" blackhawk, and I knock it down to 16.5 grains just for some safety margin. This is more or less equal to reduced loads in 44 mag with the same bullet that burn 20 grains of 2400. The lesson is that the extra case volume is pretty much just waste in a handgun. You can get equivalent performance from lighter charges in the smaller case.

When people think of Keith's loads, they always seem to think of the powerful proto-magnum loads using 2400. For my money I think his loads using Unique are more useful and certainly more fun. 6 to 6.5 grains of Unique pushing a 358429 in a Special case or crimped over the driving band in a magnum case is an excellent load. In a 4" revolver it will push to around 1100 FPS. This is for 357 magnum or heavy framed 38s only. It trails 13.5 grains of 2400 with the same bullet by about 100 FPS.

The so called Skeeter load of 7.5 grains of Unique pushing a 429421 in 44 special case pushes to around 950 FPS in most revolvers. This load as far I can know was actually discovered by Keith and promoted by Skeeter. It is much milder than the so called Keith load yet will hit to the same POI supposedly (I have not found this to be the case in either my 624 or my Blackhawk).

Some of Brian Pearce's data shows that the 429421 can be pushed by as much as 8.5 grains of Unique and come in under 22,000 PSI. In my messing around I've found that 8 - 8.5 grains with the H&G503 can be a real sweet spot for these heavy 44 special revolvers. I get around 1050 FPS from 8.5 grains of Unique pushing a 260 grain 503 cast of 96-2-2 alloy. No leading, new formulated Unique burns as clean and meters as well as any other handgun/shotgun powder I have, and stunning single digit velocity spreads, which are better than anything I've gotten from 2400.

This lower velocity load, as far as I can tell, retains nearly all the terminal efficacy of the Keith load at 75 yards or less...it makes a caliber sized hole in whatever critter it hit and will probably pass through anything smaller than a moose. It uses half the charge weight of powder, is more consistent, and is much more pleasant to shoot lacking the violent recoil of the Keith load. These loads are just subsonic, and are substantially quieter than Keith loads.

Powders between 2400 and Unique have a lot of potential I think. I've found promise in BlueDot, Herco, and PowerPistol. Herco was availabe in the 1920s and I am surprised that Keith never reported (asf far as I've read) useing it. It can get 1100 FPS with 9 grains and a 255 grain SWC, just about 100 FPS less than almost twice the charge weight of 2400. Longshot is another powder that seems to have a lot of potential, but I've not tried it.

H110/296 and 300 MP are both slower than 2400. They are dense ball powders. They are even more wasteful, noisy, and violent. The one thing they can do is push the same bullet 2400 can to a slighlly greater velocity with an equivalent chamber pressure. It is a case of diminishing returns, especially in a handgun.

I did an extensive test of 2400 vs 296 vs 300MP in 357 Magnum two summers ago. I found what Keith did. The gains are minuscule in normal barrel length revolvers (<6"). 300MP generated about 30 FPS and at most 50 FPS more than 2400 with the same bullets (I used cast, gas checked, and jacketed) in my 5" 686. To keep everything fair I used all new max load data from the same manual (the Hornady#10, which has all these powders listed for 158 XTP). Now in the Marlin the 300MP pulled away bigly, besting the 296 and 2400 by hundreds of FPS. Considering that shot to shot deviation in the revolver approached 30 FPS this "performance improvement" is nearly within the statistical range of variation; I consider it inconsequential.

For my money I'll take Unique in revolvers. It generates almost as much velocity (usually only 10-15% less) as a magnum class powder with half the charge weight with the same bullet. If I feel like I need more power then I will increase the caliber of the cartridge. I suspect Unique would rock in 45 Colt, 454, 475, and 500, too. It would be interesting to see what QuickLoad would say but I suspect just take the max load of 2400 and reduce by 66% would be a place to start and work up to about 50%. I know that Linebaugh had 12 grains of Unique with the 250 Grain SWC in 45 Long Colt as safe for SuperBlackhawks.