480 Ruger loads - Full sized BH & midframe BH customs

[princeout]

I'm not a ballistician, so I'd like to see if one of you more informed folks could enlighten me some.

I currently have one of the full sized Super Blackhawk's in 480 Ruger, 6-1/2" barrel. I've been using Hodgden's recommended starting load for H4227 with good success. It is listed in Hodgden/Winchester's online Reloading Data Center, Hodgden Reloading Data Center,as generating 1,125 FPS velocity and 39,100 psi pressure (19.5 grains behind a 420 grain lead bullet). The same site lists 19.0 grains H-110 behind the same bullet as generating 1,145 FPS velocity but with only 34,200 psi pressure. Considering the burn rate comparison between H-110 and H4227 (right next to each other), the velocity data doesn't seem unusual but the pressure difference seems like a lot.

The reason for my curiosity is twofold. I shoot the same load in a Puma M92 - Winchester replica and if I can reduce the pressure by 5K psi without any loss of velocity, I'm all for it. Wear and tear on the levergun will be a bigger issue than wear on the full sized Blackhawk.

The second reason is I'm back to thinking about getting a 5 shot, mid frame based 480. I'd like to be able to run the same ammunition in all three. I would think the lower pressured load would result in better longevity for the mid frame, but perhaps even that is too hot.

I'm already running 45 Colt ammo at three different levels, low for a 1907 Bowen tweaked Colt SAA, Ruger only for all the full size framed 6 shots and a Bowen 5 shot mid frame gun, and then finally,ridiculously hot for a Harton built full frame sized 5 shot gun. Keeping the hottest stuff out of the others is accomplished by loading heavy bullets that are too long to chamber in the other 45's, and using nickel plated brass only for the Colt level loads (same trick for 45-70 loads for an ancient Remington rolling block and a modern Marlin 1895). If I move on a midframed 480, I'd like to be able to use the same load if possible.

Anyone have some light to shed on why the big pressure difference or what acceptable loads are for the custom 5 shot midframe 480's? If you know of some literature or reading that could point me in the right direction, let me know.

Thanks,
Tim

[bigbrowndog]

Just because the two powders are next to each on a burn rate scale, doesn’t mean they will behave or react the same way with all cartridges. That said, I have found that a lower pressure cartridge in my big handguns is much nicer to shoot even if velocity and bullet remain the same.

Trapr

[bula]

Along with asking here, think I'd ask the maker. 

[taffin]

Dec 10, 2018 12:16:53 GMT -5 bula said:

Along with asking here, think I'd ask the maker. 

MOST DEFINITELY!

[princeout]

Thanks for the replies; certainly the ‘smith who builds one can recommend loads.

I’m still curious as to why H-110 exhibits a significantly lower pressure than H4227 when velocity is essentially the same. I’m certainly a fan of lower pressure (less recoil and seeming less noise) but would like to understand why the H110 is lower.
Thanks,
Tim

[taffin]

DIFFERENT POWDERS GIVE DIFFERENT RESULTS. CAL HODGON'S AND ASK THEM.

[bula]

The cylinder on my BSBH Shorty by my calipers and no coffee in me yet (work 2nd shift) goes 1.730". This of course Ruger's SS and a 5 shot. Maybe a way to compare ? I believe the custom mid-frame would have to use an over-size cylinder and maker would know the steel. Hope this helps. I think a common load to 3 guns a worthy goal. Luck

[bula]

Coffee hitting bottom. Re-read the thread and see the mid-frame not in hand. Ok, someone on this forum has one, who...?  

[leftysixgun]

Princeout, just so I am understanding correctly, when you say mid frame....are you refering to the size of a 44spl flat top frame?

[bula]

Did some searching here and Encore64 the guy with the mid-frame 480. Likely a couple others ? Halloooo ? 

[bradshaw]

princeout.... your curiosity about pressure variations between powder of similar burn rate with same bullet in same case is warranted. It is a question not easily answered. IMR and Hodgdon 4227 is a very short “stick powder.” (Note that blasters generically refer to stick dynamite as “stick powder,” which only means it is relatively dry and “solid,” not a gelatin, and that it comes wrapped in paper. Of course, stick dynamite is a high explosive and whole other animal than ammunition propellant.)

The old Improved Military Rifle (IMR) 4227 and newer Hodgdon 4227 may be one and the same thing. Both are SINGLE BASE stick propellant. I have used the two labels interchangeably with same performance in .44 Mag through a variety of guns in silhouette, and through a couple of Ruger .357 Maximums, to include the same sight settings. Single base powders are made from nitrocellulose. Winchester 296, also packaged as Hodgdon 110, is a double base spherical propellant. It earns the double base moniker from the addition of nitroglycerine to the main ingredient nitrocellulose. Nitroglycerine ramps the energy found in nitrocellulose, with the potential to increase velocity at a given pressure.

To stereotype propellant behavior is to put theory before experience. Propellant burn rate is determined in what is called a “closed bomb test.” Environ influences burn characteristics, which is why the first rule of handloading is WORK UP, NOT DOWN. In some environs, 4227 yields better performance than 296, a.k.a. H110. I don’t think we know why one propellant may yield better accuracy than another powder of similar burn rate.

Ball powders, made with nitroglycerine, are said to burn hotter. Whether this is true at a given pressure I cannot say. I used to think that the erosive effect of ball powders on a revolver forcing cone, or the bolt extension of an M-16, and flash hiders on .223’s, was due to the sandblasting effect of the tiny hard grains of powder. An oxygen-acetylene cutting torch may provide a better analogy. A large tip heats steel faster than a small tip. A large tip puts out more gas, which means more heat exposure for a given amount of time. Yet, a small diameter case such as .357 Magnum or .357 Maximum concentrates flame more than the same propellant charge in a larger case, and that concentration amount to exposure----another way of looking at time. Jim Stekl, Bench Rest Hall of Famer and developer of BR Remington cartridges, condemned bench rest barrels cooked by ball powders. Scorching forward of the chamber was caused by heat, not sandblasting effect.

As IHMSA All-American and top Python mechanic Jerry Moran says of small arms ballistics, “It IS rocket science!”

A feature of large bore revolvers is the ability to perform work----specifically with cast bullets----at moderate pressure. It just takes more pressure behind a jacketed bullet to equal the velocity of a same weight cast bullet. The .44 Remington Magnum set a high plateau for revolver cartridges which held up for years. Velocity arrived at through pressure. From a 3 pound revolver we carried all day. Three pounds became the standard for recoil control with portability. Dick Casull preserved the portability principle while pushing magnum velocity to the stratosphere with his .454 Casull in his 5-shot single action. In doing so, Dick cut the velvet rope of recoil tolerance. Along with our old maid ideas of chamber pressure. T propose 65,000 psi as a standard operating pressure doesn’t leave room for consistent measure of proof pressure. Not to mention the stress it imposes the the head gasket of a self-contained cartridge----a brass case.

Years ago I made note of pressure excursions caused by heat in the Southwest when shooting maximum loads of IMR 4227 in .44 Mag. The ramp-up felt more dramatic with 4227 than with 296/H110. When you feel extraction from the roller-burnished chambers of a Model 29, it’s time to back off the hammer. A one-grain reduction of 4227 cleared the slate, and I was back in business.

The pressure issue won’t go away; it pops out of the woodwork like some punk gunslinger. The disciplined marksman & markswoman hold the moral high ground, as they measure performance at the target, not on abstractions of POWER. A lesson may be taken from the great .357 Mag, .41 Mag, and .44 Mag: these cartridges exhibit very high intrinsic accuracy, accuracy achieved with a variety of loads. The .357 Maximum shares high intrinsic accuracy, yet is snobbish in the powder preferred for accuracy.
David Bradshaw

[princeout]

Dec 11, 2018 10:27:17 GMT -5 leftysixgun said:

Princeout, just so I am understanding correctly, when you say mid frame....are you refering to the size of a 44spl flat top frame?

Leftysixgun,
By midframe, I mean the OM 357 or the NM flattop 44 Special sized revolver.

Bula, I have mid-frames with oversized cylinders, both a 5 shot Bowen 45 Colt and a 5 shot Bowen 50 GI, along with a 5 shot Single Six in 41 Special. The 50, along with the SS 41, require moderate loads to promote long revolver life. I know several of the guys who have owned 480 Ruger mid-framed guns and wouldn't want to push the loadings to the level used in my full sized SBH 480. My main question was concerning the difference in cylinder pressure developed by two different powders while achieving similar velocities. The answer may lie in Mr. Bradshaw's post:

Dec 11, 2018 11:21:07 GMT -5 bradshaw said:

Nitroglycerine ramps the energy found in nitrocellulose, with the potential to increase velocity at a given pressure.
David Bradshaw

Thanks David.  That statement may be the explanation for the difference in pressure shown in the reloading data.

Tim