No sonic "crack" from my BP .45-70 loads, are they that slow?


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Gewehr98
June 26, 2006, 11:57 AM
I've been working a lot with 500-550gr Creedmoor type handloads for my 32" Sharps Model 1874, stuffing a lot of Goex Cartridge in the vintage Rem-UMC balloon-head cases. How much is "a lot"? A full 70gr, drop-tubed and compressed a good 0.20" to 0.30" with a powder compression die before the wad and bullet are seated.

Every time I fire this load I get good accuracy, but it's a big old "Boom", as opposed to the sharp "Crack!" I get with a 485gr Whitworth bullet on top of a light load of Alliant 2400.

I would've figured I had enough charcoal in the case, and enough barrel length, to get that bullet over the 1150 or so fps it needs to go supersonic. I'll have to drag the chronograph out I guess, but I'm really not going to get more powder in the cases without some trouble. Do the big boomers ever get past their own shock wave?

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Manyirons
June 26, 2006, 12:27 PM
Short answer, yup! Dont know as if that 550 is gonna hit 1060+ or whatever elavation yer at fer sonic velocity. and 32 inches MIGHT have ya runnin outta ooomph and coastin in tha barrel. Happens in .22 rimfire, 16 inches somethin like optimal and a 28 jus fer tha example prolly find it goin slower by more en a bit.

Have ya tried substitutes and gotten any CRACK? No NOT tha kind ya smoke! :) Have ya tried 500 grainers? Whoops! See youve tried 500 grains.

Car Knocker
June 26, 2006, 01:06 PM
I believe you have to get up to a .45-90 or .45-100 to get supersonic; either that or use a duplex load.

Jim Watson
June 26, 2006, 01:59 PM
Depends on the vintage of your Goex. They turned out some sorry stuff about five or six years ago, friend of mine was getting about 1000 fps. Late date Goex or Swiss can run the .45-70 to 1200 fps and above.
They still boom, though, without the hard crack of a nitro load.

Gewehr98
June 26, 2006, 02:17 PM
Goex Cartridge, and even my 500gr loads go "Boom" instead of "Crack". Bottom line is I'll have to drag the chronograph out to the range, and hope it doesn't get confused by the smoke.

I suppose for bullet stability's sake, staying subsonic all the way to the target is a good thing. ;)

Jim Watson
June 26, 2006, 02:31 PM
I bet you are supersonic and it is just the burning characteristcs of black versus nitro that causes you to hear it as a boom. My little .38-55 did 1200 fps with 48 grains of late '04 FFg and the 336 grain mini-Snover. Swiss 1 1/2 gives me higher velocity and lower SD, though.

BPCR shooters flirted with the all-subsonic shot a few years ago, but gave up on it. By the time I started, it was just some old articles and threads. Those big roundnose bullets are pretty stable under all conditions and higher speed means less time in the wind. Lag effect is not the problem it is with .22s.

frosty
June 26, 2006, 06:07 PM
Sir, please do not use those old style cases! I have seen them come apart...There are to many good kinds of brass to even consider it(in my opinion) As far as the crack noise, I shoot heavy bullets over H777 as well as traditional black, and you want to be in that 1050-1300 fps. area. Much faster and you will find that wind drift will increase substantually until you hit around 1700 fps. If you plan on hunting or shooting within 200 yds, it probably doesnt matter. For midrange silhouette or hunting(400 yds or so) you will find a better situation with the lower velocity. I hope this info helps. If you shoot the lighter bullets, you will definitely hear the crack noise at those higher velocities...:evil:

Gewehr98
June 26, 2006, 10:07 PM
We aren't talking tired old brass fouled by years of mercuric primers or long-forgotten BP residue. I got lucky one day several years ago. The REM-UMC balloon-head brass I have is part of a large (several hundred pieces) cache I found that was new-in-box, from the estate of an old reloader. I even have about the same amount of new-in-box .44 Special brass that came from the same fellow. I'm just waiting for a .44 Special Colt SAA to drop into my lap to start using them. :D

Also, I will never use high-pressure smokeless loads, Goex blackpowder is the only thing I use in these NOS balloon head cases. I baby them the most out of the 24 calibers I reload for. The cases get deprimed at the bench and dumped into a gallon milk jug of soapy water, then once home they're run through a laboratory ultrasonic cleaning tank with Micron solution at 130 degrees for about an hour. Inside and out, they're shiny clean, and I don't even need to tumble them.

Why do I choose to use them? Because I can get a full 70 grains of drop-tubed FFg or Cartridge BP in a balloon head case, without excessive crushing of the kernels or bullet deformation while seating, just like the folks had in the late 1800s. These are my long-range loads, using a Postell or Paul Jones Creedmoor bullet for 800-1000 yard shooting. I could seat the 500-550gr bullets I use further out, but that exposes the lube grooves as well as bumps into the throat of my Sharps 1874 Business Rifle. My Ruger #1S has an even shorter throat, and is very fussy, even rejecting certain bullet ogives.

I watch those cases like a hawk, and if they show signs of letting go, I'll stop using them. I've already started using a Montana Precision compression die with new Winchester/Remington/Starline brass, but a recent article in my latest issue of Black Powder Cartridge News emphasizes that too much BP compression can be a bad thing.

Regarding a 1700fps load in .45-70, not with black powder, and not in my Sharps. I routinely run 2100fps 405gr loads in my Ruger #1S, but it's with modern brass and Reloder #7, way too much of a load for balloon head brass and the older Sharps design.


Regarding the "Boom" vs. "Crack", I'll go with what Jim surmised until the rain around here stops, then we'll see what Mr. Chronograph has to say. I'm working up a range chart that coincides with the markings on my rear Creedmoor vernier sight, and I want the computer data to be as close as possible to real-world conditions when I make my little laminated card. ;)

frosty
June 26, 2006, 10:40 PM
I would like to say exellent! I avarage around 1100 fps with those larger bullets, and I also realize you cant get that kind of velocities with black powder loads...It is factual info I was taught by a champion match shooter(1700 fps vel. would definitely be smokless). Glad you know what your talking about! I've heard some horror stories about those old cases:what: Good luck and good shooting:evil:

JWINKS
July 3, 2006, 08:32 PM
I have been struggling to get my velocity up around 1100 Fps. I heard from one fella at a shoot that he gets this all the time. I use Elephant FFG and if I size the cases and just bell the very end of the mouth I can get an avg of 1025. Is this normal? The fellas with the 1050-1100 FPS must be using something faster right? Thanks, Jwinks

frosty
July 4, 2006, 09:17 AM
What amount of compression do you have? In the 1884 Spingfield I once owned, it took high compression and softer lead for bullet upset, to get 1100 fps and accuacy. In the gun I'm shooting now, 1-20 alloy sitting on top of the powder with lite compression will do it. One thing you could try is Winchester brass- they will hold a few grains more! Also, a federal #215 mag primer is always the norm.:evil:

sundance44s
July 5, 2006, 08:14 AM
Was shooting 45/70 this weekend with a friend he had his loaded with 65 gr of 777 2f ..and his rifle made the sonic crack .. but mine didn`t loaded with APP 65 gr. 2f . we were both useing 300 gr bullets .

Gewehr98
July 10, 2006, 12:35 AM
Matter of fact, I've been too busy with the new job, and living at my sister's house here in Wisconsin. All my toys are still in my house in Florida, just itching to get them here once we finish buying our new house up here. I'm tickled pink that the super outdoor range in Lodi is just a hop, skip, and jump away.

In the meantime, I'm going to ask this same sonic crack/no sonic crack question over at the Goex and BPCR forums, just to see what kind of info pops up there.

BTW, I got the contact info for the NASA high-BC bullet molds, Jim. I'm looking forward to getting them and casting a few of those beauties. Hopefully they shoot as good as they look!

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