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View Full Version : Is it just the chambers that are different?



Limey
10-18-2008, 04:50 PM
Is it just the chamber dimensions that are different on a Sharps 45/70, 45/90, 45/110, 45/120, 45/140?????

Or are there differences in the reciever/barrel.....ie more of it/bigger/stronger steel used etc etc?

If the answer to the above is that it is just the chamber dimensions, it must mean that the 45/70's are well over engineered and that the bigger stuff gets progressively closer to their mechanical limits.

Anybody know the answer?

Safe shooting

Limey

missionary5155
10-18-2008, 07:47 PM
In a mater of speaking.. YES.. The major difference is the capacity of the case to hold more black powder. In the day of ONLY black powder that was always a big plus... 40 grains MORE black powder was a REAL power difference. AND still is today ! A 500 -550 grain boolit needs all the black powder it can get to fly accurately 1000 yards.
When dealing with Smokeless then really a 45-120 case is getting oversize... but still it has the capacity to hold lots of slow burning smokeless where as a 45-70 case has itīs limitations.
I long throated my custom 45.70 barrel so I could seat long .45 boolits farther out of the case and gain an extra 15 grain capacity with black powder...

MtGun44
10-19-2008, 06:28 PM
Black powder doesn't develop a lot of pressure and more doesn't seem to develop
more pressure, just burns longer. I don't think a 45-140 had any higher pressure
than a .45-70, just burned more powder, so needed space to store it. Remember,
you HAVE TO fill the whole case full with black, unlike smokeless. So, you couldn't
use a 45-110 with 40 gr powder unless you seated the bullet down to touch
the powder, which would be below the case mouth, I'd guess.

Bill

missionary5155
10-20-2008, 03:33 PM
And the other option to down loading with BLACK is to fill the space from powder to boolit base with wad or filler.

Limey
10-20-2008, 04:02 PM
Currently our local range is only a 200 metre facility......plans are approved to extend it to 300 metres.....we are now working on getting the money together to fulfill the planning permission!

So, with only 200 metres to fly and only paper to 'kill' I am not looking for any more power and in fact I have been down loading my 45/70 for over a year successfully now........I use cotton wool as my free space filler.......works a treat and the load is accurate......and much cheaper!....my question was just me wondering if the really long rounds needed any more gun to keep it all in safe and sound.

I use a filled and levelled Lee 3.1cc dipper to add the European made Nobel 2F B/P and one of those make-up removing cotton wool balls that women use....(these average out at 10 grains in weight)...... I buy a large bag these from the local super market for not a lot. I cast my own bullets from straight WW that are water quenched using a Lee 420 grain hollow base mould, sized to .459, lubed with homemade slippy stuff based around bee's wax and the overall cartridge length is 69mm so the bullet is just a gnats todger short of just touching the rifling.

I also use the same space filling technique and materials to make up smokeless rounds that replicate the same tragectory as my standard B/P load.

Safe shooting

Limey

KCSO
10-20-2008, 09:32 PM
Over engineered??? For Black Powder???? The difference in pressure is very little between a 45-70 and a 45-110 compared to say the difference between a 30-30 and a 30-06. Yes a 45-80 could be rough on a trapdoor but part of that had to do with the weight of the gun. A 45-70 had an average pressure of about 16,000 psi and a 45-110 would have ben about 20,000. Now compare that to the 30-30 and the 30-06. Now as to the cases I have a special chamber ramer made to cut 45-70 to 45-110 depending on how far you feed it in. There is very little difference in the case designs. If you shoot smokless the only difference is that the 45-70 does it all and the 45-90 and above are really not well suited to smokless powder. If you were a hunter of buffalo in the old days the 45-90 ect enabled yo to kill at slightly extended ranges. This was mostly due to the greater accuracy potential of the hevier bullets in the larger cases. Even the military found that the heavier 500 gran bullet gave accuracy advantages over the lighter 405 with little difference in pressure or velocity. The big question is how much of this was really needed, just like today there were folks who were wrongly convinced that the bigger the gun the better the hunter. Sharps considered the 45-110 as big a gun as was necessary for anything. Now days te only reason for anything bigger than 45-70 is 1000 yard shooting where the 90 and up will deliver just slightly better (safer) trajectory. A 45-70 with a 405 bullet will shoot through a buffalo and any range yo are likely to get to shoot one now days.

leftiye
10-21-2008, 01:58 PM
AA gives pressure for the 45-120 as 30,000 psi (black). FWIW