Making 1874 Sharps 45-70 rifle.

[homebrew.357]

Hi all, yep I`m making a sharps rifle on my lathe, what is the best rifling twist for the 45-70 cartridge with black powder, I can get 1 in 24" and a max barrel length of 25". All the new barrels are 1in 18", some say a fast twist for this rifle. Barrel steel is 1214 ,nice for cut rifling and also what throat lead in from chamber end to rifling. Just looking for imfo before I start making this barrel, Just a home machinist, have already made a Hawken Plains rifle on my lathe, shooting good. Homebrew.357.

 

[ulav8r]

Be sure to mark the barrel "For Blackpowder Only". 1214 steel should not be used with smokeless loads.

 

[homebrew.357]

Hi, Yes UlavBr will most certainly do that, Safety, safety, way to go, the receiver and breech block are made of aisi 1045 steel and will be heat treated and tempered , this is just down from 4140 and should be good and strong, but yes a proof test to check things are ok. But still in making mode, have only made the breech block, a few springs , ejector , will take me some time to finnish this one
Cheers, Homebrew.357.

 

[Dave W]

Yahoo! Another project from homebrew.357! We want lots of feelthy peekchurs!

Many modern manufacturers use 1:20, but here's a report from 1879 saying they got better results with 1:18:

Rifles / Black Powder / 45-70 Government Ballistics Tests

Optimal twist is linked to the aspect ratio (length/diameter) of the bullet. Since diameter is fixed, basically the weight of the bullet. In general (with lots of exceptions and hand-waving here) the faster twists are a bit more flexible as far as bullet weights.

Rifling for jacketed runs about .002-.003 in depth, cast bullets .004-.005, muzzle-loader soft lead .005-.007.

 

[ahall]

Yahoo! Another project from homebrew.357! We want lots of feelthy peekchurs!

Many modern manufacturers use 1:20, but here's a report from 1879 saying they got better results with 1:18:

Rifles / Black Powder / 45-70 Government Ballistics Tests

Optimal twist is linked to the aspect ratio (length/diameter) of the bullet. Since diameter is fixed, basically the weight of the bullet. In general (with lots of exceptions and hand-waving here) the faster twists are a bit more flexible as far as bullet weights.

Rifling for jacketed runs about .002-.003 in depth, cast bullets .004-.005, muzzle-loader soft lead .005-.007.

Agreed - Best twist will depend on what your trying to push down the pipe.
A 350gr JHP and a 600 gr paper patched slug have very different requirements.

The marlin guide gun uses a 1:20 RH twist and is likely to be fed over the counter ammo (smaller jacketed hollow points and soft points).
That's probably a good reference to keep you in the ball park.

If you are paper punching with BP and big cast lead rounds you will want a faster twist than one set up for jacketed hollow points.

In general (lots of arm waving) the heavier bullets are more likely to find the mark at long ranges, but you may need a tang sight that's a foot tall.

If your thinking jacketed ammo for hunting, look at the tables in the front of your reloading books and see what velocities the bullets are intended to perform at.
The larger jacketed rounds intended for the 458 Win Mag and other high power 458 bores may not expand properly if you use them at BP velocities, especially at longer ranges.

I suspect you will find folks who swear by (or at) a particular twist, but with a little work you should be able to craft ammo that works with any reasonable twist.

 

[MilGunsmith]

I have a .451 Pedersoli Tryon muzzleloader target rifle, with a 1-18" twist. Shooting a 480gr Lyman bullet 457121PH sized to .451". I use 50gr of FFFg Goex for 1 MOA groups at 1050fps. For long range, 600yd, bump up to 65gr. The trick is to watch out for the transonic distance, the bullet becomes unstable. I have had better luck keeping it subsonic for 100 meter shooting.

 

[homebrew.357]

Hi, This Sharps will basically be a range rifle, shooting at 100/ 200/ +yards, with cast 405-500gr bullets, looking at using 2f bl/ powder . And yes I can play around with the twist, a 7" bike sprocket gives me 1-33" and a 4' one gives 1-24", so if I get a 3" one should be close to 1-18". Now I have some 45-70 cases and will check thae bullet depth with a 70grs b/powder and work out the throat length. Now I have made a new rifling cutter from a T/C saw blade, yep those tc teeth are just the right size with a bit of grinding for profile good to go. So it`s all go down under in NZ , a few pic`s, the breech block, firing pin, made in my lathe milling machine and the barrel to be. Cheers Homebrew.357.

 

[homebrew.357]

Hi guys, had a bad day today, lathe is going good and then bang, from the gearbox!!!!!?, yep gear tooth broke of and striped two gears. So have seen the suppliers for new parts, will ring me tomorrow to see if they have them, fingers X. I`m having a rethink on the 1214 steel barrel because I do have a 32" length of 4140 steel, and I have just got a second hand gun drill from the US, .444" dia, t/c and so is my rifling cutter. A gun drill cuts a slightly bigger hole than it`s size .445" I think? , so would not be much to ream .003" to .448" then .005" cut rifling , left hand twist, it`s hard stuff, that would you guys do?. I made the breech under lever in to parts, machined the front part first and then the lever bit to be welded together, polish , and bent, job done. Homebrew.357

 

[MetalCarnage]

Parts are looking good anyway but sorry to hear about the mechanical snafu. A couple of quick questions for you, if you don't mind. What set of plans are you working from and where'd you get them? Do you like the plans? Are they accurate and complete?

Thanks for posting your project,

-Ron

 

[Dave W]

I don't see a problem. How much stock did your reamer remove on the last barrel you made?

Something you might want to look at when you get to the chambering part - the transition from the chamber to the rifling is the "leade", the chamfer where the bullet engages the rifling. For the vast majority of cartridges that's 45 degrees. If you google the SAAMI chamber diagram for the .303 Enfield, you'll see it uses a more complex layout with multiple shallow angles. Though all .303 military ammunition was jacketed, the Lee-Enfields are known to be particularly friendly to cast bullets. If you're going to make your own reamer, you might want to look at how the .303 leade was done.

Granted, 45 degrees seems to work just fine for most cartridges, but there's no reason not to take every advantage you can... note the SAAMI spec for the .45-70 is a bit over 12 degrees, not 45; it's one of the few exceptions.

http://saami.org/specifications_and_information/publications/download/206.pdf

 

[homebrew.357]

Hi guys, Ok, MetalCarnage I got the plans form E bay in the US, The Quigley 1874 Sharps, they are 36"x24" sized sheets ,9 of them and I had them laminated. This is the first time I have worked from plans so I`m no pro, but they are clear and sharp, other forums say watch for mistakes and I have found one only so far, but checking what I`m making to where it goes it`s .003" fit, so I think they are good , but that's me!.
Dave W My first barrel was a bit of pain, 1045 steel ,the gundrill left a bore of .419", I was using an adjustable reamer with water base coolant and only scraping gray mud out. so left the bore at .438" , cut rifled to .447/8". No good, so ground out the rifling to .430" with 400 grit emery paper and oil and made a rifle cutter to fit the bore and recut the rifling out to .450". I made a barrel out of 1018 steel for the sharps and used oil for reaming , out came nice chips, so I`m learning, but the barrel was only 1" dia, the sharps is 1/230" , have a spare barrel with 1-24" twist. And yes I have the saami copy of the 45-70, 12.45% and have made a chamber reamer in silver steel , just have to harden it. Have just done some hardening, I have made the main spring out of a spring,Cheers, Homebrew.357.

 

[MetalCarnage]

Thanks Homebrew. I'll see if I can find a set there as well.

Keep up the nice work!

-Ron

 

[homebrew.357]

Hi Metal C, You just missed out on the Qugiley plans, Gun Auction #8203508, went for $50. I`m still waiting for the bits to get my lathe up and running, so did some a bullet casting for my .308, and .3030, 160gr lino type , just have to get some gas checks and powder, Varget ,2208, then test on the range, Cheers,Homebrew.357.

 

[MetalCarnage]

Hi Metal C, You just missed out on the Qugiley plans, Gun Auction #8203508, went for $50. I`m still waiting for the bits to get my lathe up and running, so did some a bullet casting for my .308, and .3030, 160gr lino type , just have to get some gas checks and powder, Varget ,2208, then test on the range, Cheers,Homebrew.357.
View attachment 108584

Actually, I was able to snag a set of plans off e-bay for just a few dollars more. They arrived at the house this morning but I haven't had a chance to unroll them and check them out.

Thanks again,

-Ron

 

[homebrew.357]

Hi , Good on you, the fault was in the lever to breech block link, link is .250" and gap in lever is .175" or so, watch out for more , Cheers ,Homebrew.357.

 

[MetalCarnage]

Hi , Good on you, the fault was in the lever to breech block link, link is .250" and gap in lever is .175" or so, watch out for more , Cheers ,Homebrew.357.

Thanks! I'll make a note of that.

-Ron

 

[homebrew.357]

Hi, At last, my lathe bits are on the way, carn`t complain , one gear had to be air freighted from china and they are on the way. So while I was waiting went to work on the side plate, this I made out of a chain saw bar. Theses are very hard steel, just what I wanted, so I can reharden and temper leaving a nice surfaces finish. The blade was just the right thickness so cut a chunk out with my angle grinder and annealed it with my blow touch so I could cut it and shape it, but will leave a bit for fitting. Slowly getting there, the pic`s, Homebrew.357.

 

[homebrew.357]

Hi Guys, Still working away on this sharps, stoped milling the receiver just for a rest from it and now working on the set trigger assy . The two triggers need to be hard, so I again used car spring steel as I can harden it and temper to a nice colour. pretty tricky as I have no mill, but thinking of how to do it on my lathe I usually get there . The base plate is mild steel flat, but it had a square block assy on it, so made up the block and ground a under cut and then welded it to the base plate, cleaned up the weld by milling, still had plenty holding it on. So with a bit of slot milling and a final finish with 600 grit sand paper , getting there, slowly Cheers, Homebrew.357.

 

[homebrew.357]

Hi all, Doing a bit more on this rifle, finished off the side plate and now making the tumbler and sear assy. Making the tumbler out of 4140 round stock in the lathe and using the saddle as a shaper to cut the sear and half cock notches in it, makes it more accurate than filing. A pic of my rifling head gear box to show the bike sprockets, the big one get`s me a 1-33" twist and the small one is 1-24" twist and as I`m not shooting at 600/1000 yards with 500gr bullets, I think the 1-24 should do it, I hope. Cheers, Homebrew.357.

 

[GGaskill]

You would want the faster twist for heavier bullets anyway.