Starline 50-70 Sharps and 50-70 GOVT - UPDATED - DIFFER May 2025

[El Supremo]

Hello:

Please read ALL the Posts to this Thread for progressive info. Thanks.

50-70/90 "Sharps" cases are "parents" for 56-50/56-56 cases.  There are Threads here about how to do the conversions.

My S'line SHARPS 50-70/90's, when cut-down to 56-56 or 56-50 do not require mouth reaming.  They must be reannealed to prevent mouth splits and achieve at least 25 loadings.

01MAY25 Starline's, egreer@starlinebrass.com, 800-280-6660, emailed that it is filling backorders for 50/70 brass at $588 for 500 cases, including shipping, which is roughly $1.17/case. Smaller quantities can be ordered.

A week later, I see reports of the 56-50 Taylor's also available. Smiles.
El Supremo/Kevin Tinny

[El Supremo]

Hello:
The 500 Starline 50-70 "GOVT", NOT "SHARPS" cases arrived after a two year wait. I cut a few to 1.60" and 1.05" and measured them for comparison with the Sharps ones I'd used before Covid.

Found minor, but possibly noteworthy differences.
The rim OD's and body OD just above the rim are identical.
There are slight differences in the wall thickness, mouth ID/OD of 56-50/56-56 cases cut down from the parent "SHARPS" vs "GOVT" ones.  The cut down Sharps case has slightly thicker case mouth section wall and wider cut down mouth OD than the GOVT one. 
 
More detail in a following Post.

Starline can email case drawings for comparison.
Smiles.
El Supremo/Kevin Tinny

[Blueheeler]

Midway is currently selling 50-90 sharps in 100
Case packages.

[tjiann]

Received both of my orders of 56-50  and 50-70 brass from Starline. Enough to shoot my 65 original and Armisport repro for years.

[Garret]

Greetings All,
So Kevin, from your post here it sounds like the new lot of .50-70 Gov't brass when trimmed to .56-50 length has thinner wall than your older .50-70/90 Sharps?
You mentioned at top of this thread that the Starline Sharps didn't need reaming for use in the Spencer.
Sorry, but I'm a "mite confused" recalling that you mentioned reaming the .50-70/90 brass in a previous email conversation.
Please help me become un-confused
As a refresher, my Spencer has an original action, barreled and chambered for the original cartridge.
I'm also waiting for a response from Buffalo Arms regarding their backordered .56-50 "original" brass which they made from Starline .50-70.

Many Thanks!
Gary

[El Supremo]

Hello, Gary:

My early parent case adapting process included using a case mouth inside reamer on one lot of OLDER custom 50 BASIC brass with unusually thick case walls. Those specific cases were reamed and present a visible step inside the caee. 
The outer edge of  any reamer imparted "STEP" must have a rounded  edge to prevent a stress riser which can cause case body separations.  Finding/altering a reamer to produce the radius can be an expensive chore.

Later, I learned reaming was not needed with readily available, very uniform Starline brass used in original and Romano Spencers. 

Starline 50-70 Govt and 50-90 SHARPS cut down case wall thicknesses seem fine, but wall thickness varies, properly, a little between "Govt" and "Sharps". So far, my accuracy work indicates either cut down parent case should be ok for 56-50, but might be tight on some 56-56 bullets with wider "heels".

Be sure to reanneal the shortened Starline cases to ensure good case life.

All the best,
El Supremo/Kevin Tinny

[Niederlander]

When I had a Spencer, cut-down Starline .50-70 cases worked great.  I annealed them using the "dipping in oil then molten lead" method.  I was really disappointed Starline didn't make their .56-50 brass with the same rim diameter.  They sent me twenty or twenty five rounds to play with when they were first bringing it out, and I was bummed to find out the rims weren't big enough for the blade extractor to work.  I think they really missed out on the North-South Skirmish Association guys with that oversight. 

As usual, my musings are worth about what they cost you.

[Garret]

Thanks Kevin and Niederlander!
Kevin, I appreciate your clarification.  My Spencer is .56-50 so it sounds like the  brass should be ok with trim and anneal.  As you've played with both .50-70 and .50-90 cases, is the trimmed mouth thickness the same on both?  I would have expected the .50-90 to be thicker as it's cut back farther from the original mouth.

Niederlander, like you I was also really annoyed to find the Armi Spencers weren't made to the original case dimensions and the brass was therefore unusable in originals.  I initially ordered that brass only to find it unusable in my rifle. 

I talked to Buffalo Arms this AM and am awaiting a call back with news on  whether they will be filling backorders on the .56-50 they make from the Starline .50-70.  If they do I'll wait for these.  We shall see.

Cheers!

[El Supremo]

Back to you, Garret, on comparative case dim's:

Please reread this Thread from its beginning.  Some revisions were made to earlier Posts. Thanks.

Two Flints inserted a page from my files to help with trimmed case dimensions.  Converting the photo "file" was a lot of work.  I try not to overdo his willingness. Thanks, Two Flints.

There are many small details which apply, not the least being the accuracy of measurements.

Watching You Tube vid's and chats with toolmakers about how to measure correctly taught me lots.  Then there's the aspect of where the measuring tool is placed and held. Bottom line: Even with my top quality gauge-maker STARRETT, verified to "standard" gauges, I get up to a thou variation because of tapers and flat jaws on curved surfaces.  Measuring as little as a sixteenth deeper/shallower has produced a thou.  Overall, a thou is not significant.

I was taught to carefully take FIVE measurements, discard the high and low, then average the remaining three. 

That much attention to detail might seem excessive, but unless you can "feel/accurately measure" a half-thou, as can most toolmakers, pricey tools are worth it to elim guesswork.  I have tested my fine tools using "standards" and found a half thou ZERO diff when carefully measuring.  Creeps, even taking my dead-nuts vernier and verifying it's zero, can present a half-thou more or less, AS THE TOOL SITS IN WARMER/COLDER bench temp's.

For our shooting Spencer's  to 100 yards, I don't worry about the diff's in Starline's, PROVIDED the cases are TRULY the same LENGTH.

In addition to the info in the attached photo, please note that my experience with all Starline cases has been entirely satisfactory, especially as to uniformity, over many years. HOWEVER that has not been so with some NON STARLINE cases purchased directly from a REPUTABLE custom case maker using the same machinery.  Within its same "lot" of 56-50 cases were some with the same factory EXTERNAL trim-to-length were some with an internal depth variation of .061" and weight of 42 grains.  This maker's cases that had been fine for me, taught me to check dimensions. 

Repeating what has been posted in other annealing Threads:
My careful measurements of the same spots on cut-down, annealed Starline cases produces the same, unchanged dimensions, especially case mouth wall thickness.

I was set back in my chair this week when a VERY capable friend used my Romano Spencer rifle #10030, with 36" twist, uniform cases, 34gr Swiss US 3F, CH4D dies, SPG lube, and EITHER Accurate #51-320S or 51-350S in 30:1 alloy sized .001" over groove to shoot 6" groups at 300, not a typo, yards. Maybe a fluke, but he's GOOODDD. 

Smiles,
El Supremo/Kevin Tinny

Apologies for fuzziness. Two Flints can work only so many factors - not his fault. Kevin


                                   Photo Added by Two Flints

[Arizona Trooper]

The original rim diameter of 50-70s is 0.67". Dixie cases with the DIXIE or DGW headstamps were 0.67. When Spencers became popular most of the case makers switched to 0.65" rim diameters, since the smaller diameter still extracts fine in Trapdoors and Sharps conversions. I made my first CF block a couple years before S&S came out with one, and turned down a lot of Dixie 50-70s to make Spencer cases.

[Garret]

Thanks El Supremo and Arizona!  Buffalo Arms has been a bit "non-commital" about whether they will be making the Spencer brass from their current stock of .50-70 so I may just order some stock brass from them to trim myself.  It sounds like the mouth I.D. will likely be good for what I'm working with.
Cheers!