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brass and BP amount

Posted: Mon Feb 04, 2019 9:50 am
by kenny s
Just FYI.
I was loading my 40 70 SS Shiloh...
I have been using, with success , shells made out of 30 40 Craig...they worked
I was having some separating problems, nothing major, but it happened once in a while so I
pulled out the 40 70 JBA cases and started loading them.

and here's what I noticed.
I can load 67 grains of OE 1 1/2 with 1/8 inch left in the case with the 30 40 cases.
and the same 67 will overflow the JBA cases.
I've loaded 60 in the JBA and will try them soon.

The brass is not the same thickness between the two. The old JBA looks stronger?????
again FYI...Ken

Re: brass and BP amount

Posted: Mon Feb 04, 2019 5:36 pm
by SchuetzenDave
The .40-70 Sharps Straight case is 2.500" but I understand many use .30-40 brass (2.314") that has been stretched out.

Does the stretching result in walls that are a bit too thin and with the thinner wall I assume you can put more powder into her.

Does anyone use the .405 Winchester cases trimmed back from their 2.583" length?

Re: brass and BP amount

Posted: Mon Feb 04, 2019 6:04 pm
by Don McDowell
Odd that all you can't get 67 grains in the JBA cases. I regularly load 69 grains of OE 1.5 in my 40-70 JBA brass.

Re: brass and BP amount

Posted: Mon Feb 04, 2019 6:17 pm
by rdnck
I have some Hornady 405 cases that I use in my 40-70. The big problem was inconsistent rim thickness, and I had to thin a number of rims to get them to chamber. They shoot paper patched bullets very well, and I load the paper patched 385 grain bullet over 69.5 grains of the old Goex 2f express. The Hornady brass is too thick to chamber with a .408 diameter greaser, but works well with paper patch. The Jamison cases for the 40-70 work like a champ. Shoot straight, rdnck.

Re: brass and BP amount

Posted: Tue Feb 05, 2019 8:58 am
by kenny s
interesting discussion.
I weighted the charge, and 67 1 1/2 OE is right to the top of the case. I do not want to bulge the case on compression, so I dropped the charge to 60 weighed.
You are probably right about the 30 40 case being thin, and this may cause the occasional separation I get.
I've loaded the JBA and will see . they fit the PP bullet easily and chamber nicely. don't see any problem there.
more to come..

tks all...Ken

Re: brass and BP amount

Posted: Tue Feb 05, 2019 8:58 am
by kenny s
interesting discussion.
I weighted the charge, and 67 1 1/2 OE is right to the top of the case. I do not want to bulge the case on compression, so I dropped the charge to 60 weighed.
You are probably right about the 30 40 case being thin, and this may cause the occasional separation I get.
I've loaded the JBA and will see . they fit the PP bullet easily and chamber nicely. don't see any problem there.
more to come..

tks all...Ken

Re: brass and BP amount

Posted: Tue Feb 05, 2019 8:03 pm
by SchuetzenDave
I shoot a .40-60 Maynard (just a shorter .40-70 SS) using .30-40 Krag cases.

To obtain my velocities I use Swiss FFFg very successfully without any fouling problems.

It will increase your velocities without having to compress your powder so much.

Re: brass and BP amount

Posted: Wed Feb 06, 2019 8:01 am
by Pilgrim
Ken, Have the JBA cases been fire formed?

Re: brass and BP amount

Posted: Wed Feb 06, 2019 8:48 am
by TAA
For just over 8 years I've been shooting .40-70 2 1/2 in my 74. After load testing it seems to favor either Old E or Swiss, 1 1/2.0, 68-grains. The only cases I've used are Hornady 405 WW. This same lot of 150 cases have been shot many times. I chose the 405 cases because out of the box they are too long and they can be trimmed to optimum length for the gun's chamber. I have no experience with modified .34-40 cases. So far no "too thick" rim challenges.

When the powder is drop tubed into the case, it is about 1/8" below the the top of the case. Then of course compression, etc. With a PJ Money bullet the MV is about 1,320 fps.

Tom

Re: brass and BP amount

Posted: Wed Feb 06, 2019 9:45 am
by Don McDowell
Take good care of those 405 cases, they don't make them anymore.

Re: brass and BP amount

Posted: Wed Feb 06, 2019 2:28 pm
by TAA
Don,

I have (4) unopened boxes of them, (200) in "reserve".

Tom

Re: brass and BP amount

Posted: Thu Feb 07, 2019 8:38 am
by kenny s
yup. all cases were fire formed and a 24 inch drop tube is used.
67 fills the case to the top and I use two wads, so I don't want to compress too much.

thick brass in my batch???
Ken

Re: brass and BP amount

Posted: Mon Feb 11, 2019 6:34 pm
by JWL
Who would think a slight difference in brass thickness would make that much of a difference but I can relate. My 40-60 Marlin with BA Win. cases formed from 45-70 parent cases hold 63 grains with the 245gr. Lyman bullet seated with very little compression. Same bullet in my new BA Starline brass cases only hold 57 grains to equal the same column height.

Re: brass and BP amount

Posted: Tue Feb 12, 2019 8:54 am
by AzTBH
Maximum Powder Capacities of Jamison 40-70 SS Cases and Hornady 405 Winchester Cases (Shortened & Neck Turned)
  • Jamison 40-70 SS
    74.6 grains OE 1-1/2f
    77.7 grains Swiss 1-1/2f
    82.2 grains Swiss 3f
  • Hornady 405 Winchester
    78.1 grains OE 1-1/2f
    81.9 grains Swiss 1-1/2f
    86.5 grains Swiss 3f
  • Powder Lot Numbers:
    OE 1-1/2f: E1-03/13A1106B
    Swiss 1-1/2f: 010.311
    Swiss 3f: 121.009
  • Brass Lot Numbers
    Jamison: #300-AR-112-A
    Hornady: #8691
  • Notes
    24-inch Drop Tube
    Slow-poured the powder until case was overfilled.
    The excess powder was scraped off so the remainder was level with the mouth of the case.

Re: brass and BP amount

Posted: Thu Feb 14, 2019 9:01 am
by TAA
Maybe my extensive smokeless powder experience set me off on the wrong foot when I statred this BP endeavor.

I messed around with varying charge weights of Swiss 1 1/2, from 65 to 71 grains and found that 68 made the best groups at 200-meters with my 74 chambered in .40-70 2 1/2. I never tried the "pour it in the case until it overflows" approach. The bullet is PJ Money 416-grains. When I drop tube (BACO) the 68 grains, it is about 1/8" down from the top of the case. I use 2 poly and 1 veggie wad.

Maybe WHEN this snow and cold move on, I'll have to try the overflow method and see what the powder weighs (just fir the fun of it). The cases are Hornady 405 Winch.

Tom