140gr Cowboy .357 load advice

Barnacle Brad · February 10, 2013, 07:47 PM

I have IMR sr4756 I want to use, but the load data does not list this powder (Hornady). I assume this is due to excess velocity for the lead bullet. Am I better off sticking to the listed powders?

Is there a risk in reducing the starting load given for the same weight of a jacketed bullet?

Thanks!

Barnacle Brad · February 11, 2013, 11:12 AM

Any opinion welcome!

Thanks

Hammerhead · February 11, 2013, 02:06 PM

The Hornady 140 LFP's are generally best shot using small charges of fast powder. SR 4756 is pretty slow for a light lead bullets, probably why there's no data. There is some data for a 125 grain lead bullet using 4756 at the Hodgdon site.
Trail Boss is my favorite powder for the Hornady 140's in the .357 mag. Clays works well too. Unique or Universal would probably work OK if you don't have a faster powder.

Barnacle Brad · February 11, 2013, 03:42 PM

Thanks for the info. The recipe I have that came with the bullets (from a friend) is for 3 gr Trail Boss. I just don't have it (or another fast burner) on my shelf.

Not in a position to run out and buy any right now either.

After looking more closely on the Hodgdon Site. I see data for 130gr MEI CAST LRNFP at 5.5 gr (sr4756) and 148gr HDY LHBWC at 3.8 gr. I wonder if this lack of data for the 140gr may be a marketing strategy to promote the Trail Boss powder? Curious...

Think what I will try is an average of those two loads and back it off 10%. That would give me a starting load of 4.2gr. That puts me .3gr under the max load for the 148gr bullet.

Does that sound like a rational approach?

Thanks again!

L_Killkenny · February 11, 2013, 05:12 PM

I have no idea where Hodgdons came up with their min and max for .357 trailboss loads. I use "their" formula and came up with completely different loads then theirs. Hotter for the record. Using 158gr Berry's plated bullets I came up with 3.5-5.0. Hogdons listed 3.2-4.2. I tested various loads using these bullets from 3.2 up to 4.7 without issue. Note: Bullet seating depth is the issue. Don't compress Trailboss and don't go below 70% and you'll be fine.

Hammerhead · February 12, 2013, 02:53 AM

Don't go by the 148 grain load, that's a wadcutter seated deep, so that info can't be used for a standard bullet.

The 130 cast starts at 5.5 4756
The 140 jacketed starts at 5.3 4756

I would start at 5 grains of 4756 and work up toward 6 - 6.5 grains.

They do seem to push Trail Boss some, but it's a darn fine powder for light bullets in long cases.

Barnacle Brad · February 12, 2013, 03:41 PM

Sounds good Hammerhead. Will use c.o.l. as stated in the Hornady book for the 140 cowboy.

Must have some trail boss in the future.

Thanks for your help!

Barnacle Brad · February 16, 2013, 05:15 PM

Load Data:
.357 mag Smith & Wesson Model 586 4 inch barrel
Hornady .38 caliber 140gr FP-Cowboy
IMR sr 4756 5.5gr
CCI 550 primer
C.O.L. 1.550"
Medium Crimp

Notes:
Started with 5.0gr 4756. Test fired 5 rounds.
Separate operations for bullet seat and crimp.
Muzzle velocity unknown.
Light recoil.
Very accurate off rest at 15 yards.

joneb · February 16, 2013, 11:05 PM

I ordered some 140gr RNFPBB premium grade from Penn bullets, they are slammed so I maybe waiting for awhile

Penn states these can be pushed to 1600 fps, I'm planning on trying Accurate #7 and 2400 for a 2.75" Ruger Sec. Six if I can get around 1,200 fps I'd be happy.

February 10, 2013, 07:47 PM	#1
Barnacle Brad Senior Member Join Date: March 12, 2009 Location: Greybull, Wyoming Posts: 416	140gr Cowboy .357 load advice I have IMR sr4756 I want to use, but the load data does not list this powder (Hornady). I assume this is due to excess velocity for the lead bullet. Am I better off sticking to the listed powders? Is there a risk in reducing the starting load given for the same weight of a jacketed bullet? Thanks! __________________ Brad

February 11, 2013, 11:12 AM	#2
Barnacle Brad Senior Member Join Date: March 12, 2009 Location: Greybull, Wyoming Posts: 416	please opine Any opinion welcome! Thanks __________________ Brad

February 11, 2013, 03:42 PM	#4
Barnacle Brad Senior Member Join Date: March 12, 2009 Location: Greybull, Wyoming Posts: 416	Burn Rate Thanks for the info. The recipe I have that came with the bullets (from a friend) is for 3 gr Trail Boss. I just don't have it (or another fast burner) on my shelf. Not in a position to run out and buy any right now either. After looking more closely on the Hodgdon Site. I see data for 130gr MEI CAST LRNFP at 5.5 gr (sr4756) and 148gr HDY LHBWC at 3.8 gr. I wonder if this lack of data for the 140gr may be a marketing strategy to promote the Trail Boss powder? Curious... Think what I will try is an average of those two loads and back it off 10%. That would give me a starting load of 4.2gr. That puts me .3gr under the max load for the 148gr bullet. Does that sound like a rational approach? Thanks again! __________________ Brad

February 16, 2013, 05:15 PM	#8
Barnacle Brad Senior Member Join Date: March 12, 2009 Location: Greybull, Wyoming Posts: 416	Load Data: .357 mag Smith & Wesson Model 586 4 inch barrel Hornady .38 caliber 140gr FP-Cowboy IMR sr 4756 5.5gr CCI 550 primer C.O.L. 1.550" Medium Crimp Notes: Started with 5.0gr 4756. Test fired 5 rounds. Separate operations for bullet seat and crimp. Muzzle velocity unknown. Light recoil. Very accurate off rest at 15 yards. __________________ Brad

February 11, 2013, 02:06 PM	#3
Hammerhead Senior Member Join Date: May 31, 2004 Location: Minnesota Posts: 2,432	The Hornady 140 LFP's are generally best shot using small charges of fast powder. SR 4756 is pretty slow for a light lead bullets, probably why there's no data. There is some data for a 125 grain lead bullet using 4756 at the Hodgdon site. Trail Boss is my favorite powder for the Hornady 140's in the .357 mag. Clays works well too. Unique or Universal would probably work OK if you don't have a faster powder.

February 11, 2013, 05:12 PM	#5
L_Killkenny Senior Member Join Date: February 2, 2007 Location: Iowa Posts: 2,676	I have no idea where Hodgdons came up with their min and max for .357 trailboss loads. I use "their" formula and came up with completely different loads then theirs. Hotter for the record. Using 158gr Berry's plated bullets I came up with 3.5-5.0. Hogdons listed 3.2-4.2. I tested various loads using these bullets from 3.2 up to 4.7 without issue. Note: Bullet seating depth is the issue. Don't compress Trailboss and don't go below 70% and you'll be fine.

February 12, 2013, 02:53 AM	#6
Hammerhead Senior Member Join Date: May 31, 2004 Location: Minnesota Posts: 2,432	Don't go by the 148 grain load, that's a wadcutter seated deep, so that info can't be used for a standard bullet. The 130 cast starts at 5.5 4756 The 140 jacketed starts at 5.3 4756 I would start at 5 grains of 4756 and work up toward 6 - 6.5 grains. They do seem to push Trail Boss some, but it's a darn fine powder for light bullets in long cases.

February 12, 2013, 03:41 PM	#7
Barnacle Brad Senior Member Join Date: March 12, 2009 Location: Greybull, Wyoming Posts: 416	Sounds good Hammerhead. Will use c.o.l. as stated in the Hornady book for the 140 cowboy. Must have some trail boss in the future. Thanks for your help! __________________ Brad

February 16, 2013, 11:05 PM	#9
joneb Senior Member Join Date: December 10, 2005 Location: Central , OR Posts: 1,888	I ordered some 140gr RNFPBB premium grade from Penn bullets, they are slammed so I maybe waiting for awhile Penn states these can be pushed to 1600 fps, I'm planning on trying Accurate #7 and 2400 for a 2.75" Ruger Sec. Six if I can get around 1,200 fps I'd be happy.