OAL for 180 SSP in 357 Max

[clearwater]

I have the data from Accurate (I believe it was posted here) using 1680 and the COL is way out there. 2.35" with the SSP 180 from Hornady.

This leaves much less than a caliber length in the brass.  But the pressure listed is low -24300 psi with
29 grains of A1680. The low pressure is appealing as I have an SB1 frame.

Does anyone have loading data with A1680, the ssp 180 and a shorter COL?

[petemi]

I wasn't able to get 1680 for quite a while.  I got it recently, but haven't tried it.  I've been using Lil' Gun with a COL of 2.240, with a light crimp at the cannelure.   Looking at the table below, I'm sitting here scratching my head.  How'd they loose over 12,000 psi. with 1.7 gr. more powder and the same weight bullet.    37,470 would seem to be more in line with everything else.

Pete


357 Maximum-T/C
Barrel:10" ■ Twist: 1-18.75" ■ Primer: Win WSP ■ Bullet Diameter .357"
These loads and round configurations cannot be used in standard handguns revolvers etc. It is intended
only for barrels that has been adapted to accept the much longer COL = Cartridge Overall Length
For longer barrel lengths add to the velocity(ca): 14":+9%/+150Fps 20": +18%.+300Fps
5744 180 HDY HP-XTP 20.0 1,517 22.2 1,704 39,775 2.025
5744 180 HDY SSPB 22.2 1,638 24.7 1,824 39,825 2.350
5744 200 HDY FTX 21.1 1,532 23.5 1,707 39,565 2.500
1680 180 HDY HP-XTP 25.5 1,724 28.3 1,884 39,500 2.025
1680 180 HDY SSPB 27.0 1,692 30.0 1,850 27,470 27,470 2.350
1680 200 HDY FTX 27.0 1,670 30.0 1,837 35,810 2.500
Italics = Compressed loads

[cwlongshot]

For me, with a sized and trimmed case @ 1.605''.
Then I seat a SSP to the cannalure and crimp. (After charging with 26g of AA1680 powder)

PLEASE DO NOT START AT 29GRAINS OF THIS POWDER!!!! You may get there, but start LOWER PLEASE!

In my one Maxi 26 is MAX, flat primers and sticky cases begin a just a bit more. I found no decrease in accuracy if my gun dropping from 26.5 and LIKE the added margin for error.

Please, Load safely,

 CW

[YRUpunting?]

I agree with CW, starting at 29.0 is not a good idea.  Mine shoots well at 27.2 and poorly at 28 and above.  My experience with the Handi so far has been I don't pay much attention to OAL and load them to make the jump as short as I can which will be different for each rifle.  I shot some yesterday with only .170" of the SSP seated and was happy with the results in a nasty gusty cross wind.

[clearwater]

The lower pressures are, I assume, because the bullet is seated way out past the cannelure on the ssp and give a lot more case capacity. Any data with the bullet seated to the cannelure?

[steve@357maximum.com]

Clearwater,

The load data you mentioned with Accurate powder was based off test rounds that Johan Loubser from Western Powder tested for me so I could post on my website.  Some of these loads were published in their recent manuals.  I agreed not to publish any loads that were greater than 120% load density.  I will tell you that 29.0 grains of Accurate 1680 with the Hornady 180 SSP with a C.O.L. of 2.225" resulted in 136.9% load density but still produced pressures under the SAAMI spec.  Having said that, I cannot recommend this load with the shorter C.O.L. due to the higher load density.  Johan mentioned that Accurate 1680 compresses well, but they don't have a lot of data and experience with extreme compression (greater than 120%)

Pressures with the .357 Maximum are affected quite a bit by C.O.L.  If at all possible, seat your bullets out more and get the benefit of lower chamber pressures and lower bullet jump to lands for improved accuracy.

Good Shooting,

Steve