140gr. Hornady HP/XTP 357Mag

[Dakota Bones]

Hi you all. I have not loaded a lot of pistol loads. I load more for 308 Win.
I want to load some 140 gr HP/XTP with Unique Powder, I tried the Accuracy load out of Sierra 5th Ed. with Blue Dot of 12.4 and the primer flowed around
the fire pin and stop the cylinder from turning on my 6" 686. So I gave the Blue Dot to a friend for his 10mm. Sierra list 8.3 to 9.0 for 140JHC with Unique.. Forgot it is a 357 MAG and I have CCI 550, 500 & WSPM primers. Alliant Powders list a load of 8.0 gr of Unique as Max and Sierra lists 8.3 as start. Has anyone used this combo.

Thanks

 

[OldmanFCSA]

Keep everything the same - but switch to a near-max loading of Win 296.
Its a perfect loading for 140XTP's in a 357 magnum in a strong revolver - mine is 2 Ruger GP-100's.
Years ago - one of the magazines, (shooting Times) listed it as most accurate loading ever tested - I agree.

(do not quote me but I think I used 15.6 grains of 296)

 

[Dakota Bones]

Thanks for the come back I thought I did something wrong because no said anything back. I don't have 296 but thanks anyway.

 

[wanderinwalker]

I agree with the others. That Blue Dot load sounds like you were looking for Magnum performance from your .357. Unique works well, but it's a little fast burning for optimum Magnum loads.

To me, THE load with the 140gr XTP is a max dose of Winchester 296 with a small pistol MAGNUM primer (CCI-550s for me). It shoots very, very accurately and is relatively milder recoiling than the typical 158gr loads. My S&W 19 shoots these like it was built for them.

Hodgdon's data shows 19.0gr of 296 as a max dose for this bullet.

 

[JimKirk]

Were there any charges for the same bullet and Bluedot listed that where lower charges than what you tried?

Your combo was too hot ... but that does not mean that Bluedot can't be used for the 357 mag... you've just got to find the right load. Bluedot is a workable powder for the 357 Magnum.

Jimmy K

 

[gamestalker]

O with LDman FCSA is on the nose with it. I load exclusively with 296 and H110 and those powders will agressively meet your needs. Although the pressures are in the upper working range, those powders are elemental in maintaining well managed and predictable pressures and velocities. I shoot these full house loads though my S&W 66-5 and my Taurus 608 regularly, and haven't had any adverse effects what so ever. I also like the fact that they burn extremely clean, and produce an impressive muzzle flash in both .357 mags and 44 mags. Out of my T608 velocities with a 125 gr. XTP 21.4 grs. of 296 or H110 delivers around 1650 fps. And the 110 gr. XTP with 22.8 grs. of 296 will push over 1700 fps.
Even though these powder charges are compressed and look scarry, don't reduce charges below listed minimums or pressures can spike unpredictably high. It's almost an instinctive response for someone not familar with these powders to feel the need to drastically reduce the charge when they see the powder near the top of the case. Don't worry, those two powders are made to operate safely with these high capacity powder charges which must be used with a magnum primer to assure a reliable burn rate that could other wise act like a reduced charge as a result.
Well, sorry for the long winded response, but I really like to offer my two cents when discussingthis specific subject.

 

[buck460XVR]

While Unique makes for a great powder for mild to moderate velocities in the .357, it is not the powder one wants for maximum performance. H110/296, IMR4227 and 2400 are the best choices for full blown magnum loads in revolvers. Primer flow is a sign of excessive pressure OR a firing pin hole/bushing that is too large. If I remember correctly, some of the early no-dash 686s had an issue with this. If you have an early 686, you may want to contact S&W about this.

 

[Dakota Bones]

Wow, thank you all for the feed back, As far as the blue dot I went to MBC 158 lswc and drop the load to 9.5 gr., avg.velocity of 1265, but 200fps it would very. Then I read about the pressure spikes in cold temperature, so I got some Unique. I will use it for targets and I guess I will have to try some Win 296 for the hot loads . And I checked my 686-1 and it has the M so it has been modified, once again thanks for all your expertise, and advice.