.357 mag '92 Rossi, velocity data

[Black Jaque Janaviac]

I shot a few different loads over the chronograph today.

19.8gr 300-MP, WSPM primer, Lee 358-125-rf coated with VHT epoxy
Avg. 2146fps
Ex. spread 109fps
Shots fired 15
No leading, outside of cases were sooty

20.3gr 300-MP, WSPM primer, Lee 358-125-rf coated with VHT epoxy
Avg 2178
Ex. spread 31
Shots fired 5
No leading, outside of cases were sooty

21.0gr. 300-MP, WSPM primer, Lee 358-125-rf Harbor Freight red
Avg 2264
Ex. spread 39
Shots fired 8
Bad leading in bore,

I will have to investigate that 20.3 grain load a little more. I don't know if the extreme spread is just so tight because I only fired 5 shots over the chrono, well, that the chrono picked up. If I throw out the high and low velocities of the 19.8 grain load I get an extreme spread of 47fps.

[Michael J. Spangler]

Thank you
Good info. I would love to see some 158 grain data

[Black Jaque Janaviac]

I have the Lee 358-158-rf mold and I do intend to see how it does. I am new to this powder coating epoxy coating thing. I am impressed. The lead alloy is just wheelweights. When I baked them, I turned the oven off and let them cool with the door closed so they should be as soft as wheel weights will get.

[Outer Rondacker]

I thank you for posting your results and look forward to more. I too have a rossi in 357. I have had good luck with everything I have put down the tube. I will say that with everything going on in my life at the moment I am not a the point I once was with reloading and shooting. In the coming years I plan on getting back to the details and the bench more. This is the kinda info I will be looking more into then just down a barrel to clean it and if I hit a steel plate. Thanks again for posting and keep it coming.

[Texas by God]

Please include accuracy data next time as well. I've had two .357s and one 44-40 Rossi and they were pleasingly accurate.

[Black Jaque Janaviac]

Texas,

Unfortunately my range set-up is not perfect for chronograph work. If I shoot from a bench at paper, the chronograph is underneath tree branches which screws things up. So to chronograph, I have to move out in the open so the best target I get is one of those self-sealing contraptions suspended from a chain. That was about 50 yards away and took me a few shots to figure out the sight picture, then I was making that thing dance with regularity using the 19.8gr. charge. With the 20.3gr. charge it seemed like a just got it figured out when I ran out of ammo, but it did dance a couple times. The 21.0gr. charge never hit the target. The target is orange and about 4-5" wide. I was in the kneeling position.

I think it helps to do the chronograph work first. Especially with cast boolits since I could probably use better Q/A-Q/C in my casting. The chronograph tells me if the powder is operating efficiently. The paper just tells me something is going wrong (or right perhaps), but not whether those fliers were bad boolits, bad lubes, or powder charge not running right. For example, my first run with Alliant's 300-MP was using a Rem standard pistol primer. The velocities were all over the place - like a 200+fps spread. So 300-MP does much better with mag primers.

The max charge for the 300-MP and a 125 grain bullet is 22.3 grains. I get bad leading at 21.0 grains. No need to climb the ladder any further (not to mention 2100+ fps is dang good for a plain base cast).
I'll be back with some accuracy data.

[Black Jaque Janaviac]

OK. I'm back with some velocity data using the Lee 358-158-RF bullet this time, so a bit heavier bullet. I probably won't be using this bullet much since it jams in my Rossi 92 rifle. Something about the wide meplat and bullet contacting the top of the chamber before the case rim reaches the opening in the rails.

Lee 358-158-RF coated with VHT epoxy; 17.5 grains of Alliant 300MP; WSPM primer, crimped at groove.

Avg velocity 1917 fps.
Extreme spread 114 fps.
No leading. Primers were well rounded no signs of excess pressure.

These are made with just air-cooled wheelweights, no gas check. Coated, baked, and slowly cooled (turn off oven and let cool in oven).

[Michael J. Spangler]

OK. I'm back with some velocity data using the Lee 358-158-RF bullet this time, so a bit heavier bullet. I probably won't be using this bullet much since it jams in my Rossi 92 rifle. Something about the wide meplat and bullet contacting the top of the chamber before the case rim reaches the opening in the rails.

Lee 358-158-RF coated with VHT epoxy; 17.5 grains of Alliant 300MP; WSPM primer, crimped at groove.

Avg velocity 1917 fps.
Extreme spread 114 fps.
No leading. Primers were well rounded no signs of excess pressure.

These are made with just air-cooled wheelweights, no gas check. Coated, baked, and slowly cooled (turn off oven and let cool in oven).

Seems like a high ES.
Is this normal with this powder?
What primer was being used? Was it a heavy crimp?

I’ve always wanted to try this powder for high velocity but the ES turns me off.
How was the accuracy? Thanks!

[Black Jaque Janaviac]

Mike, I would not judge the ES on my last post. If you look at the first post, I saw an ES of 109 for the lowest charge tested. The next two charges improved the ES which is what I would expect with smokeless powders especially slow-burners like 300MP. So an ES of 30 or 40 seems more like it.

This last test was done on a different day with different weather. It was heavily overcast and only a couple hours before dark. So the light was poor and though I chronographed 5 shots, there were several more that coded an error message on the chrony. Also the first two shots recorded were of fair tolerance, it was the last two that really threw the ES. The velocities in order were thus:
1948
1903
1978
1894
1864

Also the max charge for a 158 grain bullet according to Alliant is 18.3 grains. I'm only at 95% of max. I'm not exactly doing things scientifically either. You'll note that in my 125 grain test I used VHT expoxy for the lower charges and HF-Red for the top charge. And I got leading in the top charge. Is that because of the charge? OR was that a limitation of the HF-Red and perhaps the VHT epoxy would have performed better.

Stay tuned. I'll keep posting more. It's just that I'm suffering from too many things to try and not enough time to try them. Also have a 9mm and muzzleloaders that I like to shoot.

[Michael J. Spangler]

Thanks! Looking forward to the updates.

[Silvercreek Farmer]

Following

[AnthonyB]

I am also watching. I have a 16 inch Rossi 357 with a Leupold Red Dot sight. Working on loads for it and think the MP 159 grain may be a favorite. The rifle does not like the Lee 358-158 FN.
Tony

[Michael J. Spangler]

I’ll have to get some Labradar data next time I hit the range.
I did a few shots last time with the Uberti 1873 18” side by side with a 686 4”
358156 was 1225 or so out of the 4” and 1660 out of the 18”
That was with 2400 powder. Not sure on the charge but I believe it was 14 grains.

[WinchesterM1]

I have a Rossi 357 in a 20” barrel and it is a fun and accurate gun to shoot. The OP stated he was shooting the lee 358-125RF and that is 100% what my gun shoots I have even killed a deer with one over 3.5 grn of unique (on accident) she was about 10 feet below me in a tree stand about 5 feet away from the tree and I hit her right in the base of the skull.. these guns shoot great!


Junior(RIP)did a great write up on his Rossi and cast and heavy bullets

http://castbullet.com/shooting/shooting.htm

[Black Jaque Janaviac]

OK. The snow finally melted and I could set up a chrony again.

To fill in some gaps: I tested the Lee 358-158-RF with VHT epoxy only this time over a charge of 18.0 grains of Alliant 300MP. Then I went on to test the Lee TL358-158-SWC with HF-Red powder coat (I won't be using the RF because it doesn't feed in my Rossi).

158g RF - VHT
18.0g 300MP
9 shots chronied
1947 fps avg
58 ES

This is a big improvement over the data in post #7. Much better ES. But alas, it doesn't feed well in my Rossi.

158g SWC - HF red
17.5g 300MP
7 shots chronied
1908 fps avg
32 ES

158g SWC - HF red
18.0g 300MP
6 shots chronied
1951 fps avg
45 ES

No big problems with leading in either load. The Alliant website indicates a max charge of 18.6g 300MP under a 158g Speer GDHP. So I believe I'm fairly conservative in my loads. I'm dang happy with the results. I don't really see the need to run it to the max since I use Lee dippers and don't particularly care to weigh individual loads, I prefer to measure out 50 charges then spot-check a few random ones.

I think I will test the accuracy of the 20.3g powder/125g bullet load and the 18.0g powder/158g SWC load next.

[cwlongshot]

I started using MP300 last Spring when I got my hands on some. I have really been liking the results in the 300 BO and plan on trying some in the 357 mag.

I bought both these molds last fall to try them in my 357 SIG carbine. The 158g is proving problematic to feed. But the 125g is darn nice! The 158g is of coarse, not a issue for the Mag & Max and that's where I'll likely be utilizing it. Nice to see others using and having good results with it!

CW

[jmort]

It is slightly slower than 110/296.
I want to try it on 300 BO as well.

[Black Jaque Janaviac]

It is slightly slower than 110/296.
I want to try it on 300 BO as well.

By slightly slower do you mean the burn rate of the powder? Or the velocities that it yields?

[cwlongshot]

Burning rate

Velocity has been very on par with what these calibers can do.

I shoot it in my 300 Black outs as well I am liking it more and more.

[Black Jaque Janaviac]

OK. That makes sense because the velocities seem on par with H110/W296. I believe I'm fairly conservative in my charges too.