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1800 fps from a 357 Mag.

Posted: Sat Mar 21, 2026 5:54 am
by GrapeApe
Finally got to the range to
1) try out my new 10" Octagon 357 mag Contender barrel.
2) Dial in the new scope on my tuned 6" 686 and the scope I swapped over to the Contender.
3) Get some chrono data on my max loaded 160gr LBT/Li'l Gun handloads.

Used some factory Fiocchi 142gr FMJTC factory ammo for initial sight in. I didn't even put a target up, I just pick rocks and dirt clumps on the 50 yard berm and dialed in until I was busting them. Had 192fps difference between the 686 and Contender. +4" barrel length and no barrel cylinder gap, I can see that. 1310fps for the 6" 686 and 1502fps from the 10" contender

Switched over to my handloads, New Starline cases, CCI SP-M primers, Book max load of Hodgdon Li'l Gun and topped with a 162gr LBT FN cast from my "hard" alloy, sized .359" GC'd and lubed with LBT Blue soft. I loaded this ammo 4 or 5 years ago, charges weighed/dispensed from my RCBS Chargemaster. Ammo was picked from a 50rnd box at random.
From the 686, that's around what I was expecting.

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First couple of rounds from the Contender, the X1 didn't pick up. I had it set for handgun 600-1700fps. After breaking out "The sailor's book of magic word and phrases" (Dad was in the navy, I never served) I decided to set it to the 1700-5000fps range just to see what it would do.

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HOLY SPEED DEMON BATMAN!!

Second round was the fastest at 1835fps, and 7th was the slowest at 1683fps

I was expecting a 200-300fps difference. Ain't NO WAY someone could have convinced me I'd get the 502fps difference I actually got. I also would have NEVER expected to break 1800fps with a 162gr boolit, even with the long nose I specified when I ordered the mould.

I haven't cleaned them yet.
An idiot truck driver decided to back into a "No trucks" parking lot and hit the power lines and pulled a pole down, literally as I got home from the range. Power hasn't been back on very long
Looking down the barrel, before I left the range, I'm going to be mining lead tomorrow. At those speeds, I'd expect nothing less

Glad I decided to just take the previously loaded "hard" bullets. I'd hate to even imagine how the 20:1 HPs I've been casting would have left the bore at that speed

Re: 1800 fps from a 357 Mag.

Posted: Sat Mar 21, 2026 2:31 pm
by CPJ 2.0
Get thee to a harbor freight, spend a 10 spot on some powder coat. Youtoobs the process. Bet you can still run them at 1600 with them coated.

Re: 1800 fps from a 357 Mag.

Posted: Sat Mar 21, 2026 2:37 pm
by GrapeApe
CPJ 2.0 wrote: Sat Mar 21, 2026 2:31 pm Get thee to a harbor freight, spend a 10 spot on some powder coat. Youtoobs the process. Bet you can still run them at 1600 with them coated.
No thanks.

Re: 1800 fps from a 357 Mag.

Posted: Sat Mar 21, 2026 3:10 pm
by Bigslug
These things represent a learning experience, if nothing else.

The wonderful versatility of the .38/.357 can also make it a real pain in the ass. At the bottom end, you've got soft wadcutter match loads for which you could probably make your bullets out of used Bazooka bubble gum and have an alloy that's tough enough, whereas the full tilt boogie .357's need to be treated like rifles. And then you've sometimes got the possible problem of "This performs in a 4"-6" duty gun, but doesn't in a 2" snubby" to figure out.

It all comes down to what you want to accomplish with your ammo. One of my recent bouts of Weird Science got me decent recoil comfort with 170 grains /1000 fps out of a 4" revolver, and 1200 fps with a trajectory I didn't need to use a whole lot of holdover shenanigans for 100 yard plinking out of a carbine. That's at or a little off the chart of what we've considered "duty spec" ammo over the last few decades, and would certainly be "deer worthy". If you're playing the match silhouette game, that of course is something else.

Take your time and observe when you clean the guns. There's streaking, and then there's the fouling your really have to fight. Also note WHERE your fouling is - especially on the wheelgun, as that'll tell you if it's the gun or the ammo that needs a little help.

Re: 1800 fps from a 357 Mag.

Posted: Sat Mar 21, 2026 6:50 pm
by Chiro1989
Dang, that round is moving, how was the accuracy, recoil, and muzzle blast?

Re: 1800 fps from a 357 Mag.

Posted: Sat Mar 21, 2026 7:40 pm
by GrapeApe
Accuracy seemed good. I was busting rocks on the ber
Recoil wasn't bad.
Blast? I had good ear pro on, didn't really notice it

Re: 1800 fps from a 357 Mag.

Posted: Sun Mar 22, 2026 1:39 am
by JunkCollector
GrapeApe wrote: Sat Mar 21, 2026 7:40 pm Accuracy seemed good. I was busting rocks on the ber
Recoil wasn't bad.
Blast? I had good ear pro on, didn't really notice it
I'd be cringing seeing that velocity reading...lol

Re: 1800 fps from a 357 Mag.

Posted: Sun Mar 22, 2026 2:02 am
by GrapeApe
It got my attention, for sure

Re: 1800 fps from a 357 Mag.

Posted: Sun Mar 22, 2026 5:15 am
by Chiro1989
GrapeApe wrote: Sat Mar 21, 2026 7:40 pm Accuracy seemed good. I was busting rocks on the ber
Recoil wasn't bad.
Blast? I had good ear pro on, didn't really notice it
In that case, THAT is pretty cool.

Re: 1800 fps from a 357 Mag.

Posted: Sun Mar 22, 2026 6:09 am
by Justsomedude
Those were hauling some serious àss. Any pressure signs, flat primers, hard ejection?

Re: 1800 fps from a 357 Mag.

Posted: Sun Mar 22, 2026 1:29 pm
by JunkCollector
I was curious if the case stretched in length much ?

Re: 1800 fps from a 357 Mag.

Posted: Sun Mar 22, 2026 1:42 pm
by GrapeApe
no and no