Found some interesting things today while loading for the 357mag Handi

[glockky]

I have been debating reaming my 357mag handi rifle to max ever since I bought it. Today after reading Mike Bellms article http://www.bellmtcs.com/store/index.php?cid=658& on loading 357 mag cases with 357 maximum charges I decided to get the chronograph out and do some testing. This is accomplished my seating the bullet out in my case the bullet is only in the case about 1/8" and just starting to touch the rifling.

I am shooting the NOE 360 180gr WFN GC http://noebulletmolds.com/NV/product_info.php?cPath=35&products_id=411&osCsid=dshnbsjvp69lo3lotkb3b8n2j5 cast of 50/50 COWW/PB. Today I came up with some numbers that suprised me with no signs of excessive pressure. Heres the numbers I will leave out the exact powder charges due to liability reasons, but they are below max. charges in my manuals. Remember I was using 357 Max pistol load data. These were five shot strings.

powder 296 Win
COAL 1.840"
Average Velocity- 1809 FPS
ES- 61
SD- 31

powder 2400
COAL 1.840"
Average Velocity- 1840 FPS
ES- 18
SD- 9

Alliant power pro 300MP also showed some promising results. Since I was unable to find 357 Maximum load data I just went with published load data for 170Gr bullets and backed it off and worked back up. I seated these in the cannelure.

300MP
Seated in cannelure
Average velocity- 1751 FPS
ES- 26
SD- 14

I tried loading the bullets long and going up with the powder charge of 300MP and the velocity dropped to 1571fps and extreme spreads were up in the 200's lol I plan on contacting alliant to see if they have any 357 maximum data and hope to get a place to start.
I just was unaware of the capabilities of the 357 magnum until I really started digging and reading articles today. Hopefully here in the next week I will make it to the range with an accuracy report.

[C. Latch]

Isn't 300mp the SAME powder as W296/H110?

[glockky]

No is slower burning. I can not believe it does not have more of a following that it does. It works great for heavy bullets in the 357 mag, 41 mag, 44 mag and 454 casull. I truthfully couldnt believe the numbers when I first read about it in handloader magazine. I have shot it side by side with 296 several times and it usually gives me 150-250 FPS gain, with low extreme spreads.

[C. Latch]

That's interesting.

FWIW I'd say that when you loaded long with the 300-mp, if it's anything like H110, you dropped below the reliable ignition threshold.

[glockky]

Kinda what I figured I just hate to take off 4 or 5 grains over published 357 data without seeing some Max data.

[454PB]

If you can find it, try some Hodgdon Lil'Gun. It will yield some high velocities and minimal ES.

[rhead]

The Hodgdon Annual manual publishes 357 max data. It should be on their web site also.

I use 360 Dan Wesson brass and load it to 357 max length. It lets me get more of the boolit in the case without the expense of the reamer. The last time i looked Starline was taking orders and would make a run of the brass when enough orders were on hand. My rifle likes around a 90% max load using 2400. I wafer floated the barrel with a rubber washer on the post and back off a half turn on the forehand screw.

[glockky]

I am gonna see how mine does at the range. I have been in contact with Mike Bellm about reaming mine to 357 max and doing the 2 stage throat for cast bullets, along with chopping it to 16" and precision 11 deg crown.

[glockky]

If you can find it, try some Hodgdon Lil'Gun. It will yield some high velocities and minimal ES.

I havent tried lil gun yet. I have read mixed reviews on it. I hear it gives great velocity with low ES spreads but burns very hot and causes forcing cone and throat erosion. Once again this is all just read and I have no facts to back it up.

[jmort]

As noted 300 MP is slower and will out-perform 110/296.

[357maximum]

I have a custum TIGHT throated MGM 357MAX Encore barrel and with that boolit 22-23 grains of MP-300 is about MAX for MY BARREL.......that is a statement not a recommendation......fly with no parachute at your own risk....the bullets were seated in MAX brass at the designed point to do so.

Lilgun is amazingly fast but is very tempermentally "spikey" when you near is upper pressures, and it will erode a leade if enough upper end loads are shot....I can prove it in one of my own toys.

[glockky]

I have a custum TIGHT throated MGM 357MAX Encore barrel and with that boolit 22-23 grains of MP-300 is about MAX for MY BARREL.......that is a statement not a recommendation......fly with no parachute at your own risk....the bullets were seated in MAX brass at the designed point to do so.


Lilgun is amazingly fast but is very tempermentally "spikey" when you near is upper pressures, and it will erode a leade if enough upper end loads are shot....I can prove it in one of my own toys.


What kind of velocity were you getting with the 22-23gr 300MP? By max for your barrel do you mean the bullet could not be seated any deeper due to load density or were you seeing pressure signs? Its hard to find a lot of good info on the 357max loading in a rifle it seems you kind of have to figure things out for yourself.
What worries me is I think you will be way over pressure before you see any signs.

[357maximum]

My barrel is 15 inches long and it will run 2150 or so with 22.5 grains...when I said max I meant pressure wise....it is a safe yet very near top end load in MY MGM made barrel...24 grains is "too much" and the primer pockets loosen.

Babore has the same barrel 20 inches long and runs the same basic speeds with the same loads...the MAX does not want or need more than 16 inches of barrel with a 180 grain boolit, simply not enough boiler room in the case to make the extra barrel length of any use for the powders at hand ballistically wise.

I have used alot of Vhit N-120 which in the max is very similar to 300MP....I used that experience as a stepping stone for MP300...in the fly by the seat of your pants method. I can destroy a case in my Encore before I hurt the gun itself....not so with what you are playing with....as I said...you need to do this for yourself and watch everything brass/primer/chronograph wise. With my tighter throated barrel some published TC data is slightly too warm....that is why we drop back from max when working a load.

[glockky]

Well as much as I like to push things I have decided to stay with just the 357 maximum published data and not venture into the T/C data. I cannot make up my mind on whether to send my barrel to Mike Bellm or just break down and build another encore. Just hate to spend $1000 thanks for the info

[uscra112]

If you can find it, try some Hodgdon Lil'Gun. It will yield some high velocities and minimal ES.

Second that. Lil'Gun is what I finally settled on for my Contender Max.

[uscra112]

Well as much as I like to push things I have decided to stay with just the 357 maximum published data and not venture into the T/C data. I cannot make up my mind on whether to send my barrel to Mike Bellm or just break down and build another encore. Just hate to spend $1000 thanks for the info

For the price you pay to Bellm, you can almost BUY the reamer from Dave Manson and do it yourself. I did, and now that I own the reamer I can do it again for free. My cylindrical throat is not as long as Bellm's, but I see no difference since I do not try to load to the point where primer pockets open. Watch out for the pilot diameter - Dave and I caught that the SAAMI pilot for .357 Max is only .346, where the barrel lands you will be reaming are usually .350. Use an undersize pilot and you are guaranteed an off center chamber.