How Fast

[Gohon]

Situation..... casting a 158 grain SWC/GC sized .358 for a Marlin 357 magnum rifle. Using Lil'Gun, 296, H110, and 2400 I've shot from 1500 to 1950 fps. No leading, no FTF, no prtoblems ejecting and no signs of high pressure.

Problem.....for the life of me I cannot get any kind of accuracy no matter what I've tried. We're talking 4-6 inches at 50 yards. Only thing I can lay my finger on is the gun simply doesn't like these cast SWC's. BTW....the jacketed stuff will shoot clover leafs at 50 yards. So I'm thinking about trying a 160 grain Flat nose. Problem is I can't find one that is gas checked, they're all PB.

Question....... what speeds does everyone think I should be able to reach using a 160 grain Flat Nose plain base cast after oven heat treating to a BHN of 15-17? Think it possible to hit the 1700-1800 fps with little to no leading? I've got a 45 Colt that I'm getting 1658 fps with that type of bullet with no leading but I'm not sure about the 357.

Thanks............

[cabezaverde]

Did you slug your barrel?

[Gohon]

No.........never had a reason to as the 180 grain WFNGC which mic at .3575 shoot just fine.

[35remington]

The very short throating in these rifles seems to make them cast bullet sensitive, and if it is possible to size them .360" (or if they even cast that large) it would still be my preference to try them at the larger diameter.

It may be that the different ogive shape of the LBT type WFN design may be more compatible with your short throating, and that the diameter still matters on the other bullet due to different rifling engagement.

It's an easy variable to run down if you can try the larger size. If still no soap, then at least you can concentrate on other things.

"Question....... what speeds does everyone think I should be able to reach using a 160 grain Flat Nose plain base cast after oven heat treating to a BHN of 15-17? Think it possible to hit the 1700-1800 fps with little to no leading?"

My opinion would be, "No." I'd guess accuracy would be completely gone as well.

[jdgabbard]

Gohon, where abouts in oklahoma do you live? I have a Ranch Dog TLC359-190-RF mold that was specifically designed for rifles just like yours. Its a 190g 72% meplat, tumble lube, design that shoots pretty darn good. I'd be happy to cast some up for you.

[gasboffer]

I had a Marlin .357 micro-groove bbl. I slugged it and there were three tight spots in the bbl. One at the front sight cut, one at the middle, one at the dovetail slot for the rear sight.
Only bullet that I could get decent groups were the Remington (I think they were called semi-jackets) with very thin jackets. You might try some softer cast bullets. Good Luck!
Clyde

[Gohon]

jdgabbard I'm about 10 miles west of Checotah. Butted right up against Lake Eufaula. I think I'm going to order the Lee 358-158-RF and see if it works. It's only twenty bucks and supposedly it drops .360-.361 and if it works I'll then know what style to put my money towards. If I can get this .357 to shoot cast as well as the 45 Colt does I'll be one happy camper.

[jdgabbard]

Ok, I'm in Tulsa. If you decide you want to try some of these, I'd be happy to cast some up for you.

[Bret4207]

No.........never had a reason to as the 180 grain WFNGC which mic at .3575 shoot just fine.

Different designs sometimes need different sizing. I'd try a larger boolit and I doubt you'll do 1800 fps with PB.

[Shiloh]

Post #2, #4, #9.

You need to slug the barrel. You need to know where to start. This sounds like a sizing issue and that is where i'd start.

Shiloh

[Leftoverdj]

It's the plain base. I've tried at least a dozen moulds in several Marlin/NEF barrels, and cannot get any of them to shoot worth a whoop past about 1200 fps. Go to a GC design and they shoot quite well to at least 2000 fps.

I suspect the tight spots you mention are part of the problem. At a guess, the bullets are being flame cut after they pass through the tight spots. GCed bullets are much less apt to be flame cut.

Marlin barrels are notorious for tight spots. They can be caused by the roll marking of the barrel and by the broaching of the dovetails, and are of little importance to shooters of jacketed bullets, which is probably why Marlin keeps doing it. They are of the utmost importance to cast bullet shooters, and the main reason that Marlins have such a bad reputation with cast bullets.

[Gohon]

Well I'm learning there is a never ending of the surprises one runs into when playing around with cast. Just out of the blue, I took down a box of Hornady swagged 158 grain HP's, sized at .358 that I bought a long time ago to load for a 38 special snubby. I knew these to be soft because I had tested them at 9.2 BHN in the past. So I loaded 6 rounds ahead of 24 grains of 2400 using 357 brass and CCI 550 primers. Didn't set up the Chrony but estimate they were traveling somewhere 1500 fps.

At 25 yards and a sandbag across the hood of my truck I fired all six rounds. Five of the six shots were grouped at about one inch. Only the first shot from the cold barrel was outside that group about a inch to the left. That was my first surprise.

Second surprise was when I dissembled the rifle for cleaning, there were no sign of leading. Absolutely nothing. I placed a white sheet of paper under the end of the barrel and ran a brush wrapped in Chore Boy down the barrel several times and got nothing but powder residue. Granted it was only six rounds but I really did expect to see some leading. I've always suspected a lot of people shoot cast much harder than needed and this is starting to solidify that thinking with me.

I'm going to take about 50 of these things and oven heat treat them using Rick Kelter's formula and see if the BHN can be moved to 18. Don't know if there is any arsenic in these or not but if there is then it should work. I gotta find another hobby......this one is consuming all my time.

[mpmarty]

Gohon, before you harden those boolits try inching up on the velocity and see if it doesn't shrink your groups. You've already been trying "hard" cast and not been happy so why go there again?

[Thumbcocker]

Fat boolits in Marlins.