Minimum speed for 358430 ??

[Jack Stanley]

I've got one of the group buy molds for the 358430 look alike bullet . While loading I was trying to keep velocity down . Firing the loads in a Marlin .357 carbine bullets were going sideways at thirty yards untill the powder charge of Unique got to about six point three .

Starting loads of 2400 went sideways as well untill the charge reached about ten point four grains . Firing the same loads from the revolver bullets didn't go sideways but accuracy didn't show up untill about the level of the charges listed above . I think I am correct in thinking the rifling in the carbine is to slow for this bullet . At least to keep is going slow . I haven't tried to hot rod it yet ... not sure that I want to .

At eleven grains of 2400 the smudging on the side of the cases stopped but accuracy started to open up too .

Jack

[Cherokee]

Sounds like you found a sweet spot - if it fits your needs, stay with it. Is this the 150 or 200 gr version ?

[Piedmont]

The rifling twist in a Marlin .357 is supposed to be 1-16", which is at least as fast as most revolvers (Colts are faster at 1-14"). You didn't mention sizing. Maybe they are not as well supported in the Marlin chamber and throat and that is why they are tipping. At heavier charges possibly they are beginning to obturate and so fit better and don't tip. Anyway, just an idea.

[ironhead7544]

Might be due to the Microgroove rifling, if the rifle has it. Might need higher pressure to take the grooves.

[Jack Stanley]

The bullet is the hundred ninety-five grain version . Though I don't recall the alloy as I remember it was about ten or eleven BHN and the sizing diameter was .359 and these two firearms have shown a liking to that size .

I have an LBT design that is ten grains lighter and has a flat nose that seems to shoot well no matter the velocity . I know folks have used the 358430 in the 38 S&W so I'm thinking slow isn't a "bad" thing for it . Maybe the alloy is a bit hard for use with a minimal powder charge and isn't bumping up . I do notice a big difference between the LBT and Lyman design , The Lyman has a longer nose . The LBT uses some of that nose as bearing surface so perhaps Piedmont has a bead on the problem .

To fix that though I think it will take a mold modification or seat it out longer that a length that will run through a lever action .

Jack

[MtGun44]

Two possibilities - either boolits are undersized and don't grab the rifling well until there is
enough pressure to bump them up to larger diam, OR they are going too slowly to spin up fast enough
to stabilize.

I'm betting you have undersized boolits.

Bill

[wv109323]

My experience with the 158 grain SWC was that I needed to get around 825 FPS to get any accuracy. I use 4.5 gns. of WW231. You may need more spin to stabilize the 195 gn. bullet. My use was in a S&W model 14.

[DrCaveman]

This doesnt apply directly to your rifle application, but offers a little bit of real world experience to the question at hand i think

http://castboolits.gunloads.com/showthread.php?186933-How-slow-have-you-shot-a-38-spl-200-gr

[Jack Stanley]

Thanks , that thread does help some . As for the handgun loads I was using probably some were not so bad , I'm sure me testing at thirty yards was a hindrance and my old eyes didn't help .

The carbine though , .359" bullets in other weights has always worked well . I think I'll check the BHN again and see if they are harder than I thought .

Jack