A question on starting loads

[jdrslyr75]

If you load cast bullets in a caliber like the 358 Winnie where load data for the same weight jacketed bullet produces the velocity you want in the cast bullet, can the same starting charge be used safely? (250 g jacketed at 2300 fps and 250 g cast at 2300 fps) I know cast pills require less pressure to achieve the same velocity as jacketed, so would the starting charge for the jacketed projectile propel the cast bullet faster than the alloy can stand? (Assuming the casting alloy is optimum for 2300 fps) This is strictly a theoretical question that assumes a proper fitting cast bullet.
Jeremy

[sthwestvictoria]

Yes - but.

As you surmise, velocity may be slightly higher for cast in the barrel due to lower friction forces against the rifling. This may mean that the cast projectile is travelling faster than ideal of accuracy - yes you can push cast fast but where is the accuracy? The accuracy is found by attention to things like fit, pressure curve from that powder/loading, twist rate and bullet length (see Larrys velocity threshold tables).

I don't load for 358 Win but do for 35 Whelen and I have used the jacketed data, as provided by ADI (nee Hodgdon) for the 250grain and 200grain jacketed data. I am comfortable reducing AR2206H (H4895) as per the Hodgdon 60% rule but not with reducing AR2208 (varget) so I tend to use AR2206h. Even the starting jacketed loads were reduced slightly as I find at my skill level, accuracy is found around 1700-2000fps.

[Harter66]

I can't vouch for the 358 , but a 32 Rem would run w/the jacketed loads on 3gr less w/IMR4350.

[youngda9]

You should be fine with the jacketed data. Like always work up loads for your rifle. Don't just go for the max in any rifle without working up your load slowly. Typically there is very little to be gained by hot-rodding loads or firing at the max levels, especially if we're just talking about cast boolits. Much higher pressures (shortening brass life, decreasing accuracy and causing other problems with cast) for little velocity gain which doesn't mean much.

[JonB_in_Glencoe]

I'd look a little more...for cast load data. see castpics.
Typically a faster burning powder will give better results with cast boolits, so the powders listed in J-word loads 'could' be on the slow side (burn rate).

[Blackwater]

Cast don't ALWAYS produce less pressure! It depends, but on just what, I'm not sure, but I noticed recently while perusing some data that SOMETIMES, the lead bullet produced MORE pressure with the same load. It's a good idea to keep that in mind. I've imagined that the lead bullet, generally being softer than a J-bullet, has the hot gasses pushing on the base, while the front of the bullet tries to sit still due to inertia, with the result that the middle is pushed out hard toward the sides (rifling & bore), but I haven't a clue whether that's what's going on or not. It was just an explanation I imagined so far. Anyone got info on this??

[jdrslyr75]

Thanks for all the replies gents! Most data I have found for cast bullets use light charges of very fast pistol or shotgun powders, which is fine, I would just prefer a case full of the PROPER powder for my loads. The full case loads are what I am having trouble finding, but I prefer them for accuracy, safety, and not worrying about powder orientation in the case or sudden pressure spikes. I have not loaded any cast yet, but I have my molds and have cast a lot of boolits for my 30-30 (another cartridge where jacketed data runs at safe cast load speeds), which is where I will start. Black water, I think you are referring to obturation, the plastic deformation of the cast slug as it forms to your chamber and barrel under pressure. As for the 358 win. I do not currently own one but the search is on. I may have to go with the Whelen simply because they are easier to find. In any case, my next rifle purchase will be a 35 caliber

[Harter66]

Blackwater,
there are many influences straight wall cases seem more likely to produce the equal pressures for cast and jacketed.

I think you will find slow powders w/heavy for cartridge boolits to give you the closest to full cases consistantly.
I can't get 308 or 06' cases full of even 4350 even w/200 gr boolits. It seems like 4895 comes close in the 358 w/like 250gr. It also seems like Goodsteel has a write up about his 358 here someplace. Lyman says IMR4198, N130,and RL7 w/204 gr for ''normal'' rifle powders.

[jdrslyr75]

Thanks Harter, I will search for goodsteels posts!

[Silvercreek Farmer]

Same weight cast boolits can produce higher pressures than jacketed at the same charge weight and COAL due to the lead displaced by the lube grooves resulting in a longer boolit (vs jacketed) which reduces case capacity when seated. Probably not a big deal in a larger bottle neck rifle cartridge using starting loads, but in a small case like a 9mm it could result in a meaningful pressure increase, that's why we work up loads.

[youngda9]

...It seems like 4895 comes close in the 358 w/like 250gr. It also seems like Goodsteel has a write up about his 358 here someplace. Lyman says IMR4198, N130,and RL7 w/204 gr for ''normal'' rifle powders.
4895 is the perfect powder for the 358. I scoured data and 4895 gives the highest velocity for the least pressure using 225gr bullets in the 358. I did not run a similar comparison for 200 or 250 grain bullets, but I bet the results would be similar. It fills the case completely as well. I'm getting over 2200fps with a 232 grain boolit and just a smidge over 1MOA accuracy consistently at 100yds.

[jdrslyr75]

Just to set everyone at ease, I am not looking for max loads, just close to 100% load density as I can get and have the accuracy I am looking for. Velocity could be anywhere from 1700-2200 fps as long as the accuracy is there. I am a new reloader and don't have any plans to load max charges anytime soon, if ever. Seems to me the best accuracy is usually not at the ragged edge of velocity or pressure. And one reason I want high load density is to eliminate a situation where a double charge does not overflow the case. Thanks again for all of the info and keep it coming!

[MBTcustom]

I havn't tried 4895 yet. I tried 4198 and it sucked rocks (both IMR and Hodgdon).
By far, the best powder for this rifle has been IMR 3031.
In reformed military LC brass, you can fill the case as full as you can get it with a compressed charge (I was actually having the boolits get pushed back out a little and had to back off the charge) and you will still be in the sweet spot for cast lead. I was able to get to 2150FPS with soft lead boolits (9BHN) and maintain MOA accuracy.
Ah say, ah say, Poifect!!!!


That said, I know that IMR3031 is in short supply right now, so Im going to be branching out and trying 2400, 748, Unique, and some duplex loads.