.38 sp loads in .357 brass with SPM primers - is it a wash?

[Bill M.]

If you seat them the same depth I think HB and solid base wadcutters take up the same volume.

 

[CoalTrain49]

I did state the powders, but not in the first post. In post #6 I said I was looking at using Bullseye, AA#2 or Red Dot.

Sorry. Just buzzed through the thread. I know BE and RD are flake powders. AA#2 is a ball powder. You might want to use that one with your mag primers if you have a good supply. Otherwise I don't think it matters. I don't have load data handy for AA#2 so you decide.

https://www.ilrc.ucf.edu/powders/sa...ltOrder=Sorter_distributor_code&resultDir=ASC

 

[barnfrog]

If you seat them the same depth I think HB and solid base wadcutters take up the same volume.

That makes sense. After I thought about it I realized if the bullets are the same weight, they take up the same volume. So maybe the HB is longer than the DE?

 

[Riomouse911]

If you seat them the same depth I think HB and solid base wadcutters take up the same volume.

Doesn’t the cavity in the body of a hollow base wadcutter allow for more room inside the case for powder expansion than a solid base bullet seated to the same depth? (Not much more room, but a bit more.) If it does, the difference may affect pressures up or down, depending on what bullet data you are using.

Stay safe.

 

[GeoDudeFlorida]

That makes sense. After I thought about it I realized if the bullets are the same weight, they take up the same volume. So maybe the HB is longer than the DE?

The limit on pressure for a HBWC is there so you don’t blow the head off and stick the body in the barrel or cylinder gap. DEWCs don’t have that problem so they can take a lot more pressure. The thing is, these days most DEWCs are bevel base and cast from hard alloys so they don’t obturate at the base to seal the bore. That kind of bullet leaks gas pretty easily so if it’s not oversized it’s not sealed. You can run the charge up pretty high and not get as efficient a result as less charge in a softer HBWC where the skirt expands to seal the bore.

 

[barnfrog]

The limit on pressure for a HBWC is there so you don’t blow the head off and stick the body in the barrel or cylinder gap. DEWCs don’t have that problem so they can take a lot more pressure. The thing is, these days most DEWCs are bevel base and cast from hard alloys so they don’t obturate at the base to seal the bore. That kind of bullet leaks gas pretty easily so if it’s not oversized it’s not sealed. You can run the charge up pretty high and not get as efficient a result as less charge in a softer HBWC where the skirt expands to seal the bore.

That is really good info, and an excellent example of why you can't sub data from one bullet to another just because they're the same weight.

Boy, you really have to know about science and math and other technical stuff to do this right. Good thing my new endeavor (re-caning chairs) is a lot less dangerous.

 

[buck460XVR]

IMHO, .38 special loads in .357 cases is just a powder puff .357 load. Lots of published info out there for that. Magnum primers are not going to make a 10% difference at such low levels. Even if they did, 10% over a max .38 special load is still going to be a mild .357 load for both the case and the gun.

 

[styles]

Can you do the opposite? Could you load say 6 gr of AA#2 with a SPP in a 357 case? I know with slower ball powders you need the msg primer, but wondering about this.

 

[2ndtimer]

Can you do the opposite? Could you load say 6 gr of AA#2 with a SPP in a 357 case? I know with slower ball powders you need the msg primer, but wondering about this.

I have used standard SPP with faster burning powders frequently over the years, i.e. Accurate No. 5, Unique, W-231, Titegroup, Bullseye, and Universal. No problems in assorted revolvers.