.30-.357?

[Doughty]

Nueces, I went to that site but couldn't find anything. I guess my computer search skills are not up to snuff.

[Nueces]

Nueces, I went to that site but couldn't find anything. I guess my computer search skills are not up to snuff.

I haven't been on that site lately myself, but I could not just now find anything listed as pertaining to the 30/357 either. Last resort would be to surf the forum there.

The book is the best resource.

[Milky Duck]

so maybe try seating projectile like the 8mm mauser is...EG just in enough to hold it in place,1/8th inch sort of thing...no good if running around with them loose in your pockets but fine if in a plastic case until use.....

[Doughty]

Milky Duck, The rifle is a 12 pound bench rest rig used for schuetzen matches. Not a walkin' around gun. I did make up some dummy rounds with some different bullets. Would be a fun round in a lighter, slimmer rifle. With a light bullet it could substitute for a .22LR in hard times.

[Milky Duck]

well it surely is something more than just a bit different then LOL...
must be the modern equivilent of the .32/20 sort of...

[Kosh75287]

I guess you might get a better burn if you were to switch to a small rifle primer, but I wonder if your powder charge is too light to develop the best pressure for optimal burning. Since the rounds are breach-seated, there is no crimp to retard the bullet's forward progress and enable chamber pressures to elevate into ranges in which AA#9 burns best.
If you weigh a fired case that's been filled with water up to the base of the neck, then subtract the fired case's empty weight, that gives you case capacity for the round, when loaded conventionally. Since you are breech-seating bullets, however, you are, in effect, increasing case capacity, translating to lower chamber pressures and (putatively) bad powder burning.
Weighing the same unfired case when filled to the case mouth with water and dividing this result by that of the first case capacity gives you a ratio by which you can multiply starting charge weights to possibly adjust for the greater case capacity. Ordinarily, I'd be hesitant to recommend this maneuver, but since a breech-seated projectile has minimal resistance to forward motion, I would expect chamber pressures to remain in the "reasonable" range.
I do not know what your source for loading data is, so I leave it to your judgement as to how aggressively to increase the charge. As an example, if the starting load for a particular projectile, seated conventionally, is 14.0/2400, and the breech-seated capacity is greater by, say, 6%, the analogous starting load would be 14.8/2400. MY inclination would be to try 14.4/2400 first, THEN try the 14.8/2400 load.
Since you are using AA#9, I'm sure the number values will be different, but the approach would be the same. Just a thought...

[barrabruce]

I filled a case with adi 2207 and a fired adi 300 blackout case someone gave me at the range today.
The 30-357 mag holds 1.1 grains less powder.

I do size my cast bullets so they all sizes sit in the neck area.
This has to have an effect on powder capacity and pressures.
Adi recommends mags srp for there 300 blk loads.

I have had this problem a lot with slower powders and cast bullets plain based or paperpatched.
It seems like getting the pressure up to full burn is harder than jaxketed projectiles and I go a faster burn rate.

I shot this out of my 5lb open sighted 30-357 mag to day.
First shot a little high , rest with in an inch at 50yrds
Not bad for over a bag on the bench.