I shot my A&M barreled HW for a few years with a Ron Long, 187 gr, tapered spitzer, if your interested in those loads. I also made two reduced capacity cases and have data for those.

Frank

Frank, how'd you do the reduced cap. cases?

hey, I figured you had a bush they grew on

I'm just wondering how you configured the inner "powder chamber".  Full depth straight walled reduced diameter? 

I had Dave, when he ran RMC, make me several different batches of different cartridges.  Only the 220 swift were deliberately done as reduced capacity.  Others are the result of obsolete or off standard spec BN euro cases being turned with straight sided "powder chambers".

A question about brass:   is the machinable brass stock, like that machined by RMC(and I assume you too) the same as the brass drawn for cases. Do you have to heat treat it differently?  

Regarding the machined cases. I made two, the first one was made of 303 stainless steel (free machining) with a chamber diameter neck so, it would seal and reamed .3115 ID the length of the neck. From the neck to the primer pocket, it was reamed .251, giving a total case capacity of 1.8cc. It had a small primer pocket. The end of the neck was chamfered at 45 deg, out to the edge. This was my BSing case for 6-8 years, until the neck collapsed, spliting it. 

The next one was made of Bronze, the only difference is that it's reamed all the way back to the primer pocket at .3115 (under size dowel pin reamer) and it has a full case capacity of 2.8cc.

A word of causion, regarding the necks. If you plan to shoot fixed ammo, you will need to polish the inside of the case neck. Other wise, even the tool marks that a reamer leaves, can latch on to the bullet and pull the neck off. 

Regarding "was it worth it", for me the answer is yes. I got some excellent groups with both cases, I learned a lot and it's challenging machine work. Overall, I believe that there is a slight edge in accuracy, possibly similar to the difference between a Miller short and a 32/40. I never did any side by side testing with commerial cases.

Forged case heads are stronger than the common half hard brass that is most commonly found but, you can make cases that will take the same amount of pressure by making the case head thicker. All case heads have to be close to .200 thick, since primers are about .175 long. If you make your case head between .300 & .350 thick, you will not have any pressure issues with a machined cases.

I'll get my chronograph book out today and post some of my loads and results for all three cases. 

Frank

Don,
I can only tell you of my experiance with these cases as well as  a 308 Win and a 45/70 that I made. If the neck callapses, pressure had to get behind it. It may be that you weren't building enough pressure to seal the neck to chamber joint. Anealing the neck might also help but, I never did that. SS can be anealed like brass, had I done that, I might have saved the SS case.

Here is some load data, starting with the 1.9cc SS case. The above given 1.8cc is wrong. I started this back in 1989 so, the powders used were the ones that were popular back then.

My barrel is 26" long with a 12 twist. All bullets Darr lubed. All groups are at 100 yards unless specified.

9 gr 4227, F100 primer, 180 gr RCBS gc bullet, shot fixed. 1263 fps, .70 5 shot group.

11.5 gr 296, F100 primer, Ron Long 187 gr bullet, BSed, 1310 fps, no group recorded

13.0 gr RL7, F100 primer, RL 187 gr, BSed, 1347 fps, no group

14.0 gr RL7, F100 primer, RL 187 gr, BSed, 1504 fps, no group

17.6 gr AA2520, F205 primer, RL 187 gr, BSed, 1347 fps, .65 group

2.8cc Bronze case.

14.5 gr 296, F100 primer, RL 187 gr, BSed, 1443 fps, 1.9 five shot, four in .54 @ 200 yards. Only 8 fps ES with this load

This was a suprising load shot at 100 yards with a picture included. 

8.0 gr Unique, F100 primer, modified (spitzer) Lee 160 gr gc bullet, BSed, 1323 fps with only 5 fps ES. .318 five shot group. I have a note that says that 7.5 gr leaked at the neck.

Some HV fixed loads, starting and highest velocity.

24 gr AA2520, Rem 7 1/2 primer, fixed, 185 gr RCBS gc, 1892 fps

28 gr AA2520, Rem 7 1/2 primer, fixed, 185 gr RCBS gc, 2142 fps

No groups recorded for either load.

Standard 30/40 W-W case

12.5 gr 4759, F150 primer, RL 187 gr, BSed, 1244 fps, .76 five shot group

14.5 gr 4759, F150 primer, RL 187 gr, BSed, 1409 fps, 1.03 five shot, 4 in .68

ES ran about 50 fps for above loads

17 gr 4759, F150 primer, Modified (spitzer) 190 gr RCBS gc, 30/1,  BSed, 1556 fps, .70 group

Thank you Frank, that was a lot of effort on your part. I have saved all the loads on my laptop and they will be most helpful when I get this rifle up and running. 

I sincerely appreciate your time.

Don

PS. Might you have any surplus PB .30 cal molds?

You read my mind! You have given so much help I was ashamed to ask about the Long mold configuration and there it is. Hope I can return the favor some way.