Primers!?

[ebg3]

Just going on the old Keith load of 14.5grs 2400 with the 170-174gr bullet and .357 brass. When he used .38 special brass, the load was reduced to 13.5grs 2400 for a velocity of 1300-1350 for a 4 5/8" barrel. I think the 14.5gr load in full length .357 brass was around 1350 for the short barrel. I have produced 1300fps with WW 296 and .38 special brass with no apparent pressure signs. Still have not had time to do my testing...soon, maybe.
EG

 

[ebg3]

OK. I've got some test results. Went to the range this morning, 40 degrees, and ran a few loads through the chrono and tested for accuracy. All loads were with CCI small rifle primers and .357 mag brass trimmed to 1.265" to accomodate the long 174gr Keith bullet in my 50th Anniversary Flat Top. The first load I tried was 14 gr 2400 and the 6 shot average was 1319fps, shots were as follows: 1364, 1310, 1365, 1278, 1294, 1304 fps. A six shot group was just under 2" at 25 yards(I'm a bit rusty!). The next load was 14.3 gr 2400 and the six shot average was 1398 fps, only had 4 to clock and they were as follows: 1422, 1385, 1425, 1359 fps. A six shot group with this load was just barely over 1.5" at 25yards. I did not feel any friction when extracting empties but I know this load has got to be a little hot. I also tried 16.7 grs WW296 with the Keith bullet and it averaged 1282 fps with a high of 1313 and a low of 1212fps. The 1212fps round had a lot of flash when it fired. I'm done with WW296 and cast bullets in the .357. The 2400 loads are showing promise.
Next, I will try the 14.3gr load with winchester small pistol primers to compare velocity and accuracy. I will also try 14.2grs and 14.3grs(again) with the small rifle primers and check accuracy /velocity. I want to keep this bullet at 1350 fps whether I use rifle or pistol primers. Further test results soon to follow.
Eddie

 

[ebg3]

Went out and tried a few more loads in the new flattop. Tried 14.2 grs 2400 with a cci rifle primer and they were running about 1325fps. Same load with a winchester small pistol primer was just under 1300fps. That's a difference of 25 fps between the pistol and rifle primers. Next I tried 14.3 grs 2400 with the rifle primer and they were only running 1350fps today. Temp. was 55 degrees vs. the 40 degrees from the other morning when this load had two rounds go over 1400 fps. Also shot this 14.3 gr load using a winchester small pistol primer and the velocity was around 1325 fps. There again about 25 fps slower than the rifle primer. I do notice more primer flattening with the pistol primer. Not surprised by this as the pistol primer cup is softer than the rifle primer cup. Had no trouble with extraction from any of the loads. Accuracy was about the same with these loads but the 14.3 gr load with the pistol primer was 1.45" for 6 shots at 25 yds. Most of the 1.45" was a slight vertical string. I think most of the variation is from me being a bit rusty shooting revolvers. Next, I will try 14.3 grs again with the rifle and pistol primers and go up to 14.4 grs with both primers checking for pressure signs and for accuracy. I'm just looking for a solid 1350fps with good accuracy. Further results to follow.
EG

 

[gerryb158]

ebg3, your first load of 14.2 gr. 2400 at 1325 fps sounds pretty darn potent and I'd imagine it will do anything you can expect of a .357 mag handgun. Experimenting is interesting but it seems you are already close enough to your "target" velocity. Another 25 fps is not going to make any difference at all. Anyway, your data is interesting, I may try something close to what you have done just for the heck of it. Good luck. Gerry

 

[ebg3]

Yeah, I don't plan on doing much more experimenting with this load. I know I'm near max and don't want any surprises.
EG