[/quote]"I have a question regarding using SR4759 for hardcast gas-checked 405gr loads? As anyone used this powder for 45-70, from a Marlin 1895G?
do you have to use wads? can you use poly fiber wadding like the material they use in Pillows?"
mickeyjr
SR4759 works very well in the 45-70 with 405 gr bullets. It is used by many with and without a tuft of Dacron as a wad. It is used with good success mostly in single shots with the wad. SR4759 occupies to little of the case to use the Dacron as a filler. I prefer to use the Dacron as a filler instead of a wad thus I use a medium burning powder such as 4895 which occupies more of the case volume. Many advise against the use of wads because of the reported danger of ringing the chamber. All cases, very few indeed, of ringing that I am aware of either involved card wads or some combination with card wads and a large gap between the wad and the base of the bullet. However, as I have fired many thousands of cast bullet loads over the years in both straight walled and bottle necked cartridges without nary a problem I do not concern myself with ringing when Dacron is used.
The problem I encountered was with repeating rifles. With the magazine loaded, tube or box, I had many cases of "click-bang" or simply put; hang fires. These occurred with the 4th or fifth cartridges. Chronograph readings, ES and SD, also would show large variations on the 4th and 5th shots. I suspected the recoil of the previous shots had dislodged the wad. To find out I used a .223, a 30-30, a 30-06, a .375 H&H and a 45-70. I loaded 5 cartridges (all had 4759 with ½ - 1 gr wad of Dacron holding the powder against the primer) in the rifles and fired the first 4 shots. I then pulled the bullets of the 5th shots. In all the cartridges the wad was dislodged (had moved forward) creating air space between the powder and wad and the wad and base of the bullet. In the 30-06, .375 H&H and the 45-70 where there was heavier recoil not only had the wad dislodged and moved foreword but some of the powder had migrated ahead of the wad! These three cartridges were also the worst for click bang. Besides denigrating performance I didnt think this situation was all that safe. All such loaded cartridges performed with exceptional accuracy and consistency when single loaded and fired.
Since I generally dont consider my repeating rifles to be single shots I sought a solution. Remembering old articles and loading manuals where surplus 4895 was used with medium to heavy for caliber bullets in most every rifle cartridge I experimented with medium burning powders and Dacron as a filler (occupies the airspace completely between the powder and base of the bullet). I found that 4895, 3031 and RL7 occupied ½ to 3/4s of the cartridge volume (depending on cartridge and bullet weight) with accurate loads in the 1700 2100 fps range with most rifle cartridges. In cartridges up through 30-30 capacity a ½ gr of Dacron was sufficient as a filler. With larger cases 1 gr did the trick. With the 3 six bits 1 ½ gr was need for a filler with a 27t gr cast bullet and 4895. In the 45-70 a 1 gr tuft is necessary. a repeat of the same test as with the wads produced no movement of the filler (has not place to go) and no powder migration around or beyond the Dacron filler. Chronograph readings of ES and SD are as consistent with the last shots in the magazine as with the first.
I discovered all this about 20 years ago and have used medium burning powders with Dacron fillers since for medium to heavy for caliber bullets. For light weight for caliber cast bullets I prefer and use fast powders without wad or filler in all rifle cartridges. I have been using Oehler chronographs since the mid 70s and have chronographed thousands of cast loads. With medium powders and a Dacron filler there has never been a hint of a problem. If there were pressure spikes or other abnormal indicators they would have showed on the ES and SD readings. I have had such indicators with powders such as 4759, 5744, 2400 and 4227 when used in large capacity cases like the 45-70 when using light to medium weight bullets (275 to 405 in the 45-70). I have had nothing but consistent velocities and the best of accuracy with loads using medium powders and Dacron filler. Note; I mainly use milsurp 4895 because I buy large single lot quantities but any of the commercial 4895s work as well along with 3031 and RL7. Some serious cast bullet shooters are using slower powders that give 100% loading density, but that is another subject and not the topic of the discussion.
If you are using SR 4759 I suggest in your Marlin I suggest you work up the load without a wad of any sort.
Larry Gibson
