Traces recorded since 10/31/11 are shown below. Most were done to satisfy personal curiosity and some were done by request to help someone work up a load. A few of these traces have already been posted. Many have not been posted for two reasons: First, IMO, posting all of them individually as threads would be overkill. Second, for reasons I do not fully understand, with the new Bluetooth pressure trace setup, (as opposed to the older USB-connected module) marked variance in curve offset became a problem dealt with by manually aligning all traces I wished to compare so that the point at which 30% of the peak pressure was reached was close to the same for all traces in one panel. To the few more interested board members who recognized that something was different in the way some traces looked and asked about it, an explanation describing the digital alignment process was provided. But, to attempt to do the same for everyone on the SML board IMO, would have (and still may) create more questions than answers. So, I limited the number of traces I posted, preferring to post only traces which provided information specific to questions raised in posted threads and which were not significantly affected by alignment.
Loads shown below were traced from 10/31/11 to the present. Note that the index lists some traces for which no trace is presented. These were for traces not formatted for upload to photobucket. When time permits, these may be added to the thread. As new traces are created, the plan is to add them to this thread.
Disclaimers: None of the loads traced are recommended. More than a few of the loads traced were experimental, looking for “proof of concept” and NOT FOR ROUTINE USE. Double charges and minor variations in small amounts of extremely fast powders (such as Red Dot or CLAYS) may cause unwanted dangerous pressure spikes and may cause severe damage and personal injury or death. All loads traced seemed safe in conditions present at the time the traces were made in my barrels. They may not be so under any other conditions in other barrels. Also keep in mind that pressure values obtained are relative to previously posted loads I used to calibrate this system and may vary significantly from actual pressures or what others may record. Unless otherwise noted, almost all early traces shown below were traced using a Savage breech plug equipped with a .031 in. ventliner. More recently many have been done with bushing plugs with varying orifice diameters as noted on the trace. Use of a different breech plug with a different flame orifice may significantly alter both pressures and velocities from what I have shown.
There is a learning curve associated with production of realistic traces. So, as time progresses, there may be changes in the quality of the data. TG
Pressure Gage and Module Manufacturer = RSI Bluetooth model Glossary: PN=PacNor bbl K375=28in. Krieger.375 bbl (Savage plug), 50cal=50cal bbl, B375=28in Brux .375cal bbl (Arrowhead plug) rd = Red Dot, bd=Blue Dot 4759m = old 4759 from metal canister. 4759p or 4759 = 4759 from plastic jug. ST = Alliant Steel, TB = Trail Boss, Hy100 = Hybrid100 H800X= Hodgdon Hi Skor 800X, BE= Bullseye, Rtbo= Retumbo Hblu or HSB = Harvester smooth blue sabot. Hrcr or hrd = Harvester red crushed rib sabot, Hbcr = Harvester black crushed rib sabot. grw = weighed black powder equivalent. Vwool or vwl= Lubed wool over lubed .462x.062 lubed fiber wads. veg = fiber wad. Wool=wool wad. A = multiple traces from different panels were manually aligned for comparison. nurl or nrl = knurled bullet. lfc= flame channel diam. = 7/32in. vl = ventliner