Originally Posted by
Savvy Jack
A very interesting thing happened today. I was finishing up my pressure testing today and shot a lot of groups. I decided to shoot some more black powder loads as well. This time, however, I used some original BP brass cases. A variation of Western, REM-UMC and WRA cases. four of the WRA cases used small pistol primers.
First, I shot 15 modern RP cases and 5 Winchester cases. I used 39gr of Swiss FFG in the Winchester cases and 40gr in everything else. 39gr of Swiss FFG gave me an average of 1,221fps from my 20" test barrel producing 8,843 PSI. The 40gr in the RP cases resulted in 1,257fps and 8,648 psi. Here is the kicker.....
I used 40gr of Swiss FFG in 16 original semi-balloon head cases of which four were small pistol primers. Same powder, same bullets, basically the same primers.
1,373fps @ 14,100psi!!!!!! HMMMmmmmmmm!!!!!!
On another note, to include the BP tests, I shot 42 pressure testing groups of at least 10 shots per group over the past few months.
Included are all of Lyman's 49th, page 299 and 300, MAX loads for both Group I and Group II rifles using Unique, IMR4227 and 2400 with the published bullets, primers, case lengths and AOL's.
All of my Group I loads ranged between 6,594psi to 9,389psi
My "Control", Buffalo Bore's 44-40 "Heavy" was set to 11,300psi.
All of my Group II loads came in between 11,363psi to 17,837 psi
What I failed to do was shoot all loads at the same out side air temps. The "Control" was shot in about 55 deg, some loads shot around 35 deg and the rest also around 55deg. This does change things a little but not too awful much. Some could increase as much as 1,500psi and those shot in 55deg could increase in 90deg weather.
However, out of all of the loads I have ever come up with on my own, only TWO were higher than the Lyman's MAX pressure results of 17,830psi. Those two were 19,500psi and 19,628psi.
Only one Reloder 7 load came in over 13,500psi and it was a 240gr LRNFL bullet and it achieved 1,446fps.
Other 240gr LRNFP bullets with a lighter load stayed below 11,000psi
Most case capacity Reloder 7 loads stayed between 10,000psi and 13,000psi. Even a caseload of Trailboss surpassed SAAMI max out to 15,182psi
The Pressuretrace II system was well worth the $$$ for a little piece of mind as well as closing the mouths of a few Mr, been handloading for 55 years, Know-It-Alls.