17 May 2005, 11:48
GrandpasezResearch on pressure testing--
Doing research figured out the following-
This is very important that you understand
following-
People are being told that the barrel time of
loads that are spiky, ends at where the first
pressure curve ends, where secondary spike starts, and that spike is an artifact occurring after bullet is out of barrel.This is about 1.0 milli-seconds on the Pressure Trace
timelines we have seen. This is false-
Here is proof----
If you change to a powder that does not give
you a secondary spike,and about the same velocity; and the primary peak
bottoms out at about 1.4 milliseconds and that
is the time the bullet leaves barrel,
what happened....We have seen the traces of
both to compare. And getting same velocity with a non spiking powder, compared to one making spikes, means barrel time is about the same
to get same velocity--
SO THE SPIKES ARE OCCURRING while bullet is
in the barrel....Ed.
17 May 2005, 16:12
jeffeossoEd,
Let me restate that for you..
FOR the same gun at THE SAME VELOCITY LOADS
in a single spike pressure trace, the bullet leaves the barrel at or after 1.4 ms...
in a double spike (secondary), the secondary spike begins at or about 1.0 ms.
It is physically impossible for the bullet to leave the barrel before the secondary spike
physical proof,
charlie has blown off (twice) muzzle brakes from loads with secondary spikes...
manf. claims
the MAKER of the RSI says it is an issue that must be researched....
the MAKER of another tool, that doesn't show these, says "well, since my equipment doesn't see it, it must be false"
jeffe
18 May 2005, 00:38
hawkinsWhy then does the 'Spike" occur earlier (and even change polarity ) as the barrel is shortened?.
Good luck!
18 May 2005, 04:30
GrandpasezHawhins-So far the only one reported on here
or mtngun's site that does that, is mtngun's
cast loads. Those are with really oversize cast bullets jammed into the freebore and rifling.
And his jacketed comparison load has no spikes
at all in same barrel, with all lengths.
The other report of barrel shortening with light jacketed bullets shows spikes going away,
when 4 inches were cut off.As we get more results and testing I think we can figure
it out...Ed