I did some new o-ring and primer testing with conicals in the 24" NEF w/MU breech plug & BH209. The o-ring is the quad pictured below on the left, further testing will be done with the square type on the right. I shot a half dozen or so primers before heading out back to my range, absolutely clean primers with 100% seal.
Since I was going to be just shooting conicals and FPB's over a chronograph testing this new o-ring I decided to shoot from my portable bench at 50 yards. I won't bore you with the details, as they can be read off the pics. I did shoot a total of 34 shots with perfect igniton on all 34, I did get a couple strange chrono readings but most loads did very well. This is the range that we like to call elk into, all 34 shots would have been deadly as long as the bullet did it's part.
The first target was started with a 460 No Excuse, the X was my fouler in the center of the center bull. The remainder of the bulls were shot with the Hornady FPB with increasing charges. Notice how well the 80 gr load does with that bullet, I can shoot that load into one hole all day. I got a little ahead of myself when I started writing down the shot srting speeds, but I cought it after I only screwed up two. After shooting the first group I was loading the FPB, I promptly lifted my rifle straight up ramming the scope into the bench.
I think it survived but might have changed my POI a little bit.
This next target was shot with all 80 grain loads and a wad with the exception of the last group which was shot with no wad. Keep in mind these are .503" bullets in a .502" bore, basically slip fit. Had it not been for the generous flame from the Metrics Unlimited breech plug, I am not sure it would give 100% instant ignition. IMO, it is not how tight your bullet fits in the bore, it's how much flame you can get to the powder that gives the best ignition. I have shot some saboted bullets in my Knight with the o-ring modified breech plug that the ramrod practically loaded by itself, all I had to do was seat it on the powder. The flash hole in that plug was also reamed out to .040" and I got perfect ignition.
Notice the last two groups were with the same bullet, one with a wad and the last without. What shocked me was I got a few FPS faster without the wad and less deviation. I will be doing more testing in the future with the 26" barreled H&R, and will compare the velocities to the 24" barrel. After all the shooting, the quad o-ring is in very good condition and could probably go another 50+ shots without a problem. I will be testing the square o-ring in the 26" barrel with the 5/8" MU plug as well as my modified NFPJ breech plug.
The bullets and wads used in this test. Top two pics from L-R: Hornady 350 grain FPB, White 430 gr Super Slug, White 440 gr Power Punch, 460 gr No Excuses, White 480 gr Super Slug. Bottom picture is the .518" dia x .060" thick fiber gasket wads.
The o-ring after 6 primers and that round of shooting. Had to blow it up to see any wash-out, there is some but I could probably put at least 100 shots on that 7 cent o-ring. That would be the equivalent to 100 of the Knight Red Full Plastic Jackets at $10/bag, or 10 cents/shot. Plus the o-ring actually seals.
Primer side.
Powder side.