Someone once asked me, "How long will an o-ring last" in a Metrics Unlimited Breech Plug? Well, yesterday I tried to find out, but I still don't know the answer. I started with a new #60 o-ring that was bought at Lowes in a 10 pack for $1.97. I have other brands, but wanted to use a brand that nearly everyone should be able to get locally. There are several manufacturers of o-rings and several types of materials used to make them. Some will obviously be better than others, but this test was done with a common o-ring mentioned above.
I started with a 7/8" Metrics Unlimited breech plug that I tweeked to work in my Huntsman. The others will be going back to Nick for his fix. After getting the plug exactly how I wanted it I fired several different types of primers through it, a dozen of Federal 209A, CCI MAG, Winchester W209, and Winchester WML209 primers altogether. I fired 3 of each without powder before taking it out back to test it on the range.
So starting with those 12 without powder, I was planning on shooting one to failure. I guess I didn't give myself enough time? I shot 38 loads of 80 grains of Blackhorn 209 powder with several different types of bullets and sabot combinations, and was still unable to make the o-ring fail. I was also conducting another tests simultaneously, with different .429"-.430" bullets and sabots. Because I was getting variable wind gusts very frequently all the testing was done at 50 yards to reduce those effects as best as possible. The other tests were for sabot consistency, and bullet integrity. ALL loads had perfect ignition, even though some of the sabot combinations loaded so easy I hardly had to push on the range rod. I did give each load a firm hit on the range rod once seated. NO SWABBING all day long!
The o-ring started with a I.D. of .110", a O.D. of .250", and a thickness of .070". After the test with 12 primer only, and 38 powder loads of 80 grains of Blackhorn 209, the o-ring shows signs of being washed out in the I.D. as expected, but the O.D. actually grew by about .002" an the thickness only lost about .002". Remember, some o-rings may last longer while some may not last as long, so use this test for reference only. Always have a spare o-ring or two with you at all times while at the range or especially while hunting. On the 35th shot, when I removed the primer, the o-ring came out with it, luckily it fell out on my bench so I could find it easily. I put it back in and it stayed put for shots 36-38. If you were in a hunting situation, and it fell out on the ground, a black o-ring would not be very easy to find.
Before and after.
The primers themselves from the top. Some of these actually leaked between the primer and the battery cup, but the o-ring did it's job of keeping blowback gasses from leaking past on all but one primer, it was the sixth primer under load during the test. The primer is in the back row in the second picture 5th from the left or 6th from the right, the leakage was very minor. Notice how clean the other 37 primers are. The last 8 primers are in the front row of the second picture, and the 38th one looks as clean as the 1st. I think the one that leaked is a fluke because it did not happen again during the test. Some of the primers did require a little help removing, but I will polish the pocket a little before the next range trip. When I do get a stubborn primer, I slide the capper end of a CVA 209 capper/decapper (cost me $4) over the primer rim and just pull straight back, real quick and easy.
Sneak peek at the 7/8" MU plug. They did turn out very nice with a deeper hex head.
The following target is Groups 1-5 (G1-G5), I didn't measure any of the groups, but all were plenty good enough for hunting purposes. Again, ALL groups were shot at 50 yards with 80 grains of Blackhorn 209 powder, and Winchester WML209 primers. I will mention the sabot/bullet combination for each group.
G1 is in the center in white, these are the new Hornady .430" FTX in 265 grain in a green Harvester Crush Rib Sabot.
G2 lower right in orange, Hornady .430" HP/XTP 300 grain in a green Harvester Crush Rib Sabot.
G3 lower left in blue, Nosler .429" Partition-HG 250 grain in supplied Olive Green Sabot.
G4 upper left in yellow, Speer .429" Gold Dot SP 270 grain in a green Harvester Crush Rib Sabot.
G5 upper right in pink, Traditions .450" APB100 (Parker Ballistic Extreme) 275 grain in supplied black 3 petal EZ Load Sabot.
This next target was to test the green Knight High Pressure Sabots, and compare to the green Harvester Crush Rib Sabot, especially with the new Hornady FTX Bullets. The groups were opening up so for G10 I went back to the green Harvester Crush Rib to see if any thing was different, I think you will agree that it MIGHT be the sabot?
G6 center in white, Hornady .430" FTX in 265 grain in a green Knight High Pressure Sabot.
G7 lower right in orange, Hornady .430" HP/XTP 300 grain in a green Knight High Pressure Sabot.
G8 lower left in blue, Speer .429" Gold Dot SP 270 grain in a green Knight High Pressure Sabot.
G9 upper left in yellow, Hornady .430" FTX in 265 grain in a green Knight High Pressure Sabot.
G10 upper right in pink, Hornady .430" FTX in 265 grain in a green Harvester Crush Rib Sabot.
The last part of my test was to run some bullets through my own personal torture test. This test is with 80 grains of powder at 50 yards shot into a white silica sand filled heavy plastic bag. Keep in mind, this test may not have ANY relevance to what these bullet will do on living/breathing animals, but it lets me know what the bullet is made of so to speak. I want to know what a bullet may do if it encounters heavy bone, and this test is almost as brutal as shooting a bullet into a cement block. Several bullets dont fare well, and others such as the all copper Barnes do not expand well due to their need for fluid to open properly. Each test bullet is in front of the saboted and non saboted specimen.
From L-R:
Speer .429" Gold Dot SP 270 grain.
Nosler .429" Partition-HG 250 grain.
Hornady .430" HP/XTP 300 grain.
Hornady .430" FTX in 265 grain.
Traditions .450" APB100 (Parker Ballistic Extreme) 275 grain.
