Progress on the Mk.II hammer, which may be news to those on this forum. A friend is EDM'ing what will hopefully will be a somewhat more efficient design. The process has not been without drama, and the photo below will show a few "boo-boos".
What's really exciting is that another fellow has made ten or so of a different design, AND has a 10,000 frames per second camera which shows the improvements in speed. His first effort resulted in a 20% reduction in locktime, which is not bad at all! Puts it in the 6ms range, about like a M1903 Springfield.
Thare's also a very good highpower competitor who has agreed to try them in his service rifle(s). So some unbiased field reports may be forthcoming in the next year.
Well, the Mk.II Mod.1 has already supplanted the Mod.0 shown above.
As soon as it's function tested it'll be off to a photo lab shoot with a 10.000 frames per second digital video camera, and then off to a High Master highpower competitor for extended trials.
It's a "one-off" prototype, but there's an alternate design starting in limited production that ought to be available for sale early in 2012, thanks to the efforts of a fellow enthusaist and businessman who already does optically enhanced rear peep sights for Garands and M14/M1A platforms..
Art Neergaard (Shootingsight.com) maker of rectangular apertures and other goodies marketing an adjustable trigger for M1 Garand and has a "speed hammer" in development. Good guy, quality stuff.
Yah, he's having 7,62mm Firearms do him up some new. We've been going back and forth a bit on another site. I've been running one of his hammers for over a month. His are running on the heavier side, but they were just a "proof of concept" batch done up for testing. The high master high power shooter/guinea pig has been running on of his with one leg broken off for several weeks with good success. The new batch should have Art's design refined to eliminate the weakness in the RH leg.
Art is also going to do the high speed photographry mentioned above. It's not like we're in competition or anything, more of a long distance collaborative effort.
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BTW, I've gotten one down to 314gr as of 17 December but it's not suitable for general usage, as it no longer has a hammer nose extention or overtravel stop surface. It's for testing the limits of primer ignition.
An earlier test of a stock and an Art7 Mk.I test hammer is shown in the you tube video below. . I forget the exact weight, but it's in the 400gr range resulting in a 20% improvemnt in speed. Stock is about 770gr. The jm Mk.II mod.1 is in the 385gr weight range, but the next ones may be a little less.
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Some old numbers:
USGI (-2 SA) hammer: 769 grains/ 1.8oz. 100%
USGI D5546008 hammer with one sear leg missing: 747gn/ 1.7oz. 97%
art7 Mk.I hammer: 520gn/ 1.2oz. ~68%
art7 Mk.I hammer mod. 1: 490gn/ 1.1oz. ~64%--This is one of Art's early EDM'ed hammers after polishing and some further minor lightening cuts.
jmoore Mk.I hammer: 485gn/ 1.1oz. 63%
jm Mk.II Mod.1 hammer: 356.5gn
That's some fancy machine work. Looks nice. Sounds like it's as fast as an Extreme or Geiselle trigger in an AR. I asked him awhile ago about a striker design for an AR (which would be the only way to go to get close to bolt gun lock time) haven't heard any updates on that. He and Bill Geiselle have taken an AR trigger as far as possible I'd say. There aren't any durability issues so far? Or have they been worked out?
The old one keeps running just fine. The new ones are too new to know how they'll hold up over many thousands of rounds (and dry fires.) It's still in the experimental and trial production phase. But the results have been quite encouraging. Hopefully, there will be much more progress next year as more of them get into the system.
The jm Mk.II Mod.0 was sacrificed as a general purpose hammer to become a "how light can we go" test piece. At the current weight of 234.5 grains it has been clocked at 4.8 milliseconds locktime. Compared to the stock 769gn hammer at 8.2ms. Primers are indented as deeply and more crisply than ever!
The Mk.II Mod.1 was clocked at 6.2ms. It's starting service in an active NRA high power shooter's rifle this year for extended trials.
The "Hammer of Insanity" Mk.II Mod.0"test":
The old Mk.I Mod.0 has morphed into the Mk.I Mod.1, but not without a visual drama:
The hole was unintentional. It was a small breakout that's been blended to it's current size. Ugly, but shouldn't hurt anything.
Currently at 363 grains, but there will be some more coming off. It has run for years at 480 some odd grains, but it's time for further mods.
Plenty of cosmetic cleanup and durability polishing to go, too!
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