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Posted: 6/20/2015 7:51:58 AM EDT
[#1]
Quote HistoryQuoted:
The crucial difference is that the other examples you offer are locked breech firearms. In a straight blowback, the inertia of the reciprocating mass IS the locking mechanism. Springs have a minimal effect on the "unlocking" speed of a blowback. Which is why I suggested a locked breech approach to begin with. Quote HistoryQuoted:
Quoted:
My experience is only anecdotal in terms of 1911/2011 raceguns built for USPSA competition. The crucial difference is that the other examples you offer are locked breech firearms. In a straight blowback, the inertia of the reciprocating mass IS the locking mechanism. Springs have a minimal effect on the "unlocking" speed of a blowback. Which is why I suggested a locked breech approach to begin with. Yeah, if you had quoted my entire my post, you and the others following along would have also read that I also wrote: ...And yes, I do realize there are locking lugs and barrel links involved...
See those three little dots? They imply there is more to be read before and after the quoted section, and that it is just one piece extracted out of a larger post. |
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Posted: 6/20/2015 4:03:38 PM EDT
[#2]
Quote HistoryQuoted:
Greg Carlson (Carlson's Comps) has a patent on a Pulse Recoil System that puts the op rod and spring forward of the bolt to eliminate the need for the receiver extension. It is a nice clever design. He is still looking for someone to license the patent for production, which should tell you about the size of the market. Pulse Recoil Patent FWIW, this link is to a patent application, not an issued patent. The patent application was abandoned on April 21st of this year. The claimed invention was rejected as anticipated by U.S. Patent No. 970,307, which issued in 1910. |
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Posted: 6/20/2015 9:56:28 PM EDT
[#3]
Starting a rough mock up. I couldn't find my calipers and the digital ones have a dead battery. Rough it will be for now, not to mention my software too.
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Posted: 7/12/2015 5:54:44 PM EDT
[#4]
I have changed my original idea from a operating rod to a heavier block connector/gas key part.
It would require the hole for the gas tube on an upper to be milled out to make room for it but it would provide more mass and a stronger connection point to the forward bolt mass, as well as a potential connection option for a side charging handle. I need to find a super cheap rail setup to butcher on testing after I build the gas key for the bolt and mod the upper to fit. After that I need to hack up a 9mm bolt to see how much mass I will be removing and re locating. 
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Posted: 7/13/2015 12:30:00 AM EDT
[#5]
Well done.
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Posted: 7/13/2015 7:50:31 AM EDT
[#6]
Quote HistoryQuoted:
I have changed my original idea from a operating rod to a heavier block connector/gas key part. It would require the hole for the gas tube on an upper to be milled out to make room for it but it would provide more mass and a stronger connection point to the forward bolt mass, as well as a potential connection option for a side charging handle. I need to find a super cheap rail setup to butcher on testing after I build the gas key for the bolt and mod the upper to fit. After that I need to hack up a 9mm bolt to see how much mass I will be removing and re locating. http://i6.photobucket.com/albums/y238/CousinIT50/9mm%20AR/gas%20key-rod_zpsdue1hfkj.jpg The issue with this is going to be the joint between the carrier and the heavy key. Short of welding it, you will likely shear the small gas key bolts in the first few shots. On my bufferless carriers, I add a hardened hollow dowel around the gas hole, You could add something similar, but solid, and hope it can handle the impulse. See the 1/4" countebore around the gas hole. The dowel drops in there and fits in a pocket in the key. 
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Posted: 7/13/2015 8:41:14 AM EDT
[#7]
Quote HistoryQuoted: The issue with this is going to be the joint between the carrier and the heavy key. Short of welding it, you will likely shear the small gas key bolts in the first few shots.
On my bufferless carriers, I add a hardened hollow dowel around the gas hole, You could add something similar, but solid, and hope it can handle the impulse. See the 1/4" countebore around the gas hole. The dowel drops in there and fits in a pocket in the key. http://i241.photobucket.com/albums/ff206/devtucker/AR-45/IMG_20140920_171036_957.jpg http://i241.photobucket.com/albums/ff206/devtucker/AR-45/IMG_20141008_173712_915.jpg How many bits did you go through drilling that? |
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Posted: 7/13/2015 8:45:53 AM EDT
[#8]
Quote HistoryQuoted:
How many bits did you go through drilling that? Quote HistoryQuoted:
Quoted: The issue with this is going to be the joint between the carrier and the heavy key. Short of welding it, you will likely shear the small gas key bolts in the first few shots.
On my bufferless carriers, I add a hardened hollow dowel around the gas hole, You could add something similar, but solid, and hope it can handle the impulse. See the 1/4" countebore around the gas hole. The dowel drops in there and fits in a pocket in the key. http://i241.photobucket.com/albums/ff206/devtucker/AR-45/IMG_20140920_171036_957.jpg http://i241.photobucket.com/albums/ff206/devtucker/AR-45/IMG_20141008_173712_915.jpg How many bits did you go through drilling that? The counterbore? I've got a crapload of coated carbide end mills and such, zips right through when there's already a pilot hole 
The fun part is trying to drill the nitrided ejector sleeves I use for gas tubes and gas keys, I usually touch a flat with the dremel to get through the surface nitriding so I can drill it. Oh, and if you have to tap anything in a carrier, you'd better have some coated cobalt taps and a lot of patience. |
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Posted: 7/13/2015 9:36:19 PM EDT
[#9]
Quote HistoryQuoted:
The counterbore? I've got a crapload of coated carbide end mills and such, zips right through when there's already a pilot hole
The fun part is trying to drill the nitrided ejector sleeves I use for gas tubes and gas keys, I usually touch a flat with the dremel to get through the surface nitriding so I can drill it. Oh, and if you have to tap anything in a carrier, you'd better have some coated cobalt taps and a lot of patience. Quote HistoryQuoted:
Quoted:
Quoted: The issue with this is going to be the joint between the carrier and the heavy key. Short of welding it, you will likely shear the small gas key bolts in the first few shots.
On my bufferless carriers, I add a hardened hollow dowel around the gas hole, You could add something similar, but solid, and hope it can handle the impulse. See the 1/4" countebore around the gas hole. The dowel drops in there and fits in a pocket in the key. http://i241.photobucket.com/albums/ff206/devtucker/AR-45/IMG_20140920_171036_957.jpg http://i241.photobucket.com/albums/ff206/devtucker/AR-45/IMG_20141008_173712_915.jpg How many bits did you go through drilling that? The counterbore? I've got a crapload of coated carbide end mills and such, zips right through when there's already a pilot hole
The fun part is trying to drill the nitrided ejector sleeves I use for gas tubes and gas keys, I usually touch a flat with the dremel to get through the surface nitriding so I can drill it. Oh, and if you have to tap anything in a carrier, you'd better have some coated cobalt taps and a lot of patience. I see what you mean. I will look into the design and see what would work best. Looking at my bolt I think I could work in 3 keys/pins It will be interesting to see what breaks first on it though. |
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Posted: 7/14/2015 9:05:08 PM EDT
[#10]
Greetings, That's an amazing build (the MP5 upper/AR lower)! Rudy, did you ever do one; if so would you be planing to offer it for sale? Regards, Jim Quote HistoryQuoted:
This thread? http://www.weaponsguild.com/forum/index.php?topic=53142.0 Quote HistoryQuoted:
Quoted:
Can't find the thread...but a fellow on weaponsguild grafted the upper half of a an MP5 to an AR lower using the roller locks.......was a masterful build and he even included an auto sear trip as it was mounted on a registered lower. This thread? http://www.weaponsguild.com/forum/index.php?topic=53142.0 |
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