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Quoted: I look forward to seeing what happens with just the gas system being moved. Honestly, it's where I'd start, too... the reciprocating mass velocity may not be the worst problem, short-term, and smoothing out the peak of the gas system should help quite a bit either way. ETA: I should clarify, I'm not saying the bolt velocity is low, I'm saying it's far above the "ideal" 4m/s. View Quote Only meant that low velocity is often the result of simply constricting gas flow without regard to timing, dwell, impulse, etc. To the best of my knowledge, right now, even with the 6 position gas valve, one setting is too low resulting in too little energy to function properly consistently, and the next setting up is too much, resulting in torn rims, etc, because changing the gas flow alone does not account for pressure curves, timing and acceleration to a great enough degree. When it could very well be that extending dwell time by moving the gas port forward could result in necessitating an even larger gas valve setting than above in order to transfer sufficient energy for the rifle to function, while at the same time resolving extraction issues by extracting under lower chamber pressures and accelerating the bolt carrier at a lower rate. |
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Quoted: Oh I can't wait to see what you cook up on the MDR...but its just a dang shame you have to...that is all I am saying...this gun wasn't sold or marketed as a DIY fix rifle, or a custom, hand-fit model or anything like that...this craptastic rifle was sold to the masses as a battle rifle...that is why I have such bitterness to DT on this...they failed to deliver on everything but the actual "concept". View Quote |
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Quoted:
When it could very well be that extending dwell time by moving the gas port forward could result in necessitating an even larger gas valve setting than above in order to transfer sufficient energy for the rifle to function, while at the same time resolving extraction issues by extracting under lower chamber pressures and accelerating the bolt carrier at a lower rate. View Quote Would be a bandaid, but this thing is already wrapped in bandaids. |
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It's far easier for me to move the gas system than to re-engineer everything going on behind the barrel extension. Removing the gas block, plugging the existing gas port, drilling a new gas port, turning a longer gas plunger - that's it. I don't care about the silly little section of pic rail and can come up with a way to eliminate any gap in the top rail after the fact, even if it means milling a new gas block with a cantilevered rail section. We probably disagree more on what exactly the problem and solution is than anything. I'm convinced my particular rifle's problem isn't reciprocating velocity, but acceleration and timing of that acceleration. Lower the rate of acceleration and delay the unlocking of the bolt until a lower chamber pressure is present than currently, and I believe mine would run quite well. ETA - note I've never, not once, had a malfunction related to low carrier velocity or inertia. Not failure to feed, not failure to LRBHO, not failure to eject, not failure to go into battery. Maybe if I can get it slowed down I will, but to date my failures are all related to ripping rims and leaving cases in the chamber. View Quote |
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Quoted: Could add gas volume between the port and the piston, similar in concept to a fat or pigtail gas tube Would be a bandaid, but this thing is already wrapped in bandaids. View Quote |
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If you have LN around, go whole hog and aim for 0.002 interference.
Overkill, but not enough to deform the bore or introduce enough stress to crack... well, as long as the sleeve isn't too thin. Sounds like you know what you're doing already. |
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Quoted:
So best case, their testers were ignorant enough to not test with a variety of ammo, which 99.99% of their customers would actually use. Worst case, they got too far along before someone caught it and said "too late now" and hoped nobody would notice before they started getting a return on their investment. View Quote View All Quotes View All Quotes Quoted:
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(I don't believe they knowingly put such a badly flawed system out; I do think they cheaped out on tearing by using in-house ammo) Worst case, they got too far along before someone caught it and said "too late now" and hoped nobody would notice before they started getting a return on their investment. My very brief experience in this area has given me a lot more respect for Hi Point pulling off typically reliable guns at their price point; it's a goddamn miracle. I still have no idea how Hudson was able to pull of a clean-sheet design with (to my knowledge) no design or production failures of any sort, as their very first project --I assume the bulk of their staff are veteran industry badasses, that's the only explanation. |
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Could add gas volume between the port and the piston, similar in concept to a fat or pigtail gas tube Would be a bandaid, but this thing is already wrapped in bandaids. View Quote View All Quotes View All Quotes Quoted:
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When it could very well be that extending dwell time by moving the gas port forward could result in necessitating an even larger gas valve setting than above in order to transfer sufficient energy for the rifle to function, while at the same time resolving extraction issues by extracting under lower chamber pressures and accelerating the bolt carrier at a lower rate. Would be a bandaid, but this thing is already wrapped in bandaids. -Make the piston head long enough to go past the gas port when in battery -Drill a hole in the side of the piston (at a turbulence groove) so it aligns with the port when in battery -Drill a hole in the front of the piston that intersects the side-hole Gas flows through the side of the piston out the front through a longer semi-tortuous path (dropping its pressure, effectively lengthening the path even more) where it fills up the gas cup, and drives the piston rearward. Shortly after the piston moves, the turbulence ring misaligns to the gas port, shutting off additional gas flow (by this point the piston already has enough pressurized gas in front of & inside it to complete the necessary acceleration). The result is a short, quasi-self-adjusting gas system. Oh, the M76 also has a blow-off port in the front of the gas cup, which essentially 'damps' out gas cup pressure spikes as well. Lastly, the gas cup itself is adjustable rather like the MDR, with different size orifices that can be placed between the piston and the port in the gas block. If you put a tit on the end of the piston that initially blocked the blow-off port sort of like the G36, you'd have one of the most sophisticated self-regulating gas piston systems possible. |
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If you have LN around, go whole hog and aim for 0.002 interference. Overkill, but not enough to deform the bore or introduce enough stress to crack... well, as long as the sleeve isn't too thin. Sounds like you know what you're doing already. View Quote |
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Quoted: Do what they did on the Yugo M76 to 'grow' the gas system but keep the overall package much shorter than a PSL despite being in 8mm Mauser; -Make the piston head long enough to go past the gas port when in battery -Drill a hole in the side of the piston (at a turbulence groove) so it aligns with the port when in battery -Drill a hole in the front of the piston that intersects the side-hole Gas flows through the side of the piston out the front through a longer semi-tortuous path (dropping its pressure, effectively lengthening the path even more) where it fills up the gas cup, and drives the piston rearward. Shortly after the piston moves, the turbulence ring misaligns to the gas port, shutting off additional gas flow (by this point the piston already has enough pressurized gas in front of & inside it to complete the necessary acceleration). The result is a short, quasi-self-adjusting gas system. Oh, the M76 also has a blow-off port in the front of the gas cup, which essentially 'damps' out gas cup pressure spikes as well. Lastly, the gas cup itself is adjustable rather like the MDR, with different size orifices that can be placed between the piston and the port in the gas block. If you put a tit on the end of the piston that initially blocked the blow-off port sort of like the G36, you'd have one of the most sophisticated self-regulating gas piston systems possible. View Quote |
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Quoted: Do what they did on the Yugo M76 to 'grow' the gas system but keep the overall package much shorter than a PSL despite being in 8mm Mauser; -Make the piston head long enough to go past the gas port when in battery -Drill a hole in the side of the piston (at a turbulence groove) so it aligns with the port when in battery -Drill a hole in the front of the piston that intersects the side-hole Gas flows through the side of the piston out the front through a longer semi-tortuous path (dropping its pressure, effectively lengthening the path even more) where it fills up the gas cup, and drives the piston rearward. Shortly after the piston moves, the turbulence ring misaligns to the gas port, shutting off additional gas flow (by this point the piston already has enough pressurized gas in front of & inside it to complete the necessary acceleration). The result is a short, quasi-self-adjusting gas system. Oh, the M76 also has a blow-off port in the front of the gas cup, which essentially 'damps' out gas cup pressure spikes as well. Lastly, the gas cup itself is adjustable rather like the MDR, with different size orifices that can be placed between the piston and the port in the gas block. If you put a tit on the end of the piston that initially blocked the blow-off port sort of like the G36, you'd have one of the most sophisticated self-regulating gas piston systems possible. |
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Quoted: Do what they did on the Yugo M76 to 'grow' the gas system but keep the overall package much shorter than a PSL despite being in 8mm Mauser; -Make the piston head long enough to go past the gas port when in battery -Drill a hole in the side of the piston (at a turbulence groove) so it aligns with the port when in battery -Drill a hole in the front of the piston that intersects the side-hole Gas flows through the side of the piston out the front through a longer semi-tortuous path (dropping its pressure, effectively lengthening the path even more) where it fills up the gas cup, and drives the piston rearward. Shortly after the piston moves, the turbulence ring misaligns to the gas port, shutting off additional gas flow (by this point the piston already has enough pressurized gas in front of & inside it to complete the necessary acceleration). The result is a short, quasi-self-adjusting gas system. Oh, the M76 also has a blow-off port in the front of the gas cup, which essentially 'damps' out gas cup pressure spikes as well. Lastly, the gas cup itself is adjustable rather like the MDR, with different size orifices that can be placed between the piston and the port in the gas block. If you put a tit on the end of the piston that initially blocked the blow-off port sort of like the G36, you'd have one of the most sophisticated self-regulating gas piston systems possible. |
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Quoted:
that actually is pretty goddamn smart. View Quote View All Quotes View All Quotes Quoted:
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Quoted: Do what they did on the Yugo M76 to 'grow' the gas system but keep the overall package much shorter than a PSL despite being in 8mm Mauser; -Make the piston head long enough to go past the gas port when in battery -Drill a hole in the side of the piston (at a turbulence groove) so it aligns with the port when in battery -Drill a hole in the front of the piston that intersects the side-hole Gas flows through the side of the piston out the front through a longer semi-tortuous path (dropping its pressure, effectively lengthening the path even more) where it fills up the gas cup, and drives the piston rearward. Shortly after the piston moves, the turbulence ring misaligns to the gas port, shutting off additional gas flow (by this point the piston already has enough pressurized gas in front of & inside it to complete the necessary acceleration). The result is a short, quasi-self-adjusting gas system. Oh, the M76 also has a blow-off port in the front of the gas cup, which essentially 'damps' out gas cup pressure spikes as well. Lastly, the gas cup itself is adjustable rather like the MDR, with different size orifices that can be placed between the piston and the port in the gas block. If you put a tit on the end of the piston that initially blocked the blow-off port sort of like the G36, you'd have one of the most sophisticated self-regulating gas piston systems possible. "I've measured this five times; the gas port & block need to be 1/2" further out for this piston length, but the barrel journal's all wrong and the gas tube is loose. WHATTHEHELLISGOINGONEHERE?!!" It doesn't help that I was using an ORF 'receiver' (to use the term loosely) that had a half dozen gremlins of its own I was also chasing. |
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Quoted:
Or copy the RFB gas system, it's not much different than what you describe. View Quote View All Quotes View All Quotes Quoted:
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Do what they did on the Yugo M76 to 'grow' the gas system but keep the overall package much shorter than a PSL despite being in 8mm Mauser; -Make the piston head long enough to go past the gas port when in battery -Drill a hole in the side of the piston (at a turbulence groove) so it aligns with the port when in battery -Drill a hole in the front of the piston that intersects the side-hole Gas flows through the side of the piston out the front through a longer semi-tortuous path (dropping its pressure, effectively lengthening the path even more) where it fills up the gas cup, and drives the piston rearward. Shortly after the piston moves, the turbulence ring misaligns to the gas port, shutting off additional gas flow (by this point the piston already has enough pressurized gas in front of & inside it to complete the necessary acceleration). The result is a short, quasi-self-adjusting gas system. Oh, the M76 also has a blow-off port in the front of the gas cup, which essentially 'damps' out gas cup pressure spikes as well. Lastly, the gas cup itself is adjustable rather like the MDR, with different size orifices that can be placed between the piston and the port in the gas block. If you put a tit on the end of the piston that initially blocked the blow-off port sort of like the G36, you'd have one of the most sophisticated self-regulating gas piston systems possible. |
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Quoted:
Huh, I didn't know that; I figured it would be similar to my RDB...then again, IIRC the RFB had gas block issues early on, so maybe that was the fix? View Quote Mine has been running like a top since day 1 with the gen1 gas system, I've got a sub-500 SN. If you compare the RFB and MDR barrels, you'll notice the gas block on the RFB is at least a couple inches further from the chamber. The RFB also has a pretty beefy reciprocating mass compared to the MDR, and still manages to be a few ounces lighter overall... |
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The bad thing with the RFB is it's LOUD suppressed. To me it was in the realm of why even put a suppressor on it if the gas system is going to vent that much so I sold it. I don't want the mdr to be like that.
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The bad thing with the RFB is it's LOUD suppressed. To me it was in the realm of why even put a suppressor on it if the gas system is going to vent that much so I sold it. I don't want the mdr to be like that. View Quote The new gen RFBs are good to go aren’t they? |
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The bad thing with the RFB is it's LOUD suppressed. To me it was in the realm of why even put a suppressor on it if the gas system is going to vent that much so I sold it. I don't want the mdr to be like that. View Quote If Gen 2, they offer a suppressor-specific piston that reduces the gas entering the gas cup (no flat on the side of the piston stem) so you can leave the gas vent cap on. I've been toying with the idea of making up a couple test pistons for my Gen1 with smaller flats, or two flats, for a quick 120deg flip to go from unsuppressed to supppressed. I bet off to the side, you wouldn't notice much difference from an AR10, but as the shooter, well, there is a bomb going off and a lot of moving metal under your cheek bone. |
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Quoted: Gen 1 or gen 2? If Gen 2, they offer a suppressor-specific piston that reduces the gas entering the gas cup (no flat on the side of the piston stem) so you can leave the gas vent cap on. I've been toying with the idea of making up a couple test pistons for my Gen1 with smaller flats, or two flats, for a quick 120deg flip to go from unsuppressed to supppressed. I bet off to the side, you wouldn't notice much difference from an AR10, but as the shooter, well, there is a bomb going off and a lot of moving metal under your cheek bone. View Quote |
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Wonder how the RFB is with an OSS? The new gen RFBs are good to go aren’t they? View Quote View All Quotes View All Quotes Quoted:
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The bad thing with the RFB is it's LOUD suppressed. To me it was in the realm of why even put a suppressor on it if the gas system is going to vent that much so I sold it. I don't want the mdr to be like that. The new gen RFBs are good to go aren’t they? A bleed-off port that vents into the end cap of the can is the best solution --I think someone did this for AUGs at one time-- but obviously makes mount the can more difficult & proprietary. Maybe a second, tiny silencer mounted at the gas block? |
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I think a company made some baffled gas caps for the gen 1 rfbs.
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How awesome would it be if Kel-Tec offered an MDR trade-up program. Send in an MDR, get back an RFB *and* an RDB... I mean the MSRP works out about the same
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First report of the 5.56 MDR is on BPF...well an unboxing kind of sort of...the charging handles don't work as they should...and the flash hiders are still monkeyed on where it breaks removal tools...who knew...I guess DT never learns from their mistakes like they say they do...same o craptastic quality that makes it into customers' hands.
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First report of the 5.56 MDR is on BPF...well an unboxing kind of sort of...the charging handles don't work as they should...and the flash hiders are still monkeyed on where it breaks removal tools...who knew...I guess DT never learns from their mistakes like they say they do...same o craptastic quality that makes it into customers' hands. View Quote It's too pathetic to be anything but hilarious, now. |
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Can't wait to see them at Range Day at SHOT. I'm sure it will be all good
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They will just set the gas all the way up to make sure they all fire...
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Just look at how the MDR recoils in InRange's video on Setting 5 and 6...its ridiculousness...the new normal setting in 2019 is the old Setting 6 (adverse)...
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Guess that's why last year's videos looked like they kicked dang hard. View Quote View All Quotes View All Quotes |
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Is the Tavor 7 still slated for 1st quarter this year?
If so, the fat lady will have begun her Aria. The 7 is plenty accurate, having no reliability issues with any brass cased ammo ( I don't know about steel at this time ), and has improvements on a few things over the Tavor / X95, one being all you need for swapping righty to lefty is to flip the ejection port / shell deflector over ( so to speak ), just takes a few seconds, no tools, No need to remove the bolt and put in opposite way or anything like that, you don't need to open the internals at all. It uses SR25 mags so nothing proprietary, weighs 9lbs. |
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Is the Tavor 7 still slated for 1st quarter this year? If so, the fat lady will have begun her Aria. The 7 is plenty accurate, having no reliability issues with any brass cased ammo ( I don't know about steel at this time ), and has improvements on a few things over the Tavor / X95, one being all you need for swapping righty to lefty is to flip the ejection port / shell deflector over ( so to speak ), just takes a few seconds, no tools, No need to remove the bolt and put in opposite way or anything like that, you don't need to open the internals at all. It uses SR25 mags so nothing proprietary, weighs 9lbs. View Quote |
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Unfortunately not....IWI has been tight lips about its progress...probably for the better...at least they realized they had a problem...halted the release until it is 100%...
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Unfortunately not....IWI has been tight lips about its progress...probably for the better...at least they realized they had a problem...halted the release until it is 100%... View Quote |
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Range day at SHOT is Monday, hopefully IWI has a T7 at their station there to shoot, will be going to the DT setup as well if their there. I missed last year, but prior to that they weren't at the range day event, just private events.
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Range day at SHOT is Monday, hopefully IWI has a T7 at their station there to shoot, will be going to the DT setup as well if their there. I missed last year, but prior to that they weren't at the range day event, just private events. View Quote |
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Wasn't that demo to the Quick Reaction Camel Force of some middle Eastern kingdom, or did they just license them the bolt action production for that region so they could claim they don't sell product in that region?
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Pakistan's response to DT
Anyways...I wonder if DT will have ejection chutes on the 5.56 rifles at Shot |
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Doubt it, maybe a prototype. But at this point all MDR parts can be still considered prototype.
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Wasn't that demo to the Quick Reaction Camel Force of some middle Eastern kingdom, or did they just license them the bolt action production for that region so they could claim they don't sell product in that region? View Quote ETA: didn’t see the above link, which aligns pretty close with what I recalled. They tried to ask out a hot chick, were clearly getting rejected, and beat her to the punch and went all over Facebook to call her fat and ugly first. |
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On the contrary, Desert Tech never even made it to the shortlist, though the company had shown interest in securing the deal initially. Desert Tech’s first and foremost ethical responsibility should be honesty. The Company unfortunately clearly violated it by fabricating a story that at best is a publicity stunt. View Quote I read they licensed their bolt action platform to some Euro or ME company to sell it in that region. |
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I know that was a thing with their bolt guns (SRS?). I think their offering just wasn’t competitive and they pulled out so they could claim some moral high ground rather than getting rejected. I don’t know who they were demo’ing the MDR for though. I’d wager DT doesn’t know either, as they probably made it up in the first place. For their sake I hope they made it up, I can’t imagine how bad any 3rd party tests would have gone, let alone back then so early in its beta testing. ETA: didn’t see the above link, which aligns pretty close with what I recalled. They tried to ask out a hot chick, were clearly getting rejected, and beat her to the punch and went all over Facebook to call her fat and ugly first. View Quote View All Quotes View All Quotes Quoted:
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Wasn't that demo to the Quick Reaction Camel Force of some middle Eastern kingdom, or did they just license them the bolt action production for that region so they could claim they don't sell product in that region? ETA: didn’t see the above link, which aligns pretty close with what I recalled. They tried to ask out a hot chick, were clearly getting rejected, and beat her to the punch and went all over Facebook to call her fat and ugly first. Pakistan thing DT talked their way into a rifle competition for a contract in Pakistan. Meaning they must have done state department paperwork and such. Then DT started yapping about how they were taking the high road that Pakistan was begging them for rifles but DT wouldn’t sell to them because they were afraid the pakis would give them away and DT rifles would be used against US troops. It didn’t pass the sniff test. Especially since the story started on a gun website DT sponsored then only spread to jingoistic sympathetic news sources that did zero fact checking. Shortly after that Pakistan responded to news outlets basically saying “wtf? DT wasn’t going to win that contract they didn’t refuse us shit.”. Which makes sense a small fry company versus the big dogs of the world armament industry in a country with rampant corruption where kickbacks will probably come into play. So basically they lied out their ass when they realized they weren’t going to win to get free PR. The ME thing was only a few years ago. They either picked up a distributor in the UAE or allowed I think Caracal to produce their stuff for ME sales. I forget which. But it further proved how full of shit they were on the Pakistan thing as they were allowing their gear to hit third parties that they had no say over in the ME where states in the region do hand over weapons to unsavory characters who absolutely will use them against US troops in the region if given a chance. Frankly I tend not to believe a damn thing they say about anything anymore. |
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