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Posted: 10/16/2011 4:30:19 PM EDT
Are the piston systems more forgiving on the amount of gas needed to function the action properly as compared to a DI system using the 300 blk/whisper ? From the reading I'm doing about that ctg. its very specific on what loads will function and what wont .Would a piston system allow some more flexibility . Or are there other factors that come into play here like gas port size ect.
Thanks,Tim |
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I haven't messed with a 300BLK piston upper yet but Stacy from PWS tells me their Mk109 won't run unsuppressed with subsonic ammo.
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LWRC just unveiled their upcoming 300 BLK upper, which works with both super and subsonic ammo.
http://forum.lwrci.com/viewtopic.php?f=2&t=10288 |
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LWRC just unveiled their upcoming 300 BLK upper, which works with both super and subsonic ammo. http://forum.lwrci.com/viewtopic.php?f=2&t=10288 is the gun that guys holding real? the guy in the blue? i mean it looks tiny and like a toy, i mean if thats real that dude is like 8' tall |
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HAHA, the pic is real, real gun, and real Man. He's not quite 8 ft. but not far off,
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HAHA, the pic is real, real gun, and real Man. He's not quite 8 ft. but not far off, Too funny! Jarred - if you really want to confuse everyone, re-post the pic that Jessie posted on the LWRC forum with him and the OCC crew. Hilarious! |
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I think that lil stock makes it appear smaller, looks like my 7.5in just with a smaller stock
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I believe since it's a UICW variant it's collapsed OAL is 22" (vs the PSD's 25" OAL).
Also, the buffer section has been shortened. Compare the UICW CAR stock to a standard CAR stock and you'll notice it's been shortened forward of the locking mechanism. |
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LWRC just unveiled their upcoming 300 BLK upper, which works with both super and subsonic ammo. http://forum.lwrci.com/viewtopic.php?f=2&t=10288 Will it run subsonic without a suppressor? I don't think anyone can get their .300BLK or .300 Whisper upper whether it is DI or Piston to run unsuppressed with the subsonic loads without the back pressure boost of a can. |
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LWRC just unveiled their upcoming 300 BLK upper, which works with both super and subsonic ammo. http://forum.lwrci.com/viewtopic.php?f=2&t=10288 Will it run subsonic without a suppressor? I don't think anyone can get their .300BLK or .300 Whisper upper whether it is DI or Piston to run unsuppressed with the subsonic loads without the back pressure boost of a can. Since the video in that thread shows them running it FA with both types of ammo I would say... YES |
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I shot a DI 300 Blackout with both types of ammo from CMMG on full auto at Knob Creek over the weekend.
8" barrel with pistol length gas port. Dave N |
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Since the video in that thread shows them running it FA with both types of ammo I would say... YES It had a AAC can on the whole time, my question refers to unsuppressed. |
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I shot a DI 300 Blackout with both types of ammo from CMMG on full auto at Knob Creek over the weekend. 8" barrel with pistol length gas port. Dave N A piston driven gun? I didn't know CMMG was making such a critter. |
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No, it was a DI but my point was, it fired subs and super sonic with and without the suppressor. I'm having one built with an 8" barrel.
CMMG builds a lot of stuff you don't see on the web site. I always tell guys to call. Dave |
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Since the video in that thread shows them running it FA with both types of ammo I would say... YES It had a AAC can on the whole time, my question refers to unsuppressed. My bad, I wasn't paying attention. I am pretty sure it does though. |
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No, it was a DI but my point was, it fired subs and super sonic with and without the suppressor. I'm having one built with an 8" barrel. CMMG builds a lot of stuff you don't see on the web site. I always tell guys to call. Dave Thanks for clarification. I'm curious to read about your experiences. |
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Since the video in that thread shows them running it FA with both types of ammo I would say... YES It had a AAC can on the whole time, my question refers to unsuppressed. My bad, I wasn't paying attention. I am pretty sure it does though. Well, not one other manufacturer has been able to do so without making it severely over gassed with the full power loads, so I was curious. |
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Piston guns will be louder, for those who care about such things.
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Piston guns will be louder, for those who care about such things. That is dependent on the method that it vents its gas. Some piston weapons explosively vent right as the piston reaches its full length of travel, some don't. |
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Piston guns will be louder, for those who care about such things. That is dependent on the method that it vents its gas. Some piston weapons explosively vent right as the piston reaches its full length of travel, some don't. examples of each? |
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too much pressure differences, you may be able to toe the line and get ok results with the 2 extremes, or you could have a regulator, and turn it for the different scenarios(I know its a tough concept ). Look at the difference in cycle energy, the direction the brass..
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I would think an over sized gas port with an adjustable gas block would work.
Dave N |
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I would think an over sized gas port with an adjustable gas block would work. Dave N http://www.300blktalk.com/forum/viewtopic.php?f=128&t=77810 |
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I don't understand Noveske's response. My reading it just sounds like they did not want to mess with it.
And it doesn't state what the gas system was. Carbine or pistol. I would think the cyclic rate would only apply to full auto. I'm sure I'm missing something here. I may have to do some experimentation. Dave N |
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Because of the challenges with the small case for the .300-221 variants, the .30 HRT was developed to give a larger case and perhaps add some flexibility. One of our customers had us build a 16" barrel upper, carbine gas system, using the Adams Arms piston system. It required some tweaking including minor modifications to the AA piston set up (replaced the spring with one with a lower constant). In the end, however, the customer was able to shoot anything from 110 gr to 240 gr bullets without issue, suppressed and unsuppressed, using the adjustment knob on the AA piston system.
Just a thought... |
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Piston guns will be louder, for those who care about such things. That is dependent on the method that it vents its gas. Some piston weapons explosively vent right as the piston reaches its full length of travel, some don't. examples of each? Well currently the only one that I personally know of that holds the gas for a bit longer is the PWS Long Stroke design in their uppers and rifles. Everything else I've seen from the HK416, SCAR, and LWRC on down has a piston that only travels for .75 to 1 inch as it drives its Op-Rod rearward. Then that gas is dumped immediately at the onset or shortly after the action begins to open and cycle rearward. Even these designs will differ based on the internal shape and dimensions of the gas block and piston. |
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Piston guns will be louder, for those who care about such things. That is dependent on the method that it vents its gas. Some piston weapons explosively vent right as the piston reaches its full length of travel, some don't. examples of each? Well currently the only one that I personally know of that holds the gas for a bit longer is the PWS Long Stroke design in their uppers and rifles. Everything else I've seen from the HK416, SCAR, and LWRC on down has a piston that only travels for .75 to 1 inch as it drives its Op-Rod rearward. Then that gas is dumped immediately at the onset or shortly after the action begins to open and cycle rearward. Even these designs will differ based on the internal shape and dimensions of the gas block and piston. cool, thanks for the info. |
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The short stroke tappet designs only touch the carrier for a split instant in time and then the carrier separates. They actually don't even push for their full strokes against the carrier. One of the advantages of the long stroke is non impact of the gap between op rod and carrier face of the short strokes.
If you were coming out of the water and shooting a long stroke would not be what you want, the piston would have to displace water before coming home.... |
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If I wanted a non free floated long stroke system, I would just get an AK which is almost like having a 300BLK as it is.
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If I wanted a non free floated long stroke system, I would just get an AK which is almost like having a 300BLK as it is. Except for the lighter weight, barrel quality and accuracy combined with the ergonomics and muscle memory to operate an AR you are right. |
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The short stroke tappet designs only touch the carrier for a split instant in time and then the carrier separates. They actually don't even push for their full strokes against the carrier. One of the advantages of the long stroke is non impact of the gap between op rod and carrier face of the short strokes. If you were coming out of the water and shooting a long stroke would not be what you want, the piston would have to displace water before coming home.... I think every AR, DI or Piston needs to drain before being able to function safely......the water in the bore will take longer to drain that that in the piston assembly. |
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That is if you buy crappy AKs, buy a Krebs and tell me if anything beyond muscle memory applies. Things are changing in the rifle world, you are seeing more and more AKs show up to Carbine courses. They are perfect for the type of work you see at those courses. There is no way possible to put those positive attributes into an AR without making some kind of compromise in the process.
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If I wanted a non free floated long stroke system, I would just get an AK which is almost like having a 300BLK as it is. Except for the lighter weight, barrel quality and accuracy combined with the ergonomics and muscle memory to operate an AR you are right. |
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That is if you buy crappy AKs, buy a Krebs and tell me if anything beyond muscle memory applies. Things are changing in the rifle world, you are seeing more and more AKs show up to Carbine courses. They are perfect for the type of work you see at those courses. There is no way possible to put those positive attributes into an AR without making some kind of compromise in the process.Quoted:
If I wanted a non free floated long stroke system, I would just get an AK which is almost like having a 300BLK as it is. Except for the lighter weight, barrel quality and accuracy combined with the ergonomics and muscle memory to operate an AR you are right. You are right, things are changing in the rifle world. A Krebs AK is not the end all be all of carbines though. Neither is a PWS. They both share the same method of operation however and for those looking for that style of operation in a less than 7 lbs AR, the MK1 rifles from PWS are pretty tough to beat. |
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