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Posted: 8/7/2014 11:20:39 PM EDT
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I've mentioned in my LR-308 thread that I picked up a couple of lowers for builds and I'm wondering about the 300BLK now.
I have read that it was designed to deliver performance similar to the 762x39AK round but compatible with AR-15 parts. I was interested in building AK variants on an AR platform, but since Russian milsurp is corrosive, I wouldn't would to risk problems with aluminum parts. So, that leaves me thinking about building a 300BLK for a more compact 30 cal rifle with AK performance. Because I've not really thought much about the 300BLK before, I thought I'd ask you guys about the build requirements. What all would I need specifically for the 300BLK build that wouldn't be AR-15 compatible? Just the barrel? Is everything else the same? Thanks in advance. edit: Oh wait, no, I guess I would need an 80% lower to start with because my other lowers are stamped 5.56 and a mix-up by someone else would be...dangerous. |
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Quoted:
I've mentioned in my LR-308 thread that I picked up a couple of lowers for builds and I'm wondering about the 300BLK now. I have read that it was designed to deliver performance similar to the 762x39AK round but compatible with AR-15 parts. I was interested in building AK variants on an AR platform, but since Russian milsurp is corrosive, I wouldn't would to risk problems with aluminum parts. So, that leaves me thinking about building a 300BLK for a more compact 30 cal rifle with AK performance. Because I've not really thought much about the 300BLK before, I thought I'd ask you guys about the build requirements. What all would I need specifically for the 300BLK build that wouldn't be AR-15 compatible? Just the barrel? Is everything else the same? Thanks in advance. edit: Oh wait, no, I guess I would need an 80% lower to start with because my other lowers are stamped 5.56 and a mix-up by someone else would be...dangerous. HUH? You can use any lower who cares what's written on the side. The only thing you will need is a different barrel and FH. That's it. |
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Quoted:
HUH? You can use any lower who cares what's written on the side. The only thing you will need is a different barrel and FH. That's it. Well, the point is that I wouldn't want someone putting the wrong round inside, thinking it's a 5.56 since it would be stamped on the receiver as such. Sorry, what is your abbreviation FH? So, no gas changes needed or buffer weight changes for recoil? |
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^^^ 5.56 won't chamber in a 300BLK... the reverse is a bigger issue / risk. The gas is dependent on the barrel you buy (port location and size) and assuming a reputable manufacturer will likely be fine as is.
I would argue that you should be checking upper / barrel markings for caliber confirmation if confused (never the lower on an AR)... add a port door marked on both sides: 
FH is Flash Hider |
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FH - flash hider. I guess one with a 1/4" hole would be a problem. That said, I would be surprised if most had that little clearance. I am only thinking about it because I need to ream out a 308 flash hider for my 458. From a different thread Quoted: I got a brake with the hole of .281. Wanting to put it on a .243. The brake was originally designed for a. 223. Is this enough clearance to run on a. 243. |
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Quoted:
^^^ 5.56 won't chamber in a 300BLK... the reverse is a bigger issue / risk. The gas is dependent on the barrel you buy (port location and size) and assuming a reputable manufacturer will likely be fine as is. I would argue that you should be checking upper / barrel markings for caliber confirmation if confused (never the lower on an AR)... add a port door marked on both sides: http://www.hand-tools.com/images/brands/misc/huge-AR-15-ejection-port-cover-300-AAC-Blackout.jpg FH is Flash Hider Oh yeah, well I wouldn't put a 5.56 brake on the barrel. I'd just put a 308 on there. The laser engraved dust cover is a good idea. I will go that route and then I can just build a 2nd upper for 5.56 and use the same lower. A dust cover would be an inexpensive way to mark the rifle. |
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Quoted:
Oh yeah, well I wouldn't put a 5.56 brake on the barrel. I'd just put a 308 on there. The laser engraved dust cover is a good idea. I will go that route and then I can just build a 2nd upper for 5.56 and use the same lower. A dust cover would be an inexpensive way to mark the rifle. Quoted:
Quoted:
^^^ 5.56 won't chamber in a 300BLK... the reverse is a bigger issue / risk. The gas is dependent on the barrel you buy (port location and size) and assuming a reputable manufacturer will likely be fine as is. I would argue that you should be checking upper / barrel markings for caliber confirmation if confused (never the lower on an AR)... add a port door marked on both sides: http://www.hand-tools.com/images/brands/misc/huge-AR-15-ejection-port-cover-300-AAC-Blackout.jpg FH is Flash Hider Oh yeah, well I wouldn't put a 5.56 brake on the barrel. I'd just put a 308 on there. The laser engraved dust cover is a good idea. I will go that route and then I can just build a 2nd upper for 5.56 and use the same lower. A dust cover would be an inexpensive way to mark the rifle. Like they said before a .223 won't chamber in a 300BLK. It is nearly imposible for that to happen but even if you took a hammer to it and forced it in the only thing that would happen is you are now shooting a .223 out of a .308 barrel. As for the flash hider you can't put a .223 one on the 300BLK as the threads are not 1/2x28. I do have dust covers on some of my AR that say 300BLK just so people know what that ultra quiet gun down at the end of the shooting range is. |
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If im not mistaken manufacturers only put the caliber on the lower because unless it says MULTI, one cannot turn it into a pistol.
So all complete long-ARs have the caliber written on the lower so someone under the age of 21 cannot replace the upper with a pistol upper. (And remove the stock) |
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Quoted:
If im not mistaken manufacturers only put the caliber on the lower because unless it says MULTI, one cannot turn it into a pistol. So all complete long-ARs have the caliber written on the lower so someone under the age of 21 cannot replace the upper with a pistol upper. (And remove the stock) No, it doesn't matter what it says on the lower. You can put any caliber upper on a lower marked 5.56 or anything else. There are 5.56 pistols. You can buy or build an AR pistol and convert it to a riffle and back and forth all you want. You CANNOT convert a rifle to a pistol, legally. Once a rifle, always a riffle. |
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