Jgun

Can't be done. I'm not positive but I believe that the 7.62X39 AR's are built on the AR-15 platform and not the .308 AR platform because the cartridge is closer in length and power to the .223 than it is to the .308, why would you want to build an underpowered overweight large platform AR when the smaller receiver will accommodate the rd. Now don't take this for fact but as I recall when I was looking at building a 7.62X39 AR, the thing that made me go with the 300BLK instead was that in order to build one you need a proprietary AR lower that accepts the AK mags. You may find the two links interesting. http://www.quarterbore.com/kac/sr47.html http://www.ar-47.com/pics.html

welcome to the forum. Perhaps you'd care to give us some info on your 6.8? What upper/lower, BCG, how do you like the performance of the cartridge? We always like pictures around here!!!!!!

this is based on what I've read more than what I've experienced personally, but the reduced reliability that people describe seems to come from "tight" chambered semi auto guns that sometimes have failure to feed or extract/eject. The benchrest bolt guys like to have their barrels chambered tight, because it has been proven to make the gun more consistant shot to shot with hand loaded match ammo. Now if your looking for bolt gun accuracy out of an AR, you have to do what they do when building a gun. but having to be meticulous with you ammo loading comes with the territory. If you were to build a 1000 yd benchrest AR and not hand load for it your wasting the money to build the gun to that standard. The last two barrels I had made, the barrel mfg asked what my intended purpose was for the gun. I was told that they could chamber it tighter but it might be more finicky as far as what would chamber and feed without trouble. If your buying an off the shelf barrel for your build, it will be chambered so that it will not give you function problems. On the other hand, if your planning to have a barrel made to your specs, the barrel maker should discuss your needs and what level of accuracy you hope to achieve and what level of reliability you HAVE to have. It's like I said before, no one gun can do everything the best.

My friends running the ARFX on their comp AR15's all have rifle length ARFX's (vs the carbine length ARFX) and run the AR 15 rifle length buffer tube along with the AR-15 rifle buffer and buffer spring. On a .308 application would you use the .308 rifle length buffer and spring along with the AR-15 rifle length buffer tube?

Welcome to the forum. As far as I know the Ace ARFX will work fine on the .308 AR. You will just need to get the correct buffer tube, buffer,and spring for your application. the rifle length AR-15 stock uses a rifle length buffer tube . I'm assuming that will also be the case for your .308 AR but I'm sure that if you give them a call at Ace/Doublestar they will be able to tell you which are the correct parts to go with the the stock you want to use. Those ARFX's are rock solid and light weight besides, good luck.

I'm sorry, for some reason I mistakenly thought you were looking for a free floating handguard. I now see that the oracle uses non free float "glacier guards" Which look to be pretty light already . I will take a look around and see if I can find anything else besides the Troy offerings that Imshur suggested.

What do you mean "match up"? The 7.62X39 Russian is considered an intermediate cartridge while the .308 (7.62X51) is a "full size" rifle cartridge. I don't even think they actually use the same bullets. If not mistaken I think the 7.62X39 uses .311 dia bullets.

Welcome, You've come to the right place to get help with your first rifle build. I think you should have no problem accompllishing all your goals (as long as you don't mind building 3 rifles to do it!) You know how it is, you can build a gun that does one thing extremely well or you can build a gun that does many things well enough. Your 15 lb bench rest rifle is not going to be much fun to take hunting.

You might want to give these guys a call to ask if their handguard rail height matches the new DPMS height (if you like this type of handguard). I bought one of their handguards for an AR-15 and it appears to be of good quality. It's certainly lighter than the aluminum fived Quad rails, and you can add or remove rails as you see fit. The full carbon tubes may possibly be a little lighter though. http://www.apexcncmachine.com/store.php?seller=ApexMachiningCompany&navt1=19974&pd=3133547

As you say, You could actually, make a stepped pin that was .277" at the head end (where it passes through the rt side of the lower) and steps down to .250". You could then step it down further so that a .277" pin, possibly internally threaded 10-32 could screw on from the left side. That way you wouldn't have alter either the upper or lower. You also would do away with the need to slot the pins for the detente's, because they would be held in by the "caps" on the other end. You might want to have one pin come in from the right and the other coming from the left side (for strength)

bgc, I'm not up on these, but those two are single barrel trap guns, yes? I've never heard of the Milano , is it considered to be comparable to the Baretta? also what are those blue circles in each case?

bgc, Thank you for your offer of the 150's. I have 145's that I've already tried, and my buffy came through with some 155's, so I think I'm pretty well set in that weight range. I also have some MK 175's, so I think I'm just going to order 100 165/168's and then I should be ready to load some test rounds of each to see what the gun likes best.

Be carful, it can be habitforming.

Welcome to the forum. You'll find interest here in the other AR variants as well as the .308's . We'll be asking you about your 6.8, or I sould say, I'll be asking you.

I'm actually working up loads for a 300 BLK I built. I have some 175's in hand that I plan to try along with a friend that's promised me some 155's the next time I see him. I also see some 165's with that plastic tip you were talking about. I see them at Midsouth shooters supply for $21.50 per 100. I'm going to order some of them and then sit down for an extebnded loading session to make up some of each of the 3 bullet weights, with a number of different powder charges for each bullet. And then I'll have to get out to the range with a chrono. Man, I'm gonna need a secretary to keep track of all this information! thanks for your suggestions.

Welcome to the forum. If your researching .308 AR's, I think you'll find a wealth of information here. And don't forget, It's customary to post pictures of all new aquisitions (firearms related) on the forum.

Think I need to use spell check next time, LOL. That's what happens when I rush a response so I can go have dinner.

I'm in agreement with you. I find that my satisfaction with rhese projects seems to be in direct proportion to how many engineering obsticals I have to overcome. When I said that cutting the slots was a problem I was referring I think more to how much labor would be needed to make a $5 pin I don't wish to sound like I'm second guessing you, ( see this more as an enjoyable echange of idea's) But you might want to think teice about reaming out the lugs in your POF uper to fit .277" pins from the lower. If you do that and later decide to sell or do something else with the upper, you'd have to bush it back down to .250" to use it on a POF lower, and I'm thinking you'd reduce the resale value in the process.

If your going to use a POF upper, (which would have .250" holes in the lugs that take the pivot and takedown pins) and your using a DPMS type lower, Your not going to need to make bushings, Your problem will be the opposite. If you use POF pins (which match the upper) You'll want to put .250" locating holes in the lower,but as I mentioned before, I would suggest that you double check to make sure the POF pin length works for you. if you elect to go with .277" pins in the lower, you'd have to open up the holes in the POF upper to .277" (something I would strongly advise against). As far as making your own pins goes, turning the pins on the lathe is no big deal, but milling the channel for the retaining detents would be a pain (for me). Now I'm the kind of person that likes to do things differently than the other guy, so I would never second guess someone elses reasons for doing a project a certain way, but could you tell me why you have picked the POF upper/DPMS lower combination? By the way, I'm sure you already know this, but since the POF upper is a piston operated system, you will have to use their bolt carrier group. I'm not sure how the other parts might differ from the DPMS parts, but you might do well to use the POF buffer and buffer spring to match the impulse from the piston (for proper cycling?)

I just used one of these on my 300 build because I needed to be able to adjust the gas system with my lightened bolt carrier. I like that the PRI's are steel unlike a lot of the other adjudtable GB'swhich are aluminum, besides being smaller than most of the other adjustable's, no clearence problems with my Apex FF tube.

This may not aply to you of your planning to finish your own 80% lower, But I had originally planned to put together a .308 AR rifle based on the POF .308 lower (which I really like) mated to a DPMS upper. You may already know all this, but The POF .308's use .250" takedown and pivot pins while most of the others use .277" pins. Now, when I was mating the DPMS upper (with .277" holes) to the POF lower (with .250" pins) I had to make up bushings to go into the holes in the upper in order to take the slop out of the upper/lower fit. Your problem would be the opposite, unless your planning to machine the lower with .250 pivot and takedown pins. If so I suggest that you get yourself a set of the POF pins to check out because not only is the OD different than the Armalite or DPMS pins. but I seem to recall that the length was off which may give you trouble if you want to use the POF pins on a DPMS pattern lower.

I happened to see a thread on Snipershide about this. I didn't bother to see how recent it was. The concensus seemed to be that the original poster was making a big deal out of nothing because the responders claimed to have solved the problem with one of those stick on rubber buffer pads they sell. If I were the owner of the gun , I would certainly be relieved to know that there was a solution to the problem that would allow me to use the gun without any further damage to the buffer (and more serious, the buffer retainer and possibly the hole it fits into on the lower) but I would still be more than a little puzzled as to why it was happening in the first place, Maybe the threaded section at the front of the upper is a little too long? If that were the case and you measured it compared to other uppers that you knew worked, You could mill a little off the front and recut the slot for the alignment pin and solve the problem once and for all. What has me more confused is, why (if true) the mfg would tell the customer that this obvious battering damage was "normal" .

Your point that since there is no mil spec standard for the .308 AR's as there is with the AR-15's , making it difficult if not impossible for a manufacturer to cover all the possible combinations that we might come up with is valid. That being said, there is no excuse that I can think of that would justify selling an upper that you manufacture that doesn't work with the lower that you also manufacture (which DOES work with the other manufacturers uppers that you were supposedly designing it to be compatible with). And if you decide to make design revisions along the way that would effect the compatibility (gen1, gen2, etc) you have a responsibility to your customers to make it known how these changes will effect that compatibility. It's not easy to establish a good brand reputation, but it's not hard to damage it either, with this type of apparent mfg screw up. Regarding the idea of buying from mfg's that make complete guns that are known to work, Didn't IR offer complete guns? That was kind of the reason for my first post on this topic, I was trying to see if this was an isolated thing and if people who had guns with this rec set that were happy with them would respond. This stuff makes me think that I've been very lucky with the ones I've picked up. I preordered the MA TEN sight unseen because of my good experiences with their AR-15 receivers, and they don't even offer complete guns. I'm looking forward to hearing about Matt Crosses impressions of the Mega monolithic setup when his build is finished.

I guess I must be naive. I couldn't believe that a fully machined, billet receiver set which was being sold for a premium price could have such a serious design or manufacturing flaw. You know, when you opt to pay that extra money over the price of a DPMS or Amalita set, you take it for granted that your getting a part that is dimensionally correct. When I go for someting like this I figure I'm paying extra for better machine work along with unique styling. As I said earlier, it's a shame when someone comes up with a good idea that doesn't make it because they didn't take care of quality control.

So does that mean that there is something wrong with either the location of the shoulder on the barrel extension or the dimension of the thread length of the upper (not likely), or possibley the barrel was not seated against the front of upper receiver when assembled(more likely)? I'm trying to figure out what else could cause the bolt carrier to be too far forward in the upper.