I was considering the 7.62x39 10.5" Pistol AR15 upper as an alternative to the 308 10.5" AR10 upper. Because in the barrel lenth 10.5", the velocity and energy of both cartridges are not far apart. The problem is the AR15 platform is reported to be plagued with failures after a few hundred rounds firing 7.62x39, i.e. extractors, bolts, and firing pins cracking. So is it still worth buying a $175 BCA upper?
Come on people honesty, its mostly what I need from you, lol
absolutely untrue. My first AR is an X39 and it runs like a top after several thousand rounds.
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If that were the case 300 BO would have never became a thing.
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The main issue I’ve heard of is that the bolt face had to be opened up a bit for the larger x39 case head which could weaken the bolt. This isn’t an issue for the 300 BO since it’s made from the 5.56 case. I keep an extra bolt but haven’t had the need to replace the original yet.
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Obviously there’s nothing wrong with the x39 Quality wise.
Otherwise the AK47’s wouldn’t have the reputation for reliability that they do.
The AR15 version of x39, some manufacturers just don’t engineer them well.
I returned one that had same size ejection port for x39 as for 223, even though x39 is about .440 and 223 is 3/8 inch, .375.
I didn’t return it because of that, I returned it because it wasn’t cycling. It was a special variety of semi-auto where you swear once every time you pull the trigger.
The fatter bullet should have a wider ejection port.
The 300 Ham’r is a great caliber. It is compatible with some of the medium capacity AR15 magazines built for 223.
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What you point out about how the 300BO being designed for the AR15 bolt is important. The more powerful X39 as you refer was designed around the much more robust AK platform, not the AR. Specifically the bolt face edges and extractor are thin, firing pin weak against hard X39 primers break.
So you must have a hardened AR BCG, pin, and buffer specifically to withstand the X39 costing much more. Perhaps I could buy the cheaper BCA upper for far less and have the new hardened PSA BCG for X39. But then again at combined cost of both perhaps I should just buy the PSA X39 upper for $399. $175 is just so much more appealing lol.
Whats odd is that the BCA 450 Bushmaster upper also uses a very thinned out AR bolt face to accommodate that huge 450 cartridge, but doesn’t suffer the same damage. I suppose I should just accept that the X39 is best fired for the AK platform it was designed for.
By the way rockymountainjeep, very nice looking AR-X39
It just occured to me that Ruger makes a Mini 30 ($$$$), but just like my Ruger Ranch 5.56 that share 20 round magazines with the Mini 14, PSA just happens to have on sale the Ruger Ranch X39 that shares 5, 10, 20, & 30 Rd magazines with the Ruger Mini 30. So maybe this would be the perfect compromise at half the cost. What do you think? UPDATE: G4G for 478 OTD!
Oh I know, and we both have enough AR platforms right. I suppose its good to balance out some favorite calibers in “non-scary” platforms. And besides when it comes to weapons engineering, accuracy, and overal applicability, this platform has alot to offer at 5.5Lbs and magazine options. For me anyway right now, its the best of all worlds at 478
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How did you go from the above to a Ruger Ranch rifle? I think they both (5.56/7.62) are great bolt actions. But I started reading about a .30 cal 10.5" AR to a Ruger bolt. 
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OK you got me, now be kind and don’t miss the true 46 live right now!
Thanks my brother man 
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“I can reach out to manufacturing on Monday and see what their timeline looks like. Sean.psa”
Jammo - Just so you know sean.psa contacted me and of course since I already have a PSA pistol lower being assembled, yes if sean can get an upper from the manufacturer I’ll buy it. This is not an issue for me just a decision. Just wanted to put you at ease lol
Not to belabor past discussion, I believe we were comparing X39 to 450 and the AR bolt face and extractors compromise to accommodate. I cant speak to the AR9 as Ive never owned one. I can only speak intelligently to the 16" 450 Bush upper and X39 18" upper I own, and both but especially the 450 eat up but a very thin margin of the outter rim of the AR bolt face. Below you can see the difference relating to the original discussion. Also note the 450 thin rim photo. This compared to the thicker perimeter of the 5.56/.300 bolt face much more robust resistant to damage, last photo…
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Come on, you know you guys love me anyway. Even with all my flaws. Hay and for me its ditto. Were posting here to share, learn, and laugh. Now how do you pin the smily face 
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What flaws??? oh, ok, you use hay instead of hey, but I can live with that!
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i had built a 7.62x39 back right before PSA had came out with their own 7.62x39 barrel. My rifle is a 16 inch m4 clone other than the barrel and the thing runs like a top. I use ASC magazines for it, and love how the rifle performs and looks.