Idea: Tube-fed AR conversion. (pics added)

[RickRyder]

I was going to ask about that, so all I'd need is a 7.62 upper?

http://www.midwayusa.com/product/196823/olympic-ar-15-a3-flat-top-upper-assembly-762x39mm-1-in-10-twist-16-barrel-stainless-steel-black-with-m4-handguard-flash-hider-30-round-magazine-pre-ban

That is just one example, there are other companies that offer that chamber as well

[zfields]

Personally, If I wanted a 30 cal upper I'd go 300 blk. But I reload so it's not as costly.

[sharxbyte]

I don't either. I have an SKS. But you can also get a 7.62x39 upper and pin it onto your standard AR 15 lower. You can even use a standard AR mag, but they do make 7.62x39 AR magazines...

I was going to ask about that, so all I'd need is a 7.62 upper?

http://www.midwayusa.com/product/196...gazine-pre-ban

That is just one example, there are other companies that offer that chamber as well

Dont hate, Here's some info on mine.

The bad things you hear about bad things about mags are, for the most part, ancient history. The first mags (esp. 30 rd mags) had feeding issues, but ASC has sorted them out. (I haven't had feeding issues since I changed bolts)

The other thing I like about this company, is that NOT ONLY did they not jack up their prices during the rush, but they still had stock. I have 2 blocked 30's and 2 of their 10's.

Heres some info I sent to the last guy who asked. if you have any other questions I'd be happy to help.

This is the upper I'm running. The only 2 issues I've encountered were a canted gas block (easily fixed with allen keys and a level) and the stock bolt SUCKS. We're talking losing lugs at sub 200 rounds. I replaced it with the LMT (Lewis Machine and Tool company) bolt. You have to special order it from them, and it runs $155. You may be able to talk them down because its an item which is no longer manufactured, and not covered by warranty.

http://www.lewismachine.net/contact.php

I also replaced the firing pin with this


Love the rifle. Haven't done too much accuracy testing perse. I don't know if it can shoot sub MOA, but standing, offhand ,rapid, I've hit 10 round 8" groups with iron sights at ~100yds. at 25 yds with a scope i can put them all in a ragged hole, and with irons i can put then inside 1.5 inches.

I dont claim to be a marksman, and I have put about 1000 rounds though it ( mostly at 25 yds ), but thats my experience. With some more range time at longer distances optics, etc. I'm sure I can make those groups quite a bit smaller, especially sitting with a bench and bipod.

seriously consider getting that LMT bolt as a backup. It sucks to be waiting to shoot your rifle until you get a replacement especially in this buying climate.

http://www.uzitalk.com/forums/showthread.php?35861-AR47

http://www.calguns.net/calgunforum/archive/index.php/t-604838.html

http://www.ar15.com/archive/topic.html?b=3&f=121&t=572873

[/QUOTE]

[sharxbyte]

back to the topic at hand though, any other suggestions? I looked at the loading system for an autoloading shotgun and it seems doable.

[zfields]

Dont hate, Here's some info on mine.

[/QUOTE]

I'm not going to deviate after this, but having 1 bolt out of how many actually work is not a great sign that the 762x39 AR platform works well. Yours, along with a few others on calguns are by far not the only ones I have seen posted with issues from the bolt.



Back to the tube fed deal.....


The one thing I would wonder about a bit is if the flexible shell of a shotgun,along with the some what "sloppy" chambering would make that loading system work, where the tighter chamber needed with a rifle would cause issues.

[Euphoria526]

What about polymer cased ammo? Enclose the actual bullet make the whole ammo cartridge smaller and possibly cheaper for mass production? that way you can fit more ammo in the tube? Then the only hurdle to overcome is the feeding issue.

[zfields]

What about polymer cased ammo? Enclose the actual bullet make the whole ammo cartridge smaller and possibly cheaper for mass production? that way you can fit more ammo in the tube? Then the only hurdle to overcome is the feeding issue.

That is a lot of work to produce an ammo that will have a pretty low demand.

[fr33domfightr]

You might be able to use something like the m203 grenade launcher tube. Cartridges could be held in a spiral channel. When loaded it might be somewhat heavy, but there might be a way to make it work.


FF

[chead]

You might be able to use something like the m203 grenade launcher tube. Cartridges could be held in a spiral channel. When loaded it might be somewhat heavy, but there might be a way to make it work.


FF

That's a helical magazine. The entire point of the tube-fed exemption is that it's impractical to have a "high-capacity" (or center-fire) tube.

[Euphoria526]

That is a lot of work to produce an ammo that will have a pretty low demand.

Too true. But the thing is they already make it for larger calibers, what about using the same machining to figure it out with a smaller caliber though? Cut more than half the work, just a smaller projectile.

[zfields]

Too true. But the thing is they already make it for larger calibers, what about using the same machining to figure it out with a smaller caliber though? Cut more than half the work, just a smaller projectile.

OK, lets imagine the "normal" price of 223, around 30-40 cents a round. Think about how much of that caliber is produced, how many factories are kicking it out, and the quantities. Let's not forget how much of that XM855 is "rejected" or overruns of military ammo.

Now, think of this new caliber, specially made for honestly, a gun that will have little to no popularity outside of CA (and probably very limited within the state ).

So, low production, low demand, low factory support. Want to take a guess how much that ammo will cost when you figure in all of that?




If anything, I would look at just trying to produce 300blk with a flat point design. This would pretty much make it a reloaders only type of rifle though, but a specialty ammo producer would be able to still minimize cost with it.

[starsnuffer]

What about polymer cased ammo? Enclose the actual bullet make the whole ammo cartridge smaller and possibly cheaper for mass production? that way you can fit more ammo in the tube? Then the only hurdle to overcome is the feeding issue.

HK and FNH are working on this. The primary prototype is their LMGs at the moment but when they get it right they'll expand to small arms. You can check out the LSAT program for more info. Basically they're using polymer cased telescoping ammo. The big hurdle here is heat. Brass serves as a heat sink, polymer not so much. With caseless this is a huge problem to the point of cookoff.

Top is caseless ammo, middle is brass 5.56 without projectiles, the bottom is the telescoping polymer ammo with projectiles. Weight savings is somewhere around 50% over brass.



-W

[renardsubtil]

Crazy.

Why not use the tube from an underslung 'nade launcher and put two (or three?) tubes in it to feed into the mag well kinda like the KelTec KSG? This would seem to get rid of a single overly long single tube accommodating 10+ rounds.

[J.D.Allen]

Spitzer bullets plus tube fed ='s . . . .

First thing I though of when I read the thread title. There's a reason why the .30-.30 winchester round has such a round nose...

[Justintoxicated]

would a clip count as a magazine?