Could A .308 Upper For The Mac Style Family Of RRs Be Designed

mattnh

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7.62x51 typically needs a hydraulic buffer
+ a lot of gun mass to be controllable in FA
when shot offhand rather than from a bipod/tripod
 

Erevis

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Knowing the capital investment and ATF nightmare of approval, I wouldn't attempt to bring a magazine-fed .308/762 NATO upper to the market. I just really don't think there's a profitable market size for it-- especially considering the cost of .308 per round. Even a .308 belt-feed would likely get closer to profitability than a magazine-fed .308 upper.

You'd get a LOT more interest in a 5.56 belt-feed upper. Lage and RNE is going to have the magazine fed 5.56 market locked up. And Tenko will have its own niche there as well.
 

sniperdoc

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Could you please go into more detail? I am trying to understand what you are saying. Are you saying that the bolt/carrier group would fall out? Most every rifle system I can think of is held over, under, or beside the magwell and has an ejection port 90 to 180 from the magwell. So where would the hole for the bolt group to fall out of be? Could a "Locking Device" be made? Certainly but how would such a device be only activated by the actual receiver? If this "Locking Device" could be held in the open position by something like a zip tie, the ATF can say that the "upper" is easily converted. I am not trying to mock or belittle. I am just trying to understand.

Scott

1) Bolt Retention: I am thinking of a 2 piece interlocking system: the Upper is one, and a block that is inserted into the Lower is the other. Without the Lower to hold the 2nd block, the Bolt will be unsupported from the bottom and will fall out. Think of the Bolt/Carrier interaction in the SKS; without the Receiver to support them, they separate.
2) Locking Device: I haven't figured out the fine details yet, but my basic idea is a part that fits in the Lower that has an arm which fits into a slot in the Upper. The slot contains a Disconnector type Lever, which locks the Bolt until depressed by the Lever. (Almost like the Shear Line in a lock), basically working like a Magazine Disconnector
 
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Hood886

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I am fairly certain I could take a mg42/m53 parts kit and make it function on a Mac lower. Would the atf approve that? Probably not as it's a considerable variation from the original design but it would work. Also the abuse the lower would take is not known.
 

cjsoccer3

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Feeling an M14’s recoil, I’d be weary that my MAC upper could hold up without getting warped, cracked, etc.

My hunch is pistol calibers, 5.56, and maybe 7.62x39 are the furthest they could be stretched. 5.56 might even be pushing it when it’s a high round count. One reason why I’m M10/45 biased.
 

ecestu

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Only large cal FA gun worth a crap for controlability would be the 1918 BAR. Or tri/bi pod mounted.

Uh, guess you've never fired the HK-51. Roller locks are magical.
 

sniperdoc

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There are several .308/7.62×51 Beltfed MGs that are very controllable; shoulder-fired, mag-fed weapons are another kettle of fish.
 

Galil#1

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Roller-delayed blowback, Alex for $200 please... About "magical" IDK... My factory HK53 is a prima-donna... different locking pieces (#3, #7, & #15) with different grain bullet weights, with some keyholing and then the two (2) different possible barrel twist rates 1/7" the preferred etc. I can see and appreciate the "evolution" when the next gen HK MG/SMG did away with all of the locking piece drama. Also, the small pin that holds the extractor in, is such a weak point in the design IMHO. Lets not speak of the constant ish concern of proper bolt gap. Other than all that, it's a beautiful work of German engineering, again IMHO. Sorry, was not trying to jack this Post.
 

MACchat

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I don’t have a lot interest in feeding a .308 belt. But if Lage ever makes one for the M10, I’d probably be a buyer.
 

Galil#1

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Same as above and add a belt fed 7.62X39 for good measure. Build it and they will come lol!
 

A&S Conversions

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Count me in for anything smaller, and still belt fed. I’m thinking .223 or even 9mm.

That was the whole idea behind developing the Tenko adapter. The MCR/ Shrike in 5.56X45 and the Freedom Ordinance FM-9 is 9mm are already commercial available along with the Tactical Innovations AM15 upper based on the American 180. Certainly there is a small market for a beltfed .308 upper, but I think that demand for such a product would be more from guys that are priced out of the original. My understanding is that a M60-E6 would have a market value around $70,000. Would a typical Mac style RR owner be interested in a $10,000 to $15,000 upper based on the M60-E6? Probably not, but I think that the guys that want a M60-E6 that don't have $70,000 would be the market for such a product.

We are still working on developing the Tenko 10-16 adapter for resubmition. Adding complexity without reducing reliability has been very challenging. But I think that a submission that will pass is possible. We have a few tweaks to finish before submission. Would it be expensive to buy the Tenko adapter and these commercially available M16 uppers? Absolutely, but if having the basic functionality of a M16 RR for half the current market value of a M16 conversion has appeal, I think that the Tenko adapter will have a market.

Scott
Manager A&S Conversions L.L.C.
 

ecestu

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Roller-delayed blowback, Alex for $200 please... About "magical" IDK... My factory HK53 is a prima-donna... different locking pieces (#3, #7, & #15) with different grain bullet weights, with some keyholing and then the two (2) different possible barrel twist rates 1/7" the preferred etc. I can see and appreciate the "evolution" when the next gen HK MG/SMG did away with all of the locking piece drama. Also, the small pin that holds the extractor in, is such a weak point in the design IMHO. Lets not speak of the constant ish concern of proper bolt gap. Other than all that, it's a beautiful work of German engineering, again IMHO. Sorry, was not trying to jack this Post.

Lol. Well allow me to retort. When the stars and HK parts and bullet weights are aligned and it's the 5th blue moon of the year, the HK is a smooth, controllable shooter as a mag feed 7.62x51 cal automatic. But you are correct. I was never able to get my 10mm running, so I had to pass the problem child onto someone with much more patience than me.
 

Galil#1

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Lol. Well allow me to retort. When the stars and HK parts and bullet weights are aligned and it's the 5th blue moon of the year, the HK is a smooth, controllable shooter as a mag feed 7.62x51 cal automatic. But you are correct. I was never able to get my 10mm running, so I had to pass the problem child onto someone with much more patience than me.

O WoW Nice, you one of them fancy guys $$$ with your 7.62x51 belt feds and 10mm HKs! - BRAVO Sir BRAVO! Indeed it seems a love/hate/dramatic type relationship ha!
 

ecestu

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O WoW Nice, you one of them fancy guys $$$ with your 7.62x51 belt feds and 10mm HKs! - BRAVO Sir BRAVO! Indeed it seems a love/hate/dramatic type relationship ha!

Lmao. Nah, I'm a poor, but I've had cool friends.
 

Gaujo

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I remember a SAR article that purely fawned over the HK 21e. I was convinced until I looked up how much one was. I would wonder how many HK sear owners even own an HK 21 host. I have no real idea but I'd bet less than 25%, so you are getting to a pretty small pool. You could learn a lot about how much people will pay by looking at what the market will bear for HK hosts and M16 uppers. I figure there weren't many 21 hosts being made before the HK sear reached a certain price point. that MM 21e is what, 15k? If someone spends 40k on the sear they might go for it, but that's 37.5% of the transferable's value.
 

Galil#1

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Good friends are hard to find.... Nice!
Exactly, like that 'ol movie It's a mad, mad, mad world.
Just the last 3 years, so unreal the Trans., and Pre May's $$$$$.
IMHO the MG/SMGs are a bubble that will never burst.... the 07/02 are the luckiest of the lucky I reckon $. The common standard MG/SMGs... $40, $50, $70K+. Even Pre May's seem to horded and way way up $$$.
 

KickStand

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Good friends are hard to find.... Nice!
Exactly, like that 'ol movie It's a mad, mad, mad world.
Just the last 3 years, so unreal the Trans., and Pre May's $$$$$.
IMHO the MG/SMGs are a bubble that will never burst.... the 07/02 are the luckiest of the lucky I reckon $. The common standard MG/SMGs... $40, $50, $70K+. Even Pre May's seem to horded and way way up $$$.


It’ll burst; however, when is the question. It could be days, weeks, months, years or decades. Pick one of them but one day something bad will happen with a transferable and then they’ll be gone. Some politicians might be pro gun but even they will likely not put there neck on the line. I see them either raising the transfer tax to the moon, make it when you die they won’t be transferred upon death or confiscated (they know who’s got what and where). It’s sad but the good ole days will likely come to end; hopefully, later rather than sooner.



In the mean time, I’m looking forward to seeing a working prototype 308 upper.
 

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