If you've got money to burn, maybe even pay extra for some cool logo on the receiver, go the proprietary route.

If you like beating the system at it's $$ Game $$,
Windows (Except Windows 10 maybe) give results.

As bullets get longer and skinnier, cases get shorter and fatter, loading long gives you more space for bang dust.

 

Great questions. #1 seems too pricey. If I win the lotto I'll just buy a full LWRC carbine. I'm intrigued by #2. Are there any bullets with a cannelure that would let you seat them at cannelure depth and still take advantage of that extra magazine length? Also, while a 10rd mag would be great for hunting in most states, I'd need a 5rd version for here in Florida. It is hard to find much fault with #3, but it would still be heavier and less handy than an AR15.

 

The small frame 308s are only a few oz heavier than an AR15.

 

3) Buy a small frame 308 and stick any 243, 260, Creed, 7mm-08, 308 barrel in it and use common 308 pmags...gain 200fps over either of the other options.

This is the most expensive of the 3 options

4) Just build a large frame in 260 or 6.5 Creedmoor, or faster still the 6MM Creedmoor.

 

You think buying a small frame 308 is more expensive than building a rifle based on the LWRC receiver set and then paying $50 ea for a special mag?
My complete G2 cost around $900 and mags are $15 ea. To build a LR308 as light as a G2 will add some cost to the LR.
I guess my thought is why spend a ton of money to make a wildcat and a proprietary receiver and mag when I can buy a full sized rifle and use over the counter ammo that is 200fps faster and I can do it tomorrow.

 

Nevermind. I lost interest already.

 

Personally, I think LWRC is after an already slim market, but I believe they have some large overseas buyers. I also think that to the average shooter, it’s not a big deal using unmodified or modified mags. I’m getting 1/2-3/4’’ groups from mag length hand loads and just over an inch with factory. Really couldn’t ask for more in a sub $1000 budget(optics included) 6.5lbs rifle.

Anyone can try to push the envelope of what a caliber is capable of, but there is a line of diminishing returns. That goes for just about anything. For what LWRC wants for a rifle I’ll have a 2 or 3 homemade Ar’s. One for home defense, one for hunting, and another for tiny groups. Only one of those might get a windowed mag.

 

To answer you question, out of those options I’d pick #2.

 

#2 with a parent 6.5x47 case works well for me, although it limits the mags to about 6 or 7 rounds.

200 fps plus.

 

Hmmm .... I've been doing option #2 going on 6 years. Its easy to do, including modifying my receivers to load out to 2.410". I've had no issues using the windowed mags deer hunting and now rely on CCB mags because of their high quality. I went down this road initially to pursue 130 grain bullets. I found that the 130's never catch up with the 110-120 bullets designed for 6.8mm in trajectory or KE so I'm back using 6.8mm bullets. Now that the newer 6.8mm barrels have shorter freebore to be more accurate with factory ammo and mag-length handloads, loading long is not giving me the "magnum" performance I was initially getting. The only place I'm now reloading out to 2.4" is with my Valkyrie.

I've looked at going for more performance in a semi-auto platform but I've got a Tikka .270 Win that they can't compete with so those thoughts turn out to be a flash in the pan. Thus, I'm basically satisfied with 6.8mm performance (way better than 5.56mm or 300BO). I love carrying my sub 7 pound rifle with scope hunting. I only load past 2.3" for accuracy to accomplish longer range 6.8mm shots in my deer rifle. For my 6.8mm hog rifle set-up, I run standard mag-length loads and have not wished for more. Every hog has dropped. I don't need a .308, etc. (option 3)

Option 1 is a non-starter for me. There is no performance advantage that I'm aware of when using 6.8mm factory ammo in this set-up..

 

I agree with the comments regarding optionn2. I like the light weight and less expense of the AR15 platform tweaked with loading long and wildcats.

 

Already have Option 2 with CBB window mags. Got LWRC Six8 receiver set too. And I've been waiting for a metal mag for the Six8 for a long time. I believe it when I see it.

 

H has gotten his barrels to the point factory round accuracy is hard to beat no matter where you put the bullet , even if you get SST to go faster than factory all you get is a few more yards kill zone and S&B doesn't offer it's bullets as components so my reasons for rolling my own are short . I would like to have nosler AB with some speed and since CBB are still not offering loaded rounds I may have to break out the press one day .

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I found loading long doesn't necessarily mean more velocity. With 130 grain bullets it certainly did but you are using different powders, etc. However, moving a bullet closer to the lands increases chamber pressure. The only two 6.8mm bullet types I found that I could significantly increase velocity on by loading long was the 85/110 TSX and 105/120 MKZs. The only reason the TSX could be loaded out to 2.410" and still be 0.050" off the lands was the bullet doesn't reach 0.277" until the first drive band (what looks like the ogive is not the ogive). Loading long did let me get enough H322 into the case to to keep up with AA2200 and have a more temp stable load. but now the freebores are shorter. Thus, I only load long to improve accuracy.

 

For deer hunting with in 350 yds what are the advantages of the 105 over 120 mkz or visa versa . From your tests it seems both will be pass throughs and about the same size hole. The sst is crazy accurate and kill quickly, I like bounded because they pass through and S&B seems to be right in between as far as performance ( limited experience with S&B ) but I keep thinking the mkz may be the ultimate bullet.

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At those ranges, the bullet that has the advantage for me is the one that gives me the most confidence it is going where I placed it when the trigger is pulled.

 

None of the above

 

Not that it makes a difference on the topic, but the $50 per magazine is a high estimate. You can get two 6.8 pmags for $50.

 

Start up cost for new mags aren't cheap from everything I've read. With PRI mags retailing for $40, the $50 is reasonable.

 

#3 all day

and I need you to supply a 13.7” G2 308 barrel , like yesterday....

 

Option 0: Put ARP barrel on standard AR receiver set, load within 2.26 limit, and shoot sub-MOA groups. Be happy.

 

So just a thought, but a mag that handles 2.39" would handle a 22-250 right? That's where I see the biggest opportunity if it would work. You'd sell those barrels/bolts by the bucketful I think if there were receivers and mags that would handle it.

 

Olympic Arms already does that, don't think they sold them by the bucket full. http://www.olyarms.com/shop/rifles/umar-rifles.html

 

Yeah I know Oly made a 22-250, but this would allow people to build their own if the right barrel extensions and bolts were available, and without the $100 magazines and in various barrel configurations instead of the limited options they had.

 

1) Buying a LWRC SIX8 receiver set and proprietary mags that allow you to load out to 2.39" -cost est $500 for receivers and $50/mag
2) Buying any AR15 receiver set and using windowed mags capable of holding 10 rounds that allow loading out to 2.34"- cost $49/mag or cut it out yourself.
3) Buy a small frame 308 and stick any 243, 260, Creed, 7mm-08, 308 barrel in it and use common 308 pmags...gain 200fps over either of the other options.

https://www.ar15.com/forums/AR-15/2...-and-SPC-Metal-Magazine-for-the-SIX8-and-Other-Compatible-Receivers/121-736913/[/QUOTE]

I like #2 the standard AR-15 works for me. I thought about doing #1 but if your going to buy new receiver sets why not go #3. I just wouldn't spend the
money for #1 for a small improvement over a standard AR-15 when I can do a #3 and see a big difference and not get into proprietary parts......just my 02

 

Large frame as it’s pretty close to the same price as LWRC’s Six8 and I am talking 2A’s Xanthos light weight receivers. These would be the only receivers I would a large frame on.