Sbr ar-10

[Shmead]

Hey!! So I know this is a Grendel sight, but I'm getting ready to build an Ar-10. I would like to build a rifle with a short barrel, 12.5" to 13.5". I have heard this will completely kill the ballistics, so to speak. So my question, Can you speed up the twist rate to compensate for this? I'm not very familiar with barrels and the twist, so please be kind. I'm looking at spending some time and money on this so I don't want to end up with a 200yd paper weight. Any help and knowledge would be appreciated.


Chris.

[mongoosesnipe]

assuming your doing a 308 ar10 yes a 12.5 inch barrel will kill your ballistics you will be looking at similar ballistics to a 7.62x39 you could put a 1in8 barrel on it and shoot 240 gr bullets to gain a little ke and ballistics but overall it is not going to be a particularly practical long range platform though the muzzle flash is going to be a formidable weapon

[Shmead]

ok thanks. yes I meant to specify that im talking about a 308. I figured it would be a pretty big flame thrower. But I'm only looking to shoot 500-600 yard max and closer. Would I just be better off to stick with a 14.5" or 16" barrel and be done with it?

[mongoosesnipe]

I would go with 14.5 with preminatly attached flash hider or a 16 to save on paperwork

[Variable]

I would go with 14.5 with preminatly attached flash hider or a 16 to save on paperwork

This.

Unless you have a specific reason otherwise, there isn't much good to be had from a barrel that short (12.5") in .308 caliber.

I run a 10.5" Grendel, but I'm burning a lot less powder than a .308.

Now if you wanted to just do it for the fun of it--- that's different.LOL Some people love massive muzzle blast and flash. That's the whole reason for an HK51. They have "ooh" factor when playing at the range, but they aren't really practical at all.

I really nice compromise would be a 12.5" Grendel like some of the other guys have built. My 10.5" is fine for normal woods hunting, but the extra 2" would certainly help ballistics while still remaining pretty compact in the AR15 envelope. The AR10 platform is just too chunky though for being handy. I may still buy a Colt LE901 when they release them, but it's only because I'm a pony fan. It'll mostly just be a waste of money. A .308 carbine isn't really going to kill critters any deader than my 10.5" Grendel already does.... Plus it'll weigh more and be less wieldy.

One more thing--- If you plan on running a can (you'll get real tired of the noise and concussion eventually!), a .308 SBR will be brutal on the baffles of your suppressor. You'll have much more unburnt powder sandblasting your blast baffle, and your can's lifespan will decrease considerably ($$$-$$$$). The Grendel is much milder by comparison.

[Shmead]

Ok well i appreciate the info. I really want to run a can on it so I'm pretty sure I'll just stick with a 16". I wanna build this rifle for a SHTF gun. The ammo is more readily available and a little bit cheaper. I just wanted to build a gun that would be the one go to choice, like if I could only get one and go kinda thing. Maybe that's me being dumb or something?? Any ideas for parts cuz I would like to try and keep the weight down as much as possible.

[mongoosesnipe]

Depends how much you want to spend and where your line in the sand is as far as practicality vs lightness

[Shmead]

Ok well I'd like to stay around the $2500 range or less, if possible, before optics and all the other goods. I would like to use the Mega Maten matched receivers but I just can't seem to find anyone that can keep them in stock. I was also looking at the mid length quad mono upper/lower combo, but how much does it weigh? From what I've seen it looks pretty bulky? I haven't gotten to put my hands on one yet so I have no idea. It says on Mega's website that their matched receivers are compatible with Samson forearms, if so I'd like to use Rainier's version of the Samson Evo, is that doable or is the forearm a 308 specific part? I was thinkin of just going with the Rainier Arms Ultra match 16" barrel. Now where I'm getting really confused is on the receiver ext. tube/buffer tube. Are they compatible from the AR15 or is that a specific to the 308? I wanted to run a UBR stock.

[mongoosesnipe]

as long as there isnt a raised comb on the stock it should be the same as ar15 the prs is ar10 specific because the ar15 comb will interfere with the charging handle the monolithic uppers are not really any heavier than a billet upper and a aluminum quad rail if you want something a little lighter but still rock solid i recommend the pri float tube either round or delta tube they are pretty light and as long as you don't need 4 linear feet of rail they are rock solid tube also if your going to pay for the ultramatch from ranier i would look at the noveske barrels

[Shmead]

Thanks. Ok well I was looking at the ultramatch from rainier considering it will run both 308 and 7.62x51 pressuered rounds, suppossedly. The noveskes are specifically for 7.62x51 pressures, right? I like Noveske's stuff though. I can't find one in stock any where, guess I'll have to go to them directly if that's the route I choose.

Well I was just goin to do the mega billet combo n use a troy trx rail after further research today. It's almost 130 bucks less than the pri rail, and weighs less.

Another question, what buffer and spring should be used with the ubr stock? I want to keep recoil to a minimum, as does anyone.

[Variable]

The Colt CM/LE901's will be out soon. Have you looked them up yet? One guy (Shawn) over on Arfcom is testing one of the early teaser guns they've released for the press to ogle over. It seems to shoot pretty darn well so far. I've had rather good luck in general with Colt rifles FWIW (I'm a die hard pony fan).


Here is his first 100 yard shoot. Pretty good for factory stock chrome barrel and factory ammo!

http://www.ar15.com/forums/t_2_29/199659_SP901___LE901_16S__pics_news_and_info_Facts_only_please___UPDATE__Pics__page_23_on.html&page=24

He also tried it out at 1000 and 1200 yards (on page 27).LOL Not real practical with a 16" .308, but an admirable try in my book.LOL

Pony + PMags = Win!

[feetpiece]

Ok well I'd like to stay around the $2500 range or less, if possible, before optics and all the other goods...

Buy an LMT MWS and never look back. I don't. For around $500 you can change calibers depending on the flavor you desire with a simple barrel swap: 6.5 Creedmoor; .260 Remington; .338 Federal. This is my "go-to" gun for work outside the house.

Colt is a little late to the party on the 7.62 front and don't offer anything new - this coming from a Colt fanboy. If you're looking for something in that price range that is actually issued to soldiers there is no other option. Add $3K and you can get a KAC which is also an issue item. Sorry Colt, POF and LWRC. When it comes to a rifle good enough for the lowest common denominator (grunt) and not just games and mall-ninja's, someone found their offerings lacking.

[mongoosesnipe]

A gun designed to run on NATO will run 308 as NATO is a rounds are lower pressure than 308 unlike 223/5.56 my brother had a done 308 that would not run NATO until it was broken in after about 200 rounds of 308

[LR1955]

A gun designed to run on NATO will run 308 as NATO is a rounds are lower pressure than 308 unlike 223/5.56 my brother had a done 308 that would not run NATO until it was broken in after about 200 rounds of 308

That is the first time I heard anyone say that 7.62 NATO has lower pressure than .308 loads. Is it just because your brother's blaster wouldn't shoot US made Lake City ammunition that wasn't surplus?

Take my word for it, US made 7.62 NATO is hot stuff. I doubt any commercial ammo company would dare make ammo for commercial sales to NATO specs as made by Lake City.

LR1955

[Shmead]

ok so I thought that 7.62 NATO was higher pressuered than the 308? Now u guys are confusing me, haha. I want a barrel that will shoot both, considering I will not always be buying or loading the NATO stuff. It's just more practical to run 308 rounds being as theyre easier to come by. I would occasionally run some Nato rounds if I come across them or want ya kno?

feetpiece. I have no desire to swap calibers, although that sounds good for what if situations later on in the future. I'll have to look into that.