Opinions on ar-15 build

[Gilly]

Ok so I have stripped lower on its way and I am looking to put together a tack driver ar that can be used out to and even beyond 600 yards. I have little experience with the 223 I have many calibers other than this one but for some reason never got one. I own a bolt gun in 204 ruger and like it really well have shot it out to 600 with good results on paper anyways. Main use will be shooting coyotes and prairie rats with it to 500-600 probably shorter most times, I would also like to shoot steel and paper out to longer distances. I reload so that is not a problem getting the bullet powder combo I need. Here is what I am thinking of doing.

DPMS stripped slick side upper with elevated optical rail with a Shilen drop in barrel 24" in 204 ruger 1-9" twist to try to stabilize a 55 grain berger match varmint bullet with bc of .381 and a muzzle velocity of 3400 fps? that is an estimate. JBM has this thing running 1400+ fps at 1K with 269 ft/lbs. energy. Should at least puch a hole in target at that pace.

Or would I be better served to put together a fast twist 223 to shoot a 70 or 75 grain bullet? Not sure if these can be loaded to mag length without seating them way into the case?

Can a 223 with one of these bullet weights have enough muzzle velocity to keep up with the 204 out to 600 or even 800 yards? I know that the 20 cal bullets will have a higher bc for a given weight bullet so I figure it would take a heavier .224 bullet to match the bc of the .204 bullet but then I would be giving up FPS. Any suggestions on caliber bullet combos or even barrel and other parts I am all ears, well eyes actually but it would be appreciated.

 

[GIO]

Re: Opinions on ar-15 build

I don't know very much about the 204 but 223 runs out of steam and has some pretty big drops going out past 600. Any reason why you would not build a .260 on an ar10 platform?

 

[sobrbiker883]

Re: Opinions on ar-15 build

6.5 Grendel.

 

[sandwarrior]

Re: Opinions on ar-15 build

I've never shot the .204 Ruger, but I have a hard time believing the .20 cal 40 V-max outshoots the 70 gr. Berger in .224 (.223/5.56)

If you're going to shoot mostly long range with it then definitely get the longer barrel. 20" to 24". However, for General purpose I would get the carbine length barrel. With a tight enough twist you can get good velocity from heavier bullets with full loads of powder behind them. Then you can have the shorter more manueverable barrel and buttstock. I went the first route as I wanted long range. This time, I went the second route and while I have to adjust more for elevation I can still do it. As you noted the 1-7" or 1-8" twist will be a big factor.

My next question is are you really getting 3400 from a 55 gr. .204 bullet? A pretty hot load for a 5.56 is 3300 w/a 55 gr. bullet from a 20" barrel. 3400 is doable but awfully hard on brass and eventually, ...barrels.

 

[Gilly]

Re: Opinions on ar-15 build

I read that a guy chrono'd a load with a 55 gr berger at 3400 with good accuracy and minimal pressure signs using RL-15 for powder I think. I know that a 40 gr vmax will not out shoot a 70 gr 223 load that is why I am looking for a fast twist for the heavier higher bc bullet thinking it might outperform the 223 out to longer distance. The big problem I see with a good bullet choice like 80 gr Amax is that it is so long to get a good seating lenght it would not fit in mags. Would I have the same probelm with 70 gr. or will 70's load to mag lenght ok? As for going AR-10 and a larger cal I thought about that one but just did't go that route. Maybe someday.

 

[squirrelsnpr]

Re: Opinions on ar-15 build

If I were in your shoes I would visit 6mmAR.com and look at the 224 AR. It would allow you shoot the heavier .224 bullets and still have space inside the mag to load them near the lands. It looks like a really good idea.

 

[exhogflyer]

Re: Opinions on ar-15 build

77 gr SMK can be loaded to mag length, though I've heard SOME 75gr cannot.As far as range, you can get to 1k with the 223, though admittedly there ain't much poop left in it.I would second the vote for the 6.5 Grendel, this cartridge for the AR15 chassis is about as good as it gets for long range.If you are reloading it's about the same cost as the 223 match ammo.I have one and built it for the exact reasons you mentioned,though at this point I'm still in the experimenting stages.Take a look at it...might be what you're looking for.

 

[sobrbiker883]

Re: Opinions on ar-15 build

75 VLD's and Amax's won't be mag fed, 75BTHP's are fine.

If you want the size and weight of the AR15 but want the range capability of a 308, 6.5 Grendel is the way to go, and I'd go 20" (or I should say I'm going to go 20" when I can afford it).
Don't go crazy chasing speed with the 6.5G, those little lugs aren't built for it-I saw a Grendel break a couple lugs this past weekend, and I don't think it was too hot of a load.

 

[Gilly]

Re: Opinions on ar-15 build

I really looked hard at a 224 ar and even the 6mmAR and the 6mmAR with the 40 degree shoulder but $1400+ for an upper is a little over my budget especially once you add up the dies and brass. I added up all the parts for the 204 ruger with a shilen barrel along with some high end parts for bcg and a decent free float forend and all other parts for around $850 and probably cheaper for a 223. That means a lot more shooting and better glass budget over something like that.

 

[sobrbiker883]

Re: Opinions on ar-15 build

Sounds like you knew what you wanted before you asked.

Good luck with the 204 at distance in the wind. 204ruger.com talks about the 204 Ruger having 27.34" of wind drift at 500yds with the best load on listed (presumably 40gr Amax's).
http://www.204ruger.com/204_overview.php

My 75gr BTHP 223 mag length load at 2700fps has the little screamer beat by a couple inches, but I'm sure it only gets worse the farther you go.
Considering a 6.5G has better ballistics than a 308 out to 1K, that's where my next AR15 upper will be headed.

1:8 and some 1:9's will run 75's/77's fine.

 

[LS6TT]

Re: Opinions on ar-15 build

tagged

 

[Gilly]

Re: Opinions on ar-15 build

Well in terms of parts I know what I want but I don't have the caliber hashed out. And I know there are more experienced and better shooters than me here so I wanted input on which direction to go if a 223 is a better choice than the 204 I would do it. I may have to look into this 6.5 grendel more though.

 

[sandwarrior]

Re: Opinions on ar-15 build

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Gilly</div><div class="ubbcode-body">I really looked hard at a 224 ar and even the 6mmAR and the 6mmAR with the 40 degree shoulder but $1400+ for an upper is a little over my budget especially once you add up the dies and brass. I added up all the parts for the 204 ruger with a shilen barrel along with some high end parts for bcg and a decent free float forend and all other parts for around $850 and probably cheaper for a 223. That means a lot more shooting and better glass budget over something like that. </div></div>

Well, if you haven't bought an upper yet then I would look really hard and often at the auctions. I just got a Lewis Machine & Tool 5.56 carbine upper for $485 (shipped). I didn't know who they were but they are considered to be good. So far, (taken it out three times) it's shooting sub-MOA with 69 gr. match bullets. That's at 100 and 300 with a 10x scope. the prices of built uppers is coming down finally. As are lowers. During the peak of the OMG stage lowers went to over $200. But no one bought them at that price. Not at least for very long if they did. Anyhow, it's a 1-8" twist 16" SS 5.56 barrel. Flattop w/picatinny, brass def. and fwd asst. The lower I used was an Olympic (same deal, watched auctions) with an unbelievable trigger job. The guy who sold it was ex-HP. so he knew someone who could do a great job on that. All Told I've got less than $800 into the whole thing and It's exactly what I wanted. Wtih the exception of the rear sight. Still working that out.

As mentioned before, the 6.5G is a great option as well. It maintains a lot of punch way out there. If you reload for it you have to adhere to the reloading guidelines very closely. The problem is length of time the powder goes down the barrel and pressure has to be reduced as it enters the gas operation system. the 5.56 has the same drawback just not as tight of parameters as the 6.5G.

Edit:

Sorry, in my initial post I mentioned 40 gr. .204 bullet. Don't know why. Pushing a 55 gr. .204 bullet to 3400 is going to eat brass and barrel. I really think you'd be ahead to get a 1-7"/8" twist .223/5.56 and load or buy 77 gr. match bullets. Or, go the 6.5G route.

 

[distantfoe]

Re: Opinions on ar-15 build

Another option - a very reasoonably priced version of the 6mmar

http://www.accurateandreliablerifle.com/products.html
http://www.accurateandreliablerifle.com/BUILD-YOUR-UPPER.html

 

[ARsR4ME]

Re: Opinions on ar-15 build

sounds like you need a 50 bmg upper.