DPMS 18" bbl LR308 range ?'s, opinions, insight.


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w103tws
February 25, 2010, 11:15 AM
Hey guys, I'm looking at the dpms lr308b, which is a heavy bbl 18" 308. For those of you who have witnessed, or personally shot an 18'' 308 at any decent distance, what is your opinion of that barrel length.

I'm looking to replace my sporter weight 243 with this gun. This will only be used for the occasional groundhog, and no farther than 700yd backyard plinking, but most of that will be at 500yd. The reason I'm not opting for their 24" bbl is because I will have to carry this thing for g-hogs. But for most of the 700yd + shooting, I will be using my 110fp 300wm.

I've done a lot of reading and found that this rifle is very accurate, it fits my budget, and (I hope) is a good medium between a hunting and target rifle. I just don't have any experience with the 308, and don't know what the limitations are with an 18" barrel.

Or, should I just go with the 24" one, to make sure I have good enough velocity for that range, call it a dedicated bench guns, and use one of my 223's for g-hog....? I'm stumped.

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Z-Michigan
February 25, 2010, 11:31 AM
I've shot that model. It's a good gun overall. The barrel is a bull profile and results in a fairly front heavy balance, though nowhere near as bad as the 24" barrel models.

IMHO, 18" is a good length for a lot of .308 shooting out to about 500 yards. It's long enough to get most of the velocity out of the cartridge. You are losing about 50-100 yards at the most in terms of supersonic bullet flight. I think you could use the 18" model at 700 yards depending on your bullet choice and expectations - but if I were doing much shooting at 700 yards I would favor something like the 300 WM you already have.

artofwar
February 25, 2010, 11:35 AM
My LR308 is a great rifle - I can shoot 12in steel plates at 300 yds all day long (LR308 AP4 16in. w/Millett 4-16x scope). Some advice on reliability - many LR308 owners including myself have had nightmares with FTF/FTE on our brand new rifles. Mine wouldn't cycle reliably at all and I had 4 different brand new DPMS 19-rnd mags. When we switched to the new PMAGS....problems went away! I also did the extractor D-ring upgrade just for good measure.

Good luck!

aubie515
February 25, 2010, 12:34 PM
I've owned an 18 and 24" LR308...the 18"s were reported to be slightly more accurate. I went with the 18" do the those reports along with the fact that the 24" is one heavy mofo.

Dr. Tad Hussein Winslow
February 25, 2010, 12:44 PM
Personally I don't see much point in a short bbl that is also heavy - sort of giving you the worst of all worlds there. Short & thin, yes. Long & thin, yes, possibly. Long & heavy, yes, possibly. Short & thick, no - why?

Get the LR 308 L

w103tws
February 25, 2010, 02:17 PM
aubie, tell me more... Which did you prefer to shoot?, which one actually was more accurate? Is the 24" noticeably heavier? I'm may be leaning towards the 24", and if I end up really not liking the long bbl, I can always have it cut. Either length I go with, i will have it fluted (if that matters)

Z-Michigan
February 25, 2010, 03:10 PM
Personally I don't see much point in a short bbl that is also heavy - sort of giving you the worst of all worlds there. Short & thin, yes. Long & thin, yes, possibly. Long & heavy, yes, possibly. Short & thick, no - why?

short + thick = maximum stiffness = maximum accuracy

IMHO it makes very good sense.

OP, you can get the B model with a fluted barrel from the factory, either direct from DPMS or from RGuns:

http://rguns.net/rifles/rifles-semiauto-ar15-complete-308.shtml

w103tws
February 25, 2010, 03:40 PM
Yeah, I believe RGuns is going to get my money. Their prices, including some of the upgrades are much better than most others basic rifle price.

I guess I just want to know where the cutoff point is (in yards) that the 18" barreled rifle becomes unreliable and shots become less consistent.

Z-Michigan
February 25, 2010, 03:45 PM
I guess I just want to know where the cutoff point is (in yards) that the 18" barreled rifle becomes unreliable and shots become less consistent.

Whatever distance your chosen load falls below the speed of sound. It will be approximately 50-100 yards shorter distance than with the 24" barrel, depending on your load.

You might play around with this ballistic calculator:

http://www.handloads.com/calc/index.html

FYI, common 150gr FMJ has a BC around .4, 168gr match typically around .45, and the best 175-178gr long range match bullets that are suitable for a .308 Win, about .475-.495.

You can figure that the 18" barrel will shoot about 50-100fps slower than a 24" barrel, but again it depends a lot on the load.

Out to 700 yards, with most loads you will still be supersonic and the only difference will be slightly more drop and slightly more wind drift. But I would run the numbers for some specific loads to be sure.

You might find this article interesting:
http://www.tacticaloperations.com/SWATbarrel/

Dr. Tad Hussein Winslow
February 25, 2010, 05:03 PM
short + thick = maximum stiffness = maximum accuracy

For a benchrest gun, this might - and I stress *might* make sense - though they usually stop at 20" on benchrest guns

ARs are capable of outstanding accuracy with pencil thin barrels - do you really need to take your group size down from 1 MOA to 0.9 MOA by taking on a bunch of extra weight? That's about the most a stiffer barrel would help on a rifle like this with reciprocating parts. Not even close to being worth the tradeoff. We're talking about a semi-auto here. My opinion, anyways.


I'm looking to replace my sporter weight 243 with this gun.

Which is a lightweight gun. A HB 18" makes no sense whatsoever in this context, AFAIAC.

w103tws
February 25, 2010, 05:23 PM
WOW, thanks Dr. I mean you've really done a good job at addressing everything but my question about length and velocity. Also, do I really need to explain my reasoning for switching out the 243 to you??
You seem to be a very smug individual, and I would appreciate it if you would stop posting in this thread. Goodbye.

If anyone has any CONSTRUCTIVE criticism, please share. Thanks

Casefull
February 25, 2010, 11:52 PM
You are going to shoot groundhogs at 700 yds...I think you will be doing good if you are talking 700 ft. I swear half the guys on this forum do not have a clue how far a yard is. 440 yds is a quarter of a mile. You cannot even see a ground hog without optics at 1/2 the distance you are talking about. How the hell can anyone give you good advice when you are talking out of your ---.

jpwilly
February 26, 2010, 12:47 AM
You can reach 1000yrds with an LR-308 18" bbl and the right loads. They will need to be hot and the bullets must have a high BC. Although with a 24" bbl this would be much easier. With that said 500-700yrds and 18" bbl shouldn't be a problem. Although I'd keep the barrel profile to medium so humping it around wouldn't be too much work. These rifles are very accurate. You'll need a much better trigger than what they come with as well add $200 for that.

Happy hunting.

Z-Michigan
February 26, 2010, 07:47 AM
You are going to shoot groundhogs at 700 yds...I think you will be doing good if you are talking 700 ft.

Reading comprehension isn't what it used to be. See the OP's statement:

This will only be used for the occasional groundhog, and no farther than 700yd backyard plinking, but most of that will be at 500yd.

I don't see him claiming 700 yard groundhogs. I see "occasional groundhog" at no specified distance (maybe 100 yards? shorter? who knows) and plinking at 500-700 yard. Plinking at those distances is perfectly feasible depending on target size and how often you expect to hit it.

w103tws
February 26, 2010, 10:15 AM
Casefull... Wow, do you and the Dr. ride the shortbus together? Open your eyes, and read the post. You too can stop posting in this thread. It seems like more and more on this forum, that there the few guys who must have some kind of inferiority complex come out, and everything to them turns into a big wiener contest. Nobody likes your type.

Of course I'm not hunting anything at 700yds. I do however have a length of land behind my house that is a shade over 800yds. It has been measured with a wheel, and GPS. That is where we shoot at "things".

As far as the hunting goes, groundhogs inside of 500yd with the 308 will be attempted. My 300 WM is zeroed at 350yd, and animals have been taken around 600yd with it. (Yes, I do have a rangefinder, Yes I do use a ballistic calculator through my IPOD, and yes I know how to adjust my scope)

For the record 700ft is 233yds. You think somebody would be doing "good" by hitting a target at that great distance? I would hope even a novice shooter could engage a groundhog that far.

Thank You to all who have positively participated in this thread. My decision is made, I'll be going with the 24" bbl. At least that gives me the option to have it cut down in the future.

aubie515
February 26, 2010, 11:34 AM
w103tws,

If you go with the 24" make sure you have it fluted from the factory instead of having it fluted after the fact. When you flute, you may affect how the barrel shoots. I have always liked the fluted look, but I never sent out one of my rifles to have it fluted because I was concerned that it may change POI.

The 24" SS is one heavy barrel. I know I wouldn't want to drag that rifle around all day if I was able to hunt with that rifle. I'd also recommend having DPMS apply their teflon coating on it or having someone blast the SS into a matte/brushed finish.

LeverGunJunkie
February 26, 2010, 12:03 PM
w103tws;
You're pretty much a jerk aren't you? You're the only smug individual on this thread as far as I can see. You just crapped on two good dudes. If you read some of their posts with an open mind you might actually learn something from them. While Dr Tad's post was a bit caustic, it certainly didn't require your personal attacks. Given his seniority on the forum, you could've shown the guy some deference. If you're knowledge of the subject is such that you can answer all the questions yourself, and hurl disparaging remarks at everyone tyring to assist, you shouldn't start the thread in the first place. BTW: Big mistake on the 24" barrel. Should've gone with the 18".

UnTainted
February 26, 2010, 01:41 PM
a 16" barrel can keep a load supersonic to 900 yards. That is basically the accuracy potential of that legnth barrel. I would expect the 18" to go farther. At that range, there's a lot more affecting accuracy than barrel length or composition, though composition is important.

I'm happy with my semi-auto .308 that has a 16" light weight barrel. It shoots 1 moa and works great for hunting and shooting; I've hit milk jugs out to 400 yards with it so far.

w103tws
February 26, 2010, 01:41 PM
First off, Casefull offered no insight to the topic, and demeaned my thread without even applying it to the original post. Second, Dr Tad didn't even address the length vs velocity topic in question here. Neither of these two offered any assistance, they simply wanted to say something to boost their ego, and come down on me

BTW. "Seniority" Means nothing to me, it just means that you've typed a whole lot. I too could gain hundreds of posts by interrupting everybody's thread.

It seems like the 18" has the popularity vote for my application. Like I said earlier, 700yds max, mostly 500 and less. So if the 18" can keep em' supersonic at that range, I'd rather go that route.

Thanks guys, for your experience. That means more than theory and opinions.

Orion8472
February 26, 2010, 02:53 PM
I would vote for 18" as well. A bit lighter, definitely shorter, and would still have adequate velocity at the ranges you're considering. Plus. . . . 18" just looks so good.

w103tws
March 1, 2010, 10:47 AM
anyone else wanna chime in?

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