Glock Talk

Glock Talk (http://glocktalk.com/forums/index.php)
-   Black Rifle Forum (http://glocktalk.com/forums/forumdisplay.php?f=93)
-   -   OBR 7.62 barrel length. (http://glocktalk.com/forums/showthread.php?t=1447176)

Travclem 10-10-2012 18:01

OBR 7.62 barrel length.
 
I'm in the market for a Larue OBR 7.62. Since the wait for one of these bad boys is around 6 months I want to make sure I am making the right choice on barrel length. At first I was leaning toward 18" as a good compromise between weight/length and performance. The more I look at the .308, the more I lean toward 16".

From what I can tell the 16" costs you ~200fps but saves weight and length. The gun will be suppressed sometimes so length is an issue. At this time I am almost certain that I want the 16" but what say the GTBRF? Am i correct in saying the velocity loss from 2" of barrel is negligible?

NeverMore1701 10-10-2012 18:06

I'd personally go with an 18" in 7.62, but that's based on my personal preference for the look and feel of an 18" AR10 type rifle rather than any actual performance difference.

Travclem 10-10-2012 18:09

Quote:

Originally Posted by NeverMore1701 (Post 19504969)
I'd personally go with an 18" in 7.62, but that's based on my personal preference for the look and feel of an 18" AR10 type rifle rather than any actual performance difference.

I think the 16" is the best looking of the OBRs with the GB under the handguard but for follows function for me. The OBR is already a heavy beast.

NeverMore1701 10-10-2012 18:17

I don't like that particular handguard to begin with, but that's just me. If I were dropping that kind of coin on a rifle, I'd probably look into putting a Troy 13.8" .308 TRX handguard on there for a couple hundred extra bucks (if there's a compatible barrel nut out there, I honestly don't know if there is).

Travclem 10-10-2012 18:20

Quote:

Originally Posted by NeverMore1701 (Post 19505008)
I don't like that particular handguard to begin with, but that's just me. If I were dropping that kind of coin on a rifle, I'd probably look into putting a Troy 13.8" .308 TRX handguard on there for a couple hundred extra bucks (if there's a compatible barrel nut out there, I honestly don't know if there is).

I don't think so either. I'll deal with the handguard for the LaRue accuracy.

The funny part of this endeavor is I decided to buy an OBR to take my mind off of my pending tax stamps, but the LGS sold the ones they had a week before I had sold enough guns to make the $$$. So looks like I'm in for yet another 6 month wait.

NeverMore1701 10-10-2012 18:45

You'll not get much sympathy from me, bucko :tongueout:

WoodenPlank 10-10-2012 19:29

If you're planning to shoot at any significant distance, then 20" is the only choice, IMO.

AK_Stick 10-10-2012 20:41

I dunno, guys who can really shoot, are making solid hits, past 1,000 with a 16 inch tube.


Yeah, its harder, but not terribly so.


Really depends on what you want to use it for. If you're only going to punch paper, I'd get the 16 inch. If you're going to shoot at something real a long way out, maybe consider the longer tube.

WoodenPlank 10-10-2012 23:57

Quote:

Originally Posted by AK_Stick (Post 19505591)
I dunno, guys who can really shoot, are making solid hits, past 1,000 with a 16 inch tube.


Yeah, its harder, but not terribly so.


Really depends on what you want to use it for. If you're only going to punch paper, I'd get the 16 inch. If you're going to shoot at something real a long way out, maybe consider the longer tube.

Oh, I am aware that it is being done. However, it's like saying guys are winning track meets even after letting the coach whack them in the knee with a ball peen hammer.

Why hobble yourself? If it's going to be something you're humping up and down mountains, or extensive use in an urban combat area, the reduced size and weight can be a blessing. For most folks punching paper on weekend, though, that extra velocity sure is nice to have, especially at distance.

AK_Stick 10-11-2012 00:11

I don't know that 4 inches, on a 308, is going to make much of a significant issue.

You're only talking maybe, 200 fps. Maybe. load, and individual rifle dependent.

So, what, maybe 1.5 inches difference? Just not seeing that as being much, if even noticeable.

WoodenPlank 10-11-2012 00:13

Quote:

Originally Posted by AK_Stick (Post 19506041)
I don't know that 4 inches, on a 308, is going to make much of a significant issue.

You're only talking maybe, 200 fps. Maybe. load, and individual rifle dependent.

So, what, maybe 1.5 inches difference? Just not seeing that as being much, if even noticeable.

I don't get to shoot longer distances that much, so I will take all the advantages I can get...

:whistling:

AK_Stick 10-11-2012 00:23

Thats a valid though, but I think you're going to see more dispersion from your trigger/breathing, than you will see between the 16/18/20 inch tubes.

surf 10-11-2012 00:37

Is this a bench rifle? Are you humping it around hunting etc? What distances are you planning on using it at? What load(s) are you planning on putting through it?

MrMurphy 10-11-2012 03:37

I've spent considerable time on all 3 lengths of OBR and was shooting them before they were OBRs.

If you're never going to exceed 800m stick with the 16, it's the most maneuverable and the velocity loss is fairly irrelevant. The 18 is a good compromise for the thousand yard guys. The 20 is for pure bench shooters or long-range only guys.

The 18 with a PRS is my favorite for extended range stuff, though in my case, I did the majority at 100m for testing. Good shooters have kept MOA or better groups at an excess of 900m without too much trouble, and the 'good' long range guys (I am not one admittedly) have made hits at some insane distances.

Mark himself took an elk at about 400m with a 16" a couple years ago IIRC.

Suppressed, the 16 is my favorite with a Crane stock or CTR with the RISR, it gets the job done. Under 500m the 1.5-5 Leupold, 2.5-10 Nightforce and any of the 3 or 4X ACOGs do very well, especially suppressed at night with a PVS-24.

Travclem 10-11-2012 05:56

Quote:

Originally Posted by surf (Post 19506072)
Is this a bench rifle? Are you humping it around hunting etc? What distances are you planning on using it at? What load(s) are you planning on putting through it?

It will primarily be my new hog rifle, so lots of in and out of vehicles/walking/running. I'll probably shoot some long distance (600m, 800m, 1000m) steel on occasion.

Most everything I shoot are hand loads.


Outdoor Hub mobile, the outdoor information engine

Travclem 10-11-2012 05:57

Quote:

Originally Posted by MrMurphy (Post 19506177)
I've spent considerable time on all 3 lengths of OBR and was shooting them before they were OBRs.

If you're never going to exceed 800m stick with the 16, it's the most maneuverable and the velocity loss is fairly irrelevant. The 18 is a good compromise for the thousand yard guys. The 20 is for pure bench shooters or long-range only guys.

The 18 with a PRS is my favorite for extended range stuff, though in my case, I did the majority at 100m for testing. Good shooters have kept MOA or better groups at an excess of 900m without too much trouble, and the 'good' long range guys (I am not one admittedly) have made hits at some insane distances.

Mark himself took an elk at about 400m with a 16" a couple years ago IIRC.

Suppressed, the 16 is my favorite with a Crane stock or CTR with the RISR, it gets the job done. Under 500m the 1.5-5 Leupold, 2.5-10 Nightforce and any of the 3 or 4X ACOGs do very well, especially suppressed at night with a PVS-24.

Thanks for the advice! I'm intrigued by the Horus reticle right now but haven't settled on any glass.




Outdoor Hub mobile, the outdoor information engine

Travclem 10-11-2012 05:58

Quote:

Originally Posted by AK_Stick (Post 19506058)
Thats a valid though, but I think you're going to see more dispersion from your trigger/breathing, than you will see between the 16/18/20 inch tubes.

That's the direction I am leaning. I'm not so much concerned with the accuracy of the different barrel lengths, they should be the same. The difference is going to be how far it is until the bullet goes transonic and/or runs out of gas.


Outdoor Hub mobile, the outdoor information engine

Travclem 10-11-2012 06:05

Quote:

Originally Posted by Travclem (Post 19506312)
It will primarily be my new hog rifle, so lots of in and out of vehicles/walking/running. I'll probably shoot some long distance (600m, 800m, 1000m) steel on occasion.


Outdoor Hub mobile, the outdoor information engine




Outdoor Hub mobile, the outdoor information engine

Big Bird 10-11-2012 06:11

Having shot extensively at 500-1,000 yards with a .308 I will tell you that a longer barrel makes a helluva difference. 200 fps is a lot of velocity in a .308 as you won't be shooting light 150 grain bullets at 500 and beyond. You'll likely be using the 175 grain Sierra Match King. That bullet already starts out slow and you really handicap the slow powder required to drive it properly (relative to a lighter bullet) and then you cut off your other foot by using a short barrel.

Its not the trajectory that gets you its the wind. And 200 FPS means a lot in the wind.

It also means a lot when you get out to 1,000 yards. You'll go subsonic with most any .308 load in a short 16" barrel well before 1,000 yards and bullets tend to yaw and destabilize as the drop back below the sound barrier.

If you aren't honestly going to shoot beyond 500 much then go for the shorter barrel. People come up with some of the most ridiculous notions when it comes to guns--like I want to capability to shoot to 1,000 when they have never shot a target farther than 100 yards in their life. As if you just aim a little higher and you can shoot 800 or 1,000 yards just as easily as 100. Its a different ballgame and it take significant trigger time and observation of bullets in the wind to understand what I'm saying. a 10 MPH wind at 100 yards is insignificant. At 500 yards it will blow you a foot off you point of aim. At 1,000 it will blow you 3 feet off your point of aim.

It takes some logistics to shoot beyond 300 yards. Its not like you can see bullet holes with a spotting scope beyond 200 yards (you can't). Which means its a quarter mile to a half mile hike to go down and check you target. So you shot a bullet in X wind conditions...what did it do? You have to go check. You shoot another bullet wihtou marking the target you have no way of knowing what you did when. You have to check each shot and at 600 yards that's a LOT of back and forth and not much trigger time--or you can do pull targets and have a friend pull and mark your targets in the pit if you have access to that kind of range. Or you can compete in Hi-Power but a Predatar is not really meant for that kind of competition. Either way its a lot of work.

People will tell you you can make hits with a 16" gun at 1,000 yards. Yep. I can win the lottery too! A 16" .308 isn't the tool for that job. Period.

Travclem 10-11-2012 06:33

Quote:

Originally Posted by Big Bird (Post 19506332)
Having shot extensively at 500-1,000 yards with a .308 I will tell you that a longer barrel makes a helluva difference. 200 fps is a lot of velocity in a .308 as you won't be shooting light 150 grain bullets at 500 and beyond. You'll likely be using the 175 grain Sierra Match King. That bullet already starts out slow and you really handicap the slow powder required to drive it properly (relative to a lighter bullet) and then you cut off it other foot by using a short barrel.

Its not the trajectory that gets you its the wind. And 200 FPS means a lot in the wind.

It also means a lot when you get out to 1,000 yards. You'll go subsonic with most any .308 load in a short 16" barrel well before 1,000 yards and bullets tend to yaw and destabilize as the drop back below the sound barrier.

If you aren't honestly going to shoot beyond 500 much then go for the shorter barrel. People come up with some of the most ridiculous notions when it comes to guns--like I want to capability to shoot to 1,000 when they have never shot a target farther than 100 yards in their life.

It takes some logistics to shoot beyond 300 yards. Its not like you can see bullet holes with a spotting scope beyond 200 yards (you can't). Which means its a quarter mile to a half mile hike to go down and check you target. Or you can do pull targets and have a friend pull and mark your targets in the pit if you have access to that kind of range. Or you can compete in Hi-Power but a Predatar is not really meant for that kind of competition.

People will tell you you can make hits with a 16" gun at 1,000 yards. Yep. I can win the lottery too! A 16" .308 isn't the tool for that job. Period.

I understand what you are saying. I shoot out past 500 yards regularly with my 20" (cut down) 700p. I have a full dope database on my phone and on paper for that rifle with my 175gr. MatchKing load. I've just never owned a .308 shorter than 20". And was curious about the real world difference.

P.S. not wanting a PredatAr, I want the full weight OBR. The predatOBR would be ideal if they existed yet.



Outdoor Hub mobile, the outdoor information engine


All times are GMT -6. The time now is 06:55.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright 2013, Glock Talk, All Rights Reserved.