The Down Range Forum
Member Section => Tactical Rifle & Carbine => Topic started by: Rastus on March 19, 2010, 08:40:33 PM
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OK...happy call from Rock River to my FFL dealer this week. The one year wait for the production line is actually...6-8 weeks. I figured that was coming.
Anyway, I've got the LAR-8 Varmint with the 26" SS barrel coming down the skids and I'm waiting on paper from the ATF so I can possess what I own from GemTech.
Now...I need to thread the barrel, but I am thinking about cutting it down to make it lighter and more manageable....which I'll certainly do...and here is the question...how much velocity will I sacrifice going from 26" to 22"? I've read and heard that 308 ammo is optimized for 22 inch barrels, if that's the case it's a no brainer for me....I might even go to 20".
I know it depends on the load, but let's assume match bullets 168 or 175 grain, boat tail only...maybe with a polymer tip if not match. No hollow points. I really don't want to lose over about 75 fps by shortening the barrel, since the 308 is a little anemic in the speed category.
I'd appreciate guidance from someone who is a 308 guru.
Thanks,
Ken
Late Addition--I'm also wanting good quality scope rings for it. Any suggestions on good and stable rings (easily removable not a requirement, this thing will never have iron sights on it) for a 30mm tube and 50+mm objective is appreciated too. As soon as I settle on a scope, I'll need to get those rings in a height that will allow about 1/8" clearance. Also for a bipod, drag bag, etc.....
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Won't that be kinda long with a supressor at the end of a 26" barrel?
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Won't that be kinda long with a supressor at the end of a 26" barrel?
Yeah that's why I wanna chop it off...
Wanna sell that FS 2000? I might be interested.
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Rastus
Like always, the question is what do you want use it for and how long is the can? How does it effect velocity? Range gun, varmint gun, tactical? What ranges etc.? The load detail is helpful, but in mho (which needs education) is that the difference between 20" and 26", plus x inches of can, will probably not matter under 300 if we're talking about 4" groups. Beyond that, what is it for?
FQ13
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I was just talking about this with my friend (long range competitor) last week. He directed me to a couple of links with articles on barrel length vs. velocity.
It may not help. but it might.
http://www.shootingtimes.co.uk/features/136776/Barrel_length.html
Last section is on velocity:
http://www.chuckhawks.com/rifle_barrel.htm
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Thanks guys.
Overload...might be interested depending on when it was made.....
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Peg, those were pretty good references. I had been leaning towards cutting the barrel from 26 to 22 inches and those articles helped. I want to have 400 yards and closer working distances for this 308, my Remington 700 will be for a bit longer distance.
The one thing I did not see mentioned that was contained in at least one other article I read somewhere is that the 308 round is loaded with powder optimized for shorter, "tactical" barrels....at least in the rounds I'll be using like Federal Premium and Winchester Supreme. I'm still scratching to see if that is really true or an "urban myth" kind of a thing.
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As I understand it, 308 is optimized for 20 inch barrels. That's why that length is used on the M 40
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As I understand it, 308 is optimized for 20 inch barrels. That's why that length is used on the M 40
Good deal. I might even pick up some velocity going a smidgen over up to a 22" barrel. Cutting it back a few inches will make it stiffer and maybe improve the groups (though you never know about an individual barrel's harmonics). That was another motive, leaving enough barrel so I could lop off a bit more if it didn't shoot well.
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I have two of Rock River's 1-inch scope mounts and really like them. They are about $50 on their website, but I found mine at a gun show for $45 from a RRA dealer.
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Rastus, the guy I mentioned in my first reply was telling me during our discussion that he was working on a short-barreled model 700 in .308. He had a spare factory barrel left over from a project on one of his competition guns and I believe he said he had cut it down to 16 1/2" just to see if it would shoot well. I think he said it surprised him with the accuracy. He was out of town at a competition this weekend, so the next time I talk to him I'll ask again to be sure.
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Yeah that's why I wanna chop it off...
Wanna sell that FS 2000? I might be interested.
Strangely enough there's a Yankee Hill Phantom flash supressor sitting on the end of my FS2000. If only I owned a Yankee Hill Supressor...
Why is the date important with the FS2000?
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Strangely enough there's a Yankee Hill Phantom flash supressor sitting on the end of my FS2000. If only I owned a Yankee Hill Supressor...
Why is the date important with the FS2000?
Yankee Hill Phantoms thread AAC cans too.....it's what I have for my M4-2000.
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T minus two weeks. Gotta get a good mil dot scope. 30mm tube and I think 50mm objective. I've been perusing the scopes and it may be August or so before I can afford one...pretty pricey.
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T minus two weeks. Gotta get a good mil dot scope. 30mm tube and I think 50mm objective. I've been perusing the scopes and it may be August or so before I can afford one...pretty pricey.
Rastus,
I sent you a PM.....(cause I was too lazy to look up this thread :P )...about my friend's short-barreled .308.
Peg
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Rastus, is that LAR-8 going to get finicky, operational and reliability wise, when you start chping the barrel down? Does RRA offer it in a shorter barrel? I thought I read somewhere once upon a time that the .308 AR styles can get problamatic with shorter barrels.
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Rastus, is that LAR-8 going to get finicky, operational and reliability wise, when you start chping the barrel down? Does RRA offer it in a shorter barrel? I thought I read somewhere once upon a time that the .308 AR styles can get problamatic with shorter barrels.
I'll keep that in mind and look it up. I'm going to be running a can on it so there will probably be more gas coming back anyway. Thank you for the comment, it is something I should check on before having that barrel whacked off.
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New here. I am getting suppressor (YHM Phantom 7.62 with QD), which is readily attached to most of my rifles. Exception is Rock River LAR-8 26-inch heavy bull SS. Just beginning to think about this rifle. Can someone guide me a bit here? Suspect need to cut down length and add threading. But who/where to get this done and likely how much $$? Any advice is appreciated. Thanks.
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New here. I am getting suppressor (YHM Phantom 7.62 with QD), which is readily attached to most of my rifles. Exception is Rock River LAR-8 26-inch heavy bull SS. Just beginning to think about this rifle. Can someone guide me a bit here? Suspect need to cut down length and add threading. But who/where to get this done and likely how much $$? Any advice is appreciated. Thanks.
I'd say ask your dealer who is a good gunsmith with a lathe. All you need to do is turn down the barrel to the proper diameter at the end and thread it....threading it might be a chore unless they turn it down several inches which may look funky.
For me, I've had mine for over a week and will shoot it this week (provided I get the scope rings from RRA in). I've got a plan for mine based upon 1) stiff short barrels are more accurate than longer barrels and 2) .308 is optimized for 20 to 22 inch barrels in the match ammo and police ammo.
Here's what I'm going to do with mine and I hope to put pics up on it:
1. Lap the scope rings to square them up.
2. Record every shot by ammo type and manufacturer.
3. For the first few rounds, chrono every round and clean after every round until the patches come back "clean" after the first few shots. The 26" barrel is cryo treated and lapped so this may not be necessary...I'm obsessive. If my patches come back dirty to start and clean up as the barrel is burnished I'll let ya'll know.
4. The barrel starts at 26" and unless it groups 3/8" or so at 100 yards I'll cut it to 23". If I cut it I'll have chrono for everyone to compare with.
5. If the barrel is good at 23" I'll leave it...if the group stinks' I'll get the smithy to cut 1/2" or so off and try it again. Again, I'll chrono.
6. I'll continue to cut the barrel down to 21 or so inches to get a shooter...chrono along the way as I cut.
7. When it's a shooter, if it's a shooter, I'll have the end of the barrel turned and threaded for my can.
8. I'll have chrono and groups with and without the can.
Now, hopefully I'll be industrious and dilligent enough to follow through with all of this. It will be interesting to get real life chrono data and several different ammo's down the barrel with groups. If I am really diligent, I'll chronicle with pics.
Anway, this is what I'm planning on doing...hope I didn't bore anyone and DON'T HOLD YOUR BREATH WAITING TO SEE WHAT HAPPENS GUYS.
BTW, I went to Optics Planet and got a Bushnell 4200 FIRST FOCAL PLANE 6x24 power scope with 30 MM tube for under $800 delivered. 1st focal plane is what you want and I had no idea you could get one for under $800 this quality...I thought I'd have to spend over $2k to get one and it has 1/10 moa clicks. First focal plane means the mil dots are good at any magnification, not just one specified magnification.
Have fun with whatever path you follow.
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Rastus, Are you cutting the barrel down yourself? If you are and don't mind putting the extra time into it it might be interesting to try cutting an inch back at a time and chrono it inch by inch to see how it drops. You wouldn't need to recrown it every time, unless you wanted to shoot it for accuracy also, just take a hacksaw to it. :)
I posted earlier about AR based .308s being finicky with shorter barrels, but I see that the Remington R-25 has a 20" barrel and you can get the DPMS LR-308 with a 18" barrel so I would think that at least down to 18-20" barrels shoudn't be a problem. Maybe I just read some bad internet advice somewhwere about shorter barrels being a problem in .308 ARs
Looking forward to seeing your pictures and reports.
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Rastus, Are you cutting the barrel down yourself? If you are and don't mind putting the extra time into it it might be interesting to try cutting an inch back at a time and chrono it inch by inch to see how it drops. You wouldn't need to recrown it every time, unless you wanted to shoot it for accuracy also, just take a hacksaw to it. :)
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Nope, I'm going to ask Curt Higgins of S and H Arms in Owasso to do it for me. He's a real life machinest and Class III Manufacturer (He makes a integral Ruger M77 in 44 mag that's 1/2 the noise of a pellet gun). If I can get quick turnaround and on the cheap it would be really great to cut it an inch at a time....maybe he's into the science I'll have to find out.