Author Topic: Ar15 question (Read 4683 times)

zahc · « **on:** July 29, 2013, 05:50:18 PM »

So, most AR15s have flash hiders. I understand the purpose of flash hiders. However, I don't understand their popularity. For the extra 1.5 inches of length, you could get extra velocity if you just had another 1.5 inches of actual barrel.

I have actually see people who build ultra-light ARs, when they don't want to have a SBR, they get a 14.5 inch barrel and weld a flash hider on it so the barrel length is 16". But I thought we shortened barrels so they were handy, so the idea of putting a permanent flash hider on your barrel so that you can make the real barrel shorter...it does not sense. Is it majorly bad luck to have an AR with just a normally-crowned barrel?

Hutch · « **Reply #1 on:** July 29, 2013, 05:51:42 PM »

The flash hider is cooler looking. Can't overstate the value of cool.

AZRedhawk44 · « **Reply #2 on:** July 29, 2013, 05:57:35 PM »

It's a combat gun.

As such, it's of greater defensive (or offensive) utility to have a carbine at 16" with 1.5" of flash hider to protect your night vision when engaging bugaboos in your house (or elsewhere in the dark), than to have an additional 25fps and a fireball that is visible when looking through your sights or EOTech or ACOG or whatever.

I see lots of "service rifle" AR's at High Power matches with no flash hider. Full 20" barrel. They seem to think the exposed/recessed crown is greater value than the flash hider, especially since the 15+ pound rifle only gets used during peak sunlight hours in the middle of the day.

Anyways, back to the 16" issue: 16" is the arbitrary magical ATF number "thou shalt not have a barrel less than." So, go 14.5" and weld a 1.5" flash hider on it. 16", with the efficacy of the flash hider. Maximum shortiness.

Fly320s · « **Reply #3 on:** July 29, 2013, 07:03:33 PM »

Quote from: zahc on July 29, 2013, 05:50:18 PM

So, most AR15s have flash hiders. I understand the purpose of flash hiders. However, I don't understand their popularity. For the extra 1.5 inches of length, you could get extra velocity if you just had another 1.5 inches of actual barrel.

That 1.5 inches doesn't add enough velocity benefit to overcome the dramatically increased muzzle flash. My friend, Lisa, has a photo of her Bushmaster AR15, without a flash hider, creating a huge, donut-shaped fireball. This was in broad daylight, which didn't affect her vision, but using that in a low light environment could cause problems.

Quote from: zahc on July 29, 2013, 05:50:18 PM

I have actually see people who build ultra-light ARs, when they don't want to have a SBR, they get a 14.5 inch barrel and weld a flash hider on it so the barrel length is 16". But I thought we shortened barrels so they were handy, so the idea of putting a permanent flash hider on your barrel so that you can make the real barrel shorter...it does not sense. Is it majorly bad luck to have an AR with just a normally-crowned barrel?

Light rifles are good, but some states don't allow SBRs, and some owners don't want the extra cost or hassle of getting the tax stamp.

MikeB · « **Reply #4 on:** July 29, 2013, 07:42:15 PM »

Many "Flash Hiders" act as a muzzle brake, and make it easier to keep on target with rapid fire or a happy switch.

Pharmacology · « **Reply #5 on:** July 29, 2013, 07:44:14 PM »

Quote from: MikeB on July 29, 2013, 07:42:15 PM

Many "Flash Hiders" act as a muzzle brake, and make it easier to keep on target with rapid fire or a happy switch.

Yup.
I have the YHM Phantom on mine, which acts as both.

I did do research into which hider... uh... hid... the most.

RoadKingLarry · « **Reply #6 on:** July 29, 2013, 07:45:19 PM »

May not be a big issue but for a combat rifle that may get banged around a bit I thin the flash hider might also offer some protection to the muzzle.

Perd Hapley · « **Reply #7 on:** July 29, 2013, 07:51:40 PM »

Quote from: RoadKingLarry on July 29, 2013, 07:45:19 PM

May not be a big issue but for a combat rifle that may get banged around a bit I thin the flash hider might also offer some protection to the muzzle.

I think so, too. Probably not likely a crown would be damaged, but it seems like it would help.

AJ Dual · « **Reply #8 on:** July 29, 2013, 09:07:15 PM »

Don't forget it's a political statement to have it as well.

AmbulanceDriver · « **Reply #9 on:** July 29, 2013, 09:12:53 PM »

I still want to get one of Bogie's "Zombie Brain Core Sampler" units for my AR... :D

Jim147 · « **Reply #10 on:** July 29, 2013, 09:14:34 PM »

Quote from: AJ Dual on July 29, 2013, 09:07:15 PM

Don't forget it's a political statement to have it as well.

It's as American as the thing that goes up.

jim

zahc · « **Reply #11 on:** July 29, 2013, 09:24:50 PM »

This all started because I decided it would be neat to have an ultralight AR15 "for the wife". I have seen some non-SBR builds under 5 pounds, including red-dot.

Fly320s · « **Reply #12 on:** July 29, 2013, 10:25:35 PM »

FHs weigh less than barrel material.

Jim147 · « **Reply #13 on:** July 29, 2013, 10:29:35 PM »

I have a new 16" unthreaded barrel setting here that has never been installed. I'm not going to pull my threaded barrel to compare weight but I don't think the difference would be much more then that of the velocity. Little to none.

jim

zahc · « **Reply #14 on:** July 29, 2013, 10:37:26 PM »

So, are there any opinions as to the accuracy of "lightweight" barrel profiles? According to The Internet, the thinnest safe profile is about .56 inches in diameter, not counting the bits at the barrel nut and gas block, which have to be bigger to be compatible. Can I expect MOA accuracy out of a thin barrel like that, at least for the first couple rounds?

From what I understand, the M4A1 barrel profile is like .625 out to the gas block, and designed to fire some 500 rounds sustained full-auto before catastrophic failure, vhere the A2 is .75 inches out to the gas block, and goes over 900. Of course the M4 has a dinky 14-inch barrel, so I'm not sure how that plays in.

None of this matters for a gun that would be used to kill groundhogs and coyotes, with maybe 5 rounds fired.

Bob F. · « **Reply #15 on:** July 29, 2013, 11:13:36 PM »

Buddy shot in a 3gun match last weekend, I videoed the rifle portion. Afterwards: "What the hell were you shooting? Some had no flash and some had a real fireball!" He had an ammo can of mixed Fed & PMC. I was shooting PMC w/ no noticeable flash in daylight, both of us using hider/brakes. Gotta think it was his Federals flashing.

Stay safe.
Bob

Harold Tuttle · « **Reply #16 on:** July 29, 2013, 11:16:05 PM »

the 20 inch govt profile is quite nice

zahc · « **Reply #17 on:** July 30, 2013, 08:51:09 AM »

I was actually thinking about getting a 20-inch govt, chopping 3.5 inches off, and turning the end (past the sight block) down to match the beginning (just past the barrel nut). That would probably be as light as all the featherweight barrels, only cheaper (given that I have a lathe). I suppose it would rust, though, after I took off the coating. I would either get a different gas block or chop down the front sight post.

Harold Tuttle · « **Reply #18 on:** July 30, 2013, 11:06:13 AM »

a govt 20 AR15 with the PRI carbon fore arm is light enough

super light is building something up on a CAV arms lower

a full 30 round mag adds a pound

http://www.ar15.com/mobile/topic.html?b=3&f=118&t=527546

Cav Arms Lower
Carbon-15 Stipper Upper
Bushmaster Super Lightweight Barrel

5 lb. 1 oz. (without magazine)

zahc · « **Reply #19 on:** July 30, 2013, 11:12:19 AM »

Does magpul make a 10-round PMAG (or 5-round, for states with retarded hunting laws)? I really like their 20-round PMAG and use them all the time. 30 is just too big.

BryanP · « **Reply #20 on:** July 30, 2013, 11:42:17 AM »

Quote from: zahc on July 30, 2013, 11:12:19 AM

Does magpul make a 10-round PMAG (or 5-round, for states with retarded hunting laws)? I really like their 20-round PMAG and use them all the time. 30 is just too big.

http://store.magpul.com/product/MAG559/PMAG

roo_ster · « **Reply #21 on:** July 30, 2013, 12:00:27 PM »

Any folk build 20" bbls with the front sight assembly way out near the muzzle break to increase the sight radius?

Harold Tuttle · « **Reply #22 on:** July 30, 2013, 02:25:49 PM »

bloop tubes

Phantom Warrior · « **Reply #23 on:** July 31, 2013, 03:55:49 PM »

Quote from: RoadKingLarry on July 29, 2013, 07:45:19 PM

May not be a big issue but for a combat rifle that may get banged around a bit I thin the flash hider might also offer some protection to the muzzle.

Unless you stick it in something really deep a flash hider is also easier to clean mud out of than a target crowned barrel.

bedlamite · « **Reply #24 on:** July 31, 2013, 04:38:38 PM »

Quote from: zahc on July 29, 2013, 10:37:26 PM

So, are there any opinions as to the accuracy of "lightweight" barrel profiles? According to The Internet, the thinnest safe profile is about .56 inches in diameter, not counting the bits at the barrel nut and gas block, which have to be bigger to be compatible. Can I expect MOA accuracy out of a thin barrel like that, at least for the first couple rounds?

From what I understand, the M4A1 barrel profile is like .625 out to the gas block, and designed to fire some 500 rounds sustained full-auto before catastrophic failure, vhere the A2 is .75 inches out to the gas block, and goes over 900. Of course the M4 has a dinky 14-inch barrel, so I'm not sure how that plays in.

None of this matters for a gun that would be used to kill groundhogs and coyotes, with maybe 5 rounds fired.

Thin profiles can definitely be accurate. This one is a CAV MK2 lower, Clark carbon handguard, 16" Ko-Tonics barrel, and Weaver 1-3x20 scope. It's right at 6 lbs as pictured. The barrel is 6.8 SPC (.277), and it's .7" diameter under the handguard, .750 gas block, and .6 between the gas block and muzzle. The second pic was 3 rounds of 100gr Nosler Accubond over 30.0gr of AA2200 at 100 yards from that gun.

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Author Topic: Ar15 question (Read 4683 times)