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Posted: 7/25/2011 8:04:40 AM EDT
| After being on here for a couple weeks, I have not seen anyone say anything about function differences between the lengths. Is there any benefit for one lenth over another besides how it looks? Will it fiction any better as a carbine or midlength or rifle? |
| in my limited experience with ARs, i have found that the longer the gas system the smoother the recoil. My carbine has a very noticable recoil and is more difficult to hold on target for follow up shots "double taps". My rifle gas system has a very soft recoil and allows much faster follow up shots. |
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Quoted:
in my limited experience with ARs, i have found that the longer the gas system the smoother the recoil. My carbine has a very noticable recoil and is more difficult to hold on target for follow up shots "double taps". My rifle gas system has a very soft recoil and allows much faster follow up shots. Ummmm...OK! Don't quote me on the exact numbers. In theory, the Rifle is supposed to be a smoother action for sniper/longer range. It holds the gas longer to cycle the BCG, so it's a smoother operator at the sacrifice of the cyclic rate ~ 13K gas based upon the gas port being so much farther down the barrel and something like 500 microseconds. Carbines were designed to be a higher cyclic rate for CQB type operations ~ 26K gas based upon the gas port being so close to the receiver and something like 350 micro seconds. Carbines expel the gas quicker, but at the expense of jumpy and "harsh" action that reportedly damages and breaks bolts and such - That's the rumor. The Middy is supposed to be the best of both worlds - Right in the middle. However, quicker is a relative term. With a Semi-Automatic, all this is relative anyway. My Carbine was specifically built to be a carbine and is tuned to be a smooth shooter. It shoots slightly smoother than other 3 Middys I have. So, I am not a true believer in this recoil thing. Recoil is also relative...It's a damn automatic. I was taught to hold a rifle...I don't strangle it, and I don't limp arm it. Anyway, It's the spring that pushes the bolt forward...Not the gas. So, the theory of the carbines shattering a bolt...Have to be exagerated. Anyway, I like the little carbine I built, but I still build mostly Middys. ETA: There is an article somewhere on this forum about this...that is where I remember these numbers...I can't find it. |
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All things being equal, the longer the gas system, the smoother the recoil impulse. The end. Anyone who tells you otherwise is an idiot.
Their is no downside to a longer gas system, set aside the couple ounces of longer gas tube and possibly a couple inch longer handguard. Unless you are trying to pinch pennies with weight savings, you generally want to use the longest gas system for that barrel length that will function reliably. On this same note, you can play with different weight buffers to acheive a similar effect. IE 18-20" use a rifle gas, 14-16" use mid length, 10-14" use carbine, etc. You will run into debates with the overlaps (14.5 middy vs carbine and 18" mid/inter/rifle) over whether the couple extra inches of handguard weight is worth the reduced recoil impulse (or whether either is even noticable) You can have a tube covering up a low profile gas block on a pistol, carbine, mid length, rifle, .. gas length system and put the sights wherever you want so don't think that gas system length dictates sight radius. Honestly, you can write a book about the gas system on the AR15. Come to think of it, there have been many written. I would recommend googling or reading through the FAQ as their is a lot of real information that you can use to form your own opinion on gas length and barrel length. |
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