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Posted: 1/5/2010 8:46:40 PM EDT
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Anyone got a load for .223 subsonic ammo? I'm thinking of getting a suppressor for my Robinson Arms XCR. The XCR has a gas selector option for subsonic ammo, so I'm not too worried about cycling problems resulting from subsonic ammo. I've heard it's dangerous to make, but to me it seems like I should just be able to cut down powder quantity until the ammo travels slower than the speed of sound. Granted, combustion may not be optimal as the entire casing will not be filled, but I'm more interested in getting the effect of suppressed ammo, not tight groups.
Any help would be appreciated. |
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I don't think they make a .22 kit for the XCR.
I am also thinking that the gas settings were not intended specifically for for subsonic ammunition. http://jlmx.info/wiki/tiki-index.php?page=Gas+System I might be off though. Really I just wanted to know more about subsonic .223. it seems to be a holy grail to attain subsonic .223 that cycles a semi. |
| I posted this over on the XCR forum....the S setting is for shooting regular ammo with a suppressor, as the suppressor adds significant blowback, so it cuts down the amount of gas going in.....as far as a straight subload, guys were saying it could be done with the rifle set to the 4 setting (Highest setting) using a suppressor and with a subload, it would cycle....now for a good subload, I have not tried it yet in the XCR, but I have developed some good loads using titegroup, clays, and trailboss....I was having better luck accuracy wise with the trail boss, and it almost fills the case too. |
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For shooting out of an unsuppressed gun, subsonic ammo isn't a big deal. When shooting a suppressed gun, the combustion of normal ammo will be muffled, but the sound the bullet makes when it breaks the speed of sound will not be muffled. That's because typical rifle ammo is supersonic. Subsonic ammo is loaded so that the bullet will travel slower than the speed of sound (About 340 meters per second). When subsonic ammo is shot out of a suppressed gun, the crack from breaking the speed of sound is eliminated and the rifle can achieve what some would call "movie quiet," or at least as close as one can get.
The problem is shooting the ammo in a semi auto rifle. Many times there isn't enough gas to make the rifle cycle properly. |
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As a starting point for working up subsonic ammo, is it better to use larger bullets because they can withstand more pressure and force before going subsonic? As far as the suppressor setting for the XCR, it looks like you are right. I would say go as heavy as yer barrel can stabilize (75g)....the theory being heavier bullets develop pressure much quicker, except when loading subsonic you will be well faster than the sound barrier before you go over pressure.....I have plenty of subloads, but no can yet to test with. I'm really curious if the XCR on the highest gas setting can truly cycle with a good suppressor attached. |
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55gr FMJ 3.1gr Titegroup 2.200" 1,064fps I've used this one. Works fine. The novelty wears off after a few rounds. Then is just seems kind of retarded. http://data.hodgdon.com/cartridge_load.asp 55gr FMJ 4.0gr Trail Boss 2.200" 1,074 http://data.hodgdon.com/cartridge_load.asp Both are quiet, but will not cycle the action. |
| They have their purpose - they are great for popping a pesky varmint around the place and you don't want to wake the neighborhood. They are also great for starting new shooters into the AR platform. It failing to cycle the action makes it function like a bolt action repeater. It would help if the charging handle was conveniently located, but there re some out there that do. |
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Just out of pure curiousity, would it be beneficial to have a special cartridge case machined with the exterior dimensions of a .223 case but with a cylindrical interior to limit capacity and allow for more compact loads and perhaps heavier bullets? I've seen this done for .308s, but each case was hand turned on a lathe, and, quite costly....but if you had a definite purpose it let you get less deviation out of loads that where SS |
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The site search is weak. You can use google to crawl through here. Type in "subsonic .223 site:ar15.com" without the quotes into google.
I do this a bunch because often even when you are a team member you can only search 3 months back and the subforums often don't get archived for long periods of time. |
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