Forums
New posts
Search forums
What's new
New posts
New media
New media comments
Latest activity
Classifieds
Media
New media
New comments
Search media
Log in
Register
What's New?
Search
Search
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Navigation
Install the app
Install
More Options
Advertise with us
Contact Us
Close Menu
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Forums
The Range
Rifle & Shotgun Discussion
The closest thing to an M4 military rifle in a civilian model.
Search titles only
By:
Reply to Thread
This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Message
<blockquote data-quote="aestus" data-source="post: 1602655" data-attributes="member: 2989"><p>The original 55gr 5.56 round was designed around the 20" barrel. The velocities the round was able to achieve caused the round to violently tumble and fragment consistently. Using a shorter 14.5" barrel will result in having less velocity and cause the round to not tumble and violently fragment as much as it would through a 20" barrel. Note that I said "as much." They still will tumble and fragment and are still deadly, but just not as much as it would through a 20" barrel. The same is true for the XM855 62gr penetrator rounds. Those are notorious for being icepicks with little to no tumbling at all, especially through shorter barrels.</p><p></p><p>This can be compensated by using heavier 75-77 gr. rounds which will fragment and tumble at very slow velocities. The downside is that these actually will penetrate less than the old 55gr rounds. Some of the US troops deployed in the middle east are using MK262 5.56 rounds that are 77gr open tipped match grade rounds. There is also a new 62gr penetrator round that the military is using called the XM855A1, which is dubbed the "green" round since it is lead free and uses a copper core and a stacked steel tip. Supposedly these have better penetration than most .308 rounds and they tumble consistently, eliminating the icepick type wound usually associated with the old XM855 rounds.</p><p></p><p>I haven't shot the new XM855A1 (don't think it's available for civvies yet and can't find any surplus) but I can attest to the 77gr rounds. Awesome rounds, just a bit expensive to shoot. I plan on reloading my own 77gr rounds in the future.</p><p></p><p>Also, if you want to shoot heavier rounds, you'll need a 1:8 or 1:7 twist. If you want a general AR that shoots both cheap 55gr rounds and the heavier stuff, I'd recommend a 1:8. If you're only concerned with plinking and shooting targets and small varmints, then a 1:9 twist is fine.</p></blockquote><p></p>
[QUOTE="aestus, post: 1602655, member: 2989"] The original 55gr 5.56 round was designed around the 20" barrel. The velocities the round was able to achieve caused the round to violently tumble and fragment consistently. Using a shorter 14.5" barrel will result in having less velocity and cause the round to not tumble and violently fragment as much as it would through a 20" barrel. Note that I said "as much." They still will tumble and fragment and are still deadly, but just not as much as it would through a 20" barrel. The same is true for the XM855 62gr penetrator rounds. Those are notorious for being icepicks with little to no tumbling at all, especially through shorter barrels. This can be compensated by using heavier 75-77 gr. rounds which will fragment and tumble at very slow velocities. The downside is that these actually will penetrate less than the old 55gr rounds. Some of the US troops deployed in the middle east are using MK262 5.56 rounds that are 77gr open tipped match grade rounds. There is also a new 62gr penetrator round that the military is using called the XM855A1, which is dubbed the "green" round since it is lead free and uses a copper core and a stacked steel tip. Supposedly these have better penetration than most .308 rounds and they tumble consistently, eliminating the icepick type wound usually associated with the old XM855 rounds. I haven't shot the new XM855A1 (don't think it's available for civvies yet and can't find any surplus) but I can attest to the 77gr rounds. Awesome rounds, just a bit expensive to shoot. I plan on reloading my own 77gr rounds in the future. Also, if you want to shoot heavier rounds, you'll need a 1:8 or 1:7 twist. If you want a general AR that shoots both cheap 55gr rounds and the heavier stuff, I'd recommend a 1:8. If you're only concerned with plinking and shooting targets and small varmints, then a 1:9 twist is fine. [/QUOTE]
Insert Quotes…
Verification
Post Reply
Forums
The Range
Rifle & Shotgun Discussion
The closest thing to an M4 military rifle in a civilian model.
Search titles only
By:
Top
Bottom