Colt AR-15 ... Need Some Education

[msparks]

Wait about 6 months and I think you will see a flood of guns on the market. Lots more folks to lose jobs, and will need to sell them to make payments.

$1500 for any AR style gun is too much IMO (except maybe a match gun)

Run of the mill guns, 600-800 would be about right.

 

[Liquidator]

Any Good AR that meets Mil Spec and has a tight receiver should do fine. Then be sure to run 500-2000 rounds minimum before you can consider it broke-in, I'd say several thousand rounds...

 

[Steve S]

Originally Posted By: ALS
There isn't as much of a drop between barrel lengths as most expect with the .223

From a 22" barrel going down to a 16" barrel the velocity drops from 3177 fps to 2965 fps which is a 212 fps drop.

35 fps per inch is not bad at all.
It has more effect than you would think.

 

[Samilcar]

Originally Posted By: Steve S
Originally Posted By: ALS
There isn't as much of a drop between barrel lengths as most expect with the .223

From a 22" barrel going down to a 16" barrel the velocity drops from 3177 fps to 2965 fps which is a 212 fps drop.

35 fps per inch is not bad at all.
It has more effect than you would think.


Once a .223 bullet drops below about 2600 fps, it stops fragmenting when it hits tissue, and makes "ice pick" type wounds instead. This is the source of recent complaints from soldiers about the ineffectiveness of these rounds from 16" barrels when hitting targets at about 200 meters. At those ranges, a .223 bullet fired from a 20" barrel still fragments because the bullet is traveling faster than 2600 fps.

 

[Robenstein]

Well the M4 is a 14.5 inch barrel. The ss109/M885 62gr round did not have sufficient velocity and hence energy at medium distances to wound effectively. The round was just not designed for that short of a barrel. That is why you are starting to see more and more heavier 5.56 rounds and the faster twist barrels to stablize them.

Honestly, the 55gr 223 M193 load of the nam era was a pretty good stopper until the twist was tightened. What killed the rounds effectiveness by about 40% is the increase from a 1 in 14 to a 1 in 12 twist in the barrels so it could pass the arctic accuracy tests of the day. The ARPA (Advanced Research Project Agency) tests with the early 1 in 14 barreled guns showed a huge ability to blow apart enemy combatants. Some advisers participating in the project estimated a 90% fatality rate among the wounded enemies.

 

[strat81]

Originally Posted By: Samilcar


Once a .223 bullet drops below about 2600 fps, it stops fragmenting when it hits tissue, and makes "ice pick" type wounds instead. This is the source of recent complaints from soldiers about the ineffectiveness of these rounds from 16" barrels when hitting targets at about 200 meters. At those ranges, a .223 bullet fired from a 20" barrel still fragments because the bullet is traveling faster than 2600 fps.


Fragmentation of .223 bullets is not solely dependent on velocity. Bullet construction plays a role as well.

Additionally, not all .223 bullets depend on fragmentation for their wounding capabilities. The Winchester 64gr Power Point is a good example of that.

Some reading:
http://ammo.ar15.com/ammo/project/term_2700.html
http://ammo.ar15.com/ammo/project/term_expanding.html

 

[Robenstein]

I think he meant the 5.56 NATO loads were dependent on velocity and fragmentation. Their way of going around the Hague Accords which outlaw expanding or soft lead bullets.

 

[jsharp]

To the person who asked about receiver play - I have a RRA Entry Tactical. There is effectively no play between the upper and the lower. You need a plastic drift to push the pins out that hold the upper and lower together. They're too tight to remove by hand.

You can get an RRA carbine brand new for around $850 on Gun Broker, another $50+- for one with a chrome chamber and bore. The S&W M&P 15 is about the same money. You can decide for yourself if it's worth $300-$400 more money to get a Colt.

I haven't decided myself since I haven't shot the RRA yet. But I have 2 Colts already and I don't find them all that special in spite of what the web warriors seem to think.

Once I get a few thousand rounds though the RRA I'll probably be able to form a better opinion.

 

[Samilcar]

Originally Posted By: Robenstein
I think he meant the 5.56 NATO loads were dependent on velocity and fragmentation. Their way of going around the Hague Accords which outlaw expanding or soft lead bullets.


Correct. I was speaking of FMJ military rounds.

 

[Steve S]

http://forums.second-amendment.org/index.php?topic=636.0

This link is to a bullet fragmentation chart while I can't say it is true science it could be an in general guideline

 

[strat81]

Originally Posted By: Robenstein
I think he meant the 5.56 NATO loads were dependent on velocity and fragmentation. Their way of going around the Hague Accords which outlaw expanding or soft lead bullets.


Luckily US citizens are not bound by such constraints.

Similarly, if a citizen is engaging a target at a distance where fragmentation would be questionable, they're either a lousy hunter or trying to meet their local prosecutor and prison warden.

 

[Tempest]

Quote:
Once a .223 bullet drops below about 2600 fps, it stops fragmenting when it hits tissue, and makes "ice pick" type wounds instead.

Something tells me the guys getting shot at won't care.

You can carry about twice as much 5.56 as 7.62 for the same weight (plus lighter rifle). This lets you stay in the battle for much longer and at the very least keep the bad guys heads down longer while you call for the rain...

If you are in open terrain, troops should be using the 20" rifle rather than a carbine anyway.

SS109 was designed to penetrate helmets at ~600 meters. That was the primary spec, not fragmentation at close range.
Why this is I have no idea. Sounds like a poor priority list to me.

 

[Robenstein]

That may be true for the SS109 round, but the earlier M193 round had more than just penetration attached to it.

It had to pierce a standard helmet at 500 yards, wound as well as the 7.62 NATO out to 300, and be at least as accurate.

The small caliber high velocity concept will generally yield fragmentation at high velocities. The Army discovered this many many years ago in 1947 if I recall.

Now the old West German 7.62 load is just awesome. It was made with a different jacketing and caused devastating wounds by fragmentation.

 

[SuperBusa]

Originally Posted By: jsharp
To the person who asked about receiver play - I have a RRA Entry Tactical. There is effectively no play between the upper and the lower. You need a plastic drift to push the pins out that hold the upper and lower together. They're too tight to remove by hand.


My RRA Elite CAR A4 has essentially no play between the upper and lower, but I can actually push the pins out by hand.

I was in a gun store last week and looked at a brand new Colt on the wall. Gave it the upper/lower slop test and it had major play between the upper and lower. I don't think the Colt is all the "web warriors" (as you say) make it out to be.

 

[jsharp]

The Colt has better specs on paper but you have to question the importance of them in a semi auto civilian weapon.

Better barrel steel - but since I'm not running mag after mag full auto I'm not sure this matters.

MPI bolt and carrier - I suppose that might matter if the non MPI bolts were of marginal quality or I was firing proof loads all day.

Calling some of the differences "better" is just silly. For instance, Colt's have tapered pins to secure the front sight base. So what, the straight pins hold plenty well.

Same with the size of the buffer tube. RRA and some others are "mil-spec." But if you're never going to change the butt stock I don't see an advantage either way.

 

[strat81]

High quality bolts are not that expensive compared to untested bolts. Do a Google search for "broken AR bolt". Common broken bolt makers/retailers include Olympic, DPMS, Del-Ton, and Model 1.

It is uncommon (but not unheard of) to hear of a broken Colt, BCM, DD, LMT, or Young bolt.

In most cases, the bolt shears lugs or breaks at the cam pin hole. MPI and HPT bolts are less likely to experience these failures. The cost for bolts with these features is minimal compared to their untested counterparts.

If your rifle is a range toy, this is a non-issue. If you are in LE, a competitor, or depend on your rifle for your safety, a broken bolt can be very problematic.

Also, RRA uses commercial buffer tubes, not mil-spec. That doesn't make them bad tubes, but it can affect fit of certain aftermarket stocks.

 

[Steve S]

Would you say the carbines beat up the partstdue to the higher gas pressures?

 

[Steve S]

Originally Posted By: Tempest
Quote:
Once a .223 bullet drops below about 2600 fps, it stops fragmenting when it hits tissue, and makes "ice pick" type wounds instead.

Something tells me the guys getting shot at won't care.

You can carry about twice as much 5.56 as 7.62 for the same weight (plus lighter rifle). This lets you stay in the battle for much longer and at the very least keep the bad guys heads down longer while you call for the rain...

If you are in open terrain, troops should be using the 20" rifle rather than a carbine anyway.

SS109 was designed to penetrate helmets at ~600 meters. That was the primary spec, not fragmentation at close range.
Why this is I have no idea. Sounds like a poor priority list to me.
SS109 was designed for the saw weapons.

 

[jsharp]

Originally Posted By: strat81
High quality bolts are not that expensive compared to untested bolts. Do a Google search for "broken AR bolt". Common broken bolt makers/retailers include Olympic, DPMS, Del-Ton, and Model 1.

It is uncommon (but not unheard of) to hear of a broken Colt, BCM, DD, LMT, or Young bolt.

In most cases, the bolt shears lugs or breaks at the cam pin hole. MPI and HPT bolts are less likely to experience these failures. The cost for bolts with these features is minimal compared to their untested counterparts.

If your rifle is a range toy, this is a non-issue. If you are in LE, a competitor, or depend on your rifle for your safety, a broken bolt can be very problematic.

Also, RRA uses commercial buffer tubes, not mil-spec. That doesn't make them bad tubes, but it can affect fit of certain aftermarket stocks.


I can certainly see the bolt change if you're firing high pressure loads very often. Using commercial .223 ammo I'm not sure it's much of a worry.

Interesting thing about MPI bolts though. It seems like they should be proof fired first, then checked for cracks. I could be wrong since I'm not a metallurgist, but I doubt you'll see much cracking in the material just from machining and heat treating. Having them made out of substandard material would worry me more than how they're inspected.

The commercial buffer tube is a non-problem if you're not going to change stocks. Just like the older Colt large pin fire control components were a non-problem if you weren't going to change them out.

SteveS- I fired my RRA Saturday and judging by the ejection pattern it's over-gassed. I put an honest to Hartford Colt M-16 bolt carrier in it that's heavier than the RRA AR-15 carrier and the ejection looks slightly better.

I ordered an H carbine buffer for it this morning to see if that helps. I also ordered an allegedly better quality bolt to use in the M-16 carrier I had around while I was at it. It's only $$ right?

And this way I have the RRA complete bolt carrier assembly as a spare just in case.

 

[Tempest]

If you put a LOT of rounds through your gun, then MPI might be a big deal. Even still, you'd probably go through 2 or 3 barrels before it becomes much of a concern. Full auto makes this much worse, though...if you have one.

If you can afford that much ammo, just replace the bolt every time you replace the barrel and don't worry about it. Now a days a bolt is cheap relative to the ammo.