Semi-auto 5.56 rifles

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d2wing said:
The new Browning BAR if it come in semi-auto.
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I wasn't aware that Browning was building full auto weapons at this time.

Mosin Bubba said:
I'm with the OP. There are plenty of semi-auto 223s out there, but 95% of them are some flavor of "assault rifle" and the Mini feels half baked. It's basically a $400 rifle with an $800 price tag.

The SU-16s always looked cool - something like 5 pounds unloaded, folds in half, gives you a chintzy little built-in bipod, etc. Wish I had got one when they were a bit cheaper.
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There are no "assault" rifles. Don't fall into that trap.
 
John_R said:
Me, too. Where would one find such a thing?
index.php
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I had one like that. I also had a Saiga. Saiga is by far the most accurate of the AK type rifles I have shot
 
if you had chevy selling cars for $2000, and they were actually good cars you may still see Fords/Toyota.... but you would think the only cars anyone bought were chevy's. Thats exactly it.
 
IndianaBoy said:
Because the AR is so superlative that the competition has largely given up.
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My perception is that it’s more because ARs are as modular as legos and volume of production is so high that per unit costs are low.

ARs can be handy lightweight, reliable rifles, but the ergonomics aren’t great and certain parts are insufficiently durable.

BSW
 
BSA1 said:
I am new to the world of AR’s. What certain parts are you talking about?
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When Metal Injection Molding was first used for AR hammers, there were some breakages, but this seems to be mostly in the past. AR bolts are considered wear items, but usually break after many thousands of rounds- and will often continue functioning even with one or two lugs missing.
GI aluminum mags are easily damaged if stepped on or dropped on the feed lips, but PMAGs are nigh indestructible.

Otherwise they are pretty dang durable, not sure what BSW is referring to?
 
BSA1 said:
I am new to the world of AR’s. What certain parts are you talking about?
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AR bolts will break at the locking lugs or cam pin hole. Usually not under 10,000 rounds but the bolt probably won’t last 25k rounds. Admittedly, by the time you get to 10k rounds you’ve spent more on ammo than the rifle cost, but properly designed rifles don’t break bolts without being grossly overloaded.

The bolts that hold the gas key to the bolt carrier can also fail. The rifle may still be functional but the broken head of the bolt can cause a stoppage. Rarer is breaking the lower receiver at the area where the tube is screwed in, usually by dropping the rifle.

AR are obviously sufficiently durable for the vast majority of uses, but it is a 1950s design. Better steels and other materials (plastics) have been invented since then. Other manufacturers have built on the lessons learned from the M16s service life.

BSW
 
briansmithwins said:
AR bolts will break at the locking lugs or cam pin hole. Usually not under 10,000 rounds but the bolt probably won’t last 25k rounds. Admittedly, by the time you get to 10k rounds you’ve spent more on ammo than the rifle cost, but properly designed rifles don’t break bolts without being grossly overloaded.

The bolts that hold the gas key to the bolt carrier can also fail. The rifle may still be functional but the broken head of the bolt can cause a stoppage. Rarer is breaking the lower receiver at the area where the tube is screwed in, usually by dropping the rifle.

AR are obviously sufficiently durable for the vast majority of uses, but it is a 1950s design. Better steels and other materials (plastics) have been invented since then. Other manufacturers have built on the lessons learned from the M16s service life.

BSW
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Fair 'nuff, though I would say the direction most armies are going, using those lessons and new manufacturing techniques, is for even cheaper, lighter, disposable, infantry weapons which poorly trained conscripts can achieve better hit probabilities with- not necessarily a weapon with a longer service life.

Berettas dont last as long as 1911's, and I doubt the P320 will last as long as the Beretta. If it breaks, through it away and grab another....

Hard to believe that those were the original design criteria for the M16 and AK, yet by todays standards they are overbuilt!

As the Germans have discovered with the G36, newer dont mean better. :)
 
briansmithwins said:
AR bolts will break at the locking lugs or cam pin hole. Usually not under 10,000 rounds but the bolt probably won’t last 25k rounds. Admittedly, by the time you get to 10k rounds you’ve spent more on ammo than the rifle cost, but properly designed rifles don’t break bolts without being grossly overloaded.

The bolts that hold the gas key to the bolt carrier can also fail. The rifle may still be functional but the broken head of the bolt can cause a stoppage. Rarer is breaking the lower receiver at the area where the tube is screwed in, usually by dropping the rifle.

AR are obviously sufficiently durable for the vast majority of uses, but it is a 1950s design. Better steels and other materials (plastics) have been invented since then. Other manufacturers have built on the lessons learned from the M16s service life.

BSW
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A barrel is usually toast about the same time as a bolt becomes a concern.

A rifle like the SCAR may offer an increased service life but at such a cost penalty that you could just replace your AR barrel and bolt every 5k rounds for much less cost.

I don't think a Knight's Armament SR15 E3 bolt has ever broken, if you want a rifle that might not ever break.


The idea that a rifle will never wear out is a strange one. Do you plan to drive the same car forever?
 
<*(((>< : Superb list you knew, or found.

The only two I knew about besides the AR and Mini are the rare .223 VZ-58, Sigs and Israeli Galil.

Also, the Romanian SAR-3 AK clone and Norinco .223/5.56 AK clone (might have thumbhole stocks like the MAK 90). But magazines for the Norinco ($150?) and possibly the SAR-3 are Very expensive.
 
briansmithwins said:
AR bolts will break at the locking lugs or cam pin hole. Usually not under 10,000 rounds but the bolt probably won’t last 25k rounds. Admittedly, by the time you get to 10k rounds you’ve spent more on ammo than the rifle cost, but properly designed rifles don’t break bolts without being grossly overloaded.

The bolts that hold the gas key to the bolt carrier can also fail. The rifle may still be functional but the broken head of the bolt can cause a stoppage. Rarer is breaking the lower receiver at the area where the tube is screwed in, usually by dropping the rifle.

AR are obviously sufficiently durable for the vast majority of uses, but it is a 1950s design. Better steels and other materials (plastics) have been invented since then. Other manufacturers have built on the lessons learned from the M16s service life.

BSW
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So a bolt that has been HPI /MPI tested does not offer any advantages over a inexpensive bolt?

When you say "properly designed rifles don’t break bolts without being grossly overloaded" are comparing it to other semi automatic rifles (apples to apples) or to bolt action rifles (apples to oranges)? I thought the bolt is considered to be a normal wear part by the military.

I had not read of the bolt that fits in the BCG breaking. Sounds like a easy part to inspect when I clean my gun, Guess I will add one to my parts kit. Actually it is more likely I will drop the dang thing when cleaning the bcg at the range and not being able to find it in the grass so a spare is a good idea.

I don't follow your concern about the length of barrel life. The life barrels of high power varmint and competition rifles are measured in just a few thousand rounds. I often read of the barrel being replaced in as little as 2,000 rounds due to the drop-off in accuracy.

Just to be clear you are saying that if I accidently drop my rifle (probably about 3') there is a chance that the lower will break render it toast? Is this a good chance or are the odds the same as me winning the lottery?

I have read and seen videos of the area on the lower where it attaches the buffer tube breaking on plastic lowers. This is understandable to me since the receiver is not designed to use plastic. (I don't get using a plastic lower anyway but I am not into being a Operator or Tacticool kind of guy). The videos I have seen of aluminum frames ones sure stand up to a lot of abuse.
 
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BSA1 said:
So a bolt that has been HPI /MPI tested does not offer any advantages over a inexpensive bolt?......
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The testing is done in two ways. Some companies take a few from a "batch" of bolts and test them, others test each individual bolt. These later are individually marked (usually), while the first are not. The testing reveals internal imperfections that weaken a bolt, but all bolts, like everything else, are subject to wear.
An individual marked bolt provides assurance that there are no interior defects. If it's not marked, then, well, probably it's OK, but there could be some tiny percent chance it has a defect that might cause a breakage.

I have several ARs, some of which have marked bolts, some don't. I've never had any fail .... atleast not yet. But I'm not going to lose sleep over the unmarked bolts.
It's not that the marked ones are necessarily better, just that it's KNOWN they've been tested.
 
Don't forget the Zastava M90NP...the variant of the 5.56 M90 that has a factory installed adapter to use AR mags. Thicker 1.5mm receiver, bulged front RPK style trunnion, 18" CHFCL barrel, and adjustable gas...it's a heavy bastard child of an AK, but it's not much of an exaggeration to say it's nearly like shooting 22LR once the gas is tuned. Just a real pleasure to shoot.
 
Tommygunn said:
The testing is done in two ways. Some companies take a few from a "batch" of bolts and test them, others test each individual bolt. These later are individually marked (usually), while the first are not. The testing reveals internal imperfections that weaken a bolt, but all bolts, like everything else, are subject to wear.
An individual marked bolt provides assurance that there are no interior defects. If it's not marked, then, well, probably it's OK, but there could be some tiny percent chance it has a defect that might cause a breakage.
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Are the specs and tolerances on a HPI / MPI measured also?

The reason I ask is PSA keeps running a BCG on sale for $50.00 and I wonder if it worth the money to buy one to add to my parts kits.
 
BSA1 said:
So a bolt that has been HPI /MPI tested does not offer any advantages over a inexpensive bolt?

When you say "properly designed rifles don’t break bolts without being grossly overloaded" are comparing it to other semi automatic rifles (apples to apples) or to bolt action rifles (apples to oranges)? I thought the bolt is considered to be a normal wear part by the military.

I had not read of the bolt that fits in the BCG breaking. Sounds like a easy part to inspect when I clean my gun, Guess I will add one to my parts kit. Actually it is more likely I will drop the dang thing when cleaning the bcg at the range and not being able to find it in the grass so a spare is a good idea.

I don't follow your concern about the length of barrel life. The life barrels of high power varmint and competition rifles are measured in just a few thousand rounds. I often read of the barrel being replaced in as little as 2,000 rounds due to the drop-off in accuracy.

Just to be clear you are saying that if I accidently drop my rifle (probably about 3') there is a chance that the lower will break render it toast? Is this a good chance or are the odds the same as me winning the lottery?

I have read and seen videos of the area on the lower where it attaches the buffer tube breaking on plastic lowers. This is understandable to me since the receiver is not designed to use plastic. (I don't get using a plastic lower anyway but I am not into being a Operator or Tacticool kind of guy). The videos I have seen of aluminum frames ones sure stand up to a lot of abuse.
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I was comparing the AR bolt to other semi auto rifles. Even the other semi autos that use Johnson type multi lug bolts avoid breaking.

MPI testing just means the bolt was manufactured without flaws. The problem with the AR bolt is that it’s asymmetrical, which causes the locking lugs on either side of the extractor to carry more load than the other lugs. Those two lugs are also the weakest as they are undercut for the extractor. That’s why those two lugs break first.

The cam pin hole is also stress riser, which is why the bolts also fail in that area.

BSW
 
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BSA1 said:
Just to be clear you are saying that if I accidently drop my rifle (probably about 3') there is a chance that the lower will break render it toast? Is this a good chance or are the odds the same as me winning the lottery?

I have read and seen videos of the area on the lower where it attaches the buffer tube breaking on plastic lowers. This is understandable to me since the receiver is not designed to use plastic. (I don't get using a plastic lower anyway but I am not into being a Operator or Tacticool kind of guy). The videos I have seen of aluminum frames ones sure stand up to a lot of abuse.
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Far and away the majority of cracked poly lowers are 80% home builds that were cut too thin or have holes misaligned. Haven't really seen this issue much with recent factory built receivers.

* or someone stripping the receiver by over-torquing a castle nut when changing out a buffer tube
 
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A guy pretending a bolt service life of 10,000-25,000 rounds is unacceptable is no different than pretending he should be able to drive his car without changing tires every 60,000 miles, or changing oil every 5,000. Moving parts, and parts under pressure are expected to wear and fatigue - such is the nature of these things. We don’t buy a new car every 60,000 miles simply because our tires are bald, and we don’t throw away AR’s every 20,000 rounds simply because the bolt lugs are fatiguing. We replace the consumable parts and continue on.

For a civilian semiauto AR, it’s an absolute fluke of a bolt breaks young in a service life, and anyone complaining about any parts wear and tear after 20,000 rounds is just complaining. Let’s monetize that at around 35¢/round * 20,000 rounds = $7,000 in ammunition fired, so let’s not pretend it’s challenging to replace your $50 bolt every 10,000 rounds to avoid a fracture. Barrels will go every 2500-5,000 rounds, extractor springs and even extractors every 5,000-10,000, replace the $10 buffer spring every 5-10,000 (relaxed length indicated). Even hammer springs fatigue and need replaced typically within 10,000 rounds...

Even bolt action rifles have consumable parts, and require preventative maintenance. Some bolt action triggers should be replaced or at least resprung within 10-25,000 rounds, and naturally, not many bolt action centerfire cartridge barrels will hold on past 5,000 rounds. It’s often recommended guys touch up (re-skim bed) their actions every so often as well....

In other words - nothing which is used will last forever without a maintenance plan, and scheduled replacement or repairs are just part of any good preventative maintenance strategy.
 
My point is towards the idea that other semi auto rifles don’t need bolt replacements even after the barrel is shot out.

As far as the broken receivers a google image search will turn up multiple examples of broken aluminum receivers. Plastic lowers shouldn’t even enter the discussion.

BSW
 
briansmithwins said:
My point is towards the idea that other semi auto rifles don’t need bolt replacements even after the barrel is shot out.

As far as the broken receivers a google image search will turn up multiple examples of broken aluminum receivers. Plastic lowers shouldn’t even enter the discussion.

BSW
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I have some of these type of videos you are talking about. I have also seen videos where the tester deliberately tries to break the lower by beating the stock and buffer tube repeatedly on something hard. It seems like most of the time it is the buffer tube that gives away first.

So if you are that type of user then I understand where you are coming from. But if you can afford to destroy the lower and buffer tube by smashing it repeatedly onto the ground, a tree or something else hard then surely you have the money to buy a replacement bolt although I suspect you never keep the gun in one piece long enough to wear out the bolt / BCG.

Since you consider the AR to be fragile discussing wood stocked rifles is out of the question.

Why not include plastic lower in the discussion? They are commonly used.
 
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