Speaking of AR's again

[jjamna]

Sorry about another AR thread But I am still trying to get mine to shoot with Condom bullets.
What grain would be best with a 1 in 10 twist. I have been shooting 55 gr. Rem spire tips. accu tips ( both Factory loads) the best so far are my handloads with a 55gr Hornady v-Max but they are nothing to brag about. I picked up some 65 gr Sierras today and will try them. I just thought I may save some $ and reloading time by asking.
Gun is a Vulcan Lower. Have not found out what the upper is, Havn't taken it apart and it does not say anything on the barrel.
It is 223 rem cal 20 inch Floated barrel with a scope on it

[BlackRifleShooter]

lighter bullets should shoot better for you in that 1-10 twist. ARe you sure it is 1-10? 1-12 and 1-9 are more common. I would try some 50 grn - 45 grn loads.

[jjamna]

No I am not sure. I tried to measure with a cleaning rod. It could be any one you listed.

[danski26]

Unknown barrel equals unknown performance. There are a lot of garbage barrels out there. What kind of accuracy are you getting?

[jjamna]

I haven't really tried much at 100 yds. But setting the scope at 25 yds it was like 1 1/2 inch. I would be very happy with that at 100 but this is 25. I agree on the junk and I have been looking at new uppers. Any suggestions? J & T Distributing has an ad in shotgun news Advertising 1 hole at 100 yds Kit for $534.95
Gun will be used mainly for hunting

[danski26]

A friend of mine just asked me about those J&T distributing deals. I have no experience with those. I don't know who is making the barrel they are offering. If you are looking to rebarrel it's hard to go wrong with Colt or Bushmaster. If you want match grade, I have had good luck with Krieger barrels. But I would like to try a Wilson barrel also.

[jjamna]

I forgot to put in the other reply- they told me it was a matching gun when I bought it. (same upper and lower) however I sent the company an email and they said they sold it as a Lower only. I can't find any writing on the upper anywhere. I took the handguard off and still nothing.

[Triggerhappy]

You'll want to double check what the twist rate is on the barrel. A 1 in 10 twist will not stabilize the heavier bullets. If it's truly a 1 in 10 stick with the 50-55 grain bullets. Since you're getting inch and a half at only 25 yards I'd check the scope and mount too. That's a lot of variance unless you're tumbling the bullet and I doubt that at 25 yards that's all of the problem. Are you using factory ammo? If reloads, how consistent are they? How fast are you pushing the bullet?

Might make sure that the barrel isn't loose in the upper. Seen that happen a few times on the 15's. The scope is on the upper receiver, so if the barrel gets a little loose it tends to cause problems. Chuck the receiver in a padded vice and see if you can move the barrel by hand. Any movement is a bad thing.

Is the barrel chambered for .223 or 5.56? If shooting .223 in a 5.56 barrel you can expect a little less accuracy. The barrel should be at least marked for the caliber. Might also check the bore and throat for extreme wear.

Most AR's will shoot under 1.5" at 100 yards provided the bullet and load match the barrel twist. The faster the twist the heavier bullet you can stabilize, in theory. In my competition AR's I shoot 77 and 80 grain for long distances and always achieve sub 1" groups, usually sub .5".

I would suggest that you isolate the problem before you go throw money at it. If you want to hunt with the weapon you should get a 1 in 9 or 1 in 8 twist barrel for the heavier bullets. Unless of course by hunting you mean prairie dogs and squirrels. Larger game needs a heavier bullet, heavier bullets need a fast barrel.

One more thing, shouldn't matter if the upper and lower are matched. A lot of people put a lot of stock in how tight the match is. In my opinion it doesn't make that much difference and I don't spend a lot of effort on it. Much more important are the upper receiver, barrel and optics association. The rest shouldn't make that much of a difference.

Brian.

[Larry Gibson]

I've found the Sierra 52 gr Match bullet over 26.5 gr H335 with a WSR primer to be very accurate in 7, 9, 10 (Mini14), 12 and 14" twists. It has shot extremely well in all 7, 9 and 12" twist ARs. Try that load. If it isn't accurate then it is the barrel, the cahmber or possibly the crown. One other thing. You obviously bought the AR used(?) the barrel could be shot out. There's lots of older ARs out there that have had a lot of "blasting" through them.

Larry Gibson

[jjamna]

I just shot a 5 shot string at 100 yds. Right at 2 inches but none really together. 1 right 1 high 1 low ect. These were 55 grain hornady's and IMR 3031 don't remember the grains but can check.Velocities were not over 20 FPS difference on the 5, right at 2700 There are no markings anywhere on the barrel that I can find. The only thing I can find is the lower say's 5.56. I have checked the empties going in the chamber and they seem to be right. (same Caliber) I have no sighns of high pressure and action cycles real good. Have not had a hang up yet with around 200 rds.
I will check the barrel tightness. I tried with the cleaning rod to get the twist again with no luck. Either to lose or couldn't get it in (Ha Ha)
I am thinking poor quality or shot out myself but I don't know that much about barrels. I just shoot and clean.
Yes I got it used.
Used for hunting Groundhog and coyotes

[Triggerhappy]

2" at 100 Y isn't that bad. As long as everything is tight I would try some different loads. Try different powders and vary the loads .3 grains (within specs) or so until you find on the load that barrel likes. Try different bullets too. Combinations make the difference. Keep track of what works and what doesn't. You'll probably want to keep the OAL at 2.250" for the AR's.

As long as the barrel isn't worn out you should be able to tighten that group up.

B.

[jjamna]

Is there a sure way to check the Barrel? Low Cost.

[jjamna]

What a bad day Loaded some 65 gr Serria's to check them and shot my Chrony. went to take the hand guard off and the whole barrel nut came off.(this could be part of problem).
Dumb ?---- Is changing the barrel on an AR a drop in deal or do you need to headspace it like on a bolt action

[EMC45]

When you get it back together try 24 gr. IMR 4895 under a 55-60 gr. bullet. That was my load awhile ago.

[jjamna]

Barrel does move very little at receiver and you can't get it to tighten. Do I try a new Barrel, whole new upper or maybe a new barrel extender?

[nicholst55]

I'm a little confused by your description of things. Does your rifle have a freefloat handguard that screws onto the barrel nut? That's what it sounds like. Installing AR barrels isn't rocket science - the headspace is set at the factory when the barrel is chambered, and SHOULD be correct.

Olympic Arms is the only one I know of who has made AR barrels with a 1-10" twist. Their barrels have a pretty good reputation. Most any AR with a barrel that isn't totally shot out should group decent ammo right at 1" at 100 yards, or slightly less.

I would suggest that you check the crown on your muzzle. If it doesn't look right, either recrown it yourself or pay a gunsmith to do it. It should cost you $50 or less. Then either reinstall your barrel or have the gunsmith do it for you. Again, this should run $50 or less.

If it still won't shoot, I'd consider trying a different barrel or upper. J&T has a good reputation, and they sell a lot of stuff. They've been around for a long time, and I wouldn't hesitate to buy a barrel from them. Not sure who makes their barrels now, but they have used Wilson, ER Shaw, and others over the years. None of them are bad barrels, although everyone screws up now and then.

[jjamna]

Yes Freefloated Handguard. I tried some Remington Accutips which is supposed to be pretty good ammo. It sprayed them all over just like it did with Rem Cheap stuff UMC. When I say spray I mean Like a piece of paper that your printer prints Five shots would be all over it. I have got the hand loads to shoot better but they are a lot slower than the factory loads.
All together I have tried 5 different factory loads and 3 handloads. None have shot anything consistant. I have had 2 different scopes and one red dot scope scope on it. All the same. One scope and the red dot are proven shooters on other rifles the other scope is brand new.
The crown don't look to bad just looking at it but I could miss something easy
enough. Here is a Pic of the crown. I do see a little dimple or something at about 8 o-clock

I can get a Barrel from J&T for around $200
Complete upper Close to $500
Midway has a DPMS that I like for $509. It gets good reviews.

I am ready to do something. I can't stand a gun that will not shoot. I have only had one in my life and I traded it in a hurry.

[DaveInFloweryBranchGA]

Sounds like you're throwing money at a problem without bothering to have the gun checked out by a gunsmith or AR armorer. I suggest you do that first. He may be able to determine the condition of the gun and resolve the barrel/handguard/nut issue for some very minor cost.

Regards,

Dave

[nicholst55]

Sounds like you're throwing money at a problem without bothering to have the gun checked out by a gunsmith or AR armorer. I suggest you do that first. He may be able to determine the condition of the gun and resolve the barrel/handguard/nut issue for some very minor cost.

Regards,

Dave


+1. An AR that shoots that badly is unusual, in my experience. Even most military M16s shoot better than that, with GI Ball ammo.

[jjamna]

I will be taking it to someone, I just need to figuire out who.

[BlackRifleShooter]

I have had good luck with RRA, and White Oak Armory Barrels. I prefer shorter barrels and usually run 16". The RRA was a post ban un-floated A2 Midlength carbine. I was getting 1" to 1 1/4" 5 shot gruops at 100 yards. I removed the A2 upper and swapped it for an A4 and Added a Daniels Deffense Railed Free Float Tube. My Groups shrunk to 3/4" , later I went to the WOA 16" SS match barrel with a Wylde Chamber and my groups dropped to 1/2 " and sometimes better than that. I miss that upper. I now have two 16" M4's and 1 20 " A2s None are truly impressive accuracy wise. They are all around 1 1/2" before long I will start swapping out parts though and see what we can get. I gues sthat was a long way of me suggesting you try an RRA or WOA barrel

[redneckdan]

Like others have said, isn't hard to get an AR to shoot, just need to float a decent barrel. Upper to lower fit doesn't really matter, as long as its not a intererence fit between the halves, which would cause stress on the upper. Tollerances of the upper are not that important because its pretty much just a sleave to control the movement of the carrier. Only part that really matters is that the barrel extension fits close to the diameter of the upper. One thing to check, take the bolt off, put the lubricated carrier back in. Flip the upper back and forth to let gravity cycle it. It should more smoothly. If you lightly touch the gas tube while doing this you should feel a slight click. The idea is to check that the gas tube is entering the gas key on an even plane. If the gas tube is not entering easily it needs to be LIGHTLY tweaked until it does. If the gas tube is putting un even pressure on the bolt it will cause vertical stringing.


PS- if the *sproooong* sound that the buffer and spring makes bothers you, grease the hell out of it. will cycle smoother and not as noisey.

[jjamna]

Guy's I have looked up one side down the other inside and out. I can't find a mark on this thing as to who made the barrel or what caliber it is. I put a bullet in an empty and closed the bolt. I am posting a photo of the results. Looks to me like an awful long chamber. Redneck as soon as I get done posting this I will check what you posted. I think I may need to put a headspace gauge in it. (anybody got one).

Cartridge on left is empty with bullet in it One on right a Factory

[mike in co]

just a normal chamber.....not match...not custom( tho i guess you could call a long throat 80 gr chamber "custom")
now it could be a shot out chamber too.

this is what happens when you buy someone elses "stuff".

the good news...most likely by simply replacing the bbl you will have a good gun.


mike in co

[jjamna]

So you do think this is my problem?????????

[jjamna]

It will shoot now. Will post targets later today.

[jjamna]

I hope you can see them ok. This is shots 20 thru 40 of the breakin shots. When I do my part groups are coming out great. They are not bad when I don't do my part.

[Hip's Ax]

I had a heck of a time getting my NM Armalite to shoot at 100 for reduced course matches. My mentor then told me to try 52 gr Sierras and WW748. Groups are awesome! Try some WW748 with your 50-55 gr bullets, bet you get a nice surprise.

[Triggerhappy]

One of my pet loads is the 55g Montana Gold (cause they're cheap) and 23.3 of H322. Check the specs but there's some latitude on both sides of that load. I get great accuracy that's fairly affordable. I tried Varget, 748, Tac, and three of four others before I came up with this load. I use it for practice and shots out to about 300 yards in competitions. longer shots get longer bullets.

Brian.

[jjamna]

I have a 1 in 9 inch twist. what is the biggest I can shoot respectfully? It is shooting the 65 grainers pretty good. But it likes the 50 Grain Hornadies to.

[RugerFan]

What a bad day Loaded some 65 gr Serria's to check them and shot my Chrony. went to take the hand guard off and the whole barrel nut came off.(this could be part of problem).
Dumb ?---- Is changing the barrel on an AR a drop in deal or do you need to headspace it like on a bolt action

Yes, absolutely check headspace after swapping barrel or bolt.

[Just Duke]

Give me a jingle and I'll help you out.

[Just Duke]

Can you take pics and list the components with the pics. Try DPMS and Lothar Walthar Barrels next time around. Lothar Walther make the barrels for Armalite and they are all tack drivers. At least the several I have do.

[jjamna]

I put a DPMS Upper on it. It is shooting great now. (When I do my part) I am still breaking in the new barrel and have some groups go well under an inch at 100yds. The 50 grains bullets shoot as good as the 65 or vice versa. I am looking at having a 6mm x 45 mm made for it. When I get a good trigger for it and a good scope maybe it will go under 1/2 inch. Right now it just has a 30 yr old Tasco on it.

This is not a good pic but maybe you can see it.
Jeff

[mike in co]

Can you take pics and list the components with the pics. Try DPMS and Lothar Walthar Barrels next time around. Lothar Walther make the barrels for Armalite and they are all tack drivers. At least the several I have do.


ME THINKS THIS MAY NOT BE CORRECT...

but i'll listen.


the ar-10 match bbls were at one time lothar bbls, but at one time also rock(not rock river) bbls.

std bbls are not either......

mike in co

[Scrounger]

ME THINKS THIS MAY NOT BE CORRECT...

but i'll listen.


the ar-10 match bbls were at one time lothar bbls, but at one time also rock(not rock river) bbls.

std bbls are not either......

mike in co

Lothar Walther...

[mike in co]

i think that is what i said.....


which of thier chrome lined bbls does he make ??

thanks
mike in co

[mike in co]

if you go to benchrest central you will find a pic of my group......134's at 2900 fps.......

the group measures 0.116"


the best out of berger 175's was a 0.338"


yep all at 100 yds

mike in co

[jjamna]

There is an artical in this months Handloader Magazine on the 6x45. Page 44 All it is is a 223 necked up to 6mm. I wouldn't think the pressures would be much more than a heavy bullet 223. You may want to use powders that tend to have lower pressures. As for hijacking the thread, Have at it, it don't bother me.
SSK Industries will make a bull barrel for around $400
Can anyone tell me what contour barrel blank you neet to barrel an AR? Can you make any contour work?

[Triggerhappy]

Duke,

If anything over 70g breaks the bolt after a short time, what's different with the Grendel? Or is there a difference? I hadn't heard that the 6.5 was hard on bolts. I'm genuinely interested. I'd like to build up a Grendel as I got my butt waxed buy one earlier this year at a match. Sure seem like a neat way to go. They have the ballistics, power and in a light weight package.

I need the long distance shot. Would you recommend going to the AR-10 platform instead of an AR-15 Grendel? I shot one at a match for the heavy power factor a year ago and found the follow up shots too slow. The .308 scores get beat by .223 guns because they don't leave the target and allow faster follow up shots.

Thanks,

Brian.

[Triggerhappy]

Thanks, appreciate the input. I agree that combat and race guns are very different critters. They don't even reside in the same safe at my place. Just hadn't heard about the bolt issue in regards to shooting the heavy bullets.

B

[jjamna]

Same here I had not heard of the bolt issue but it does make since.

[Triggerhappy]

Duke,

Does the 6.8 SPC have the same bolt problem?

[Leadforbrains]

Duke those are some nice rifles you got there. I have one AR-10, and it is an Armalite 16 inch model A2. My 14 year old son loves to shoot it. So much so in fact that he is trying to claim it for his own.

[jjamna]

I think I found the problem om the first upper. I put another barrel on it and it done the same thing( 12 inch ghroups at 100 yds) Now to the problem.

I am not sure yet but I think this is the problem- It has a composit upper reciever and a floated barrel. I am thinking the composit reciever don't have the muscle to hold a barrel in place with a floated barrel. With what I call the military style upper the hand guard helps hold the barrel in place by being held at each end. Therefore the composit upper will work ok.
Sound logical????

I am trying to round up an aluminum upper reciever . When I get one and get to test it I will let you know.

[BD]

Hi Duke,
Are you referring to broken bolts on the 6mm and 6.5 mms on the AR15 platform? Or heavy bullets in general? There's a lot of high power shooters out there shooting nothing but 77 grains and up in .223. Some of these guys are using carrier weights, but not all of them. My Bushy DCM has 5 or 6,000 rounds through it without a weight and only about 100 of them weighed under 77 grains. I look at the bolt pretty closely every couple hundred rounds and I haven't seen any sign of abuse. Maybe I should be more worried?
BD

[BD]

So what's breaking? Lugs breaking off?
BD

[jjamna]

Oh well

[mike in co]

Match shooting guns and real life conflicts guns are two different animals. It's like the difference between a Dragster on the NHRA ciruit and and Humm-V in combat. If you want to replace bolts around 1200 round go ahead. Normal practice from my contacts is the bolt is just replaced at 1200 rounds. Now you can have guys run over here and debate this issue but I used to run/business/party/trade with many maufactures of these parts. So I here it from the horses mouth.

.

Oh! and by the way. I know a guy that has a 5 gal bucket of broken AR bolts.


.



well since my name on a bunch of forums, including ar15.com is ar10ar15man.....
i'm throwing up the flag, and putting out the bs alarm.

i have been around ar's and competition shooters for years...lots of years. and some ot the top ar builders the same time.
STANDARD WITH THEM is replace the bolt when you rebbl, but not REQUIRED. rebbl is typically 3500-7000 rounds.
i know of no competent gunsmith that reccommends a 1200 round replacement.

I WOULD LOVE TO SEE A PICTURE OF A " a 5 gal bucket of broken AR bolts. "......WITH DOCUMENTATION OF THE MANUFACTURER, AND CALIBER.

this is std and match rifles in 223/5.56. ar15 cmp/dcm.

NOW ONE OF THE CURRENT ar15 wildcat rounds does cause an issue with bolts and the designer uses a special bolt. if you build it yourself from a stock ar15 bolt you will probably have issues. this is ONE chambering of all the current chamberings used in the ar platform.

i have had conversations with duke, so he will just have to bite his lip for a while and furnish the info to back up his statement.
i honestly feel posting statements like changing your bolt "every 1200 rounds" is irresposible.
i shoot a 6ppc in an ar15 platform. anyone who knows benchrest will tell your that there is no published data for the pressure used in 6ppc benchrest rifles...way beyond 223.5.56. BUT my bolt is a custom finished bolt in this one rifle.

post the specifics on given rifles that have failed,,,no generalities.

there have been bad batches of bolts in the past, but few and to my knowledge, quickly replaced by the company involved.

mike in co
ar10ar15man
m.a. nagengast

[mike in co]

Congats!!!!
Can you tell me about you 6 X 45?
Remember heavier bullets on this platform will cause inevitable bolt failure. You will be lucky to go 1200 rounds. Normal operating pressure for an AR hover around 50,000. When you change that by going with the big heavies it can run 80,000.
Remember that's 80,000 psi 2 inches from your nose and eye balls.
Armalite makes an AR-10 in .243. ;)


sorry but this is an irresposible statement...all of you should ignore this, which make me think we should question the source.

80,000 psi....are you wacked ???

you would not get the case out, nor open the bolt.


i'll be back....

i'm back..
i just ran quick load data on a couple of popular loads in ar's......77 sierra and the 80 gr sierra.
the 77 is designed to shot from the mag so oal is 2.260, the 80 is designed to shoot single loaded..not from the mag OAL around 2.450.
there are three pressure limits for this family of cartridges. saami around 55k for 223, 58k for 5.56, and cip is 62k .
aa2520,and varget at 100 percent load density, presusres are in line with the above pressures. at 105 percent load density we are still ok, no problems till you hit 110 percent load density...no room for the bullet.
can some one hit 80 k in an ar? sure but not twice!. a competent loader with correct families of powders for the bullet weight will never get there "for normal competition. folks a match is 88 rounds, half of these are typically with bullets over 70 grains. 44 rounds at over 80 k ??? come on.

mike in co

[jjamna]

What about the Composit Reciever and a free floated barrel????????????????????????

[Just Duke]

It's all yours Mike I am done here!

[mike in co]

all i am asking is documentation of the statement.

i have shot cmp/dcm matches with an ar, three gun matches, two gun matches,local club mil matches, and then the benchrest rifles. i have worked with mark w of armalite, bill wylde of the "wylde" chamber design, and frank white of campass lake . i have participated in lots of online disscussions about building and shooting the ar in competition. never once in all the years of all this have i ever heard of massive bolt failures(as in a bucketful) nor any reference to changing bolts at such a low round(1200)count. the military is currently testing/evaluation of the sierra 77gr otm (open tip match...politically incorrect to use hp/hollow point geneva convention ) not once have i heard of bolt life being an issue in these tests....and the first lot of ammo was 100,000 rounds..i would guess most test rifles got more than 1200 rounds of testing.

again, all i am asking for is some sort of documentation to support these statements. these statements, in the context of std chamberings in the ar platform, are not reasonable.

mike in co

[jjamna]

What about we not worry about weather a 77 grain bullet will mess up a bolt. Is a composit reciever tough enough for a floated barrel?

[mike in co]

the handguards in a non-free floated upper, do not "support" the bbl. they allow the shooter, with enough sling tension, to inflluence poi(point of impact).

so its a non-issue.


you say you put "another" bbl on...was it a new bbl ? or just another used, no known quality bbl?

are the sights on firmly ?

have you had anyone else shoot the rifle ?

i have never had a gun shoot this bad....ar's are fairly accurate out of the box, and just get better. so something is really wrong.

mike in co

[jjamna]

#1 Brand new barrel DPMS #2 Scope Firm #3 No but the same lower with a New DPMS Upper I get 1/2 inch groups now. #4 yes once a Rossie Single Barrel, Head space was real bad to big. Traded it.
It has to be something in the bolt or reciever that is all that is left.

[redneckdan]

I have seen 2 broken bolts in across the course rifles. These both had less than 2 seasons on them...figure in the area of 2.5k rds a season. Both had seen many rounds of heavy weight bullets. 77s for rapids and 80-90s for slow fire. Keep in mind that my population sample is many orders of magnitude smaller than what adam has seen.

[BD]

Well, I'm breathing easier as I get deeper into my third 8 pound jug of Varget pushing the 77 gr. Sierra's off into the distance. Was worried there for a minute.
BD

[mike in co]

#1 Brand new barrel DPMS #2 Scope Firm #3 No but the same lower with a New DPMS Upper I get 1/2 inch groups now. #4 yes once a Rossie Single Barrel, Head space was real bad to big. Traded it.
It has to be something in the bolt or reciever that is all that is left.
ok take the offending bbl out of the composite upper and put it in the alloy dpms upper and shoot it.
has the scope been changed out...sometimes they start bouncing crosshairs.

if the new bbl in the alloy upper shoots, put the composite scope on the alloy upper and reshoot.


tell us what happens

mike in co

[jjamna]

Mike
I have only checked it with a red dot scope but it looks like the reciever solved the problem. I did notice the barrels are a lot tighter on the new reciever.
Jeff

[mike in co]

i asked armalite about the bolt life question....this was the question...

" is there a reccommended round count for bolt replacement.

say a typical cmp/dcm rifle in 200/300/600 yd competition"

here is armalite's answer.......

"The rule of thumb is to change the bolt when you rebarrel your rifle though this isn't a hard and fast rule. You should be fine until then."

i hope this puts to bed this issue.

mike in co

[Triggerhappy]

AMEN! Thanks for checking Mike. I know a lot of folks shooting the 70g pellets out of an AR without any problems, including me. And I know that I have close to 10k rounds thru mine without any adverse wear or issues. Not to say that I won't have, but...

Brian.

[GabbyM]

I would assume if you hot rod your loads up above 60K psi a barrel would wear down just as fast as the BR guns that shoot those pressures. I've burned through a few 243 WIN barrels in way under 2K rounds and that's just typical. My 223 varmint rifle last longer but I don't get 2K rounds from a barrel. With an AR you buy a new barrel with fitted and head spaced bolt and it's ready to go. Takes about fifteen minutes to swap a barrel. Once it's on the bench.
Many shooters will spend lots of money to gain a bit of an edge.

I"ve an SP-1 here that' had many thousands of pills down the pipe. Most were hand loads of 10% or so reduced from book max. 52gr HP at around 3,000 fps. I've done more damge to the barrel with poor cleaning practise than shooting it. But I could destroy it in eight minutes if I wanted.

I have a story: Friend of mine told of a USMC LT whom walked out to the edge of the wagon circle one dark night in NAM up in I corps. Two boxes of those 20 round mags and two privates to hand him clips. NVA had been making noise outside the perimeter. He started firing. Empty one clip grab another from his helpers hand, slam it it and go. LT had a pile of empty mags at his feet when the glow of the barrel started reflecting off the grass. When he'd drop the bolt the rounds would cook off pop pop pop then he'd pull the trigger and empty it. My friend says about the time he saw the barrel glow red past the hand guard the bullets started falling short of the tree line. A few mags latter the barrel actually sagged and bent down. LT threw the CAR down and walked away. No more noise from out their for the rest of the night. Don't know what the round count on that barrel was but it was used up.

[mike in co]

""Typical" use varies so much between shoooters, as well as the round count, cleaning method, etc...that giving an iron clad number/frequency is difficult. My best advisse would be to check for any visible damage/wear anytime you have it out of the upper. The areas you particularly want to look at would be the face (any significant pitting, damaged edges,etc...) and around the cam pin hole (weakest spot on the bolt) for any cracks, advanced wear, etc...) Replace the extractor and ejector and their springs every few thousand rounds (or if you start to have difficulties with either). Same with the gas rings.
You would certainly, at a minimum, chech head space any time you go to use THE BOLT with a NEW/different barrel/barrel extension.
Steve/RRA"


just one more major ar company speaks up with no special warnings for heavy bullets or 1200 round count. they were given the same question as armalite.

mike in co

[jjamna]

Mike I found the problem. A little embarrassed to tell but will anyway. Was not torqueing the handguard / barrel nut enough.

[jjamna]

Now back to the bolt.--------You are saying they will hold up to a 6mm-223?

[mike in co]

not an issue, as long as one observes the pressure limits of 5.56/223 saami/cip.....gives you a little room to try the ragged edge.
6 was shot a while back....about 20 yrs back...but is still seen every now and then.

mike in co