my AR10 explosed

[sourdough44]

All I'll add is reloading for a semi-auto needs increased vigilance with the rounds. Things are always easier with a bolt gun. Besides feeding into the chamber you need proper pressure to work the action. That action may not be as strong as a bolt gun.

In many manuals you will see different listings when loading for a semi-auto. No I'm not familiar with the powder the O.P. mentioned. As usual, I thank him for posting up his experience.

Say one got primed cases from someone else, you could still check them for sizing, length & a few other things without removing the primer. I've even got complete reloads from another. I usually dismantle them to check the details.

In general, I don't consider many AR-10 actions as strong as other types, yes I know, should be fine at SAAMI(?) specs.

 

[Fuch]

He blew up a gun so maybe he doesn't know all of it.

obviously no one can say that he knows everything and I know that, simply I trusted an old man of 93 years who had a great experience, moreover the casings that I had recovered were already primed so in principle recalibrated , but maybe a defect on a sleeve that I did not see, or insufficient crimping, you have to learn from your mistakes

 

[glowe]

Do "AR" style rifles have pressure relief "action holes"? I have never owned a semi-auto rifle, but all bolt rifles I have owned had the pressure relief holes drilled in the receiver directing potential over-pressure/caes failures to be ported, reducing the chance of the bolt coming out or receiver blowing up.

 

[cmj8591]

obviously no one can say that he knows everything and I know that, simply I trusted an old man of 93 years who had a great experience, moreover the casings that I had recovered were already primed so in principle recalibrated , but maybe a defect on a sleeve that I did not see, or insufficient crimping, you have to learn from your mistakes

You didn't do anything wrong. It's just a question of what happened. Some other shooters posted their experiences here, I'm sure in the spirit of helping others to understand the circumstances. For some reason, those posts were taken as condescending. My post was aimed at that, not finding fault with anything that you did.

I still think that you had an out of battery detonation. In an AR, it is difficult for that to happen but certainly not impossible. It could be that it was caused by a problem in the gun its self and had nothing to do with your reloads. It's hard to diagnose a cause without actually handling the remains of the gun. There are lots of things other than the ammo that could have gone wrong. Everything from debris in the chamber to failure of a part in the fire control system. Out of battery detonation is probably what happened. Why it happened is still an open question.

 

[cmj8591]

Do "AR" style rifles have pressure relief "action holes"? I have never owned a semi-auto rifle, but all bolt rifles I have owned had the pressure relief holes drilled in the receiver directing potential over-pressure/caes failures to be ported, reducing the chance of the bolt coming out or receiver blowing up.

There are no relief holes in an AR. The bolt system is designed to direct the force of a ruptured case down through the magazine well and out of the ejection port. Sort of like most of the semi auto handguns that use the tilt barrel system.

 

[TheTinMan]

Glad everything has worked out for you.

Myself, I wound never recommend or encourage reloaders not to crimp their semi-auto reloads.

UPDATE
Since "to crimp or not to crimp" seems to be a contentious topic for gas operated rifles, I have been doing more research. A tech at Hornady told me that "crimping is not required but it is recommended." However, when we discussed specific bullets for 308 Winchester in gas guns he said to crimp with their seating die "only if the bullet has a cannelure." He suggest possibly using a bushing die to ensure adequate neck tension for bullets without a cannelure.

Some people believe that the 308 Winchester cartridge requires crimping to be used safely in a semiautomatic rifle. Many do not. Some are re-thinking their reloading process and/or bullet choices

Redding and Lee both make a taper crimp die for 308 Winchester. I will note that the Redding 308 taper crimp dies are relatively new products. Lee also sells their Factory Crimp Die for 308, in addition to every other cartridge. RCBS does sell a small base die set that includes the option to taper crimp with the seater die; however, none of their normal 308 die sets perform a crimp.

As far as I can discover, neither Hornady nor Lyman make either separate crimp dies for 308 Winchester nor do they include a crimp function on their seater dies for this cartridge.
CORRECTION: both the Hornady and the standard Lyman 308 seater die can perform a roll crimp. Neither company makes a taper crimp die for 308.

Somehow I forgot Forster - their seating does do not apply a crimp.

I went through my reloading manuals: Hornady 7th and 11th Editions, Sierra 5th Edition, and Lyman 49th Edition. The Hornady manuals include separate sections for both 223 and 308 "service rifle" data and neither mentions crimping. These manuals do generally specify crimping for semiauto pistol cartridges, revolvers, and rifles with tubular magazines. Some of the time the data for a specific cartridge mentions crimping; however, none refer to crimping for 223 or 308.

Glen Zediker explicitly says that crimping is unnecessary in his book "Reloading for the Match M14".

I posted a question about taper crimping for 223 on the M14 forum 10 years ago including a poll that 47 handloaders responded to. Just over half said no crimp, no way. A third are advocates for the Lee Factory Crimp Die. The consensus seems to tip the other way on the 308 AR forum that I frequent. That's interesting because an AR isn't as violent with cartridges as an M14 is.

In conclusion, opinions vary on the subject of crimping bottlenecked cartridges for semiautomatic rifles. If it actually was dangerous not to crimp as your post clearly implies, I feel certain that ALL die manufacturers would make crimp dies and every reloading manual would explicitly state the need to crimp.

 

[scooter123]

I suspect this was caused by a Case Failure. Rifle cases will stretch with each firing and that stretch region is a band roughly .3 inches above the case head. If you saw a case in half you will find the bases is sort of a bowl shape that blends into the thin walls of the case going towards the shoulder. That region where the thin wall starts is the region where cases stretch. Eventually that region will visibly become necked down and if you see that then the case can rupture at that point. When this happens it will resemble an OOB firing cycle but one feature that is common for a case rupture is the head of the case will be completely separated from the case. In many OOB events the case will split down one side and the case head will be retained.

Note when a case necks down the thinning will be evenly divided between the inside and outside surfaces, which is why it's critical to discard when it first becomes visible. Point is what you see is only half of the weakening of the case. I'll also note I've found that looking down the case from the case head end makes this necking easier to pick up.

On a bolt action rifle one method for reducing stretch is to fire form the case to the chamber so that there is ZERO gap between the breach face and the case head. The bad news for doing this is that within 2 or 3 firing cycles that very well supported case will stretch enough that bolt drag will become significant which requires a full length sizing. So this technique will extend the service life of a case but these cases will at some point get enough stretch they should be discarded.

When reloading for semi auto rifles Fire Forming the cases will at some point lead to a chamber jam, so it's not something you want to do for ammo being used in a Semi. Semi auto ammunition should always be built to a SAAMI spec case gage, if you don't own one then don't do any reloading until you have one. Note, your Chamber is NOT a case gauge, dimensionally they are different.

 

[TheTinMan]

the powder I used is the Vihtavuori N550 high energy and the load: 38.5 grains, the primers: RWS Berdan, case FN nato, bullet Hornady 150 grains FMJ without crimping

No one has commented on the powder charge yet. VV specifies the following loads with 150 grain bullets and N550:
Nosler Accubond 45.8-50.5
Sierra HPBT 44.5-50.3
Swift Scirocco 42.4-46.8

I believe that these bullets are comparable to whatever Hornady bullet the OP used. If so, then the powder charge was significantly BELOW the minimum specified by Vihtavuori. It doesn't sound like there was a squib lodged in the barrel. However, some powders behave very badly with too small a charge in the case.

ETA: My 11th Edition Hornady manual only shows data for VV N140 for a 150 grain bullet for generic 308 Winchester loads. For "service rifle" it shows N140 and N150, but only for 155 grain bullets.

 

[WR Moore]

I'm not going to speculate on what happened in the rifle failure. I do have some comments on moving forward with reloading.

1. The OP should purchase and use a cartridge gauge if he doesn't already do so. I've had sizing dies creep out of adjustment once or twice. Also keep an eye on cartridge case length and trim as required.

2. Now about dies......virtually every maker of standard rifle reloading dies includes a crimp function in their seating die. The instructions in setting up the dies gives you the choice of crimp/no crimp. Dillon doesn't as they include a taper crimp die in all their brand of reloading dies. There's no crimp function in my Forster Ultra match seaters, possibly some precision match dies by other manufacturers omit the crimp feature too. Then there's the opportunity to sell another (taper crimp) die

3. When I got into long range competition, I hung out at the Benchrest Central website to pick up loading tips. Light crimping was suggested as a way to help get a uniform bullet pull and improve accuracy. ADDED NOTE:
bench rest bullets do not have cannelures, you don't need a cannelure to lightly (0.001-0.002 in.) taper crimp. Any theoretical distortion of the bullet gets ironed out when the bullet is engraved by the rifling. Given the OCD case prep BR competitors do, that would seem to be excessive, but it was working. Opinions are going to differ where accuracy is the over riding concern. Yes, I do it on my accuracy loads for bolt guns and ALL ammunition for self loading firearms. See below.

While I was still working, I saw warnings that crimping of AR ammunition was a critical requirement, especially in the carbine versions of the design. I note that all mil spec ammo comes that way. Come to think of it, M118LR ammunition comes with a very slight crimp.

 

[kend]

A mans gotta know his limitations. Reloading isn't rocket surgery but you do have to be knowledgeable and pay attention, there are a number of mistakes one could make while reloading and never get hurt but there are some that can seriously injure, or kill you. There are way too many folks reloading that aren't experts but manage to get by so if you don't think you're capable of doing it safely then you probably aren't, you're the only one that can answer that.

This thread is another reminder of why I do not reload. If one is going to reload, he should do everything himself and have an incredible eye for detail. Reloading mistakes are very unforgiving.

 

[kend]

No one has commented on the powder charge yet. VV specifies the following loads with 150 grain bullets and N550:
Nosler Accubond 45.8-50.5
Sierra HPBT 44.5-50.3
Swift Scirocco 42.4-46.8

I believe that these bullets are comparable to whatever Hornady bullet the OP used. If so, then the powder charge was significantly BELOW the minimum specified by Vihtavuori. It doesn't sound like there was a squib lodged in the barrel. However, some powders behave very badly with too small a charge in the case.

ETA: My 11th Edition Hornady manual only shows data for VV N140 for a 150 grain bullet for generic 308 Winchester loads. For "service rifle" it shows N140 and N150, but only for 155 grain bullets.

That was the first thing I thought of, what was the powder and charge? An under charge can be worse than an over charge with certain cartridges and powders.

 

[kend]

Casings are for sausage.
Cases are for ammo

Lighten up Francis. From reading his other posts it appears maybe he's from another country and his English may not be as good as we'd like.

 

[shil]

Terrible news. Using someone else's reloads is always chancy.

 

[shil]

Lighten up Francis. From reading his other posts it appears maybe he's from another country and his English may not be as good as we'd like.

Good of you to chime in, kend. He's in the south of Belgium. English is a second language for him.

 

[Imissedagain]

Lighten up Francis. From reading his other posts it appears maybe he's from another country and his English may not be as good as we'd like.

Just a bit of nomenclature humor Pilgrim.
Nothing more
Nothing less

Reading aloud often solves problems people have when reading technical stuff as the mind may miss things that their ears pic up.

I spent four decades teaching marine electronics and other boating needs to people from all over the globe and the OP's English is great compared to many others.

How you knew my name is Francis is a mystery.

[ame]https://m.youtube.com/watch?v=syV2LkGpQB0[/ame]

We use a slight firm up/easy taper crimp on our 223/5.56 ammo.
Proper neck tension rules.

Over and Out.

 

[Cdog]

Regardless of the cause of failure, there are things we as humans can miss.

If I buy new primed brass, short of uniforming flash holes I still prep it the same as any other. Inspect, debur case mouth, either remove or raise the decapping pin and Full Length Size. Uniform length debur and lightly chamfer case mouth. For me full (calibration) of primed brass isn't an option, it's a necessity.

Having OCD tendencies isn't always a bad thing.

As THETINMAN already noted, the load seems to be around 15% below suggested minimum starting point for N550/150gr combo.

Very Good News that no one was injured.

 

[Fuch]

Lighten up Francis. From reading his other posts it appears maybe he's from another country and his English may not be as good as we'd like.

sorry for the form of my messages but indeed I am Belgian and I do not fully master your language, please excuse me, however one thing is certain I share with you a passion for S&W and weapons, henceforth speaking of box I would say "brass"

 

[white cloud]

Your English is a lot better than my German, French or Dutch.

Thanks for your post. I have learned a lot from the replies but I am sorry that your rifle is damaged.

 

[Pisgah]

I will add "reloading advice" to "legal advice" in my "list of things never to ask for" in an online forum...

 

[Eddie Southgate]

I will add "reloading advice" to "legal advice" in my "list of things never to ask for" in an online forum...

Very smart move on your part , your IQ just jumped by 40 points at least.