Now is the time to take a step back and take that gun to someone who really knows WTF they’re doing to be checked out. I hope you don’t think you’re going to grab a new bolt and slap it back together and it’s gonna be good. Best case scenario only the BCG, and barrel extension should be replaced.
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What the hell just happened?
- Thread starter MAGA4LIFE
- Start date
Good advice. I think the OP said that it's all Aero stuff... So send it to Aero! They make very, very good AR's. Let them fix it up!
Cheers,
Sirhr
Would be best to go to a third party first for inspection to determine if it’s ammo related, build related, or part related. When you buy parts and assemble the rifle and then load your own ammo too then the responsibilities of determining the problem is solely on you, not send it to who manufactures most of the parts in it.
True... unless he bought an 'assembled' Aero upper.
And I am pretty sure there is no gun problem (well, there wasn't to begin with). I doubt there is much forensics to do on that upper. I think it's all in the handloads. The upper was fine to start with.
So get it professonally repaired and back to having fun!
Sirhr
I go with out of battery ignition.
Look at the bulge just above the base.
Look at the bulge just above the base.
COL is fine ,,, no clue what neck tension ,,, just resized and reloaded COL for the bullet Mnfgr is correct
I was thinking the same ... But i just went out and bought a box of Hornady 147 ELD Match rounds, and the COL is the same as my reloads, as is the case base width . I'm 99.98 % certain that it is NOT from a heavy charge, no way possible to DOUBLE charge a case ,, hell the powder won't fit . Been reloading for 4+ years now ..... No way it was THAT heavy to do that . I have a scope cam and even put the cam down the bore and watched as I slowly pushed the cartridge into the chamber. it doesn't appear that the Ogive is engaging the Lans.
COL is irrelevant for semis as long is it fits and feeds from the mag....you always want to use a bullet comparator and take a base-ogive measurement then adjust the seating die until you get the jump you want....typical jump distance for most semi autos is .050.100 (usually limited by the magazine) but most will still shoot and perform well if the rifle likes the load overall.
Luckily nothing really bad happened to you (rifles are replaceable).
fortunately ,,, the chamber and the lugs all look to be fine ,, no damage . just the bolt ,, it bent the ejector, have to ge a new bolt
Thanks man ,, I appreciate that .... this is my first build and the Upper came assembled , so I'm sure that the head space is fine,, but the BTO is something that I'm very new to . No clue how to do that . But I'm thinking i need to PULL all remaining loads and start over . I don't need to be wearing an eye patch next time . or worse. So do I Mic. from the base to the top of case neck or base to start of Ogive? How the fik do you do that ? Over? lol
Hornady comparator tools.
Otherwise.
You can take a loaded round in your bolt (less the ejector) Should have a small amount of wiggle with lugs engaged.
You could also color a round with sharpie and look for rub marks
Otherwise.
You can take a loaded round in your bolt (less the ejector) Should have a small amount of wiggle with lugs engaged.
You could also color a round with sharpie and look for rub marks
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The portion of the bullet that makes contact with the lands and groves is the Ogive...Base to Ogive measurement is essentially for confirming bullet jump, which becomes more important in bolt guns than semi autos but consistent jump helps the load perform consistently to expectations.
Upstream step - determine loaded round case head-Ogive length when the bullet’s ogive is seated so it touches the rifle lands (not as critical since the magazine internal length will likely prevent you from getting to the lands anyway but if loading for bolt gun, this step must be performed before the below...
Step one: acquire a dial indicator and bullet comparator (I use Sinclair’s but Hornady also makes a nice kit).
Step two: Grab your box of bullets and measure the bullet base to ogive (just the bullet not the loaded round - you’ll do that later)
Step Three: group all the bullets based on their measurements into 3-6 “buckets” ... record the measurement for each bullet and the group mean and put them in the buckets (I use old 100 count bullet boxes) This is called Ogive sorting and will save you time later in the process. My task for today so figured I’d take a pic).
Generally I try to shoot for a tolerance of .004 (ie a bullet from the same bucket, when seated into the case, will have a jump that varies by no more than .004 in either direction from the bucket’s mean.
Step 4: Prep, size, prime and charge your case as normal
Step 5: grab a bullet from one of buckets (doesn’t matter which one) and seat it into the case
Step 6: Measure the loaded round from the case head to ogive using your comparator. Make sure your caliper end isn’t covering the primer (see pic)
Step 7: adjust seating die until you get the depth you want (I seat the bullet as far out as I can get away with before it becomes too long to reliably load into and feed from the magazine).
Step 8: seat all the bullets from that bucket, spot checking along the way.
Step 9: repeat steps 5-8
This prob won’t address why your gun nearly blew up but will help you get the most out of your loads in all your rifles
I use Sierra Matchkings for my semi autos (175 and 77) and they are more tolerant to jump given their Tangent ogive...pure secant ogive vld type bullets are very sensitive to jump and I generally don’t recommend them for semi autos unless you have a chamber cut specifically for them that allows you to close to or at the lands regardless of the internal magazine length.
Hope that helps.
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What @nn87said is good info.
On Semi auto I simply load back to factory ammo specs which is usually saami minimum and will run in anything. Powder and bullet type being the only variables.
On Semi auto I simply load back to factory ammo specs which is usually saami minimum and will run in anything. Powder and bullet type being the only variables.
What happened was you had one of them KABOOMS!
I just started reloading last year and have done very little of it. I have never heard of a SB Resizing die until now. I just purchased a basic Redding 3-die set for 308. Never had any issues. However, I have only ever reloaded M118 Brass.
Good to know about not using Winchester brass in AR. I get M118 so cheap it actually costs less to simply pull all the bullets. I get M118LR for less per round then I can order 175gr SMK's. At least for now.
I just started reloading last year and have done very little of it. I have never heard of a SB Resizing die until now. I just purchased a basic Redding 3-die set for 308. Never had any issues. However, I have only ever reloaded M118 Brass.
Good to know about not using Winchester brass in AR. I get M118 so cheap it actually costs less to simply pull all the bullets. I get M118LR for less per round then I can order 175gr SMK's. At least for now.
So how the hell did i get SOOOOOO much pressure that it completely extruded the brass into the ejector hole,, thats a BOATLOAD of pressure, and i had to PRY that SOB off the bolt face. was the charge I used 43.5 grain of Varget to push HORNADY 147 gn ELD Match
Do you have a clue about bullet setback? Did you test for it?
What does book say about 43.5 Of Varget Pushing a 147?
?
Almost 10 grains over max published...what's the worst that could happen?
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Almost 10 grains over max published...what's the worst that could happen?
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What was your headspace on those rounds fired that day?
You may have gotten some particulate matter in the chamber on that round, which combined with zero cartridge-chamber clearance, it may have created a run-away condition in the chamber.
Just a guess....
I'm loading less than 40gr of Varget with a 130gr bullet in 6.5 Creedmoor out of a bolt gun. 43.5 is more like a 308 load in a semi auto.
All other questions are irrelevant. 43.5gr of Varget was clearly WAY too much powder and pressure that ruptured that case. Even the best brass wouldn't hold up to that. I'm wondering how the OP even got that much powder in a 6.5 Creedmoor case.
Not necessarily, if you jam a light load it may only show pressure but if you jam a hot load you break things.
This load may function if everything else is perfect.
Maybe 43.5 is a typo and he's really at
34.5gr
Easy to mix up numbers.
I would double check the load data and pull a couple rounds and weigh them.
Not sure I’d say the other questions are completely irrelevant overall but perhaps not relevant to determining the direct cause of this event.
Seems like the OP could use all the info he can get so something like this doesn’t happen again (may not be as lucky next time)... Reading some of his posts I get the impression he isnt aware of some important reloading fundamentals and practices; this thread is a good opportunity to learn....make him aware of what he didn’t know so he can bone up before taking another crack at it on the bench.
I'll concede that. I meant all questions pertaining to why it happened.
I use small base dies in my 6.5 Creedmoor bolt action. I had issues with sticking cases even with the lightest of powder charges and zero pressure signs.
I use small base dies in my 6.5 Creedmoor bolt action. I had issues with sticking cases even with the lightest of powder charges and zero pressure signs.
Want to know if you’re at pressure before physical signs on the brass?
For any given charge weight, measure the base of the case above the extractor grove before firing then after and record/calculate the difference. Anything more than .0015 expansion is too much in an AR (I’m ok with .002 in a bolt gun)....Likely you won’t see physical signs beyond that (ie primers collapsed, ejector/extractor marks, nuclear detonations, lol)
If that's not a typo then there it is right there. Even if you meant 43.5 of H4350 even that's a hot load with a 140 for a gas gun. It's hot for a bolt gun. And you used a FASTER powder and HEAVIER bullet.
Cartridge overall length is only important for fitting in your magazine.
There are three measurements you need to know and load for.
First your rifle headspace, this is measured with gauges, typically a GO and a NO-GO which will tell you that your rifle is within the specs for the cartridge but not an exact value.
Your rifle headspace is set by your barrel, barrel extension and bolt, nothing else. The receiver face, bolt carrier, Cerakote and anything else you can imagine have no effect. Your barrel and barrel extension are threaded and pinned together, you should never have to replace one without the other unless it was damaged or improperly assembled in the first place.
Next you need to measure your brass headspace which is the cartridge base to a datum on the shoulder. Use a Hornady headspace gauge to measure that and confirm your shoulder is not set back too far.
Last, you need cartridge base to ogive. This is done with a Hornady bullet comparator, a modified case and another tool whose name I'm blanking on. It used to be called a Stoney Point gauge I believe. This measurement of your ammo and barrel throat will let you determine how much bullet jump you have to the lands. This is important to make sure you are not jammed in to the lands and creating excess pressure that way.
Luckily with magazine length you are probably going to have excessive jump rather than jam but you still want to check.
If your barrel extension survived, and does not show any stress cracks, you should be able to just replace your bolt but make sure you check headspace. If it flunks replace the whole barrel because something bad happened.
Then reload using small base dies and work up your loads from book minimum. Don't jump to the middle or off the deep end.
For the light strikes, what trigger are you using? Go to a stock LPK trigger with standard springs to confirm your trigger isn't an issue.
There are three measurements you need to know and load for.
First your rifle headspace, this is measured with gauges, typically a GO and a NO-GO which will tell you that your rifle is within the specs for the cartridge but not an exact value.
Your rifle headspace is set by your barrel, barrel extension and bolt, nothing else. The receiver face, bolt carrier, Cerakote and anything else you can imagine have no effect. Your barrel and barrel extension are threaded and pinned together, you should never have to replace one without the other unless it was damaged or improperly assembled in the first place.
Next you need to measure your brass headspace which is the cartridge base to a datum on the shoulder. Use a Hornady headspace gauge to measure that and confirm your shoulder is not set back too far.
Last, you need cartridge base to ogive. This is done with a Hornady bullet comparator, a modified case and another tool whose name I'm blanking on. It used to be called a Stoney Point gauge I believe. This measurement of your ammo and barrel throat will let you determine how much bullet jump you have to the lands. This is important to make sure you are not jammed in to the lands and creating excess pressure that way.
Luckily with magazine length you are probably going to have excessive jump rather than jam but you still want to check.
If your barrel extension survived, and does not show any stress cracks, you should be able to just replace your bolt but make sure you check headspace. If it flunks replace the whole barrel because something bad happened.
Then reload using small base dies and work up your loads from book minimum. Don't jump to the middle or off the deep end.
For the light strikes, what trigger are you using? Go to a stock LPK trigger with standard springs to confirm your trigger isn't an issue.
Guys I want to THANK everyone for their input on this and upon pulling these remaining rounds and weighing the charges I think it's clear here ,,,,, WHERE I utterly FUCKED UP. I'm grateful I still have my face in tact . No clue where or HOW I got that number but This will NEVER happen again .. I'm just glad I didn't hurt my gun ,,, got over 2 grand in to it ,lol Gorgeous AR-10 be a shame to fuck it up due to stupidity . Thanks again Gents ya'll were a HUGE help .
Nothing in a gasser. Well, maybe in an ARMALITE or JP.
You're pushing it, in a gasser, when you hit:
77/80gr in 5.56
175/178gr in 308WIN
140/143gr in 260REM/6.5CM
That includes using + 2-3" gas ports with proper diameters.
From 1976 to today, I have never had a subMOA gasser barrel require Small Base dies.
That goes from 223/5.56, 7.62/308, 6.8x43mm, the 3 SOCOMs or 6.5CM. That covers a whole
bunch of respected folks from Krieger, Criterion, Proof Research, Dracos, yada. Probably jinxed
myself for stating that.
2 separate issues going on here.
Failure to feed and failure to fire is likely Improper sizing or jamming bullets. My bet is on the bullets and seating depth since he was testing various bullets and using the same OACL. Could be combination of both.
Is the ogive on the 147s closer to the tip than the other bullets?
You just have to use Full Length dies. Small base is not necessarily required.
The higher end AR's have the tightest chambers but still not anything requiring SB dies. Incorrect headspace and over powdered loads will definitely cause issues. I'm quite sure the overload of Varget (possibly in conjunction with COAL or headspace) was the problem here.
