So here is my theroy and experience with my BCL. Started working up a load the other day for it and couldn't get it to group at all, the factory ammo I had shot OK so I thought barrel must not like these projectiles so I ended it and went home. Was reading mystic presicions thread on shooting out to 250 and it caught my eye what he said about COAL and I decided to set a dummy round at 2.74 instead of 2.8 like I had been. Well to my surprise I as I released the bolt holding the charging handle and letting it in slow the bullet went up the feed ramps and hit just below the feed cone and actually held the bolt open. So i made up 4 dummy rounds measured them and recorded it on the side of the case and let the bolt slam shut. Upon remeasuring all the COAL had shrunk by at least 20 thou if not more. I repeated this with 5 different types of projectiles all with the same results projectiles being pushed farther into the case. So if your full size die is not set right and you are not crimping and running 44 grains of powder if this happened you coud have an over pressure. So needless to say i have a new barrel and bcg ( the bcl one would not fit in a dpms barrel) I have mentioned this problem to several friends and they all seem to have the same problem. Just my 2 cents.
BCL 102 catastrophic failure
- Thread starter slash547
- Start date
- Location
- West Quebec
Don't see any and tried two browsers
No chance, had a fresh bottle of IMR 4064 and using a Lee turret press and a RCBS Charge Master 1500 to dispense powder
LordEvilPepper
CGN Ultra frequent flyer
- Location
- Under a rusty barge in BC
Ok when my ruger gss blew up it was a result of the federal (gold medal match factory ammo) cases being to long and stubbing out on the lands. This caused a crimping effect. when fired it resulted in an over pressure that r
With the cases head letting go like yours...
Was your brass trimmed properly? FC cases are very soft, i find there .308 cases grow 10 to 14 though on a FL size... so if you trim before resize you might be setup for a catastrophic failure on a tight chamber.
With the cases head letting go like yours...
Was your brass trimmed properly? FC cases are very soft, i find there .308 cases grow 10 to 14 though on a FL size... so if you trim before resize you might be setup for a catastrophic failure on a tight chamber.
sillymike
CGN Ultra frequent flyer
I guess I'm a little on the paranoid-side, I always double-checked it with a go/no-go gauge.
A number of things could have gone wrong with the reloads
- When were the case last trimmed? How many reloads through them? Full-length or neck sizing?
- seating too far in/out
- powder charges, were they each weighted or used as throw from the powder dispenser?
Looks to me like the bolt cam key was rotated into place in the recess of the upper receiver?
I'm guessing that as it removed material on the upper receiver as the bcg went rearward, in the locked position during the catastrophic failure.
Can you see if any of the lugs are sheered off the bolt slash547?
I'm guessing that as it removed material on the upper receiver as the bcg went rearward, in the locked position during the catastrophic failure.
Can you see if any of the lugs are sheered off the bolt slash547?
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That's what I am wondering to. Until the bolt cam key rotates into the upper receiver groove, the AR design isn't supposed to be able to fire... Scratching my head here...
If the force pushing the BCG backwards is on the bolt face rather than the carrier then the tendency would be for the bolt to collapse into the carrier, rotating the cam pin. If there's no damage to any of the lugs on either the bolt or barrel extension then the bolt was probably not locked into the barrel extension when the event occurred.
In that case, the gouge in the upper receiver would probably just be a result of the bolt being forced back into the carrier with a large amount of force, causing the cam pin to rotate into that position. During normal operation it wouldn't be possible to move the BCG backwards in the collapsed position because the cam pin would interfere with the receiver, but if you push it hard enough it seems that gouge is the result.
How does the barrel extension look?
I think it might be a poor heat treatment on the barrel extension, the lugs then sheared off. I can’t figure out why the brass is deformed like that. Where did you find the brass? Was it still in the gun?
I think it might be a poor heat treatment on the barrel extension, the lugs then sheared off. I can’t figure out why the brass is deformed like that. Where did you find the brass? Was it still in the gun?
Wrong. The bolt is already fully into the carrier when upon firing.
If the force is only on the bolt face, i;e: no gas flow through gas tube, the bolt will stay locked. The AR system is an internal piston, gas goes though gas key, enters boat tail/bolt carrier piston chamber, PUSHES the bolt towards the front (alleviates pressure on the lugs for the unlocking phase) and the bolt carrier towards the back, while the bolt carrier moves back the bolt's cam pin engages the cam pin slot in the carrier, forcing the bolt to rotate and unlock while the carrier is moving back.
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Checked all 35 cases I shot yesterday and all except two are at or just below 2.015" OAL. One at 2.019 and the other at 2.024. Never trimmed as I check every 5th case and never seen an out of spec length...till now.
Not sure on reload count but would guess ~5
Full length Lee Turret press sizing
Seating should be perfect and consistent using Lee turret press finishing with the factory crimp die
Charges weighed each with an RCBS Charge master 1500- very accurate
