Fiocchi 150 grn 300BLKC Issues? What is wrong with this pic

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DDutchman
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Fiocchi 150 grn 300BLKC Issues? What is wrong with this pic

Post by DDutchman »

There I was...

Went out to shoot my new Stag left hand upper with my first 300 AAC Blackout rounds and to sight in with the Leupold scope I had just mounted. Fired a round. It ejected. Bolt closed. No round in chamber. Jacked in a new round. Most of the first 30 rounds needed to be jacked in. On the 30th round the bolt carrier stuck half way. Used the same magazine I use successfully for my 5.56/.223 ammo.

I popped apart the upper and lower to discover a spent primer covering the buffer stop pin. I collected the brass and found two cases with missing primers. Wish I had taken a picture of the little cap on the pin.

I remembered how I used to spend oh, so many hours cleaning my M16 and stripped the rifle down and spent oh, so many more hours cleaning both the upper and lower very, very dirty rifle parts.

I have yet to fire more of the Fiocchi until I find out if others have had similar experiences with cycling. Anyone?
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dellet
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Re: Fiocchi 150 grn 300BLKC Issues? What is wrong with this

Post by dellet »

DDutchman wrote:There I was...

Went out to shoot my new Stag left hand upper with my first 300 AAC Blackout rounds and to sight in with the Leupold scope I had just mounted. Fired a round. It ejected. Bolt closed. No round in chamber. Jacked in a new round. Most of the first 30 rounds needed to be jacked in. On the 30th round the bolt carrier stuck half way. Used the same magazine I use successfully for my 5.56/.223 ammo.

I popped apart the upper and lower to discover a spent primer covering the buffer stop pin. I collected the brass and found two cases with missing primers. Wish I had taken a picture of the little cap on the pin.

I remembered how I used to spend oh, so many hours cleaning my M16 and stripped the rifle down and spent oh, so many more hours cleaning both the upper and lower very, very dirty rifle parts.

I have yet to fire more of the Fiocchi until I find out if others have had similar experiences with cycling. Anyone?
I think it's because they are confused about which way the exit door is. :lol:

Seriously tho, I have ran about half a box and yes they are dirty. There have been a few people with good reports that have tried them, you are the first I have read with problems.

The concern tho, is the popped primers.

I would check two things since these are the first rounds through the upper:

Headspace in the chamber.

Cartridge length and length to the ogive of the bullet if possible, this would require a comparator and a way to also measure your chamber.

If you do not have a comparator, hopefully you will at least have a set of calipers. Measure cartridge overall length, carefully chamber a cartridge, remove it and check length again. If it has shortened the bullet is being pushed back from contact in the bore and this is where the excessive pressure is coming from.

Do any of the other fired cases show signs of pressure? flat or loose primers? A primer that is no longer flush with the bottom of the case?
300 Blackout, not just for sub-sonics.
Hardrockshot
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Re: Fiocchi 150 grn 300BLKC Issues? What is wrong with this

Post by Hardrockshot »

If you suspect an ammo problem check the ammo with a case gauge. I like the Sheridan case gauge if you don't already have one.
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JoeHarley13
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Re: Fiocchi 150 grn 300BLKC Issues? What is wrong with this

Post by JoeHarley13 »

I have gone through 1 box (50 rounds) without any issues.
No signs of high pressure. I've read it takes over 70k psi to pop a primer (unless you have lose primer pockets) so I think you have another problem - I agree with above poster, I'd suspect your headspace is significantly out of spec.

Would be interesting to know if this happens with any other ammo.
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Re: Fiocchi 150 grn 300BLKC Issues? What is wrong with this

Post by 300Blk »

True that even proof rounds generally don't drop primers. And proof rounds are 72,000 psi.
DDutchman
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Re: Fiocchi 150 grn 300BLKC Issues? What is wrong with this

Post by DDutchman »

Excellent recommendations all. Overall case length is minimum length. Other dimensions are within spec. No split cases or protruding primers. No signs of overpressure I can see. Maybe you might, but I cannot figure out how to upload photos to this board using Safari.

I am looking for a modified Hornady 300BLK case for their OAL gauge, since I have one, but they are in scarce supply. No, wait, I ordered one that was supposed to be in stock from OpticsPlanet. Guess what?

Contacted Stag to see if anyone else has reported issues. Service response was if the primers are popping out use different ammo. Fact is I was trying to kill two birds with one cartridge and use the brass for loading my own rounds. From what I can tell brass is more expensive than buying the loaded Fiocchi rounds. Yeah, I can hear the comments, now. But I never heard anything bad about Fiocchi. Meanwhile, I have Sierra 220grn MatchKing bullets in quantity, Remington 9.5 primers and enough IMR4227 to keep me going for a good long while. I just need brass.

And I did contact Fiocchi, too, but I have not seen a response.

I am going to go back over AR cycling steps and do more research on other calibers, and I am going to make sure the headspace and timing on the new upper are what Stag says they should be.

Seems to me that there was enough pressure to send the round down range but maybe in some cases the bolt retracted back away so that the bolt face did not present support long enough for the extractor to extract and eject the case allowing the primer to blow out.

I tried to find my chronograph to see if the muzzle velocity is within bounds, but i am still looking for it, too. And then there is that other Lee press I took out of the storage box to set up the bench and I cannot find it even though it HAS to be within ten feet.

I will do the measurements and try other ammo and post what I find.

Thanks again, all.
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Re: Fiocchi 150 grn 300BLKC Issues? What is wrong with this

Post by regroovable »

I had a loose primer on 1 of my first 5 Fiocchi's pop out and 1 blown out of an early box of the 125 Remington Match last outing.

I have a feeling these are the growing pains with bringing new ammo to market. It didn't do it with my handloads that are loaded to max and there is not primer cratering so it is likely just loose pockets - crappy that I have to throw away once fired brass though.
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Re: Fiocchi 150 grn 300BLKC Issues? What is wrong with this

Post by bangbangping »

DDutchman wrote:I am looking for a modified Hornady 300BLK case for their OAL gauge, since I have one, but they are in scarce supply.
For the price of a drill bit and a tap you can make a modified case for every caliber you need. Even better than the Hornady, because it will be a case fired in your chamber.
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dellet
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Re: Fiocchi 150 grn 300BLKC Issues? What is wrong with this

Post by dellet »

bangbangping wrote:
DDutchman wrote:I am looking for a modified Hornady 300BLK case for their OAL gauge, since I have one, but they are in scarce supply.
For the price of a drill bit and a tap you can make a modified case for every caliber you need. Even better than the Hornady, because it will be a case fired in your chamber.
Or a second best solution if you have your dies already is to buy a 223 gauge case, and convert it like you would any other piece of brass. You will need to seat and pull a bullet to stretch the neck so it will slide in the gauge. There is just no reason to wait on optics planet if you want to use the gauge this year :roll:
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DDutchman
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Re: Fiocchi 150 grn 300BLKC Issues? What is wrong with this

Post by DDutchman »

bangbangping wrote:
DDutchman wrote:I am looking for a modified Hornady 300BLK case for their OAL gauge, since I have one, but they are in scarce supply.
For the price of a drill bit and a tap you can make a modified case for every caliber you need. Even better than the Hornady, because it will be a case fired in your chamber.
Excellent point!
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