Primers Blown out. !!

[Minky]

We were having an informal clay shoot and a mate was using 2x28 gauges.  1 was a Beretta O/U AND the other was an auto.  When using the auto, the primers were dislodging from the case and generally jamming between the spent case and the top of the action. In one case we had to remove the barrel, the gas piston and linkage.  A lot of wiggling and tapping of the action to get the mangled primer out of the action.  Shooting recontinued.  Never ever seen or heard of this ones.  Bornagi cartridges.

[Ultrastu]

I use bornaghi carts in 20b in a semi auto .never had an issue like that .

Infact they are my fave brand  they kill really well   

[Lever357]

I would take the box the cartridges were in, if it is still available, back to the shop so they can feed back to the factory

[Stonepark]

1 hour ago, Minky said:

We were having an informal clay shoot and a mate was using 2x28 gauges.  1 was a Beretta O/U AND the other was an auto.  When using the auto, the primers were dislodging from the case and generally jamming between the spent case and the top of the action. In one case we had to remove the barrel, the gas piston and linkage.  A lot of wiggling and tapping of the action to get the mangled primer out of the action.  Shooting recontinued.  Never ever seen or heard of this ones.  Bornagi cartridges.

Were the primers showing issues with the OU?

If not, did any other ammo get used with the Semi Auto?

Is it possible the semi auto is unlocking before the pressure has dropped causing the primers which are only friction fit to blow out?

[Vince Green]

10 hours ago, Stonepark said:

Were the primers showing issues with the OU?

If not, did any other ammo get used with the Semi Auto?

Is it possible the semi auto is unlocking before the pressure has dropped causing the primers which are only friction fit to blow out?

This

The primers can't blow out if the back of the cartridge is tight against the breech

Edited May 1, 2023 by Vince Green

[Minky]

It's a really odd situation.  The cartridges are great and the gun shot loads of them spraying the ejected cases all over the place.  It isn't my gun but it shot well and strangely enough it was only some cartridges that did this.  One primer that was blown out got into the bolt action area and jammed the whole lot solid.  We had to strip the for end, the barell, the gas piston.  The bolt was stuck firmly so I manualy jerked the action bar and suddenly a mangled primer fell out off the action.  Reassembled it shot ok and ejected ok.  I took a picture which shows a primer on top of the semi ejected case jammed between the case and the top of the action.  Because this happens at super high spèd there is no way of knowing quite what is happening.

[Stonepark]

6 hours ago, Minky said:

It's a really odd situation.  The cartridges are great and the gun shot loads of them spraying the ejected cases all over the place.  It isn't my gun but it shot well and strangely enough it was only some cartridges that did this.  One primer that was blown out got into the bolt action area and jammed the whole lot solid.  We had to strip the for end, the barell, the gas piston.  The bolt was stuck firmly so I manualy jerked the action bar and suddenly a mangled primer fell out off the action.  Reassembled it shot ok and ejected ok.  I took a picture which shows a primer on top of the semi ejected case jammed between the case and the top of the action.  Because this happens at super high spèd there is no way of knowing quite what is happening.

You don't give the make and model of the semi, however the blown primers are telling you the problem..... either,

1. The gun is not going into battery (i.e. the bolt is not locked as the gun is fired) or
2. The gun is coming out of battery too early.

 

On the semi auto, either there is carbon or crud build up on the bolt lugs or or the barrel lugs stopping bolt locking in place and/or the spring within the bolt head is too weak due to crud and/or/broken and being unable to close the rotating bolt head during firing are the most likely causes and the former is easy to check, whilst the latter can be more challenging.

I would suggest as first step, a full strip (including taking the bolt apart) and a good clean of all parts of carbon and crud!

[Walker570]

On 30/04/2023 at 21:32, Lever357 said:

I would take the box the cartridges were in, if it is still available, back to the shop so they can feed back to the factory

As above. Over the years I have witnessed similar but never personally and every time retyrned to maker.

[Minky]

3 hours ago, Stonepark said:

You don't give the make and model of the semi, however the blown primers are telling you the problem..... either,

1. The gun is not going into battery (i.e. the bolt is not locked as the gun is fired) or
2. The gun is coming out of battery too early.

 

On the semi auto, either there is carbon or crud build up on the bolt lugs or or the barrel lugs stopping bolt locking in place and/or the spring within the bolt head is too weak due to crud and/or/broken and being unable to close the rotating bolt head during firing are the most likely causes and the former is easy to check, whilst the latter can be more challenging.

I would suggest as first step, a full strip (including taking the bolt apart) and a good clean of all parts of carbon and crud!

The strange thing in all of this is that the cartridges go bang, they kill the clay AND most of the time they eject quite happily. They were also fired in a Beretta with no problems or issues at all. no external signs of difference. they all came from same slab.  The gun is as clean as a whistle so crud build up is a small consideration at present. The problem with diagnosing this is that it isn't a consistent fault and the only time that you know that something odd has happened is when you pull the trigger and nothing happens.  the speed of the action is such that you'd never see what happened.  when the cartridge jam is cleared the gun may shoot a couple of boxes before the next issue.  He will do a full strip (including taking the bolt apart) and a good clean of all parts of carbon and crud! and see what is found .... If anything.  We only shoot for fun so there is no pull or scoring and we have multiple electric traps so there may be a lot of clays in the air at any time with several guns shooting these at the same time.  we shoot until either no ammo left, no clays left or the guns are so hot you can't hold them.  good fun.

1 hour ago, Walker570 said:

As above. Over the years I have witnessed similar but never personally and every time retyrned to maker.

The bloke wouldn't bother because the cartridge are all going bang and killing the clays.  the vast majority work ok.. we don't bother shooting competition and don't score.  the only inconvenience is the stoppage.  if the cartridges were that bad he'd probably just break them down.  He bought a slab from auction so no shop to return to. 

Note.. position of blown primer which has jammed action. That is the spent fired case which suggests that the primer has been blown out the back, then rebounded to that position with an amount of force BEFORE the case has had time /travel to be ejected.

[Newbie to this]

Extractor problem maybe?

[Walker570]

I have shot thousands of rounds from semi autos and pumps, had a few hang ups but never a blown primer. The fault I think was with the cartridge..maybe an overload.

I would still notify the priducers it keeps them on their toes specialy when you mention you have shared the information with the shooting community.

[Minky]

It's all a bit of a guessing game with this one because they shoot very well and when used in the Beretta you would never know anything was different.  I have used a vernier and checked the primer pocket diameters and they appear to have a couple of thou tension so they shouldn't blow out.  I have saved the mangled primer that was found inside of the action but because it was mangled it doesn't contribute any evidence.  The bloke who's gun and cartridge they are isn't someone who would consider contacting a manufacturer about these because basically even though there are /were problems they still went bang and broke the clays very well.  we don't score and as previously written we don't have just one shooter shooting one clay at a time.  it is a sort od flurry of clays and shooting.  I think that he shot the slab off on that day.  If the gun played up another day with some other slab brand then he might clean the action out or more likely get rid of the gun.  He has loads of other guns to shoot so it doesn't really matter.  It was so unusual to have this happen.

Ps.  when I next communicate with him I will enquire if he has given it a bit of a clean.  In the meantime I brought the feed sack of cases home to go through for certain ones for reloading so I'll do a bit more measuring of primers and pockets when I get the time.

Edited May 4, 2023 by Minky