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  #31  
Old 08-17-2018, 08:29 PM
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Quote:
Originally Posted by bunnytoo View Post
The only thing I notice was a build up of burnt powder around the chamber mouth on the barrel. This could of acted as a slight bushing and prevent the case from fully seating by perhaps 1/64".
Also known as the Breech Face where the 22 rimfire cartridge receives its correct headspace.

In light of your statement.......The semi-auto 22LR regardless of brand "will" (not maybe) (not could) but WILL release the firing pin every time on any cartridge which is slightly out of battery due to residue buildup.

You can open the bolt slightly on a 22LR semi-auto and pull the trigger in order to get the sear/spring/firing pin to release without peening their breech faces.

This isn't a design flaw rather more the nature of the design. Too much precision would be needed, or that much precision would likely be impossible, where the rifle's bolt only allowed the firing pin release when fully closed.
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  #32  
Old 08-23-2018, 10:35 AM
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I have been reloading 22 Long Rifle for the past 4 years. When initially working up loads, I pushed the limits. Even to the point of filling the case (4.2 gn) of modern smokeless powder.
A normal load is approximately 40% to 50% of case capacity. It appears to me that the case separation you show is due to a double charge of powder.
I have found that cases start to bulge with the equivalent to approximately 1300 FPS with a 40 grain bullet. Case failure is almost inevitable at 1650 FPS with a 40 grain bullet. And a double charge (no way of knowing what speed the bullet would have achieved because of the gasses escaping out the breach) causes the complete head separation. With the type of powder that I use, a 2.75 gn load will cause the beginning case failure. 2.5 gn will begin show case deformation. I write this with the caveat that not all breaches are the same. Some designs will hold greater pressures. It seems that the newer guns I have encountered have the breaches designed to allow case failure and vent gasses away from the shooters face in this event. You may have noticed that many newer guns have a relief or open space on the bottom of the bolt face. This is where when the case fails, the gasses flow to. In the last blown case I had, ( Savage Mk II) the case blew, the gasses flowed into the magazine, splitting the magazine. I have an old Remington 514 which does not have the safety feature of routing of gas down and away from the shooters face upon case failure. I got a face full of gasses, burnt powder and sparks through the bolt with this gun. Fortunately I always wear eye protection when doing these ill fated over-loads. Here are some pictures of case failures sustained.
https://www.dropbox.com/s/iqm2gwt71f...P0737.JPG?dl=0

Last edited by traffer; 08-23-2018 at 10:44 AM.
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  #33  
Old 08-23-2018, 07:39 PM
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Had this with Remington green box

Had three blown rims - none as neat as yours! - on some Remington green box 22LR ammo last year. This was on the firing line at the juniors rifle class that I run. Happened twice on a 10/22 and once on a bolt gun. Had the mag blown out and a little powder burn on the former. The remainder of that lot is now for adults only in bolt guns, can't trust it.
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  #34  
Old 08-24-2018, 07:33 AM
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Quote:
Originally Posted by traffer View Post
I have been reloading 22 Long Rifle for the past 4 years. When initially working up loads, I pushed the limits. Even to the point of filling the case (4.2 gn) of modern smokeless powder.
A normal load is approximately 40% to 50% of case capacity. It appears to me that the case separation you show is due to a double charge of powder.
I have found that cases start to bulge with the equivalent to approximately 1300 FPS with a 40 grain bullet. Case failure is almost inevitable at 1650 FPS with a 40 grain bullet. And a double charge (no way of knowing what speed the bullet would have achieved because of the gasses escaping out the breach) causes the complete head separation. With the type of powder that I use, a 2.75 gn load will cause the beginning case failure. 2.5 gn will begin show case deformation. I write this with the caveat that not all breaches are the same. Some designs will hold greater pressures. It seems that the newer guns I have encountered have the breaches designed to allow case failure and vent gasses away from the shooters face in this event. You may have noticed that many newer guns have a relief or open space on the bottom of the bolt face. This is where when the case fails, the gasses flow to. In the last blown case I had, ( Savage Mk II) the case blew, the gasses flowed into the magazine, splitting the magazine. I have an old Remington 514 which does not have the safety feature of routing of gas down and away from the shooters face upon case failure. I got a face full of gasses, burnt powder and sparks through the bolt with this gun. Fortunately I always wear eye protection when doing these ill fated over-loads. Here are some pictures of case failures sustained.
https://www.dropbox.com/s/iqm2gwt71f...P0737.JPG?dl=0
Excellent synopsis traffer, thank you.
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  #35  
Old 08-24-2018, 09:44 AM
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Double Charge Speculation

A new load operator at Remington might have stopped the loading process to clear a jam and not advanced the machine. Does anyone know if they use optical checkers for powder charge? Seems like it would be a good idea to reject such cartridges but I've had one with a hole in the brass case near the rim get by quality control in the past. It is possible that there was a defect in the brass sheet used to draw that case or a problem annealing the brass.
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  #36  
Old 08-24-2018, 02:19 PM
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Mouth separation

Several years ago I was shooting a Kimber Model 82 rifle using Remington subsonic .22's. Upon firing I heard several pings. Part of the case mouth had broken free and followed the bullet down the barrel. Not a problem with the rim but nevertheless disconcerting.
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  #37  
Old 08-31-2018, 09:11 AM
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Quote:
Originally Posted by bunnytoo View Post

Has anyone seen this before? The case "head" (do not know what to call it on a rimfire) popped cleanly and completely off. I heard a very load bang, got a face full of powder and saw the little disc on the shooting bench; looked in the chamber and pulled out the case body. the barrel was clear so the projectile fired. Is this a case of weak brass or a double primed case? Winchester bulk 333, kind of disconcerting.
https://www.rimfirecentral.com/forum...d.php?t=582257

It happens. In my case SB said it was most likely a weak spot when the case was formed. Many thousands of rounds later no problem. DT
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