[tbryanh]

Toward the end of this lengthy video
Gun Firing Pin Fit: GunTech #14 - In the Classroom - YouTube

The speaker says that if the firing pin fits sloppy, is too long, or is too pointed, the primer can spring a leak, and gasses from the cartridge case can flow backwards.

When this happens, he says that if you are not wearing glasses and you don't have a modern gun that has some kind of gas deflection system in it, the gases can go in face and burn/blind you.

What gas deflection system does Ruger use in the Mini?

 

[bwraven]

The GDSS is called Ruger.

They will not allow you to buy a firing pin. It must be fitted at the factory to your bolt to prevent the above mentioned issue from occuring.

 

[tbryanh]

The GDSS probably has nothing to do with the firing pin. It is apparently something in the design of modern rifles that older rifles did not have. As far as I know, at least in the context of the video I linked to, the older rifles had firing pins but did not have GDSS's.

 

[bwraven]

I realize that.

What I'm saying is that the gasses flowing backwards is caused by a pierced primer.

Ruger custom fits the firing pin to the bolt to avoid any chance of piercing a primer. By custom fitting the firing pins (allowing the proper firing pin protrusion from the face of the bolt) they avoid the issue, and, most importantly, the liability.

 

[SUBlime]

I'm just venturing a guess, but if gas was to escape through the primer and onto the bolt face it would have to go into the space between the firing pin and the bolt itself. Then, it'd have to travel through the length of the bolt and emerge from the back end, which is inside the receiver where the hammer is, all in the millisecond before the bolt is disengaged and is force back and the case is ejected. I wouldn't lose any sleep over this.

 

[tbryanh]

Information on this subject is hard to find, but I found some other info that indicates that it is not just firing pin fit that is the issue, there can also be catastrophic failure of the round. The casing can split or the joint between the primer and the casing can separate.

The gases are under extreem pressures, according to the speaker, over 30,000 psi. The gases probably can escape quickly through a malfunctioning round or misfit firing pin. The gases probably escape before the bullet travels past the gas tube to activate the piston to disingage the bolt. The bolt is probably still locked when the gases are escaping.

 

[Crowcifier666]

I pierced a primer once out of probably 2000 rounds I've fired out of my mini. I blame the ammo. You can see the firing pin hit is clean, I don't know much about reloading but maybe the primer was seated wrong.

BOXER PRIMED TULAMMO bought at wally world. I thought the round was a dud til it started smoking around the bolt locked in battery. Not super pressurized, but enough to make me put the rifle down and step back til she cooled off. I don't buy Tula anymore.

 

[subscriber]

if the firing pin fits sloppy, is too long, or is too pointed, the primer can spring a leak, and gasses from the cartridge case can flow backwards.

When this happens, he says that if you are not wearing glasses and you don't have a modern gun that has some kind of gas deflection system in it, the gases can go in face and burn/blind you.

What gas deflection system does Ruger use in the Mini?

The Mini's bolt runs in a receiver that is closed at the back end - not open like a bolt action. Gas running along the firing pin from a pieced primer would first run into the hammer face inside the receiver. Such gas would have a lot of room to exapand into and no direct path to get to your face - the receiver is also open upward and downward away from the shooter. The Mini's firing pin length, or more exactly protrusion and the shape of the tip need to be within spec or there is a risk of primer piercing.

To make matters more intereting, firing pins have to be fitted to the bolt they will be used in - this is why Ruger insist on fitting your replacement firing pin, should you loose or break one - they don't sell spare firing pins because they don't want pieced primers. Even if a pieced primer in a Mini does not singe your eye lashes, it it happened on every shot the hot gas will erode the bolt face.

Good bolt action designs have vent holes in the bolt and sometimes the receiver ring to allow hot gas to escape away from the shooter in case of piered or leaky primers.

 

[subscriber]

there can also be catastrophic failure of the round.

Sometimes a batch of ammunition is sold that contains some defective rounds that were not detected during manufacturing. Usually recalls are issued as soon as such problems are reported and confirmed. If you fire some rounds and they seem to be much louder with more recoil than others in that caliber you should stop and think about the reason for this. Sometimes there is a simple explanation.

For instance, if you have been shooting 1 oz shotgun loads and then shoot some 1 7/8 oz loads you will notice the difference, but that is normal. If rifle or handgun rounds seem "too strong" and the fired cases have a bulge, ring around the case near the head or other obvious visible distortion then you should stop using those rounds and investigate.

Some recalls are for rounds producing excessive pressure. If you fired a hot round in a gun that was worn to the point that the head space was over spec, the cartridge case could split at the head and allow a large volume of very high pressure gas to escape into the action. The potential for injury in such events is real and people have been bruised, lost fingers or eyes as a result.

What you can do is to ensure your firearms are in spec, that the barrel is free from obstruction or corrosion, that you do not shoot suspect ammo and always wear eye protection. You should also check your guns for cracked parts whenever you clean them - some guns will fail slowly and give warning before they let go completely; if you pay attention.

I am not worried about my guns blowing up - a real concern is other people at public ranges and their muzzle and trigger finger discipline, or lack thereof.

 

[tri70]

Even if the round fails like the hole the primer ignites the powder thru may get oversized and blow the case head off. The solid design of the receiver, locking lug wall and the back of the enclosed receiver wall will protect your face.

 

[tbryanh]

It appears semiauto rifles are safer than bolt action rifles vhen it comes to the gas escaping issue.

 

[Jeff F]

I pierced a primer once out of probably 2000 rounds I've fired out of my mini. I blame the ammo. You can see the firing pin hit is clean, I don't know much about reloading but maybe the primer was seated wrong.

BOXER PRIMED TULAMMO bought at wally world. I thought the round was a dud til it started smoking around the bolt locked in battery. Not super pressurized, but enough to make me put the rifle down and step back til she cooled off. I don't buy Tula anymore.

If that round did not fire (the front part of the picture is out of focus, but it kind of looks like the bullet is still there) that was not a pieced primer. That was a blown primer caused because there was no flash hole in the case leading to the powder charge. I have had the same thing happen three times with Herter's .223 from Cabela's which is Tula ammo.

Not as bad as a pieced primer where you a lot more high pressure gas from the powder charge going off and trying to blast back into your face. Still not good. I pulled one of the dud rounds with a kinetic bullet puller and dumped the powder then probed the bottom of the case with a pick, could not feel anything so I chucked the case mouth up in my vice and cut the back of the case off about 3/4 of an inch from the head for a better look, no flash hole.

As far as gas deflection systems being a newer design then old, I don't know about that. The Enfield rifles have had a gas deflection system in the No1 and No4 rifles that work so well that when there is a case head separation the shooter does not even know it over half the time untill they try and chamber another round.

 

[SUBlime]

"The Mini's bolt runs in a receiver that is closed at the back end - not open like a bolt action. Gas running along the firing pin from a pieced primer would first run into the hammer face inside the receiver. Such gas would have a lot of room to exapand into and no direct path to get to your face"

This was one of the points I was trying to make in my above post. Even were the gas to make it to the rear, the Mini has an enclosed action and no way for the gas to get into your face. At worst, it'd probably vent out through the trigger group.