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Slamfire in a '73?


Warhorse

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Normally, I use .357 Magnum cartridges in my '73 short rifle because I know that they will feed well. A couple of days ago, I was testing a .38 Special cartridge in my '73 to see how well it would feed and it went off! :huh: The hammer was still back and the casing was under the carrier. I called a halt at that point, completely disassembled the receiver and, finding nothing obviously wrong, reassembled everything and, after testing the action for proper performance with .357 snap caps, quit there.

 

I have no idea what may have caused the apparent slam fire but am going back to the range tomorrow to see if I can get a reoccurrence of the apparent slam fire. I have never had this problem with the .357 Magnum cartridges (downloaded to Cowboy specs.)

 

Has anyone else observed this phenomenon? Any information or insight would be appreciated.

 

In any event, will repost tomorrow with the results of my next experiment with .38 Special.

 

 

Warhorse

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When you say "the casing was under the carrier" what are you trying to say? Was the carrier up in loading battery position? Was the Carrier dropping to pick up next round? The term "slam fire" means the round goes off as the bolt travels forward into battery, activated by the firing pin, usually this is result of hammer following bolt forward, or firing pin being stuck out of bolt (usually by rust inside bolt).

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Your description is ....... odd. Where exactly was the cartridge that fired?? Thousands of '73s digest 38s without problem. If the round was chambered, I would suspect either a stuck firing pin or the extension rod coming forward from inertia, either of which could/would also occur with .357 cases.

 

Coffinmaker

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I agree Colorado Coffinmaker. I am not sure what he is trying to convey in his discription of the "slamfire". the only true "slam fires" I have personally seen were an M-1 where the firing pin was restricted by rust inside the bolt, and a Uberti 1866 with same situation. Back in late 60-s in a place far away, some new fangled rifles also slam fired due to bolts being crusted with calcium carbide and such, they also failed to chamber rounds, but the slam fire was no big deal as folks wer trying to pop off rounds as fast as possible.

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YES, most definitely a 73 CAN slam fire! Not only have I seen videos of this, I have seen it in person! (One was first hand however I was not able to determine that this was the exact cause...it was the most likely, however)

 

The 73's have a firing pin that is held away from the breechface by a spring. This is part of the safety system. If this spring is weak and the action is closed forcefully, the inertia of the bolt going forward can be enough to overcome the tension of the spring with enough force so the firing pin has enough 'oomph' to hit the primer and fire the cartridge.

 

This system is similar to a 1911 and I absolutely assure you that slamfires with the wrong firing pin/recoil spring combination can happen!

 

I am confused by this 'the casing was under the carrier'. so perhaps...that wasn't it?

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Howdy

 

I too am confused by your description of a round being under the carrier.

 

However it was proven a few years ago that a '73 can have an out of battery discharge in certain circumstances even though the hammer is still cocked. The scenario is that if a round jams going into the chamber, and if the shooter then forces the lever, giving it a good jerk, the forward motion of the jerk overcomes the spring holding the firing pin back, and the firing pin rides forward forcefully enough to fire a primer. All this while the bolt is still open, possibly resulting in the brass giving way and shrapnel going everywhere. This was demonstrated a few years ago by at least one gunsmith I know. He managed to get the firing pin to fire the primer in a test round with no powder in it.

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YES, most definitely a 73 CAN slam fire! Not only have I seen videos of this, I have seen it in person! (One was first hand however I was not able to determine that this was the exact cause...it was the most likely, however)

 

The 73's have a firing pin that is held away from the breechface by a spring. This is part of the safety system. If this spring is weak and the action is closed forcefully, the inertia of the bolt going forward can be enough to overcome the tension of the spring with enough force so the firing pin has enough 'oomph' to hit the primer and fire the cartridge.

 

This system is similar to a 1911 and I absolutely assure you that slamfires with the wrong firing pin/recoil spring combination can happen!

 

I am confused by this 'the casing was under the carrier'. so perhaps...that wasn't it?

 

OK. Paragraph 2 above is pretty much what I think happened. Thanks Dubious Don.

 

Let me try a little better description.

 

First of all, I had disassembled, cleaned and lubed the entire receiver. After putting everything back together, I tested the action with .357 Magnum snap caps and it functioned perfectly. I do have a short action modification that was done by Long Hunter and in the two years I have had the rifle have had no problem other than the bent tab on the bolt bottom that was repaired by Long Hunter recently. (This was the subject of another thread of considerable length a few months ago.)

 

Then I got the bright idea of testing the action with a single .38 Special round to see if I would have any feeding problem with that cartridge. I did work the action vigorously, as we all do when trying for speed. I deliberately kept my finger well away from the trigger as I only wanted to test the action. Much to my surprise, the round fired, apparently before it was fully chambered. The casing backed out into the receiver UNDER the lifter. The hammer never fell. I had to re-chamber the fired case in order to eject the case.

 

The case appeared to be undamaged and there WAS a fully defined firing pin indentation in the primer. However, it is possible that the full indentation was actually caused by the recoil of the case working against the inertia of the firing pin extension. There is no way that I can reliably determine that, of course.

 

The firing pin moved freely both before and after the kaboom and, yes, the spring is in place and does withdraw the firing pin as it should. I had checked this both right after reassembly and after the kaboom. It definitely is not a case of the firing pin stuck and protruding from the face of the bolt.

 

Now, the thing that has me worried is if the round was fired solely due to me vigorously working the action on chambering and the weight of the firing pin extension causing the firing pin to strike the primer with sufficient force to fire the round. (NOTE: so far, this has only happened once with the single .38 Special round I used. I have put literally thousands of .357 Magnum Cowboy rounds thru this rifle with no problem.)

 

I am heading to the range this afternoon to test the rifle with both .357 Magnum and .38 Special cartridges to see if I can recreate this rather disconcerting situation. If it does do it again, my first guess is that the firing spring pin has somehow weakened and I need to replace it.

 

Will keep you posted on the results as soon as I can.

 

 

Warhorse

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Great video's from Cypress Sam.

 

That issue can be reduced if not eliminated through use of a lightened firing pin extension - 40% lighter than OEM. It generates less inertia when the action is closed rapidly which reduces the chances of an out of battery discharge and also requires less main spring and firing pin return spring tension while still firing reliably when trigger is pulled.

See Here near the bottom of the page. You will need to determine which version you have........Late or Early design.

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Gunner,

 

Well........not bad considering. Brass shrapnel through the ear cartilage and hole in the hat along with some minor splatter bleeding

 

Todays lesson: GOOD SAFETY GLASSES

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Gunner,

 

Well........not bad considering. Brass shrapnel through the ear cartilage and hole in the hat along with some minor splatter bleeding

 

Todays lesson: GOOD SAFETY GLASSES

 

 

:huh: well. I reckon so on the injury

 

..and I REALLY reckon so on glasses!! ;)

 

Thank again for posting...

 

GG ~ :FlagAm:

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Related to what Monco said I think that is why the lightweight extensions were first made available, I remember yrs ago at a SASS convention, I don't remember if it was at the C&I booth, or the Pioneer booth but they had a video that showed accidental fire with the heavy extension but could not duplicate the process with the light weight version. It usually happens when the lever is quickly slammed forward to get a jammed shell to chamber.

Get a light extension for sure, and if need be check all your rounds so you don't have one that is too fat to chamber easily.

 

Doc

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OK, '73's don't have a lifter, they have a carrier block, and if a case was truly under the lifter/carrier, wouldn't it fall out of the bottom of the gun? Still not picturing what you are saying.

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"The casing backed out into the receiver UNDER the lifter. The hammer never fell. I had to re-chamber the fired case in order to eject the case"

 

 

 

I suspect what the poster meant about the fired case was that it ended up inside the carrier in the channel that normally moves the round from the magazine to the chamber. He stated he had to close lever & chamber the rnd to remove it.

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Let me see if I understand... The firing pin in these repro '73's has a retracting sping? (I haven't checked my Navy Arms Uberti-made Henry to see if that's how it is made. IIRC, original '73's have a firing pin retractor, but no spring. Of course the retractor is released as you complete the stroke into battery. Maybe it was possible that the repro's spring was overcome by inertial forces? Correct?

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Let me see if I understand... The firing pin in these repro '73's has a retracting sping? (I haven't checked my Navy Arms Uberti-made Henry to see if that's how it is made. IIRC, original '73's have a firing pin retractor, but no spring. Of course the retractor is released as you complete the stroke into battery. Maybe it was possible that the repro's spring was overcome by inertial forces? Correct?

Yup. Or if the firing pin and bolt are dirty, the firing pin can stick. Or the firing pin spring was got too light or was removed.

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OK, folks. Here's the latest update on the cause of the increase in my laundry bill a few days ago.

 

I just returned from the range where I sent 50 rounds of .357 Cowboy and 50 rounds of .38 Special Cowboy thru my '73, working the action as fast as I could, with nary a hitch or kaboom of any kind. I made no changes to the rifle and did not even clean it after the previously noted disconcerting episode.

 

The only conclusion that I can reach is that something was wrong with the particular, factory manufactured .38 Special cartridge causing it to bind on entering the chamber and the inertia of the firing pin extension set off the primer, just as shown by the videos posted by Wyatt. Surprise! Surprise! :angry: I was lucky that the case did not rupture in the process. [NOTE: Yes, I did examine the remaining 49 cartridges in the box and could find nothing obviously wrong with any of them. However, I do not plan to use any of these particular cartridges in any of my rifles, just in case I missed something.]

 

I have already taken the suggestion made by Monco and ordered a lighter firing pin extension. If this situation never occurs again, it will still be too soon.

 

Thanks to all who responded. I really appreciate the education, not only because it verified my initial analysis but also offered solutions to the problem.

 

 

Warhorse

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And we should re-think the habit of looking into the action as we vigoursly work the lever on a round that won't chamber.

 

Oh, yeah! I'll give a hearty "Amen" to that one!

 

 

Warhorse

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At a recent black powder match I managed to get a .45 Schofield pistol round mixed in with the .44-40 rounds for my '73 rifle (this actually happened twice to the delight of my friends). The first time I thought I just had a slightly oversized round and tried to force the issue including banging the lever a bit ala the Cypress Sam video. After I realized what the problem was, I put the rifle down and moved on.

 

When I pulled the magazine cap and got the remaining rounds out of the rifle at the unloading table, including the Schofield round, I found that the primer on the Schofield round had a significant dent on it. This rifle has a fairly heavy firing pin return spring but the firing pin was still able to hit the primer by inertia. In hindsight this was pretty scary since the .452" bullet would not have fit in the .429" barrel and the blowup would have been extreme.

 

Moral, never bang the lever to chamber a reluctant round.

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Trailrider,

Apparently your PM inbox is full. Tried to send you a PM.

Yes, your Navy Arms Henry has three pieces to the firing pin. The firing pin itself, a firing pin return spring and the firing pin extension rod. The problem is the extension rod and physics.

 

Coffinmaker

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This is an additional update to my post #19 re the lighter firing pin extension for my New Model '73. :blink:

 

I ordered one from Pioneer Gun Works and it arrived promptly. However, to my surprise it turned out not to be a simple "drop in" replacement.

 

WARNING: THE LIGHTER FIRING PIN EXTENSION FOR MY '73 REQUIRED SOME FILING AND FITTING BEFORE IT WOULD WORK PROPERLY. I found this out the hard way by trying to drop it in and promptly discovered three problems that took some filing to correct. Fortunately it wasn't difficult and I was able to do a fix in about a half hour.

 

1. The ramp that rides up over the hammer was nearly 1/4" too short. It was necessary to grind the ramp back that distance and essentially re-cut the ramp so that the extension would clear the arc of the hammer pivot while the hammer was cocked by the end of the extension pushing on the nose of the hammer.

 

2. The slot in the extension where the flat plate that connects the bolt to the firing pin extension mates was not cut correctly. Although the plate would go into the bolt and secure the extension, the extension was forced against the firing pin so that the tip of the firing pin extended fully out of the face of the bolt all the time. [Yikes! Talk about your slam fire potential! This would have guaranteed that happening EVERY TIME the action was closed solidly!] It took quite a bit of filing of both the forward part of the slot and the nose of the firing pin extension to allow the firing pin itself to fully retract as it should. The slot had been cut square and the forward edge needed to be tapered to properly accommodate the plate that secured the bolt and extension together without pushing the firing pin out of the face of the bolt. [No I did NOT have the flat plate in backwards. It will only fit one way.]

 

3. Some minor filing was necessary on the outside edges of both the cut slot and the perimeter of the front of the extension to remove burrs that both made it difficult to insert the extension into the hole in the bolt and to ensure that the extension would properly retract without hanging up. Not a big deal but necessary.

 

NOTE: I am not criticizing Pioneer except that a warning that some fitting would be required should have been prominently displayed on the part description. [if there was a warning somewhere, I obviously missed it. I thought I should warn anyone else who follows this route to check the proper fit of this, as well as any other, replacement part before attempting to fire the gun.]

 

 

Warhorse

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2. The slot in the extension where the flat plate that connects the bolt to the firing pin extension mates was not cut correctly. Although the plate would go into the bolt and secure the extension, the extension was forced against the firing pin so that the tip of the firing pin extended fully out of the face of the bolt all the time. [Yikes! Talk about your slam fire potential! This would have guaranteed that happening EVERY TIME the action was closed solidly!] It took quite a bit of filing of both the forward part of the slot and the nose of the firing pin extension to allow the firing pin itself to fully retract as it should. The slot had been cut square and the forward edge needed to be tapered to properly accommodate the plate that secured the bolt and extension together without pushing the firing pin out of the face of the bolt. [No I did NOT have the flat plate in backwards. It will

 

 

 

 

Warhorse

 

 

What firing pin does your gun have? There are two different lengths. I got news for you, there is no such thing as a drop in part when the gun comes from Uberti. Even if the gun functions most of the time they don't function right with just drop in parts.

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I'm glad that you were not hurt in the AD in your rifle. I'm also glad that you found the video of my AD helpful in determining what happened in your case.

 

One thing that comes to mind is if your AD was with .357 cartridges after fining .38 rounds, there could have been a build up of carbon at the end of the .38 case that caused the .357 case to hang up 1/8" short of complete chambering. When you then close the lever with force, the inertia of the firing pin caused the primer to fire without the hammer falling.

 

The same thing can occur when a bullet lodges in the bore just forward of the case causing the following case to stop just short of completely chambering.

 

Just a note about Wyatt's posting. The second video was an experiment I did with only a primed case with a stop placed in the case to prevent the last 1/4" of the case from chambering. I was able to duplicate the slam fire every time with the stock firing pin, extension and stock spring. When I substituted a titanium firing pin extension, I was not able to duplicate the slam fire, even though the primer was dented slightly.

 

My advice to anyone having a round that is hard to chamber: Don't even try to force it into the chamber.

 

And if it won't extract: Don't try to drive it out with a ramrod if the bolt is in contact with the case head. This can cause an AD also! Always release the extractor from the rim before touching the case with a ramrod. In fact it's better to prise it out with a screwdriver.

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Series such as this experence should be welcomed byall of us. Above discussions are indeed welcome and very useful. I have had three bad experences in my lifetime and none were expected when it happen. One was Winchester factory ammo in a Thompson Sub Machine gun that had a round go off out of battery and I got brass in my belly and the magazine was blow apart with the next round on top with bullet cut in half, No damage to $25,000 gun. Second was when a beauitful 12 SKB side by side blew the top of the right barrel just over the forearm cutting my hand and ruining the barrels and the ammo was Winchester factory number 7 shot. Reason turned out to be a carbon flaw in steel. Experence three was a blow off cyclinder top and top of frame in a 45 Colt American Arms using reloaded blue dot shotgun powder and cast 260 grain bullet. Never knew what caused it.

 

I think one of the worst experences happen to my brother at the shooting range when his pre mark five Weatherby 300 Mag. let go blowing the gun in half and the lugs on the bolt all shared off letting the bolt movre back half an inch with the only thing keeping it from going thur his head was brass wegded between the bolt and the receiver. He siad He saw a huge flash then bright light and then total darkness. The flast had tempary blinded him and the darkness was when the range owner threw a towel ove rhis haed to stop the bleeding. Cause of the gun to let go, A carbon spot in the metal running from between the lover two locking lugs to the firing pin hole and to the left letting a full 1/4 of the bolt blow away.

 

One other experence I was next to at the time was in my early life my best friend and I were hunting snakes when his 1905 Colt had a misfire. He snapped his 45 and nothing happen and he reply waskwhat the hell and turning the gun toward his face to look at the gun it went off a couple of secounds later with the 45 bullet blowing the hat off his head just over his skull.

 

I also was witness to a young lawman with a 45 Colt auto in his hand standing next to me when things turned bad as he fired his 45 in the heat of things and after it was over in a few seconds He discovered he had forgot to take the safty off and he had not fired a single round in the shootout. A year or so later He was killed in a shootout. One I always had to laught about was a cusin of my first wife who was a lawman in East Texas and word had come that the local bank was going to get hit. He and and Texas ranger, Tom Arnold were staking the bank out waiting on the bad guys when word came to them they had been shot up in a gunfight just a few miles away. Leaving the bank they were on the way back to the office when Tom Arnold stopped at a creek bed where someone had hung a hubcap on the tree and they used it was a target. Tom pulled out his two 45s he carried on each hip and let go hitting ever shot and then turning to his partner in the stakeout he said lets see what you can do with that old 45 you have. My wifes cusin raised the 45 and pulled the trigger only to find nothing happen and Tom said let me look art that gun and handing it to him Tom checked it out and ask when he got it from and he said off a dude had arrested and he said he could have the gun. As Tom handed the old 45 back he said hell man this gun does nort have a firing pin in it. I ask what Tom thoght about the experence and he said I don tknow he never said another word the reat of the way.

 

One has to remember, all guns have high preasure in them and many things can and will go wrong over time.

 

Your Pard, Texas Man

 

PS Special thanks to showing the vides, Very infomative.

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