light primer striking problem

[donki1967]

I made an artisanal test to increase the length of the cases by using stickers for shooting targets.
Barrel pointed down, stickers on the primed case bottom:
1.280 Nothing
1.281 Nothing
1.282 Nothing
1.283 Bang

Gentlemen,
for today I give up ...thank you for your help.

[DaveHH]

I would give the FP a very close look. I bought a few spares that looked great, but under a good lens, they looked like a volcano, big chunks of hard face off, pits, dents etc. The extractor also grabs and should hold the case hard against the bolt face, making excess headspace a non factor. Buy some new cases from say Remington and the length will be all over the map. Some short, some long, some very short. I would try swapping out the extractor and making sure it is fitted correctly against the bold recess (many are not, many have never been apart). A new extractor spring might help. Point being: A great many carbines are long on headspace but still work fine. Consider that many,many bolts have never been taken apart and cleaned (the hole and spring) making the extractor a critical part in your puzzle.

[floydthecat]

I would give the FP a very close look. I bought a few spares that looked great, but under a good lens, they looked like a volcano, big chunks of hard face off, pits, dents etc. The extractor also grabs and should hold the case hard against the bolt face, making excess headspace a non factor. Buy some new cases from say Remington and the length will be all over the map. Some short, some long, some very short. I would try swapping out the extractor and making sure it is fitted correctly against the bold recess (many are not, many have never been apart). A new extractor spring might help. Point being: A great many carbines are long on headspace but still work fine. Consider that many,many bolts have never been taken apart and cleaned (the hole and spring) making the extractor a critical part in your puzzle.

Many of us fall into the category of thinking long head space is greatly overplayed. It’s something collectors get gitty over, but that’s okay too. The carbine chamber fully supports the brass and ruptures are much less likely. Can’t say there never has been one, but they only rupture I have read about was eventually traced to poor quality ammo. SAAMI gives you 22 thousandths when considering a 1.280 case and a 1.302 field gauge. Carbines will continue to shoot well past 1.302 with the right length brass. Like mentioned, if the extractor won’t catch the rim, or the head space gets seriously long…it might not shoot.

[DaveHH]

If the headspace measures from the case front edge and the case is short (as most are) there is nothing to keep the base of the case near the bolt but the extractor. Without the extractor, the round would just lay in there at whatever length the case is cut. Long cases are dangerous, so short cases should be safe. The extractor must be sharp, correctly shaped and have no chips or faults. Beyond that, the extractor must have enough movement to snap over the rimless case and stay there when it does. You should be able to put your thumb on the extractor and make it move back and forth watching how much movement takes place and how much effort is required to move it. I've seen the extractor pawl hole so full of crap and debris that there is zero movement. Same with the ejector spring hole. Having the extractor pound against an immovable object without moving itself has got to damage something and it usually is the extractor or pawl. That is why it is essential to take the bolt apart and carefully examine the bolt, the shelf that the pawl plunger rests on, the springs and clean out the holes. I had to take a jeweler's file and refresh the pawl and shelf on my original Winchester as I didn't want to have to change any parts. The pawl was installed backward and had been that way for decades.

[donki1967]

I agree with that the extractor is a bit hard to move, but I don't have the tool for disassembling the bolt.
I will soak the hole in kerosene and work the ejector and extractor with a case.
(The extractor moves better on my Garand bolt...)
Bolt head pics will follow soon.
Have a nice day.

[donki1967]

Attachment 118202Attachment 118203Attachment 118204Attachment 118205Gentlemen, while inspecting the recoil spring guide I noticed that it was slightly crooked, do you think this may be a cause of my problem?
BTW, the operating slide spring has the good length, and seems not to be damaged.

[floydthecat]

Attachment 118202Attachment 118203Attachment 118204Attachment 118205Gentlemen, while inspecting the recoil spring guide I noticed that it was slightly crooked, do you think this may be a cause of my problem?
BTW, the operating slide spring has the good length, and seems not to be damaged.

Not likely as long as the operating spring force is sufficient to strip a fresh round, close, rotate and lock the bolt. I just assume here that you have observed the bolt lock up. If the slide is not able to fully lock the bolt, then it might be far enough out of position that the firing pin tang is blocked by the bridge safety, which would cause it not to fire.

[donki1967]

I'm not sure now, but I thought I observed that at the end of the striking motion, the bolt lug locked a little more to the right.

[floydthecat]

I'm not sure now, but I thought I observed that at the end of the striking motion, the bolt lug locked a little more to the right.

If the slide cam does not fully rotate the bolt due to binding weak spring, bent guide or rub, when the hammer falls against the rear of the bolt, it will rotate the right lug on down….you can see that movement. You have to notice closely and use a case in the chamber. On an empty chamber, the bolt will usually move a little….make the observation with a case chambered. A dummy or live round (in a safe place) should be in the magazine to be stripped. Some force is lost on slide closure and you need to make this observation by stripping a round to get a factual test.

If a carbine bolt has not fully rotated, it might still fire if it has rotated just enough to release the tang on the firing pin. Exactly when this occurs is carbine specific due to wear and tolerances. Or, it might not fire, or fire sporadically. Firing out of position can easily crack the right bolt lug…or worse.

If in fact that bent guide was binding the spring, it certainly could have led to improper bolt rotation. Rotated just enough to fire randomly.

This, of course, is just a guess. I don’t have the carbine to see what’s happening.

[browningautorifle]

I thought I observed that at the end of the striking motion, the bolt lug locked a little more to the right.

During dry firing they will do that. Live firing, I can't imagine how you'd be able to see that.