Problem with No4 MkI Bolt

I am having a problem with a No 4 Mk I. It is a Savage, with a matching bolt and a 1952 FTR. The problem is that when fired, the bolt head jumps out of the track. I have to hand raise it to the vertical release orientation to get the bolt open. The ammunition I used was PPU FMJ BT 174 grain.

I did check the headspace and it does not close on an 0.071 gauge. I followed the procedure in T.J. Evans's Guide to the Lee Enfield rifle to remove and replace the extractor to perform the headspace check. I didn't dismantle the bolt further.

It seems to open and close smoothly with no round in the chamber.

The only other observation I have is that the bolt head does not tighten flush with the bolt body when the bolt and bolt head are aligned, so there is a little play between the bold head and bolt body. (Does that make sense?)

Could this problem be caused by my re-assembly or do I have a bigger problem with this rifle?

Thanks.

Have a look at the 'rail' that the bolt head slides in.
In the 'cut out' area where you lift the bolt head out of the rail are the corners damaged ?

This damage allows the bolt head to jump out of the rail and is potentially dangerous.

It is a common fault on Savage, and to some extent Long Branch ,and was the price to pay for speeding up production.

Once rifles had this damage they were scrapped, but in civilian life, some folks have managed to rebuild the 'corners' with weld without affecting the hardness of the action.

Have a look at this old post

https://www.milsurps.com/showthread.php?t=55809

Bolt head overturn shouldn’t be more than 1/8”. If excessive, the recoil is transmitted to the threads instead of the locking lugs on the bolt body as designed. Not good. In service, Armourers had large supplies of bolt heads from which to select fit. We aren’t so well off these days so have to bring them back as close to spec as is possible with the parts we have.

My Savage No.4 Mk.1* arrived by US mail in 1958 - complete with a Canadian armorer's tag indicating it had been condemned for a "worn bolt guide". Having no welding skills or equipment at 13 years age, I simply peened the remains a tad to alleviate the problem. (Later, I learned a little chamfer on the bolt head could help prevent further damage.) After 62 years it still works perfectly.

https://www.milsurps.com/attachment....28&cid=1&stc=1

Many thanks for the replies. This is my first Enfield and I clearly have a lot to learn. I will post some pictures of the receiver and bolt later today for comment.

Deleted until I can figure out how to size photos.

Here are some pictures of the receiver. It doesn't look as damaged as some in the links folks have provided.

https://www.milsurps.com/images/impo...Rq8iF4Cm-1.jpg https://www.milsurps.com/images/impo...no9tcBnm-1.jpg
https://www.milsurps.com/images/impo...UY8dreYm-1.jpg

Here are some pictures of the bolt and bolt head, trying to show the rotation and the channel.

https://www.milsurps.com/images/impo...7NAijI7m-1.jpg https://www.milsurps.com/images/impo...xroyI3hm-1.jpghttps://www.milsurps.com/images/impo...CNw8j7om-1.jpg https://www.milsurps.com/images/impo...9VZGpHRm-1.jpg

I will be grateful for any comments or recommendations.

Check the length of the cut-out and then check the length of the bolt head guide. I had one like your, years ago, and found out too late that some doofus had carefully filed the cut out wider, presumably because the moron thought it would make removing and/or inserting the bolt easier. Visually, I couldn't see the difference because the cut-out wasn't damaged. It was only after I took the calipers and measured it that I found out what had been done. After I took a magnifying glass to cut-out, I could see the file marks. Good luck to you.

The cut out does appear filed at the rear cut. Unfortunately, someone may have tried to dress it up after it chipped and elongated the slot. Maybe you can peen it a bit to tighten it up. The bolt head overturn is definitely out of spec. The only cure for that is to select fit bolt heads until you find one that indexes with zero overturn.

Quote:

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Originally Posted by lawrence_n

Check the length of the cut-out and then check the length of the bolt head guide.

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Looks like the bolt head guide is 0.539" and the cutout is about 0.547" (hard to measure with my HF calipers). Does anyone know the specification values?

Also, it looks like I have a Longbranch bolt head. Right?
https://www.milsurps.com/images/impo...SuSQhV8m-1.jpg
Would that cause a problem?

Quote:

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Originally Posted by dewey1424

it looks like I have a Longbranch bolt head.

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That's right...

dewey, from your initial post, it sounds like your bolt head jumps out of the track on firing - not on cycling the bolt - is that correct?

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Originally Posted by RobD

dewey, from your initial post, it sounds like your bolt head jumps out of the track on firing - not on cycling the bolt - is that correct?

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Yes sir. That is correct - it pops out when fired. It cycles OK when dry fired or using a snap cap.

That don’t sound terribly safe!

There is something DEFINITELY awry if the bolt-head "jumps" up on firing. There should be a section of the guide-rail still engaging the bolt-head. Furthermore, the extractor should be in the appropriate narrow recess in the rear of the barrel and held against the radiused ramp surface by the extractor spring. Another factor is that there will be a difference in "bolt float' between feeding ammo from a full mag and dry cycling.

If the bolt is flopping all over the place during dry cycling, either it is badly worn, the Body is seriously worn, or, embracing the power of "and", BOTH important bits are totally flogged out.

Quickest test is to "borrow" a brand-new bolt body; one that is JUST a bolt body, i.e., nothing fitted. Run it into your rifle and compare the vertical play, just before lockup. If there is significantly less, a NEW bolt body may get you out of trouble for a few thousand more rounds. If the "slop"is just as bad with the "new" bolt body, your rifle body is in pretty dire shape.

I think a professional gunsmith needs to help you with this. Brian Dick [see post no. 3 above] is the top man in the USA for Lee Enfields. I wouldn't shoot it until it has been fixed.

I think he means that it pops out when he retracts the bolt after primary and secondary extraction. Looking at the pictures, I can't for the life of me see how it can pop out upon firing. I've never seen or heard of that happening with any Lee Enfield rifle. How about a clarification?

Quote:

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Originally Posted by Brian Dick

I think he means that it pops out when he retracts the bolt after primary and secondary extraction. Looking at the pictures, I can't for the life of me see how it can pop out upon firing. I've never seen or heard of that happening with any Lee Enfield rifle. How about a clarification?

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I have taken this rifle to the range twice since I bought it last fall. The second time, earlier this month, the sequence was this. I loaded a single round and closed the bolt. When I fired the rifle, the bolt stayed in place but I could not withdraw the bolt. In each case, I had tried to raise the bolt handle to eject the case when I encountered a stuck bolt. But I could manually raise the bolt head to the vertical position with my thumb and then remove the bolt. It appeared to me that the bolt head had jumped the track. This happened 3 times at which point I reached the same conclusion as Mr. Doyne. [Slow learner.]

I have since tried loading a snap cap again from the magazine and from lying on top of the magazine. It loads, the bolt stays in track, and it is extracted OK, with the bolt head staying in the track. Whatever the problem is, it appears to be associated with firing, but I didn't think to take any pictures of the problem when it occurred.

I have put 19 rounds through the rifle. I believe I would have noticed this behavior the first time I took it to the range. In between the first and second visits I stripped the bolt head and rechecked the headspace with the 0.071 gauge.

Here are some more images.

https://www.milsurps.com/images/impo...MyEfHSGm-1.jpg https://www.milsurps.com/images/impo...hMDthvIm-1.jpg
https://www.milsurps.com/images/impo...dbL00N5m-1.jpg

As you can tell, I'm new to these rifles. The only thing I could think of is that front part of the channel is worn or bent up, the bolt head is too wobbly or worn, and/or I didn't get the bolt reassembled correctly... or I did not correctly assess the sequence of events.

Is it possible when loading a single round to close the bolt and fire without the extractor engaging the rim or to commit some other "operator error" that could cause this behavior?

Is it possible that a worn or damaged throat that wouldn't show up in a headspace check could cause this problem?

Thanks to all who are weighing in on this problem. I would prefer not to relegate this one to wall hanger status, but if it can't be made safe then needs must.

Your bolt head overturn should not be more than 12° if I remember Peter's comments correctly.

Furthermore, your bolt head does not have the necessary chamfer at ether end of the guide rib, as per the bolt head shown above. A little surprising considering it is a Long Branch made bolt head.

Get out the needle files and go to it?

The bolt head retaining slot on your rifle does not look worn enough to condemn it, nor cause problems if the bolt head rib is properly chamfered.

That photo showing the rear of the chamber looks odd. You should be able to see a clearly-defined "collar" in the body, just behind the actual barrel face. The barrel should not be touching this "collar" (known as the "inner ring" because No4s breech up on the front of the Body, as opposed to all its predecessors, which, like a Mauser, breeched up against that inner ring.

Another part of the "mechanical safety" designed into the Lee Enfield family is that the the very front of the blot-head enters this close-matching aperture in the rear of the breech ring, thus centralizing (more or less) the bolt-head with the chamber.

IF that aperture is oversized, the bolt-head alignment will not be as good. If the bolt-head alignment is "wonky", so will be the bearing of the locking lugs. If the bolt assembly can be "drifted" to the right, the left lug will disengage. Thus, on firing, the initial back-thrust will be primarily on the RHS locking shoulder. Asymmetric back-thrust in an asymmetric (or any other) body will produce undesirable wave / vibrations that no amount of fancy bedding will overcome.

If, somehow, the rear of the breech ring does NOT closely surround, the very front of the bolt-head, there WILL be problems The bolt cannot move off-axis to the left because of the substantial support from the left side of the Body. As the bolt closes, the extractor engages its slot (or at least, it SHOULD) and this tries to pull the bolt-head to the right. HOWEVER, at the same time, that inner breech ring is "capturing" the bolt-head and centralizing it.

In the unlikely event of a catastrophic overload, or a seriously faulty cartridge case, the relatively soft body will not shatter like a grenade, but the slightly less substantial right side of the body will "stretch". NOTE; what is envisaged here is not something caused by a few extra grains of powder, but like an overloaded proof cartridge or worse. Even then, what is more likely to happen is that the extreme pressure (and temperature), will blow out via the primer pocket. Again, the engineers thought of this. That is why the extractor has a bit of "air-gap" around it and there is a vent port directly opposite on the left side of the breech ring. These features prevent a "scary" event escalating into something MUCH worse. Lee Enfield vent "case blow-outs" from the front of the receiver. Herr Mauser's designs conveniently allowed the generous bolt-lug guides to allow escaping hot gases to vent rearwards, hopefully dissipating as they went. That is why Mauser type rifles have that rather large shroud over the rear of the striker assembly. It's a SHIELD against stuff that can blot out your eyesight.

SMLEs and earlier are slightly SOFTER in the body than No4s. When they "blow up", they tend to bend more readily; the earlier pattern ones the the magazine cut-off slot slightly moreso. They also wear in the bolt-head retention area; to the point that the bolt-head can disengage from the body when only halfway closed. This of course takes a a LOT of action manipulations, dry and live.

I'm stumped without having it in hand. The bolt assembly is out of spec. and needs to be sorted. That much I can see. I recently had an SMLE come here for barreling and I found the body had been blown up and the rear of the breech ring was physically blown upwards and backwards, (the first I'd ever seen), so that's a possibility as Bruce has said although the physical damage isn't evident on your No.4. A wild *** guess is that your body is just plain worn out beyond repair with the bolt flopping around in the runway but I could be wrong.

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Originally Posted by Bruce_in_Oz

That photo showing the rear of the chamber looks odd. You should be able to see a clearly-defined "collar" in the body, just behind the actual barrel face. The barrel should not be touching this "collar" (known as the "inner ring" because No4s breech up on the front of the Body, as opposed to all its predecessors, which, like a Mauser, breeched up against that inner ring....

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I agree, it does look a bit odd, but there is no sign of another extractor slot, so unless it has been set back an entire turn and the slot deepened...? Someone who wanted to recut the chamber with a smaller than milspec reamer?

Maybe take off the rear handguard and lets see the Nock's Form?

I doubt it's been set back as the forend wouldn't fit properly unless it was shortened and the cap refitted. I had a genius send me Long Branch many years ago that was done that way and it was completely knackered. He had unbreeched it through the magazine well using a bar of tool steel and twisted the body in the process. The result was I sold him a new rifle after unsuccessfully trying to repair it. Did you know that the bolt head will religiously pop out of the cut in the rail when the body is twisted? I didn't at the time but I sure learned! It was a wartime Canadian owned/issued rifle too which was really sad as they aren't that common.

I had a 1957 Mk.2 receiver someone had done that to as well. :mad: I suppose the bolt was gone and he didn't think it was worth anything...

My first thought was this rifle had a bar inserted to twist the receiver off.
I’m dealing with one myself.

OP

Look inside the corners from underneath in the mag well, do you see signs of force applied?
If a bar was used to take the action off the damage would be inside the mag well openings.
If the top left side of the action was moved left (Bent outwards when bar was forced against it) it could be causing your bolt to sit too far left and disconnecting it from the rail when fired.

In your pictures I can’t see any damage to the upper left side rail but maybe it was dressed down??? I dunno, pretty big spit ball...

My intent is to turn this rifle over to the "pro" but that's on hold for now. It turns out I'm one of those old guys who is supposed to be careful and stay home for a while. In the mean time, here is a picture of the Knox form and a mark on the right side of the barrel. The blurry feature closest to the receiver looks like four closely spaced punches. Is that a hardness verification? The mark on the right of the barrel looks like 'F 52." Is that a barrel date, matching up with the 1952 FTR? There is also a mark on the right side near the muzzle that looks like "NP 18 Ton," a number 2, and something else illegible.

https://www.milsurps.com/images/impo...8NzdaKEm-1.jpg https://www.milsurps.com/images/impo...73I8yAQm-1.jpg

Be safe.
Keep Calm and Wash Your Hands.

---------- Post added at 02:30 PM ---------- Previous post was at 02:21 PM ----------

Not sure what I'm looking for here.

https://i.imgur.com/zHvirVum.jpg

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Originally Posted by dewey1424

The mark on the right of the barrel looks like 'F 52." Is that a barrel date, matching up with the 1952 FTR? There is also a mark on the right side near the muzzle that looks like "NP 18 Ton," a number 2, and something else illegible.

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F52 = Barrel year
NP 18 ton = BNP 18 tons per sq inch (Civilian Proof test when it was sold into the UK Civilian gun market)
2xxx = 2.222" = cartridge length

Should be 303" calibre marking in there as well

Quote:

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Originally Posted by dewey1424

I am having a problem with a No 4 Mk I....

The problem is that when fired, the bolt head jumps out of the track. I have to hand raise it to the vertical release orientation to get the bolt open.

It seems to open and close smoothly with no round in the chamber.

The only other observation I have is that the bolt head does not tighten flush with the bolt body when the bolt and bolt head are aligned, so there is a little play between the bold head and bolt body. (Does that make sense?)....

Could this problem be caused by my re-assembly or do I have a bigger problem with this rifle?

Thanks.

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Now that we've seen the photos, personally I can't see any way in which the bolt head could escape the guide rail when the bolt is closed and the rifle is fired.

Nor can I see any way for the bolt head to be "raised to vertical" with the bolt closed, even if there was no rail at all, as the extractor and spring cannot rotate to vertical without being withdrawn from the extractor slot in the barrel & receiver.

2+2 does not equal 5.

I would save all the conjecture and send it off to Brian Dick at BDL Ltd and let him sweat it out. Here's a link, PM him... https://www.milsurps.com/member.php?u=2818

Any pictures of fired cases?

Jsne

I'm with Rob on this one. I can't for the life of me see how the bolt head jumps up upon firing with the bolt closed. I can see that maybe it pops out of the track after primary and secondary extraction when the bolt is withdrawn. That's a whole other can or worms as we've discussed here earlier.

Quote:

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Originally Posted by Brian Dick

I'm with Rob on this one.

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Or post #29? A qualified gunsmith...?

Make a five second video of the malfunction to show us.