Bolt Head Problem

[Igor]

Hi there! first time posting in this site, looking to find a posible solution to fix this problem, before posting I contacted Team Mauser and they let Me down with no answer to resolve My problem, 

Problem explained:

My bolt head is supposed to work for Calibers going from 6.5X55 to 9.3X62

My Magazine is Type C.

The bolt head of My Mauser does not extract the cartridge of the 6.5X55 SE, and the cartridge gets stuck in the bolt head, as You know the base in this caliber is wider than in a 30-06 Cal. 

(30-06 extraction works flawlessly)

What to do?

Thanks.

Igor.

[Rick - Mauser M03 Blog author]

Hi Igor. Rick is my name - author of the blog that goes together with this little forum.

I’m sorry to hear about the problems you are having with your M03’s bolt head. The removable bolt head is a great feature of this rifle system, so it has to work perfectly! It can’t be a cause of jamming or failed extraction. I’m sure we will be able to figure out what the specific concern is. We might have to tinkle the bell in the Mauser factory, to wake up the worker elves there, but let’s see if a simpler solution is possible first.

I am also using the same combination of calibres with one of my M03s, without any case extraction or case sticking problems. Let me ask some questions, to help fill out the shape of the problem.

- what brand are the cases you’re using, in 6.5x55 and any other caliber used with this bolt head?
- are these reloads or factory new?
- if reloads, are the cases being full length resized?
- if reloads, what are the load details? Primers, powder type and load, bullet weight, cartridge overall length, etc
- are the fired cases showing any signs of being hot or high pressure loads?
- how does the extractor hook look? Any wear or damage?

I will measure the inside diameter of my bolt heads with a vernier calliper, to compare with yours. I will also measure the case head diameter of the Lapua cases I’m using for 6.5x55. Stand by for my next message. 🙂

Regards, Rick.

[Igor]

Hi Rick, thank You very much for responding to My concern.
Details on ammunition:
New Norma Oryx 156gr
New Sellier& Bellot soft point 156 gr.
There is no sign of wear in My bolt head, works flawlessly with Hornady in 30-06 factory loaded.
I have shot in this cal. Only 90 shots and I feel that wear is unlikely,
I never use reloaded cartriges, I am sorry I am not able to measure My extractor at this time, I am using My M03 in 30-06 for the General Open Season of Hunting here in Canada.
Problem explained furthermore:
After the shot using New Norma Oryx or New Sellier & Bellot, the bolt head bites on the empty cartriges and either drops it in to the magazine or gets stock in the bolt head.
What I did is to ask for a new bolt head and if doesn't worlk well I will take it to a gunsmith and ask him to tweak it and make it a dedicated bolt head for My 6.5X55 SE.
I am happy to hear tha Your M03 in the SE cal works just fine, this gives Me hope.

Remain with kindest regards.

Igor.

PS: please don't feel ignored if after the 6th of October I don't answer to Your response immediately, I will be in a remote area unable to see any message.

[Rick - Mauser M03 Blog author]

Hello Igor. Here’s what I’ve measured.

The inside diameter of the bolt face recess is 0.480” at the deepest, widest point. It is exactly the same for all three bolt heads I have.

My Lapua cases, fired, in 6.5x55 measure 0.477” across the outside of the rim. These have been fired around five times.

The same cases from the same batch, unfired, are 0.476”.

Igor, let’s discuss the measurements you get. I’m going to take a punt and suggest that the problem you’re having has something to do with case head size.

Ah, but I’ve now read your new post, where you describe how cases of both brands are not being thrown away from the bolt. This is sounding like a problem with the ejector plunger, perhaps in combination with tight case heads in the bolt face recess. How does the ejector look and feel? Is it moving freely, unimpeded, with a strong springiness?

Try this test - take a fired 6.5 case and hook the rim under the bolt head’s extractor. Tilt the case so the head pushes down against the ejector plunger. How does it feel? Does it move freely or is there binding? Now try with a 30-06 case. Any different?

[Igor]

The plunger feels fine with both cartriges, but there is a difference, the 30-06 feels smooth and well calibrated, in contrast with the 6.5X55 SE this one feel like rubbing the side of the bolt head, this is to say that the size of the head and the thickness of the SE might be the problem. As You already suspected,

[Rick - Mauser M03 Blog author]

The 6.5x55 Swedish calibre is something of a problem child I’ll admit, though its combination of accuracy, penetration, mild shooting and the great ballistic coefficient of its projectiles makes it worth the effort.

I noticed the same catchiness feeling when testing the 6.5 case hooked under the extractor and pressing down on the ejector plunger. It would tend to snag and grab a little at times, whereas the 30-06 cases would glide in and out like precision butter. 🙂 However, if I pressed the 6.5 against the plunger using only my finger on the opening of the case mouth, so I could flick it, it would flick out of the bolt head perfectly every time.

I’m wondering, do you find the ejection failure problem tends to happen when you are operating the bolt slowly? I ask because I’ve had problems with the 6.5x55 when I’m being quiet and careful with the bolt. I’ve had jamming when slowly chambering handloads with long, pointy projectiles seated way out to almost reach the lands - which are deeply set with the 6.5. What happens if you open the bolt and pull it back like you’ve got a grizzly coming at you? Can you chamber a fired case and do some tests, comparing slow and fast? Or maybe fire off a bunch of test shots from your apartment balcony or in the back yard? It wasn’t the solution I was really looking for but I found my problems with the 6.5x55 went away when I started operating the bolt with gusto. I’ll be interested to hear what you find in this respect.

The least likely problem in my view will be the dimensions of the recess in the bolt face. The integrity of the Mauser M03 system and its interchangeable barrel design depends on the tight tolerances of the bolt head to barrel chamber interface. We’ll have to keep minds open to the possibility that you’ve got a tight bolt head though.

[Igor]

Hi Rick, I always action My bolt at a moderate speed, not slow not fast, this is the way I do it even in conditions of high stress during hunting, but just for the fun of it, I did several fast cycles, the empty cartridges drop on the magazine, and a couple get stuck, same happens when shooting, the cartriges of the SE and the bolt head don't work in sync, this is why I asked Mauser to make Me as a special order a dedicated bolt head for the SE, but they declined saying that they don't do such a bolt head, a prudent solution is to buy a new bolt head and if works fine I will use it as a dedicated SE caliber, if the new bolt head doesn't work properly with the SE, I will send it to adjust with My gunsmith.
and keeping the other bolt head as a dedicated 30-06 Spring.
Now that I read that You have similar problems with the SE cal. I confirm that My request for a new bolt head is the right course of action.
In My opinion, a bolt head for all standar calibers is a very broad spectrum when the utmost precision is needed.
I am going to take it slowly and wait until the new bolt head is here and depart from there. Right now I have my 30-06 for hunting in this season and I feel fortunate to have it ready.

[Rick - Mauser M03 Blog author]

Hi Igor. Thanks for running the tests with extracting cartridges at a faster pace. Hmmm. The way your cases are being dropped on top of the magazine has got me puzzled. This could be happening because the extractor is losing grip on the rim as the case is coming out of the chamber. The spring pressure of the ejector pushes the case so that its mouth drags along the chamber wall. The angle of the case tilting could be enough to cause the extractor to lose grip. This would result in the case no longer being flicked by the combination of drag from the extractor and push from the ejector.

Can you see what’s going on if you eject a case really slowly, with the barrel pointing down so that the case can’t easily fall into the magazine? Does the case get pushed by the ejector against the side wall of the chamber? Can you detect the point where the bolt head is losing control of the case? It’d be cool if you could make a video of the problem. We could make a new post for the blog with it, hopefully leading to diagnosis and rectification.

Keep in mind that the trouble I’ve had with 6.5x55 was with chambering handloads, with long pointy projectiles, and only then when doing it slowly. I’ve had no trouble with extracting fired cases, at all.

When I get home from helping wifey with the grocery shopping I’m going to see if I can replicate the problem you’re having. I’ll report back. 🙂

[Igor]

Rick thanks so much for following up with this problem, I am sorry for not posting the video for now, is complicated at work, it always happens when is close to My hunting trip.

Pointing the barrel down makes no difference is exactly the same either drops the empty case on the magazine or gets stuck in the bolt head.

I found a post that might illustrate the same problem with more clarity:

Problem and solution from another poster.

I have two 6.5x55 rifles one has had the bold face opened up and one has not. Both are built on a rem 700 270 actions. The F-class rifle has had the bolt face opened up and I use Lapua brass with that rifle. The other rifle has not had any work on the bolt face and if I use lapua bass with it the brass will stick on the bolt and I need to pull it of with my hand. If I use Winchester brass it works just fine. 
I will be getting my bolt face opened up on my rile and would not build a 6.5 x 55 again without having this done. It is not a big deal to have done and everything just works better. I know lots on people say there is no need to have t is done but my experience tells me otherwise.

and this is the link: https://www.longrangehunting.com/threads/6-5x55-swede-bolt-face-clarification.115095/

I realize that the poster above is not talking about a Mauser M03, but shows a problem with cartridge head size, 30-06 is .473,  SE head size is .480 this is why is rubbing the sides of the bolt head in Mine. and I will add that the Rim size is also thicker than a 30-06 case. I also hear that American Manufactures of ammo make the case size for the SE in .473

However My M03 is European Made for European ammo, in fact Mauser test its new rifles with Norma Oryx as is been reported in My new barrels purchase from Mauser.

If You can contact Mauser and ask them if this is a manufacturing problem that they can resolve will be appreciated,  when I ask about this being a warranty issue they gave Me no answer.

[Rick - Mauser M03 Blog author]

Hi Igor.

Thanks for trying the extraction tests nice and slowly and with the barrel pointing down. The text you’ve pasted in from the other forum discussion is also very illuminating. As mentioned, I’ve not had trouble with extraction with my Swede, but it’s clearly an issue out there and more broadly than with just Mauser M03s.

A couple of things you’ve written have given me an idea for a very good test. To nail down the problem we need to increase the clearance between the case rim and the recess in the bolt face. This could be done by opening up the bolt face (a difficult and drastic thing to do just for a test!) or, by reducing the rim diameter of a few of your 6.5x55 cases, so they more closely match your 30-06 cases (easy to do!). Please take a couple of your fired cases, put them in a drill, spin them and use some fine sand paper or a sharpening stone or a finger nail emery board or anything abrasive you have handy to take off a few thousands of brass from the rim. Don’t take too much off. Use your fingers to compare with the 30-06 case heads, rim to rim. Does removing just a tiny amount of brass from the Swede’s rim make extraction work? If a drill isn’t handy it will still be possible to run this test by just sanding or abrading the rim by hand.

I’ll be keen to see how you go with this test! 🧐🙂

Of course the sticking case problem you’re having could be caused by the extractor claw being slightly too thick or proud. That would make it press too tightly on the rim. There could even be some gunk caught behind the extractor claw, stopping it from moving freely or resting in the right position. Tweaking the fit of the extractor could be all that’s needed. Hmmm...

[Rick - Mauser M03 Blog author]

Another thought I’m having while you’re sleeping is, can you see when exactly in the extraction process that the extractor is letting go of the case? I’m curious about how the case is falling into the magazine well. When this happens, is the extractor still grabbing on to the rim when the case mouth clears the receiver? If so, the case should flick out. So my question is, is it flicking out in the wrong direction, hitting something (scope?) and falling back into the magazine well? If so, this could be happening because the case head is not being released out of the bolt face recess smoothly. The tight fit of the 6.5x55 case head in the bolt face recess could mean it is binding a little and being thrown slightly off direction.

Or, for the times when the case lands in the magazine, has the extractor already lost grip of the case rim before the case mouth clears the receiver? I think this is the less likely scenario.

We need a high speed camera, to allow us to analyse the heck out of this! Do you have a camera that can video in slow motion? 🙂

[Igor]

Hi Rick: I was today with My gunsmith, He measured My bolt face and said that it needs to be opened 0.007 to accept European Amo in the SE Caliber, I declined and I will wait for My new bolt head, if some work is needed then I will keep one dedicated to the 30-06 and the other for the 6.5X55SE.

 To answer Your question "Or, for the times when the case lands in the magazine, has the extractor already lost grip of the case rim before the case mouth clears the receiver? I think this is the less likely scenario"

Answer the case does not fit entirely inside the bolt face the lower part the extractor grabs the upper rim and the rest of the case remains out of the bolt face. is what I suspected since the beginning case size matters here,  I only hope that Mauser had spotted this problem, and I hope that My new bolt head will be calibrated properly to accept the Swedish Cal.

I will keep You posted.

[Rick - Mauser M03 Blog author]

Hi Igor.

Thanks for this update. Did your gunsmith give you the measurements he took of the bolt head? I'm curious how his measurements compare with mine, being 0.480" at the base of the bolt face recess. I see on Wikipedia's page for the 6.5x55 SE that the rim diameter is listed as 0.480". As mentioned earlier, my Lapua cases are 0.476" unfired and 0.477" fired.

Opening up the recess in the face of the bolt head is sure to make it work well with your preferred ammunition. The gunsmith might also polish the arm of the extractor, to remove a tiny amount of metal and increase clearance there.

I've dug out the proof certificate for my Mauser M03 6.5x55 SE barrel (picture attached). It shows that the test ammunition was Norma 10.1g Oryx. I assume these cases extracted properly during test firing at the factory, so it seems strange that you're having trouble with the same ammo. Very interesting. Hmmm. :-|

Hand-loaders are well aware that there are differences in case dimensions between ammunition manufacturers; even between production lots by the one manufacturer sometimes. Earlier I mentioned the idea of taking one of your fired cases and trimming a little brass to reduce the rim's diameter, to bring it down to match your 30-06 cases. It would still be worthwhile doing this, to see if opening up the bolt face is going to be a good solution. Yesterday I was thinking that a solution could be to use a chamfering tool or fine sanding paper to trim the rims of your factory ammunition - all of it, before you use it. :-) This would work and would save on gunsmith costs. It would give you time to consult with other manufacturers, to find cases that fit. Is there a manufacturer who uses the Lapua cases I've had success with?     

Anyway, you have a new bolt head en route. If it's different from the one you already have I will say, 'Wow! I didn't expect that!'. Still, if it works better - you've got a result. :-)

Why can't I get this photo the right way up! Right click and open in a new tab, to be able to read it. Sheesh.

[Igor]

Hi Rick:

Thank You for the picture,  I was able see that Mauser test new barrels with Norma Oryx 10.1,  that is exactly what I said in My post #5, that Mauser tests barrels with Norma 10.1 Oryx, but not with My bolt head that in this particular situation is failing Me in the SE Cal. 

I don't doubt about the quality of Mauser Rifles, but I think I have a badly calibrated Bolt Head, it might have to do with the serial number mine has "MB002892" "L" for left hand.

But if I open the bolt face right now, this can put a delay My hunting trip, this is why I ordered a new bolt head, if it doesn't work as it should be I will have it modified.

Can You please tell Me about the serial number in Your bolt head? and if is right or left hand?

Remain...

[Igor]

  I have an idea, Rick, will You be able to fire some test shots with Norma Oryx 10.1 gr. factory loaded? will be interesting to see how this works duplicating the same scenario I am having....

[Rick - Mauser M03 Blog author]

There’s no ‘L’ at the end of my serial number. Is yours a left hand rifle?

[Rick - Mauser M03 Blog author]

Hi Igor. I called a local gun shop. They don’t stock Norma Oryx ammunition but can get it from the importer. However, I would need to order 10 boxes! So that’s not going to happen. 🤪

I make hand loads for all of my Mauser M03 rifles. Other rifles too. I’m trying to remember the last time I bought factory ammo ... . I was about to say it was nearly 40 years ago, but I bought some factory 270 Win ammo when my Mauser 270 was delivered about five years ago. This was the easiest way to get 60 cases, for ongoing hand loading.

My gun shop has S&B ammo in 6.5x55 SE. I will call them back and ask them to measure the rim diameter of a few rounds. I’m curious to see if the S&B rim is wider than my Lapua cases. Stand by.

[Rick - Mauser M03 Blog author]

Hi Igor. The S&B factory ammunition at my local gun shop has been measured by a helpful salesman. The rim diameter averaged at around 0.472” to 0.473”. This is smaller than what I get with my Lapua cases, which are 0.476”. I’m genuinely puzzled by what is going on with your bolt head. 🧐😕

You’re getting ready for your hunting trip, but if you have time it would be great to get the recess in the bolt face measured. All three of mine are 0.480”, at the deepest, widest part of the circular recess. If yours is smaller than this, then that is something to be discussed with the people at the Mauser factory. 😐 I’ll wait to see if you can measure this, which might be after your trip. Good luck and straight shooting!