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Modified M38 bolt.

Mauser bolt modification

Spend any time exploring gun forums and corners of the internet dedicated to military surplus firearms, and you’ll quickly encounter the opinion that Mauser’s bolt design is the standard by which all other bolt actions should be judged, and that most subsequent “improvements” were purely cost-saving modifications.

As a big fan of the small-ring Mauser variants, especially in the super-accurate Swede, it was only a matter of time before I started pulling apart my Husqvarna M38 to see what I could improve. Most Mauser bolt mods are bent handles to allow for scope clearance – something which has been covered ad nauseam all over the place.

So, instead of going over the same ground about oxy-acetylene torches, vices and hammers to get your military Mauser into sporting condition, I’m instead going to look how to reduce lock time by shaving some material off the cocking piece and firing pin. As always, remember that modifying your firearm is dangerous/irreversible/stupid, etc.

What is lock time?

Lock time is the minuscule period of time between when you pull the trigger and when the firing pin crushes the primer to set off the powder inside the cartridge. In other words, how long it takes the firing pin to travel to the primer from the time it is released by the pull of the trigger and the disengagement of the sear. The term lock time comes from the age of muskets – flint locks and wheel locks – the time it it took for the lock to work.

Essentially, the longer the lock time, the more likely it is that the shooter’s natural movements will move the rifle off target. The other period of time that is quite significant is how long it takes the bullet to leave the barrel, as again, the shooter can move slightly during this time.

So, naturally, it’s in a shooter’s best interests to have as short a lock time as possible. Modern bolt actions are incredibly quick compared to old military surplus rifles, and the chief ways in which lock time can be decreased are through eliminating excess material which causes resistance, friction or drag, and making modifications to the main spring, or replacing it and/or the firing pin. There are a few “speed lock” products out there, which are kits aimed to help you reduce the length of travel of the striker, and usually the trigger pull as well. Often, they will also convert your cock-on-closing Mauser to a cock-on-opening action.

Personally, I quite like the cock-on-closing action on older rifles, as it allows you to “feel” more of the chambering and extraction process – a real plus for reloaders.

Removing material

This is something you can’t afford to do wrong, especially if you’re working on a rifle with hard-to-replace parts. Fortunately for me, I had recently bought a replacement bolt due to a different issue and had some good parts on the old bolt to work with.

If you’ve spent any time on Mauser-related forums, you’ll have come across Dutchman, or Dutch. A very knowledgeable gentleman with his own website dedicated to everything Mauser. I came across one of his posts, in which he showed the modifications that were made to cocking pieces and firing pins in order to produce the bolts for the super-accurate CG63s and CG80s. With this as inspiration, I set off on my own bolt-modification adventure.

I removed the thumb piece on the back of the cocking piece to reduce weight and drag, and made the firing pin short enough to match. As you can see in the picture below, the previous owner of this rifle cut down the main spring to decrease cocking effort on the rifle, but this can lead to unreliable firing and pierced primers, so I’ll be swapping that spring for the one on the blued bolt I recently bought.

Modified Mauser firing pin.
Modified Mauser firing pin.

As you can see in Dutchman’s post, there is more material that can be removed in order to reduce friction, as he shows some rifles with scalloped bolt sleeves. Whether I attempt this or not is still yet to be seen, I’d like to see the difference this makes first before going any further. The sear engagement on the cocking piece can also be altered according to his pics, but it looks like a welder would be needed to reinforce the sear engagement section. There’s also the fact that you’ll need to case harden this section again, as a cut-up sear piece will quickly wear away, creating a dangerous firearm.

I’ve opted to leave this bit for now, as I’m planning on replacing the factory trigger with a Timney trigger in the near future. I want to see what it’s like with the new bang button, before I go and make any permanent changes.

It’s all about the looks

The flush fit of the cut firing pin is much more attractive than the thumb piece.
The flush fit of the cut firing pin is much more attractive than the thumb piece.

Well, not all about the looks, but it does play some part. I’ve got to admit, the cut down cocking piece looks a lot more modern and svelte than its military-style counterpart. I’ll take this opportunity to remind you that this rifle was not in collectors condition when I got it from the previous owner, so it is purely a project – no one is cutting up a pristine M38 here!

Another thing I wanted to do was break up the solid black of my rifle. The “new” bolt I bought had been blued and combined with the matte black paint job I did on the action and barrel, it was starting to look pretty boring. For a bit of contrast I took the un-blued extractor and extractor collar from the original bolt and added it to my new hybrid monster. The end result is a little bit of flair, with no real practical relevance. Be warned though, that while the extractor is easy enough to remove, the collar does not spring back into shape nicely for you to put teh extractor back on. You’ll need to hold it shut while sliding the extractor over – which isn’t easy without the armourer’s tools. I used a pair of circlip pliers, which while tricky to do, managed the job in the end.

The blued bolt body creates a contrast for the polished extractor and extractor collar.
The blued bolt body creates a contrast for the polished extractor and extractor collar.


Geoff is a shooting and reloading enthusiast who would rather be at the range, but is content to write about it. He is a member of Waiuku Pistol Club, and shoots rifle, pistol and shotgun in various disciplines, occasionally, managing to get out for a hunt.

4 thoughts to “Mauser bolt modification”

  1. The last image shows skid marks on the bolt, presumably from the extractor.
    I’m having very similar issues with the M41B of my own.
    Is this anything I should be worried about?

  2. Hi Boris,

    There are drag marks from the extractor visible. On the opposite side of the bolt, you will likely also have a long drag mark almost the length of the bolt, that turns at a 45 degree angle on the handle end. This is from the bolt rubbing against the extractor.

    All of this is perfectly normal. Because the bolts are built to such tight tolerances, the moving parts will rub. This won’t do any damage to the bolt, except change the looks a bit. If you are concerned about that, you can try disassembling the bolt and polishing it, or even putting on a light coat of metal-specific protective wax. Alternatively, a small bit of silicone spray or lubricant will stop the metal parts rubbing so harshly.

    If there are gouges in the metal, you may have a chipped extractor that is eating into the bolt body.


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