Cutting down mauser mainspring

[Ervin]

Because of competition firing reasons, Im considering cutting down on the cocking spring of a Mauser type bolt.
I got an extra standing by if this goes wrong but, do you think I could just snip away at it until the bolt opening phase becomes smoother?
This spring is 100% fresh, so it's stiffer when you go to cock and extract.

I'll have primed cases on hand to make sure they will still ignite on impact.


any other ideas?

[brickeyee]

Have you tried polishing the surfaces involved in cocking?

[mapsjanhere]

The Mauser system is not known to be the fastest to begin with, you might get improved cocking but even longer delay times. There are lighter firing pins available, so maybe if you lighten the main spring add a lighter pin to make up for it.

[James K]

By reducing mainspring tension, you might also get pierced primers if the firing pin momentum is not enough to prevent the primer from backing up into the firing pin hole in the bolt.

Jim

[HiBC]

I do not know anything about your competition,but a turned down Mauser bolt handle does not give a lot of leverage .It might be acceptable to upgrade your bolt handle.

I have no experience with it,but Tubbs makes a lightweight firing pin and speedlock spring.

I am not a big fan of shortenining springs.Without the preload,performance is lame.Better if spring rate is reduced with wire size.

You might talk to Wolfe or ?. Likely they have a springwinder machine that can do prototype,semi custom,etc.

A little fine lap and then some lube may help.EP moly on the cam would not be wrong.

[amd6547]

What weight spring are you running?
I just ordered a heavier weight spring for my Yugo refurb 98k to help with 50's Yugo ammo.
What kind of competition?

[Scorch]

When people start talking about cutting springs to lighten cocking effort, I just cringe. It's not an issue of spring tension, it's an issue of surface finishes and geometry. Polish the surfaces, work harden them, and watch how easy the rifle cocks.

Lock time on Mausers can be shortened by using a lighter firing pin. Titanium firing pins are available, Tubbs sells an aluminum and steel firing pin, and Wolfe makes a higher tension spring. If you know someone who has an indexing head for their mill and carbide cutters, you can lighten firing pins by fluting the firing pin shaft and fluting the cocking piece.

[Dfariswheel]

DON'T cut the spring.
This causes all sorts of problems including pierced primers, mis-fires, and slow lock time.

Your first step is to fully disassemble the bolt and thoroughly clean everything.
Don't remove the extractor collar from the bolt.

After it's all clean, lubricate everything, then apply any good grease to the cocking cam on the rear of the bolt and the cocking piece.
This will almost always cure hard operation as long as there isn't some other problem.

If the bolt has had the bolt handle bent over, forged, or a new one welded on, there's a possibility a bad job may have softened the cocking cam area and the soft metal will be very sticky to operate.
If this is the case, the bolt is ruined.

[4V50 Gary]

What JamesK and Dfariswheel say. Don't cut the spring. Lightly polish the surfaces instead.

[Ervin]

I cut the spring, works beautifully now. Almost as smooth as my K98
Ignites primer properly, no out of the ordinary signs on the primer after firing, even with hot loads.

The original tension of this spring had most chances of puncturing the primer than it does now.

[brickeyee]

"The original tension of this spring had most chances of puncturing the primer than it does now."

No, the weaker spring is less able to support the primer indent against full chamber pressure, the actual cause of primer piercing.

[Goatwhiskers]

"Some people learn by instruction, some people learn by observation, some people just have to p-- on the electric fence anyway." Will Rogers

[HiBC]

The stereotype gunsmith is generally pictured as somewhat cranky.

This is one of the ways they get that way.

You had a plan.Cut the spring,but you were unsure.

You ask for help.Folks take time to help.They give you good information.Information that is concensus between knowledgable and experienced people.

You argue a little,cut the spring anyway,then seem to come back to say"You guys don't know anything,I cut it,....."

Why ask questions if you know so much?

Let us know if your targets are better.

[Don P]

Beautifully said Goatwhiskers. Let me stick my butter knife in the electrical outlet to see if I get shocked cause I think Mom was lying to me that it would happen.

[James K]

Hi, brickeyee,

I am glad someone understands what causes "pierced" primers. Just for fun, I once worked over an old Mauser bolt until I got 1/4 inch firing pin protrusion. I put the bolt in a rifle and fired it by hammering on the rear of the firing pin with a heavy machinist's hammer. I then loaded cases fired in another rifle and did the same thing, repeatedly. I never did get any pierced primers and don't believe any spring that could fit into a bolt could cause a firing pin to punch through a primer (unless the firing pin came to a needle point). Just isn't going to happen.

But reducing spring tension will result in "pierced" primers just as you say, as well as small discs of primer trapped inside the bolt that will eventually block the firing pin. I did some experiments in that direction, also. I reduced a Mauser firing pin spring gradually. At first, the gun fired normally and bolt operation was improved (the stage the OP has apparently reached). As I cut the spring down, I began to get pierced primers until I got one every shot. Then I got misfires because the little discs built up inside the bolt and stopped the firing pin.

There is no question that the original Mauser springs are overstrength. Those rifles were designed as military rifles and made so they would fire under the most severe conditions. There is a point to which the spring tension can be reduced without problems, but it must be approached carefully.

Jim