Ishy 2A Bolt movement on firing

[how1erd]

I've got an Ishy where upon firing, the bolt rides up enough (about 1/3 to 1/2 up from from closed battery to reaching the angle cut on the reciever that springs the bolt open the vertical) to raise concern about the bolt coming unlocked and flying back.

The bolt lockup is tight, no headspace problem signs with factory and handloads, but I noticed the engagement surfaces of rear of bolt handle and front of receiver are highly polished. I think that's my only problem.

Ideas I had were:

1.) Replace extractor spring with new one.
2.) roughing up both surfaces with matching horizontal coarse sandpaper serrations for better 'purchase' when in battery,

Any other suggestions or advice?

I'd like to keep the gun, as I've worked up a load that does just over 1" at 100 yrds repeatedly, but the prospect of having the bolt ripping my face open isn't an inspiring thought.

Information

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[RJW NZ]

Unnerving, isn't it?

Someone else will chime in but for now, you've noticed an effect that comes from the untensioning of the spring inside the bolt. On a target rifle I built I added pairs of thin brass washers at each end of the spring, and I buffed off any friction points on the ends of the spring and have no more bolt handle movement, zero.
I'm pretty sure this effect will happen on an unloaded dry fire but not when using live rounds.
Nothing to worry about, unless you're getting large movement on live fires, it happens to all no 1 mk3's.

I agree with JMoore, do a search and it'll come up.

[Edward Horton]

When the bolt has 45,000 CUP pressing against it it isn't going to move, you have the right idea about replacing the extractor spring. The two most used and abused springs are the extractor spring and firing pin spring.

Just replace both the firing pin spring and extractor spring, you should get faster lock times and less bolt jump. Sand, polish, stone the ends of the firing pin spring so they can't dig into the bolt body and the collar on the firing pin spring. The sharp ends cause torque to be stored in the spring when compressed.

Replacing the springs "might" very possibly help but your bolt and lug recesses just might be well polished from much use. Bolt jump to the best of my knowledge has NEVER killed anyone and it has the advantage of speeding up your cyclic rate of fire.

You must remember you have the slickest and fastest bolt action in the world and the Enfield action is slicker than snot on a door knob.

(replace the springs and see what happens, the worst that can happen is you will know your bolt inside and out)

[jmoore]

Been discussed at length in the past on this forum, w/ some definitive answers by Peter Laidler. No time right now to search. Working!

ETA- Short answer- Not a concern. If everything else is OK, no worries!

[how1erd]

I ordered everything needed for a complete bolt from Numrich (good to have a spare, right?). Trial and error part swapping found that replacing 1.)Bolt Body, firing pin spring, and extractor spring did the trick. I'm now holding the rifle properly, with no bolt movement. Prior to this, I would lay my thumb up across the bolt on firing to keep it down. Thanks for everyones input and help.

[MVolkJ]

You now need to have the rifle rechecked for headspace; bolt bodies are not interchangable and need to be properly fitted to their individual rifle.

-Mark

[Edward Horton]

how1erd

Your original bolt and receiver had a oiled proof round fired to stress test the bolt and receiver and also seat the the bolt lugs.

Your original bolt and receiver are a matched pair and have been polished smooth from use. Your new bolt isn't moving or jumping upward because its bolt lug surfaces are rough and are "non-matching" to your receiver.

Put the original bolt back in and test it for bolt jump with the new firing pin spring and extractor spring. When the bolt is cocked the firing pin spring is pulling the bolt to the rear and the extractor spring is "pushing" the bolt to the rear and both are putting closing force on the bolt lugs.

When you pull the trigger the cartridge goes "bang" and then the bolt has 49,000 PSI pressing against it keeping it from moving. The bolt CAN NOT move until the chamber pressure is relieved and the bullet has left the barrel.

A scientist was doing tests on frogs, the scientist put a frog on a table in front of him and then slapped the table hard and the frog jumped.

The scientist wrote in his note book, "loud noise caused frog to jump".

The scientist then surgically removed the frogs left rear leg placed it on the table and slapped the table again.

The scientist wrote in his note book, "removing the frogs left leg and load noise caused the frog to jump to the right."

The scientist then surgically removed the frogs right rear leg placed it on the table and slapped the table again and the frog didn't jump.

The scientist wrote in his note book. Upon removing both rear legs the subject frog went deaf.


Moral of story, don't get froggy with your bolt until you understand why it jumps.

The above story is from my new Enfield novel called "How to explain bolt jump without angering Thunderbox"

[Peter Laidler]

Not a wise move there Howard. You can be rest assured that while your bolt might lift when you're sat there dry fiting it, it won't (?) life when you fire a full house round through it. And even if it DID lift and fully open, the mechanical safety built into the mechanism of the action has been carefully thought out so that it could NEVER lift while dangerous pressures remained in the barrel.

Put the original bolt back...............