TargetTalk

Hello!

Following enhancements were made to reduce recoil:

"DOUBLE SPRING" (c) :-)



Imagine bolt's movement during a shot and You will understand its work.

Edited by Shin: I resized original picture. Click on the image to get full version.

Here we have more difficult tuning: machinery + engineer's skills are necessary.

Put special attention at bolt parts!!! When top part goes back, it pulls bottom part with. Recoil - super!!!

Ruig,
Thank you for the pictures. Is the longer spring in the picture the original recoil spring? Or did you shorten the original spring to accommodate the second spring? Do you have any data for the shorter spring - wire diameter, number of turns, turns/cm?
My understanding is that the second spring acts like a buffer, bringing the slide to a more gradual stop. So the second spring must be stiffer and does not compress until the long spring is fully/almost fully compressed.
How much softer is the recoil?
Regards,
Fred

Dear Fred,
and All Sirs, who wrote me personally about this enhancement:

I'll write so full instruction as possible in Friday (I'll try...).
Before my answer I'm going to measure every spring... etc... you know.


Yourszzz,
i.

[1] Every pistol has its own peculiar properties
[2] Laying on all mentioned above: lenght of your springs may be different with mine
[3] Cut springs by little steps, until you'll like, like works your cartridge "loading/shell's unloading" system
[4] I have no possibility to say exactly "recoil reduce degree"... i just can say: "softer" as never before.


Long spring (IZh35's nature spring):
lenght: 80mm (normal state)
turns: 53

Short spring (TOZ35's firing pin's spring):
lenght: 24mm (normal state)
turns: 13

Metal partition (between springs):
WxHxD = 10mm x 8mm x 2mm
hole diameter: a little bigger than pin

If I can get a piece of TOZ 35 spring I will manufacture one piece of this assembly.

I will then send it to Wulffe (www.gunsprings.com) and see if they can make a progressive spring for this application.

Anyone know where I can get a piece of TOZ mainspring?

Ed

Ed,
I don't know whether Wolff will do a custom spring, but they do offer various spring assortments. See http://www.gunsprings.com/1ndex.html and look in their general purpose springs listing. I am going to order their light duty and heavy metric packages and see if one will come close to the TOZ firing pin spring. Big problem (for me) will be to find some IZH recoil springs. Maybe some in the Wolff kit will do. Now I just need to find my old mechanical engineering handbook with all the spring formulas. :-)

Fred

You don't need the manual, you just need to measure the compressed length and it would be fairly simple to remove it and the rod and measure the force required to compress it to that length.

I bet it's on the order of 5-6 pounds, so a trigger scale may work.

Ed

Could someone please measure the thickness of this spring for me?

I take it you are talking about the IZH-35. The IZH-35M supposedly already has reduced recoil to suit rapidfire matches, or are they the same in this regard and therefore the 35M also needs a spring job?

I was looking for the Toz 35 firing spring wire diameter..

My intent was not strictly for recoil reduction, but mainly as a possibllity to buffer slide/bolt impact. From what I have treied so far, this method will increase the force of the impact when the slide closes up against the chamber face.

On mine, I would have to cut the original IZH slide spring for the slide to go back enough to pick up a round from the magazine.

From a new unused IZH 35M recoil spring - wire diameter 0.60mm, free length 136mm, spring od 4.70mm, spring id 3.35, approx 5 turns per 10 mm.

diopter wrote:My intent was not strictly for recoil reduction, but mainly as a possibllity to buffer slide/bolt impact.

When I disassembled and cleaned my IZH-35 on Saturday, I wondered:

Has anybody here experimented with a (plastic, nylon, rubber) buffer piece between the front of the frame and the (rather lightweight) slide, to dampen the impact when using faster ammunition (such as e.g. Federal's "American Eagle", which is quite accurate in my gun, but causes doubling)?

Alexander

I've been thinking about it, I don't like those metal bits smacking against each other.

Alexander wrote:

diopter wrote:My intent was not strictly for recoil reduction, but mainly as a possibllity to buffer slide/bolt impact.

When I disassembled and cleaned my IZH-35 on Saturday, I wondered:

Has anybody here experimented with a (plastic, nylon, rubber) buffer piece between the front of the frame and the (rather lightweight) slide, to dampen the impact when using faster ammunition (such as e.g. Federal's "American Eagle", which is quite accurate in my gun, but causes doubling)?

Alexander

The peening of the bolt face on the breach is what causes headspace to be reduced and results in doubling.

Anonymous wrote:The peening of the bolt face on the breach is what causes headspace to be reduced and results in doubling.

That is only one of many factors that can contribute. Several had been named here before.

Alexander

Alexander wrote: Has anybody here experimented with a (plastic, nylon, rubber) buffer piece between the front of the frame and the (rather lightweight) slide, to dampen the impact when using faster ammunition (such as e.g. Federal's "American Eagle", which is quite accurate in my gun, but causes doubling)?

I've thought about it, but adding a plastic buffer is not straightforward. Simply adding a buffer, reduces the slide travel and this may effect ejection and/or feeding. The recoil spring can be shortened to allow for the thickness of the buffer, but of course this will effect spring force. Finally, there is the selection of an appropriate material for the buffer. Life is too short; I would rather spend my time just shooting a very nice pistol :-)
Fred

http://smg.photobucket.com/albums/0703/ ... 010260.jpg

http://smg.photobucket.com/albums/0703/ ... 0258-1.jpg

http://smg.photobucket.com/albums/0703/ ... 0025-1.jpg


Just pull it over barrel block and front sight onto the barrel.
It's been on mine for a couple of years now. Plain plumbing O Ring.
Mine was occasionally doubling before the o ring even after removing metal peening.
No problems since.
But I have switch to a Pardini as mine main tool.