Indians For Guns

Having acquired 2 good air rifles I decided it was time to use the gyan I have gained to operate on my 20 plus year old SDB 50

I removed the screws holding the steel to wood - two on the sides and two holding triggger guard..

I then detached the cocking lever.

Using techniques that I saw on a YouTube video on operating on a Weihrauch rifle I removed the breech cap and gently tapped out one pin holding the trigger and then went on to the last pin.

I was prepared. So I was safe. As soon as the pin was tapped out the entire pre-compressed spring and guide rod shot out like an artillery shell - sliding along the floor where I had placed the rifle. The piston was tight inside. I extracted it. The 1 inch washer looked sick, but I decided to ignore that for now. I cleaned everything with surgical spirit. The tip of piston was very tight with a diameter of 2.6 cm. The hind part was a close fit at 2.55 cm. I sanded the front bit down to about 2.57 to 2.58 to make it a snug but smooth fit. Lubricated with gun grease. I do not have Moly grease and did not want to buy the industrial quantities available on SJP road.

Put everything back and struggled like hell and took the help of others to compress the barrel and breech on a 1" water pipe plug while the holding pin was inserted. This is not something I fancy doing often.

On test firing
1. Power was down with muzzle velocities of 130 to 140 mps (140 to 150 earlier) - not a problem for me
2. The trigger had become dangerously light - almost an auto-fire. Too dangerous for me. Or anyone.

The rifle will be taken to a rifle hospital today for repair.

rather the patient is in coma

bennedose wrote:Having acquired 2 good air rifles I decided it was time to use the gyan I have gained to operate on my 20 plus year old SDB 50

I removed the screws holding the steel to wood - two on the sides and two holding triggger guard..

I then detached the cocking lever.

Using techniques that I saw on a YouTube video on operating on a Weihrauch rifle I removed the breech cap and gently tapped out one pin holding the trigger and then went on to the last pin.

I was prepared. So I was safe. As soon as the pin was tapped out the entire pre-compressed spring and guide rod shot out like an artillery shell - sliding along the floor where I had placed the rifle. The piston was tight inside. I extracted it. The 1 inch washer looked sick, but I decided to ignore that for now. I cleaned everything with surgical spirit. The tip of piston was very tight with a diameter of 2.6 cm. The hind part was a close fit at 2.55 cm. I sanded the front bit down to about 2.57 to 2.58 to make it a snug but smooth fit. Lubricated with gun grease. I do not have Moly grease and did not want to buy the industrial quantities available on SJP road.

Put everything back and struggled like hell and took the help of others to compress the barrel and breech on a 1" water pipe plug while the holding pin was inserted. This is not something I fancy doing often.

On test firing
1. Power was down with muzzle velocities of 130 to 140 mps (140 to 150 earlier) - not a problem for me
2. The trigger had become dangerously light - almost an auto-fire. Too dangerous for me. Or anyone.

The rifle will be taken to a rifle hospital today for repair.

> The Moral of the Story = Practice Makes One Perfect... Now you know the DOs & DONTs
> Everything comes with a "Price" attached
> Take a quick rewind of the entire procedure you went through - What went right & What went wrong / Follow the right & forget the wrong
> Soon you'll be a DIY Tuner
Briha

You could have held the whole piston assembly in a carpenter's vice, removed the the 2 retaining pins and then slowly loosened the vice. This is how is used to do during the springer days.
Regs
Sudhaiob

sudhaiob wrote:You could have held the whole piston assembly in a carpenter's vice, removed the the 2 retaining pins and then slowly loosened the vice. This is how is used to do during the springer days.
Regs
Sudhaiob

Removal was not the problem. Compression to replace the spring and piston was the real problem.

Here is something I have not figured out. In order to compress the assembly the jaws of a vise would have to be over 30 cm apart - that would be a huge vise. I am thinking of getting a vise but I was thinking more in terms of drilling vise than a carpenter's vise and I was looking at "small. cute" models for general use at home.

BTW I discovered this morning that I have pulled my left pectoral muscle while compressing the device using my body weight while reaching out to try and replace the pin in position

Lessons learned ? Are you kidding Brihaji ?

This is shocking.......

It is A CASE STUDY of how things are NOT done while working with springers.

Obviously the OP knows nothing about opening and putting springers back and what tools and equipment are required for the job at hand.

He is lucky to get away without any serious injury to himself and others around him.

Let this be a lesson to others thinking of dabbling with tuning, without the proper knowledge, equipment and tools, lest it give us airgunners a bad reputation of being a bunch reckless, irresponsible idiots, which we are clearly not.

M.

brihacharan wrote:

bennedose wrote:Having acquired 2 good air rifles I decided it was time to use the gyan I have gained to operate on my 20 plus year old SDB 50

I removed the screws holding the steel to wood - two on the sides and two holding triggger guard..

I then detached the cocking lever.

Using techniques that I saw on a YouTube video on operating on a Weihrauch rifle I removed the breech cap and gently tapped out one pin holding the trigger and then went on to the last pin.

I was prepared. So I was safe. As soon as the pin was tapped out the entire pre-compressed spring and guide rod shot out like an artillery shell - sliding along the floor where I had placed the rifle. The piston was tight inside. I extracted it. The 1 inch washer looked sick, but I decided to ignore that for now. I cleaned everything with surgical spirit. The tip of piston was very tight with a diameter of 2.6 cm. The hind part was a close fit at 2.55 cm. I sanded the front bit down to about 2.57 to 2.58 to make it a snug but smooth fit. Lubricated with gun grease. I do not have Moly grease and did not want to buy the industrial quantities available on SJP road.

Put everything back and struggled like hell and took the help of others to compress the barrel and breech on a 1" water pipe plug while the holding pin was inserted. This is not something I fancy doing often.

On test firing
1. Power was down with muzzle velocities of 130 to 140 mps (140 to 150 earlier) - not a problem for me
2. The trigger had become dangerously light - almost an auto-fire. Too dangerous for me. Or anyone.

The rifle will be taken to a rifle hospital today for repair.

> The Moral of the Story = Practice Makes One Perfect... Now you know the DOs & DONTs
> Everything comes with a "Price" attached
> Take a quick rewind of the entire procedure you went through - What went right & What went wrong / Follow the right & forget the wrong
> Soon you'll be a DIY Tuner
Briha

fantumfan2003 wrote: Let this be a lesson to others thinking of dabbling with tuning, without the proper knowledge, equipment and tools, lest it give us airgunners a bad reputation of being a bunch reckless, irresponsible idiots, which we are clearly not.

I must point out that I was encouraged by many posts in the Gunsmithing section on this forum to try this out. There is no warning that tells amateurs not to try it. I particular I cannot recall a single helpful post from you, who who have chosen to butt in now, claiming to be oh so responsible, while bearing the heavy cross of responsibility for "us airgunners". There really should be a prominent warning on the forum that some of this stuff can be dangerous or statements like we are not "reckless, irresponsible idiots," rings ludicrously hollow and hypocrtical - clearly added as an opportunistic, if feeble, afterthought.

I knew of the danger only because of a random YouTube video. Your loudly proclaimed sense of responsibility, being advertised with eagerness now now, was notable by its absence when it was needed by a novice. I remain responsible for my actions, but if you think any mythical irresponsibility on my part will reflect on your innocent self and the larger conmmunity of "us airgunners", wipe off the froth, and put your money where your mouth is and put down a warning where it can be seen by anyone who wants to open up his air gun rather than simply choosing an issue where no damage occured to pompously pontificate in retrospect and score an undeserved brownie to try and don a vicarious halo. Words are cheap, but can be made valuable if used at the right time and place.

Irresponsible actions based on half baked knowledge by likes of yourself are indeed a very serious matter.

Are you saying that you did not come across a SINGLE "how to" on springer tuning (on youtube and here) that mentioned using a spring compressor as a safety measure to extract and put the spring back into the springer ? Of course not, you chose to ignore it, by your own admission and THAT makes you irresponsible. Towards yourself, others around you and the community.

You did go through this 5 page thread before embarking on your mis-adventure and I am sure you did take a look at the spring compressor on Page 2 of that thread, oh, please tell me you did.....

http://indiansforguns.com/viewtopic.php?f=22&t=1319

Your choice of not putting moly grease also points to the same......you did go through this post did'nt you ? Did you ?

http://indiansforguns.com/viewtopic.php?f=22&t=1319

And you did see this latest post made only a few days ago.......Did you ?

http://indiansforguns.com/viewtopic.php?f=22&t=20257

So far as experience goes, lets just say you know nothing about the darker side of springer tuning, that is why I discourage them when I see them going in the wrong direction, it may be difficult for you, but trust me on this one. The "Search" here is your best friend.....

As for my being responsible with airguns, not withstanding your English gibberish and expletives directed at me, I let my work do the talking........

Are you still offended with reckless and irresponsible, YEAH you should be.......

As for the title of your post, even if it was in a lighter vein, should have an addendum, ....and Surgeon Almost Got Killed

M.

bennedose wrote:

fantumfan2003 wrote: Let this be a lesson to others thinking of dabbling with tuning, without the proper knowledge, equipment and tools, lest it give us airgunners a bad reputation of being a bunch reckless, irresponsible idiots, which we are clearly not.

I must point out that I was encouraged by many posts in the Gunsmithing section on this forum to try this out. There is no warning that tells amateurs not to try it. I particular I cannot recall a single helpful post from you, who walk in late, claiming to be oh so responsible, while bearing the heavy cross of responsibility for "us airgunners". There really should be a prominent warning on the forum that some of this stuff can be dangerous or statements like we are not "reckless, irresponsible idiots," rings ludicrously hollow and hypocrtical - clearly added as an opportunistic, if feeble, afterthought.

I knew of the danger only because of a random YouTube video. I remain responsible for my actions, but if you think any mythical irresponsibility on my part will reflect on your innocent self, wipe off the froth, and put your money where your mouth is and put down a warning where it can be seen by anyone who wants to open up his air gun rather than simply choosing an issue where no damage occured to pompously pontificate in retrospect and score an undeserved brownie to try and don a vicarious halo.

Gentlemen,
Differ and argue as much as you like, but please do not get personal. Just look at what is being said about tuning air rifles and discuss on that.



Best-
Vikram

Bennedose:
Everyone begins somewhere! And you began too! Congratulations!
Now you know what to do and not to do next time!
Dont let the brickbats affect you and listen to what brihacharan says!
Happy tinkering!
Best
A

I will follow your sage advice Vikram, and thanks for the encouraging words Safarigent

Let me post a follow up.

The rifle returned from ICU a couple of days ago, and I have been testing it over the weekend, I had asked the gunsmith (Bangalore Armoury) if he had Moly grease. He did not and I left it at that. He changed the spring and washer and thankfully readjusted the trigger to its usual SDB grade hard trigger which I am accustomed to handling.

On testing - for the first 50 to 75 shots the rifle was dieseling disgustingly. Apart from the sharp report the smell of the smoke was sickening after a few shots. He seems to have put a monster of a spring (Cherokee?) that has greatly increased cocking effort - but more on that below. This particular SDB rifle had a liking for Diana shot pellets and used to give great grouping with that (local make) brand name. But that had gone. Pellets were striking at any point on a 15 cm circle at 10 meters. The dieseling reduced after I had nearly exhausted a box of 100 pellets. I then cleaned the barrel using ear buds and cotton wads using a stick from a standard road-sweeper's "jhaadu" (broom) to push it through. The cotton came out black in the first 5 or 6 passes, and got clearer after that. This method leaves some cotton fibres inside the barrel and I do not actually recommend it as the best method - but let me say I am simply using my old SDB to learn. I used a compressed air can (for cleaning of keyboards/electronics) to try and blow out as much as possible from the barrel. The first shot after that still released a small tuft of cotton fibres.

Out of frustration at the amount of dieseling oil that had been put in, I added a few drops of silicone oil into the piston chamber. That actually reduced dieseling over the next 20-30 shots as the silicone oil seems to have diluted the mix. I then cleaned the barrel again and got down to some more serious testing.

After that it seemed like the new spring and washer were beginning to settle. Accuracy with a different pellet type (Matershot Flat head) was decent.

Regarding power, I mentioned that the cocking effort has increased greatly. Unfortunately the testing area I have has walls on 3 sides that act as an echo chamber and Chrono Connect mobile software went completely nuts. Initial readings were 300 meters per sec and 40 Joules which was rubbish. I can judge the pellet velocity approximately by the time lag between firing and hitting the target. After adjusting the software and positioning of target to reduce echoes I was still getting readings of 200 meters per sec and 16 Joules. I knew this must be wrong because tin can penetration was telling me that the figure must be lower. Finally I reverted to several tests using the old sound-recording and Audacity software. I am getting a much more believable 140 to 150 meters per second by this method. That is probably the most accurate estimate. I can live with that provided accuracy is good and consistent.

Will post more as the rifle gets "broken in"

fantumfan2003 wrote: And you did see this latest post made only a few days ago.......Did you ?

http://indiansforguns.com/viewtopic.php?f=22&t=20257

Too late. That warning post was made after I had started this thread.

You did not check the dates...Did you ?

bennedose

on your follow up post.....looks like your gun is not just dieseling , its detonating. there is a difference.

adding silicone oil in the chamber of a gun....that is dieseling/detonating...can only worsen the situation.

using heavier pellets, will help control the dieseling...not detonation... to an extent.

i would suggest.....strip the gun and get rid of the excessive lube in the chamber and on the face of the seal. if its a leather seal, stay with silicone .

lets not get too carried away with these home made diy kits. come on Bennedose , a broom stick and cotton to clean the barrel !!

take some time out to research before getting down to what you intend to achieve......assuming of course, that you are clear on what you intend to achieve. its all out there....even how to make a simple pull through for your barrel. innovations and experimenting is part of air guning and this is not to discourage you...but knowledge is helpful.

first step.....make yourself a spring compressor.

step 2...stop sticking nails on pellets...LOL.

A lame excuse at not reading up on the theory before starting with the practicals.........



M.

bennedose wrote:

fantumfan2003 wrote: And you did see this latest post made only a few days ago.......Did you ?

http://indiansforguns.com/viewtopic.php?f=22&t=20257

Too late. That warning post was made after I had started this thread.

You did not check the dates...Did you ?

An excellent writeup on airgun accidents......Must read for all.............

http://www.pyramydair.com/blog/2008/07/ ... dents.html

M.