Author Topic: An enjoyable day spent tweaking.  (Read 2335 times)

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Offline Gambo

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An enjoyable day spent tweaking.
« on: January 25, 2012, 06:48:40 PM »
I recently read on here somebody saying that they enjoyed tinkering with their air rifles, just as much as they do shooting them.

As I agree with that statement 101%, I was motivated enough by it into finishing a rifle I started tuning before Christmas.....but something  happened which had diverted my attention away from it..........can't for the life of me remember what that was though! ::)



Anyway, as I said,  I thought it was about time I got my ass into gear, and put it all back together.............so today I did.

The rifle in question is a little SMuKy SynXS, which I have had for about 2 years. It shoots very accurately, but it was a bit graunchy on cocking, caused by the cocking arm running over the spring coils. It was also twangy upon firing. None of this really detracted from the enjoyment of shooting it, as it is a budget plinker, and it did that job admirably.

Before Christmas I had stripped the gun, and made some breech shims ( la Weihrauch) , to remove a very slight bit of sideways slop in the jaws. I also fitted a pin through the cocking arm, near the shoe/foot end where it goes through the cylinder wall to engage/push the piston rearwards. That has the effect of stopping the foot riding over the spring coils, as the pin now stops the foot from entering into the cylinder too far, as the pin now contacts and slides up along outside of the cylinder slot. The shape of the cocking foot was modified to give increased clearance for an intended piston sleeve to be fitted.

So I made a piston sleeve, to take-up some excess clearance between the OD of the spring and the internal wall of the piston. The 4 thou shim stock I used was not enough though, so I had to make 2 more, to remove the space, and control the twang. Some washers were added to either end of the spring to facilitate slip, and reduce thrust torgue. The exterior of the piston skirt was polished, though not to a mirror finish, as I wanted it to hold lube. The spring guide was polished likewise. A new piston washer was sized to the cylinder bore, and the whole lot was then reassembled using the correct lubes in all the right places.

I refitted the stock, and took it out in the garden for a few test shoots. The rifle was now VERY smooth and silent to cock. A Superdome was fed into the breech, aim was taken, and the gun discharged. It was really nice, absolutely no twang whatsoever, with a very subdued nudge evident as recoil. The pellet hit the target with quite a wallop, so after a few more shots were fired, I took it in the garage to check over the chrono. Velocity was found to have risen 50fps, or near offer, which must all be down to increased efficiency, as the original standard spring was retained. Consistency was surprisingly good, considering the rifle had only fired a dozen shots since being rebuilt, and so I was not expecting it to be as tight as it was.

So all in all, a very enjoyable and productive day spent tweaking and tinkering.  :)



Have any of you guys got half finished abandoned projects on the go, but lack the motivation to get 'em sorted??

Offline pigeonmenace

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Re: An enjoyable day spent tweaking.
« Reply #1 on: January 25, 2012, 07:35:10 PM »

Nice days work Gareth  8)

I've got into tweaking over the past few months and it really is very satisfying.

I'm curious about these Chinese airguns.  I wonder if I could tweak up an SMK 25 pistol in a similar way?  ie reducing clearances, adding shims where necessary?   

Hmm, got me thinking.  Ouch.  :o
Weihrauch HW40 PCA
Crosman American Classic .22
Crosman 2240 Custom .177
Webley Tempest .22
Umarex CP88 Black

Offline Ieazo

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Re: An enjoyable day spent tweaking.
« Reply #2 on: January 25, 2012, 07:46:30 PM »
Oh you know I do, but it's not motivation it's time that I lack :(

Hope to finish up that .22 G25 soon though, then thats me all sorted.

Springers:- SMK VXS19 - 18 GRT3 trigger & HW97k V-Glide
PCP's:- Uncle Barry's Daystate Mk3 (FAC), BSA Superten & AA S510
FAC :- Anschutz 1417 .22LR, CZ 452 .17HMR & Tikka T3 .223 1:8
Shotguns:- 12 Gauge Bettinsoli Xtrail O/U & Beretta A302 Semi-Auto

Offline GaryL

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Re: An enjoyable day spent tweaking.
« Reply #3 on: January 27, 2012, 07:40:56 PM »
I just can't help fettling my guns,polishing here and there  ::) Just have to be carefull with the power  ;) ,It's just satisfaction when the gun's operating smoother than new & getting a silencer to be  quieter than standard.

Offline Tallerhauzen

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Re: An enjoyable day spent tweaking.
« Reply #4 on: January 27, 2012, 11:46:05 PM »
Great write up Gareth.
You seem to be a natural tinkerer.
I'm fully aware of your abilities and find your knowledge fantastic.
I wish I knew half what you do.
I expect you learn all the parts and places via doing a project like this
HW100sk in .22
MTC mamba 4-16x50
Deben 9-13" bipod
Ultra fire 501b red lamp
Homebrew night vision

Offline Gambo

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Re: An enjoyable day spent tweaking.
« Reply #5 on: January 29, 2012, 10:26:15 AM »
Gee, Shucks Phil!!

Offline Gambo

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Re: An enjoyable day spent tweaking.
« Reply #6 on: February 03, 2012, 07:26:14 PM »
This little rifle never ceases to amaze me........so much so, I just can't shop shooting it, and find myself picking it up at every opportunity just for a quick plink in the garden.

Down the club on Monday, it was printing one hole groups with open sights, using Superdomes (Kris will verify that).

Then today, I found a tin of those dreadful Rothery 5.6 Wasps, and just out of curiosity, I fired a few through the SYNXS to see what they went like.

I was astounded.........they were nearly as accurate as the 'Domes.......and the only time I have seen those crappy pellets give anything but shite groups.

So I then went and fetched some of my genuine ELEY 5.6 Wasps, and although they were tight going into the breech, and so gave a noticeable reduction in velocity, they grouped really tightly.



This little Chinese rifle is not in the slightest bit pellet fussy.....and after a bit of a fettle, now shoots REALLY sweetly........

............and all for the price of a bag of chips!!!!!  ;D ;D

Offline Ieazo

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Re: An enjoyable day spent tweaking.
« Reply #7 on: February 09, 2012, 10:00:08 PM »

Nice days work Gareth  8)

I've got into tweaking over the past few months and it really is very satisfying.

I'm curious about these Chinese airguns.  I wonder if I could tweak up an SMK 25 pistol in a similar way?  ie reducing clearances, adding shims where necessary?   

Hmm, got me thinking.  Ouch.  :o

I've done a little SMK springer pistol, pm me your email addy and I'll send you some decent pics. They were taken before this forum and are too high resolution to post of I resize them I think they will go all blurry. It was dead easy to do and good fun with a huge improvement in the feel of the pistol.
Springers:- SMK VXS19 - 18 GRT3 trigger & HW97k V-Glide
PCP's:- Uncle Barry's Daystate Mk3 (FAC), BSA Superten & AA S510
FAC :- Anschutz 1417 .22LR, CZ 452 .17HMR & Tikka T3 .223 1:8
Shotguns:- 12 Gauge Bettinsoli Xtrail O/U & Beretta A302 Semi-Auto