Author Topic: .22 stealth  (Read 6792 times)

Offline Scuba1

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.22 stealth
« on: May 02, 2011, 09:58:10 AM »
I brought back a .22 air rifle from a shooting meet that belongs to a friend of mine who got it a while ago second hand and does not get on with it very well as it is very inconsistent. So I said I'll take it with me and when i have a bit of spare time, I'll have a look at it. I stripped it down today and the previous owner must have had a go of "tuning" it and made a right dogs dinner of the job. Most of the parts in there look like they have been chewed to measure by a badly trained rat and a lot of it will have to be binned and made from scratch. I don't like the sloppy spring in there either or the mixed hammer made in two bits. One is brass and the other bit looks like it is made of some sort of ex plastic
pipe fitting. So I'll make that out of aluminium in one bit. The crown looks like it has been filed to size by someone with Parkinson and the barrel, even though it is a Walther Lothar match barrel will have to be trued up and machined to a proper size and the guide surfaces where the hammer is going to run turned down and polished. So By the looks of it I have a bit of a job on my hands to turn this ugly duckling into a proper shooter.

Here is the " before" picture.


Today i stripped it down and gave all the bits a good dose of looking at.




Last but not least the "crown" looks more like a old wet bowler hat then a crown to me.



But watch this space. I'll carry this thread on as I go along turning this thing into a gun.

ATB
« Last Edit: May 04, 2011, 04:29:15 PM by Scuba1 »
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Offline Brass_Machine

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Re: .22 stealth
« Reply #1 on: May 02, 2011, 11:18:36 AM »
I have a renewed interest in air guns... I like to target shoot, these may do what I want...

Will be watching with interest.

Eric
Science is fun.

We're all mad here. I'm mad. You're mad.

Offline Scuba1

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Re: .22 stealth
« Reply #2 on: May 02, 2011, 01:26:51 PM »
Untill about 2 years ago I was never that much of a fan of air rifles. Sure, I had one in the cupboard back in Spain to knock the odd rat out of the chicken pen but that was as far as it went. The I came to the UK and was introduced to PCP rifles and I bought one of them just to keep my eye in as I have a gun and hunting license for Germany and for Spain but not for the UK so had to leave my powder burners back in Spain when I came over here. But in those two years those things have grown on me and now I make air rifle bits and tune guns for the target shooters here, much in the same way that I used to do some work for the powder burning target brigade back home. A year ago I found out that they are quite capable for small game hunting as well so, yes I do miss my rifles, but those air guns are not all bad and I am going to keep mine and take it with me when I leave here again.
With mine I won the 100 yard easter egg shoot last weekend, so I must be doing something right.  :wave:

Michael
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Offline Scuba1

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Re: .22 stealth
« Reply #3 on: May 04, 2011, 03:08:18 PM »
So I started with the barrel. Trued it up ( thank you sir Bogs for the idea with the nudger :bow: ) That thing is a pretty nifty tool to have around. Again using the nudger I got the barrel running within 0.002 mm in my 3 jaw chuck. I was happy with that and it saved me changing chucks over for what was to come next. I faced of the end and got rid of the chewed bits and recessed the crown and put a small 45 degree chamfer on the insode and out and then with the help of a carbide tipped dead centre and a spot of jeweller's rouge I cleaned up the chamfer on the inside of the barrel so that all the lands are trued up. I did  not have time to do more today but will have a look at the other end of the thing tomorrow and change the hammer guide.






All in all there was not much in the way of swarf making today as it is just fine touch up stuff at the moment, but the god of swarf should still be happy, as I made a few buckets full of the stuff at work today. :ddb: :ddb:

ATB

Michael

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Offline Imagineering

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Re: .22 stealth
« Reply #4 on: May 04, 2011, 07:43:29 PM »
then with the help of a carbide tipped dead centre and a spot of jeweller's rouge I cleaned up the chamfer on the inside of the barrel so that all the lands are trued up.
Michael

I'm speaking from the experience that I have attained as a Smallbore Target Shooter at National Level, (Anshutz 0.22 Rimfire), and Fullbore Shooter at Local level.
Our local Gunsmith, who also competed in both Small and Fullbore, would crown our Barrels square to the Bore, not Chamfered.
Experiments have been conducted within our controlled 25 Yard Range, (indoors, no wind & Benchrests), which strongly indicated that a 'Square Cut Crown' is much more accurate than a 'Chamfered Crown'.

A few years ago, I had a .223 Cal Target Rifle which would only shoot 150mm 5 Round Groups at 300Metres with the original Factory Chamfered Crown.
This Rifle, after being Block Bedded  and Square crowned, then achieved consistant 50mm 5 Round Groups at 300Metres in still conditions.
All of these Groups were shot off a Bipod from Prone Position with self loaded Ammunition.

Murray.

Offline Scuba1

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Re: .22 stealth
« Reply #5 on: May 05, 2011, 02:08:37 PM »
Thanks for the heads up. as from factory, the Walther Lothar match barrels come with this chamfer so I just renewed it. I'll try it out as it is now and then if the results are not up to my liking, change it to a sharp end. Having looked at my 22-250 and that has a light chamfer on it as well and that shoots sub MOA. See how it goes but I'll keep your tip in mind and change as required.

Thank you

Michael
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Offline andyf

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Re: .22 stealth
« Reply #6 on: May 05, 2011, 03:12:06 PM »
Michael and Murray, my curiosity was aroused, so I had a look at my .22 rimfire target rifles, an Anschutz Match 54 and a BSA Martini Mark III. Both are chamfered, and though long in the tooth, still shoot more accurately than I can.

Andy
Sale, Cheshire
I've cut the end off it twice, but it's still too short

Offline Scuba1

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Re: .22 stealth
« Reply #7 on: May 06, 2011, 09:54:26 AM »
Thanks for the heads up. as from factory, the Walther Lothar match barrels come with this chamfer so I just renewed it. I'll try it out as it is now and then if the results are not up to my liking, change it to a sharp end. Having looked at my 22-250 and that has a light chamfer on it as well and that shoots sub MOA. See how it goes but I'll keep your tip in mind and change as required.

Thank you

Michael
Skype: scuba-1

Offline Jonny

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Re: .22 stealth
« Reply #8 on: May 06, 2011, 07:18:39 PM »
Looks too long for the standard Lothar basic barrel. In fact it looks like a Lothar Walther bog standard spec from tubing, used to be 15 each buying 50 off in a crate still got two left.

Though your intensions are right, you have gone about it the wrong way. You should have trued up from the bore not the o/d, its not uncommon to find out of centre bores more so on tapered barrels on cheap centrefire.
Next question has the choke been cut off?

A chamfer is easier to do than a smooth unrounded flat face, i have a tool does it in 3 secs.
To back up above the most accurate barrel i have ever come across for air rifles was an old Hammerli hammer forged from the 70's - 5 shots at 55 and 60 yards not even leave a .22 hole. Bent like a banana at one time, straightened and twanged like a tuning fork with polished 1200 grit flat face at muzzle. My 7k Anchutz and March's wont do that on a good day.

Changing the weight of the hammer will affect the power curve as its only a knock open unregulated rifle. ie harder to open the valve at 232 bar than at 70 bar with same preload and hammer weight. = no power the higher the pressure put in. Normally set right an unregulated will gradually rise then tail off again. Also have to keep dumping air in bottle to unscrew the knock open valve to adjust, right pain.