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Author Topic: New BSA 16-3466 barrel issue from Knibbs  (Read 781 times)

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Specman

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New BSA 16-3466 barrel issue from Knibbs
« on: January 01, 2018, 11:18:54 PM »

Hi,
I ordered a replacement barrel for either a BSA Supersport or Meteor

When I tried to fit the cocking linkages the washer between the plates didn't fit so I machined off an acetal, thinner replacement. Well, I'm back to the Meteor not cocking again but in the process of repeated cocking the link plates buckled. Looking closer I compared barrels, the cocking slot in the old barrels is 6.44mm and the cocking slot gap in the new one is 5.04mm! Anybody else come across this?  :sign0163:

Also, why are the cocking lever plates so butter soft? They are rubbishy! You can bend them by hand! I would be interested in a solution for both these issues. Anybody make new levers from decent steel? Perhaps there is a quicker, better solution.

To my mind the BSA Meteor is one of the hardest guns I've worked on (mind you it was completely knackered to start with!) it's taken about 9 months so far, mainly because the parts are so crap with very sloppy tolerances, just bent bits of tin! Makes the Chinese guns look good! I don't remember my Meteor as a kid being so bad. I should have given up time wise, and definitely financially months ago on this, should never have started it to be honest, but now I'm just plain stubborn!

I have had it shooting with open sights and I loved it, trouble was the finish I used (plasticote) just was not durable. I sprayed an old Diana pistol 5 or 6 years ago and for some reason I figured I used Plasticote, but now I'm wondering if it was Hammerite (both old cans in the shed), anyway the finish on the Diana is beautiful, like baked on, rock hard and very durable. The plasticote was like butter, started coming off immediately, so I stripped it and plan to start again now I know it's a shooter. Anyway I was machining some top hat and Spring guide kits for the Meteor and wanted to test them, make sure they worked with the standard Spring, so I put it back together. It wouldn't cock! You guessed it, I had made some small error which I corrected, still didn't cock! So I thought, OK, as a bench line lets go back to standard parts. Still wouldn't cock! So I'm back to square one again.  :03:

Comments and advice welcome and appreciated. Thanks
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RANCiDTOM

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Re: New BSA 16-3466 barrel issue from Knibbs
« Reply #1 on: January 02, 2018, 10:56:57 AM »

If it won't cock with standard parts then I suspect either a trigger sear or piston fault.
As regards the cocking links being too soft are you 100% certain you don't have a spring in there that is too strong? This could also be a problem with the cocking, if the spring is becoming coil bound the sear will not engage on the piston.
Is the spring guide correctly locating on the cross pin?
You may have a Mk5 barrel which if I remember correctly has a narrower cocking link slot, it should be fine with the correct linkage and spacer washer. If the link plates are bending I suspect you have the wrong spring fitted. Does your stock have the  hard plastic thrust pad stapled in place? This should keep the cocking linkage in the correct alignment when cocking, if missing it can cause the gun not to cock.
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Specman

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Re: New BSA 16-3466 barrel issue from Knibbs
« Reply #2 on: January 03, 2018, 05:18:36 PM »

Thanks once again for the reply.
I have had the gun functioning perfectly, but as i said I decided to take it apart. The spring should be a standard BSA spring, that is what I ordered. Do you know the overall length and amount of coils in a standard spring by chance? You may be right about coil bound with a top hat, but I have reverted back to full standard bits and still no joy. The spring guide is locating correctly I am sure of that. Yes, I have the thrust pad on the stock and thank you for identifying the MK5 barrel.

When assembled and cocking I take it that the cocking lever bumps into the front end of the sear (hence the horrible Meteor 'clunk' when cocking). Do you know the relationship between the rear of the sear and the spring guide steel washer? There seems to be a cut or 'slot' in the cylinder, behind the trigger assembly and you can see the spring guide washer through there. Is it meant to clear the washer or bump over it as it cocks? Just trying to visualise what's happening to the sears as the gun is cocked.
I might order some more link plates from Knibbs. Will a MK5 cocking linkage fit better?
Thanks for your time
Mark
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RANCiDTOM

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Re: New BSA 16-3466 barrel issue from Knibbs
« Reply #3 on: January 03, 2018, 07:05:37 PM »

Not sure as I don't have a totally standard Meteor to hand at the moment to check against. I'll try to dig my old Mk4 out in the next few days and see if I can see what you mean but from memory the linkage doesn't get as far back as the sear when cocking, the sear is engaged by the spring into the slot on the piston. Are you certain you have the right linkage for this?
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Specman

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Re: New BSA 16-3466 barrel issue from Knibbs
« Reply #4 on: January 03, 2018, 10:58:29 PM »

Gone the other way now! The gun now cocks (replaced the spring) and now does not fire!  :sign0085:
I had this happen previously and adjustment of the trigger screw sorted it out, however no joy this time. The trigger plate doesn't seem anywhere near the sear to disengage it. I will post pics and update my progress tomorrow if possible.  I took my life in my hands trying to de-cock it, took best part of an hour!
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charlie caller

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Re: New BSA 16-3466 barrel issue from Knibbs
« Reply #5 on: January 04, 2018, 11:52:56 AM »

The old man gave me a Meteor he had acquired the other day, it needs the barrel pin replacing, so it sounds like I may have fun, hope you get yours sorted mate.
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Specman

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Re: New BSA 16-3466 barrel issue from Knibbs
« Reply #6 on: January 04, 2018, 10:35:46 PM »

Had another go at it tonight and gave up!
Compared the old cylinder to the replacement part and the internal diameter is different.

The old MK5 cylinder (TH serial number gun) has an internal diameter of 25.35mm
The replacement 16-2128 cylinder I got from Knibbs has an internal diameter of 25.85mm, 0.5mm difference.

The gun either cocks and won't fire or wont cock at all. I have replaced the sear, trigger spring, cylinder, mainspring and spring guide. The meteor trigger is so basic, surely I haven't assembled it incorrectly. How many ways can it fit anyway?

Interestingly when the gun has cocked the two 'faces', between trigger plate and sear are not engaged in anyway. pulling the trigger does nothing. The piston slides a little two easy into the cylinder. The more I think of it then it must be the new cylinder, it is the only part replaced since the gun fired sweet as a nut!

Here is a pic i got off the web of my trigger arrangement. I fit the rear stop rivet first, then the trigger blade and plate and finally the sear pin. I'm sure that is the correct sequence.

As for the barrel, I think I will get it machined out, not happy with the more narrow slot. with the barrel shut the cocking levers stand clear of the action.
« Last Edit: January 04, 2018, 10:38:12 PM by Specman »
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RANCiDTOM

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Re: New BSA 16-3466 barrel issue from Knibbs
« Reply #7 on: January 05, 2018, 10:14:50 AM »

OK it would seem to me that the reason the gun is not cocking reliably will be that the piston is now too slack a fit in the cylinder.
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Specman

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Re: New BSA 16-3466 barrel issue from Knibbs
« Reply #8 on: January 05, 2018, 11:44:33 AM »

I agree Tom
But this is a MK5 cylinder, Getting an oversized piston will be the issue, I will speak to BSA.

Well I spoke to Dean, the Airgunsmith at Knibbs (nice guy, very knowledgeable ) and he checked out a few measurements for me. We measured the piston sizes and the MK6 piston is actually smaller than the MK5 which blows my theory out the window that I had a 'late' gun mid upgrade.
So I have a piston too loose for my cylinder, so what to do about it that won't cost more than the gun is worth!

It's become a bit like 'Triggers Broom'!
« Last Edit: January 05, 2018, 10:28:19 PM by Specman »
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RANCiDTOM

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Re: New BSA 16-3466 barrel issue from Knibbs
« Reply #9 on: January 05, 2018, 02:03:51 PM »

I have just pulled a Mk4 cylinder out of my parts collection and measured the internal diam as being 25.78-25.82mm depending where I measure. I have a visibly worn piston that may or may not be associated with this cylinder (but I think it is as it was in the same box of odds'n'sods) which has a 25.2-25.3mm skirt so 0.5mm clearance looks possible although I can't vouch that this piston and cylinder will actually cock and fire. It seems excessive and without stripping my working meteor I can't say further but BSA won't supply you with an oversize piston I would put a tenner on that and I'm not a betting man. J.Knibbs appears to be out of stock of Mk1-5 pistons so it looks as though the only option would be Protek or get an oversize made, possibly get the skirt "buttoned" (not my favourite but it's possible) or have the skirt welded and machined for a better fit. Do this with caution as it will affect sear engagement as the effective depth of the sear flat will be increased and the engagement slot will need to be profiled correctly to ensure safe cocking.
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Specman

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Re: New BSA 16-3466 barrel issue from Knibbs
« Reply #10 on: January 05, 2018, 10:46:47 PM »

Thanks for coming back to me Tom
So it looks like my original Metoer was an early MK5 or at least used a MK4 cylinder and piston, so this would explain why the MK5 cylinder is oversized. I have measured the original piston andit is by no means round on the bearing surfaces, but is 24.9mm on the horizontal axis and 24.27mm on the vertical at the rear and 24.77mm and 24.86mm at the front. my piston head is also too small for the new cylinder. When I put the piston in the old cylinder it is 'snug' and you need to be careful you don't pinch the 'o'-ring, on the new cylinder it just pops in, barely touching the sides.
Without a doubt, this piston (possible MK4 in a MK5 build) will not function in a MK 5 Cylinder.
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Specman

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Re: New BSA 16-3466 barrel issue from Knibbs
« Reply #11 on: January 20, 2018, 10:49:44 PM »

Well I finally got a replacement piston for the Meteor and fitted one of Knibb's piston heads that screw on. After a lot of messing about with the adjustment screw I got it to fire, sometimes! It cocks OK and the sears engage but when I could fire it it was a heavy pull. Also when it did hang, slackening off the rear stock screw caused it to fire.
I have now decided it needs a new trigger sear, so as this has become a bit like 'Triggers broom' in Only Fools & Horses i have decided to break it! Any love and nostalgia I had for the BSA Meteor has been consigned to history and that is where it can stay. I'm going to put the .22 barrel on the Supersport I restored and use that with the open sights. The gun shot fine with the original barrel and cylinder but they were so badly rusted they couldn't be left. The failed paint job (product confusion) was disheartening after putting so much effort into it. Although I stripped it all back I lost enthusiasm about starting again. The replacement cylinder and barrel was a luxury work around but this problem regarding cocking and firing has me beat! No, me and the BSA Meteor are finished for good! Do you know, the only original parts in that gun are the stock and the trigger plate and blade, oh and a few pins!

thanks for all your help guys. 
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admbnm

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Re: New BSA 16-3466 barrel issue from Knibbs
« Reply #12 on: January 21, 2018, 11:54:55 AM »

a vernier guage is highly recommended to double check with knibb's bsa barrel fitment specs,and anything else they sell as fitting a bsa.
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Specman

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Re: New BSA 16-3466 barrel issue from Knibbs
« Reply #13 on: January 21, 2018, 09:03:58 PM »

Yes I have discovered the variation between 'identical' parts! I have also had a thought regarding the trigger firing or not firing. I think that the rear trigger pin (rivet) needs to rotate with the trigger plate against it when you pull the trigger.
I had to fit a new rivet and I think it's binding against the stock stopping rotation, might be a bit long.
If I can be bothered to have another go I will test the theory.
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