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Airguns by Make and Model > Cometa Airguns
Ancient Cometa rebuild
AR1911:
That upright receiver hole is for a bolt that goes through the trigger guard>stock>receiver to anchor the rear of the receiver to the stock. It serves no other purpose.
AR1911:
--- Quote from: TF89 on June 03, 2023, 01:07:10 PM ---I know next to nothing regarding how the barrel is mated to the breech. I once tried to switch out a barrel on an older Chinese springer. In that case a cross pin was used to secure the barrel to the breech. It was very hard to see the pin as it blended almost invisibly. My attempt was not a success, even after driving out that pin, which was hard to do, I could not get the barrel to budge. I didn't have a press of any kind, and I'm sure it would have made all the difference. I think using a press will give you the results you seek, just make sure there is not a cross pin.
--- End quote ---
Good points. I see no hint of a crosspin here. Based on the finish of the rest of the gun, I can't imagine such being that well blended.
I do have a good 10-ton press here. I'll make a fixture and see if I can coax it to move.
Thanks for the input
AR1911:
So, I made a press fixture for support and also a piloted pusher. I loaded up the old barrel/breech-block and pumped up to 3 tons. I was afraid to go much more because the breech face and the end of the barrel are not 90-degrees to the bore, so the load was a bit unbalanced to one side. Nevertheless, I added some kroil and heat while it was loaded, and then added more pressure (back up to 3-tons plus a little more). It finally popped and I was able to push it on out easily.
You can see a divot of metal that came out. I can't ell where that came from. Maybe the Invisible Pin.
The Crosman barrel was slightly bigger at .507" OD, so I had to ream out my fixture a little, then loaded it back up. Using the same technique - pressure, Kroil, Heat - it would only give up about .015". I took it out of the press to look it over and saw there acually WAS a crosspin. I guess the slight movement was enough to make the joint visible. I drove the pin out and the barrel came out without further drama.
Now I just need to turn the new barrel down to fit, press it in, and then dress the breechface to match the angle of the original.
I'll need to cut the pivot bolt hole into the underside of the barrel
One thing I need to determine is how much to allow for the breech seal. As I have it now, the breech seal would need to be:
13mm OD
8.8mm ID
2.5-3mm deep/long
Is that anywhere close to a standard size? Is there a list or table somewhere I can use to fit this to a standard size?
Barring that, I guess I could turn some from teflon or delrin. Is there a better material?
Gimmly:
Hi from Spain.
The size of the break seal is a standard o ring,is OR 6,60-2,40 NBR 70SH
I don't know why the forum won't let me post links (maybe because I'll have few messages) but you can search in Youtube "Restauración de una carabina Cometa V" and you can see a complete video of restoration of a cometa V model .
Cometa 5 or Cometa V it is the same model.
If you have another question about the cometa 5 you can ask to me, here in Spain it is a very popular model for many years.
regards
AR1911:
Thank you sir, that is very helpful.
My biggest issue right now is how to disassemble the powerplant. Perhaps the video will help.
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