GTA
Airguns by Make and Model => Diana Airguns => Topic started by: Harpoon1 on April 03, 2017, 08:46:07 PM
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Have the 48 disassembled, and actually everything looks great, except for the breech seal which appears to be missing altogether. And was apparently my problem all along!
So, any tips, tricks for getting a new breech seal back in? Undamaged? ::). Yep, I've already destroyed the one, and only one, I ordered. For some inexplicable reason I ordered 4, 5, 6, of everything else, but only one breech seal! So, back on hold for few days waiting on the new ones to arrive. Maybe get it wet this time, make it slippery? Heat gun? Sacrifice a goat? I've tried driving it in, first with a dowel, then a punch, and a nut driver(had high hopes with that but it was probably just the wrong size), all gently at first. Then I thought I could, maybe, just maybe, use the cocking lever as a rachet and lever it in. Nope! Then I went with the bigger hammer! And now you know how that went. Any ideas on doing it an easier way, or the right way next time? ;D
Also, if I did the math correctly, looks like I'll have around 6mm of wiggle room leftover inside the piston with the new spring and tophat. Would slipping a washer between the tophat and piston help? Or, is the tophat alone enough? Maybe a second washer on the spring guide?
Thanks!
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At the risk of sounding REALLY foolish, are you SURE you had no breech seal in the beginning? If you have one already in place it's not likely you'll have space for a second.
As far as the spring goes, I wonder if you received the correct spring. Did you request a low power kit? That is usually accomplished with thinner spring wire not a shorter spring. There is normally an inch or two of preload on the spring.
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Thomas,
I wouldn't bet my life on it but, I sure think it was missing. Piston seal and spring are in great shape, and a missing breech seal would explain 100-200 fps loss of speed. Of course I'll get achance to look at it again! ;D
Seeing how much preload there was taking it apart with the old spring, I'm guessing there will still be about an inch or so using the new spring. Mostly because its that much shorter than the stock spring uncompressed. And who said anything about "low power"! ;D The new spring is actually longer than the stock spring when fully compressed. While it has less coils, 28 vs 31, it has thicker wire 3.65 vs 3.25. So, compressed, the new spring should be 102.2 mm vs 100.75 for the old spring. If Im calculating that right?
So, that should leave me, after going over it again, 4 mm (and not the 6mm I said earlier)leftover of wiggle room inside the piston.
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I can only guess you ordered a few breech seals this time around.
Be sure the area the seal goes in is clear of any remains of the old seal. I would also assume if the seal was completely missing, you would loose more than 100-200 fps. When looking into the area the seal seats in, you should see nothing but the metal cavity with no other "stuff" in it.
You could try putting a thin coat of silicon on the new seal and it should just slide in place. I have replaced them before with no issues like you are having.
You should try the gun with the new spring and see how it shoots. It my be just what you are looking for. The spring on the 48 is under a good bit of pre-load so it may not be necessary to take it to the limit with the addition of extra washers.