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Old 01-18-2013, 10:35 PM   #1
Clifford
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Join Date: Oct 2012
Posts: 86
Default BAM B-50 Tweaking/Tuning

So after hearing Mike M. had some .22 b-50's in stock I had to try one. Ordered from him bone stock, straight off the boat from China.

When it first arrived it held some pressure but leaked down to around 1k

so I tore it down (sorry no pictures as I had just gotten it) and put in a replacement o ring that it was shipped with. O ring #18 in exploded view here:

http://i99.photobucket.com/albums/l3..._schematic.jpg


This solved the leaking down problem but the next day the fill valve o ring and breech seal blew as well. I will say that the #006 seals were probably in the worst condition on this gun.

Once I let it sit overnight and knew it wasn't leaking down I did some rough chrony testing with 2.8k fills. Sorry, I'm still figuring out my chrony lighting situation so I don't always get the best strings but the gun was shooting 15.89gr JSB's at a high around 900fps and stable around 885fps, easily hitting between 25-28fpe out of the box (not bad)

Moving forward, I opted to look into 2k fill tweaks for the b50 since I do not have a 4500psi tank (yet)

I was lead towards the "book" found here:

http://www.toolfarm.no/ViewFile.aspx?itemID=430

And placed an order for the McMaster-Carr spring, part #94125K125

They come in a 5 pack and are relatively inexpensive.

In the next section I'll discuss installation procedure for the spring and my terrible chrony work will rear it's head yet again.
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