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Thread: Aluminum13-XX FTP Kit from S&A

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    Senior Member Doc Sharptail's Avatar
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    Sun Jan 1 2012
    Up The Escarpment

    Aluminum13-XX FTP Kit from S&A

    While waiting for my latest parts order for the 78's to get here, I decided to do a little work up with one of the kits I had ordered in from Eric a while ago. Figured I'd go with .177 as I'll soon be doing one of the 78's in that caliber.

    I wanted to achieve a couple of things:

    Get close to 500 fps, with minimal pumps.

    Get close to the 560-600 fps that most of the European competition guns are tuned for.

    Platform is a 22-89 back-packer, with 24" .177 bbl, and SBK steel breech kit aboard.

    I went with the stock 13-XX hammer spring and valve-stem return spring, just to try and get this into a neophyte type of experience for those considering it for the first time. I didn't port the exhaust hole in the valve, or manipulate the the stock transfer port in any way. It is a 22-89 transfer port. I did not modify the piston, or valve in any way.

    For you guys that have been around for a while, there are modest volume gains to be made over what's already in the package. The valve face could lose up to .008" or so, and still be fine. The piston face could with-stand about .006". I'd reduce the diameter of the rear piston half of the piston assembly, by a couple of thou, just to smooth out the pumping a little.

    I tested with the 8.2 gr RWS Meister.

    5 pumps averaged 513.2 fps over ten shots. Just a hair over. Going to a heavier pellet like the Cr. Ultra Mag would probably give numbers in the upper 480's.

    7 pumps averaged 584.8 with the Meister- very close to what the big names are tuning for in their upper end competition guns.

    I think the package is a good one. The lock-nut system is robust and strong, with no slipping of the final adjustments. The new parts should be dis-assembled, and cleaned before installation- there is a bit of aluminum powder in the parts from the machining process...


    Doc Sharptail
    Last edited by Doc Sharptail; May 02 2013 at 02:04 AM.
    "Ain't No Half Way"


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