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Posted: 5/26/2011 3:23:01 PM EDT
| how loose should my fsb be on my barrel before it its pinned and is there a way to tighten this or will it tighten and seal off better when i install the pins, mine slides on with no effort at all. thanks for the input |
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Does it rattle?
Seriously, are the pin holes drilled already? If not, block alignment can be very tricky as a DIY project when drilling the pinholes, plus needing a taper reamer. If the holes are there, then the pins should pull the block downward, making the top tight against the barrel. |
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LocTite the base before sending home the pins, allow it to dry and it should be snug.
Remember one thing, once the FSb is pinned and the loctite is setting you want to use an air can with a thin hose on it through the upper receiver and into the gas tube to blow out any possible loctite from the gas port. |
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FSB should not be loose.......barrel is supposed to be .7495 +0/ -.0007 and the FSB should be reamed to .750....it should be a very snug fit....and if they have pin holes that were not drilled together........most likely they aren't gonna fit. I can't find the FSB drawing now....but I'm sure it is on my office computer...I'll look in the morning.
When I make a barrel with an FSB I usually make it about .0005 interference fit and heat the fsb for install prior to pinning......with that kind of fit....you really don't need to pin it....  but I do anyway
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