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I still dont know what the problem with making this a sticy. muttman
yes a long way back. and Im still working on the .308 and the 5.56 is in the finishing stages. time does fly when you are haveing fun. but still fun. muttmanI here you it and a couple other posts were what started the the whole calibure conversion forum. I originaly posted this thread in the build it your self area and it was moved here when this area was opend.
the chamber pressures thread should be a sticky as well . HCPOOKIE and myself and many other members have put a lot of info into that thread. I should copy it incase something were to happen.
this is one of the few sites that has this kind of info and talk avaliable. Those two threads should be a must read for any one thinking of a conversion.
there are a few numbrs in the thread that should be edited as new info was added on the CUP vs PSI in regarding military info and how the 308 and the 7.62x51 nato are closer than originaly thought. I cant believe it was that long ago when I started this thread. damm things have changed. Im glad I couldnt post pics back then LOL
I found this very interesting
The AK Forum :: Log in
the bolt second from the right is a 308 Galil bolt.
It appears identical to a standard a 7.62x39 bolt with only the bolt face inlarged!!!
I believe it is a spring loaded pin.
This should calm some fears that a 2 lug bolt is over loaded in 308. there are some sources for these bolts as well.
I wouldlike to see some specs on the ammo these gun shot in actualy use. they were also sold in the US in SA mode in this configuration I believe.
Both the Valmet and Yugo 308 bolts are longer in head/lug but only the Valmet increases the size of the left bolt lug too. The Yugo has the right lug increased with the bolt head but the left bolt lug is standard size. I'm not certain but I got the impression that most of the 308 Galil failures were the receivers but looking at the bolt I wonder. The 7.62x39 Saiga has a two lug bolt the size of the AK74 bolt. For a two lug bolt, that one might be easier to open up for a larger rim.So there are some reported failures of Galil's in 308 interesting. well so much for that. On the Valimit I think the bolt is bigger mainly so the barrel can be moved forward and not loose trigger guard clerance. I could be wrong. Im aware of the the differances of the m77&76 and theres pics some were in this thread.
as far as 5.45 bolt being heavier Im not sure why? the 223/ 5.56 run the same if not higher pressure ( I think what is the pressure of 5.45?) and they seem to be ok with the same smaller lug. the Sagia 223 must have passed CIP testing I belive that bolt is the same.
I have been looking really close at the 5.45 bolt lately, it could possably be opend up to a 308 win size face and might infact be stronger with the much longer RH lug and slightly longer LH lug. it would also allow the barrel to moved sligtly forward giving more finger clearance. I wonder if the bolt on the 5.45 is longer to help feeding rather than strength possably?? It would give a higher bullet height before it reaches the chamber.
In exploring the 5.45 bolt for conversion use ive noted the ramp on the bullet guide will need to be moved slightly forward. the lug engagement on a yugo M72 trunion is very good and the bolt tail is pointing straight back.
Im planning a 243 win on a two lug bolt build in the near future if the 5.45 bolt is stronger then it should be used. The small bolt stem could also be sleaved for a larger bore carrier and that sleave could be fitted for a more percise more accurate fit.
also that sleave might be used to retain a spring loaded pin while im at it. A sleave would also be a good way to lengthen a bolt. I could gain a little finger guard clearance with the bolt lug to bolt face increase and if i sleaved a small stem bolt and made it longer I could move the trunion forward. I would be pretty close to gaining back that lost 1/2 or so of mag well required to use a 308 length mag. I might be able to leave the center support and mag latch/trigger guard in the origional location. HMMMMMMMMM
I wish they were cheaper.