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Question about AR-15 BCGs
willonkauai
Member Posts: 14 ✭✭
Can you take BCG from a 5.56 and use it in a ar chambered for 7.62x39 or 6.8spc ?
Comments
Correct. The bolt itself is the only part which needs to be replaced because of rim diameter differences.
7.62x39 = 0.447" diameter
6.8 SPC = 0.422" diameter
Depending on the cost though some find it easier to replace the whole BCG as a matter of course. Six of one, half dozen of the other.
In ascending order of cost though, many folks just keep the complete upper on hand in order to just push the pins out and have a complete new upper in place.
Best.
The spring and buffer may also have to be replaced, if so, a complete dedicated upper would be the best way to go - but I know how that goes - new uppers seem to attract new lowers.
Never seen one yet that has needed changed, in that area. The pressure is controlled by the size of the gas port in the barrel.