How much barrel length loss going AI??

[LongDraw]

From what I understand you need to adjust the headspacce when going Ackley improved. Typically how much barrel length do you lose when this is performed??

 

[Andy]

Zero. You lose absolutely nothing.

 

[Rembo]

you lose .004" minimum...or...basically nothing...unless you're the type that wants your factory stamping in the original location or your iron sight holes on the top..then you'll lose one thread or about 1/16" of an inch depending on the pitch of your barrel thread....factory barrels without iron sight holes are sometimes turned a third or a half turn to put the factory stamping under the stock and then restamped with the AI designation.