1552
Typical modifications include a match-grade barrel fitted with a recoil compensator , electronic optical sights , match-grade hammer and sear , a tuned trigger , and " skeletonizing " ( cutouts to reduce weight . )
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 None