For my Husqvarna 1640 I use these loads and they both shoot exactly an inch group every time (and also to the same POI so I can swap between them at will)

180 grain Interlock SP with 57.5g of H4350
Federal brass / CCI primer OAL 3.25
Chrony: 2819fps

150 grain SPBT interlock with 60.0g of H4350
FED/CCI OAL 3.25
Chrony:3018fps

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