I purchased a Howa 1500 HS Precision in 300 Win Mag early this summer and finally got it out to sight in this weekend. I has some Federal Premium 180 grain and some Sako Gamehead 180 grain. After my first shot with the Federal, the bolt would not open. I had to use a small rubber mallet to finally get it to open. The cartridge had fed fine but would not release the bolt. When it finally opened, the extractor flipped the cartridge out as it should. This happened on my next 4 rounds. They all fed no problem, but after the shot, the bolt would not open without the aid of the rubber mallet. I then switched to the Sako and had the exact same issues. I put 3 rounds of the Sako through the gun and decided that was enough. After looking online, I gave it a good cleaning including the chamber. Out of curiosity, I tried to feed the fired brass into the gun and the Federal would not even chamber, stopping about 1/8 of an inch from allowing the bolt to close, and then required the rubber mallet again to get it back enough to eject. The fired Sako brass was slightly better and I could get it to load in completely and close the bolt but could not get the bolt open again without really yanking on it. I tried the fired brass in my Bergara 300 Win Mag and it fed and extracted with no issues at all. So it appears that the ammo is not the problem. I have reached out to Howa's warranty department but not heard back. Anyone have any thoughts on what the issue could be? I am fearing the chamber may be out of spec but am I by now means an expert on these things.