Beef chuck sometimes needs a higher finish temp. Never rush it. Did you wrap and rest for a couple hours after you took it out? If not there lies your problem. Always wrap in two layers of foil and hold in a dry cooler with towels for at least an hour and 2 or 3 is better. Chuck is tough and needs lots of low and slow and a good long rest to finish cooking and redistribute the juices. I sometimes have to take them to 210 to get them tender. I am willing to bet your thermometer is way inaccurate. Get a digital and test it.Well i did it. It had a nice flavor bug wasnt soft. It didnt pass the toothpick tes while it was at 203 and i didnt want to wait so i took it off. It wasnt crazy tough but it had some snap. What i do wrong?
test whatever therm you do have and yes tightly wrapped in foil. Read above post about resting and finish temp.I have the weber thermometer i know its not the best but i cant afford a maverick. I rested it for an hour in the foil that i cooked it in. I put it in a 9/13 and the covered is that the reason i didnt tightly foil it.