Like many folks here I added some new guns to the collection during quarantine, and finally popped my 10mm cherry with a 1066, followed recently by a 1006. No deals on either one, but since I'd already purchased some newly-assembled 10mm mags, it seemed like the next logical step.
Stocked up on ammo and broke the 1066 down to give it a good cleaning, as it was in pretty sorry shape. Replaced a number of smaller springs that were fairly well rusted, put a new factory recoil spring and one-piece guide rod in, swapped in some MIM components for a smoother trigger, and waited for the shooting ranges to open up.
First day at the range I had an absolute blast with the 1066, she was softer-shooting than expected and ate a few boxes of Blazer Brass 180g FMJ no problems. Then I tested out a small number of Underwood rounds, and everything went off without a hitch until I fired a 150g XTP (the hottest round I had). It apparently had a FTE, as the fired case was still in the chamber and the next round was stovepiped against it, caught under the slide. In all honesty, this was the first FTE that I had experienced with a handgun, and am not sure how normal it is for the next round to be caught under the slide.
So, my guess is that, in light of the poor condition of some of the other springs in this gun, the extractor spring may need to be replaced. Extractor itself is not apparently damaged. What are your thoughts on this, fellow forumites?
The other question I had was do most folks use factory recoil springs on their S&W 10mm's? I do on all of my other 3rd Gens, but 10mm is a bit stronger than the other calibers I own, and that Underwood 150g is HOT!
Any help and opinions are appreciated, Thanks!

Stocked up on ammo and broke the 1066 down to give it a good cleaning, as it was in pretty sorry shape. Replaced a number of smaller springs that were fairly well rusted, put a new factory recoil spring and one-piece guide rod in, swapped in some MIM components for a smoother trigger, and waited for the shooting ranges to open up.
First day at the range I had an absolute blast with the 1066, she was softer-shooting than expected and ate a few boxes of Blazer Brass 180g FMJ no problems. Then I tested out a small number of Underwood rounds, and everything went off without a hitch until I fired a 150g XTP (the hottest round I had). It apparently had a FTE, as the fired case was still in the chamber and the next round was stovepiped against it, caught under the slide. In all honesty, this was the first FTE that I had experienced with a handgun, and am not sure how normal it is for the next round to be caught under the slide.
So, my guess is that, in light of the poor condition of some of the other springs in this gun, the extractor spring may need to be replaced. Extractor itself is not apparently damaged. What are your thoughts on this, fellow forumites?
The other question I had was do most folks use factory recoil springs on their S&W 10mm's? I do on all of my other 3rd Gens, but 10mm is a bit stronger than the other calibers I own, and that Underwood 150g is HOT!
Any help and opinions are appreciated, Thanks!