Since my review article on the new Springfield Armory XDs was posted I've heard from no less than a dozen SurvivalBlog readers, who were having "problems" with their XDs .45s - most of the problems were related to light firing pin strikes. I've also had two SurvivalBlog readers live nearby come to me for this problem, and I was able to get the problem "fixed."
Here's what you're looking at with the XDs: First of all, we have a sub-compact .45 ACP pistol. It is very small and light-weight - only 21.5 ounces empty. And, it has a polymer frame. So, as it is with all polymer frame handguns, you have to have a firm grip on the gun - NO limp-wristing it. If you limp-wrist the XDs, the slide doesn't go fully into battery - it will be out of battery by a few thousandths of an inch - which means, the barrel isn't fully locked-up, and when you pull the trigger, the striker hits high on the primer - 'causing a misfire because it is not hitting the primer dead center - it will be hitting too high on the primer. [JWR Adds: And if the slide is not fully in the battery position, then the firing pin will not impart all of the intended energy on the primer.]
Additionally, the XDs is a very tight handgun - this contributes to the match-grade accuracy of the little pistols. So, when you first get your factory-new XDs, make sure you clean-off the rust-preventative oil. This is not intended as daily use lubrication, as many suspect. Then, properly oil the mating surfaces on the frame and the slide with a good lube like Break Free CLP, and be a little bit generous, initially. The XDs needs a little bit of a break-in period with some of the guns because they are so tightly fit - again this contributes to the outstanding, match-grade accuracy.
So, you have two things to address: One is, no limp-wristing the XDs - it's a sub-compact, polymer frame handgun, that needs a tight grip on it, in order to properly function and feed rounds into the chamber. Secondly, add enough lube to the contact areas, this means the slide rail recesses and the small contact areas on the frame, that holds the slide onto the frame.
Dave Williams, the head of Springfield Armory's Custom Shop, says he tells people who call, until he is blue in the face, that you have to follow the above steps, if you want your XDs to function 100% of the time. And, like many new handguns, that are tightly fit, a little bit of a break-in period might be required as well. I've mentioned this in numerous articles, that you should run at least 100-rds through a new handgun (and preferably 200-rds) to make sure the gun will function 100% of the time.
The folks I heard from, who were having problems with "light" strikes on the primers, didn't contact me again, after I explained the above procedures to them - their guns are working 100%. And, the two SB readers, who came to me for assistance - their guns are working 100% of the time. So, don't think you have a "defective" XDs if you are getting light hits on the primers - you're not! Get a good grip on the XDs and make sure you have lubed it properly, and your XDs will just keep perking along. To date, I now have well over 1,000 rounds through my XDs and only one failure to fire - a Winchester USA-brand 230-gr FMJ round - and I put it back in the magazine and tried to fire it several times - it wouldn't go off. It was just a dud round - it happens with the best ammo, every now and then.
JWR Adds: I witnessed a the same problem first hand with a XD(M) .45 Compact. In this case it was one of the models that has a two-column magazine. This was a brand new gun, shooting 230 grain ball factory duplication handloads. As with the other pistols that Pat mentioned, the problem turned out to be insufficient lubrication. Just a squirt of Break Free CLP on the slide rails and barrel assembly immediately solved the problem. In the event of a light primer strike, your "tap-rack-ready" clearance drill should be executed. If you are a well-trained pistol shooter, this drill should become so ingrained so that you do it hardly without thinking, to get you pistol back "up and running."