Over the last 9 months I've had the chance to shoot and carry my DB9 pretty extensively. I estimate that my original DB9 now has over 750 rounds through it. The initial issues with the DB9 pistol were resolved over the last few months with a redesigned magazine follower and a free set of knurled pins that eliminated the walking frame pins.
I found another issue developed with the magazines as they aged and lost some of their initial spring tension. This started happening about 3 to 4 months after I got my DB9. For me, this issue has been problematic because I would like to carry Federal's excellent performing 124 grain HST round. I know this round performs perfectly in the short barreled DB9 because I tested it and reported on it here. Unfortunately, this round starts to cause nose diving issues in the DB9 magazines as they start to get some age on them. The also excellent Speer Gold Dot 124 grain will also nose dive and fail to feed from older magazines.
Diamondback Firearms has heard the complaints of their customers, but has yet to do anything about the magazine failures to feed these two ammunition loadings. Their response has been to use the Hornady 115 grain Critical Defense round. I've never tested Hornady Critical Defense so I have been using Remington/UMC 115 grain JHP ammo that's available at Walmart and many other sources. I've run enough of the Remington ammo through this gun that I have full confidence it will feed all the time.
Last week I ordered some magazine components for a Kel-Tec PF9 magazine in hopes that I could modify them to work in the DB9 magazine and possibly get my DB9 to feed the HST and Gold Dot rounds again.
I ordered magazine springs and followers. The next few photos show the Diamondback magazine parts next to the Kel-Tec magazine parts.
I tried a few things with the components that I won't bore you with. Let's just say that after fitting the follower it made no improvement with feeding. I'd love to have the 45 minutes of my life back that was spent slowly sanding, filing, and smoothing the oversize follower to fit the Diamondback magazine tube. The photo below shows the outcome of trying to load the top round of a magazine full of HST rounds. Both followers cause the rims to lock on the top two rounds and force the nose of the bullet down and into the feed ramp.
Next I tried modifying the spring. The stock PF-9 magazine spring is too long to fit in the DB9 magazine. That makes perfect sense when you realize the PF-9 magazine is designed to hold 7 rounds vs. the DB9 magazine with a capacity of 6 rounds. I started trimming off coils from the PF-9 magazine spring until I could get it to fit the DB9 magazine tube. I had to trim off two coils, which left me with a slightly longer than standard spring. Two Diamondback standard factory springs are on the left and my modified PF-9 spring is on the right.
After installing the new spring with a stock DB9 follower, I noticed some pretty significant differences in the follower performance. Filling up the modified magazine with HST ammo, I noticed a significant reduction/elimination of nose diving with the top round. The HST rims didn't lock together as hard as they had previously, so the propensity to nose dive was dramatically reduced. I'm not willing to claim victory yet, but so far it looks like the PF-9 spring that has been trimmed to fit the DB9 magazine may allow me to go back to using my HST in my DB9 again.
The improvement is subtle, but if you are experiencing this yourself, you will be able to really see the difference. This photo shows a round of HST that failed to feed and was jammed into the feed ramp. Notice how low the nose of the bullet sits in the magazine.
The next photo shows a modified magazine with the trimmed PF-9 magazine spring installed. You can see the round flows down the magazine lips without nose diving. The reason for the change is a more balanced spring pressure across the entire follower keeps the rims of the top two cartridges from a hard lock up, thereby reducing the top rounds propensity to nose dive.
I have to get out the range tomorrow and see how this new spring works under fire. I'm pretty confident it will work.
How ironic would it be if a Kel-Tec part ended up being a fix for a Diamondback product?