The reason that some shooters seek out milspec guns and parts is that, taken as a whole, milspec guns are generally more reliable than commercial guns of similar configuration. This point cannot really be argued - professional trainers who see hundreds or thousands of AR-pattern guns per year have well and truly documented what guns run, and what guns don't.
Now, no one is saying that your individual Del-Ton, or DPMS, or Bushmaster AR will not run. Just that you're somewhat more likely to have trouble at some point, especially if you do a lot of shooting. I find that a lot of 'reliable' guns start to choke when they fire 1200 rounds during a 2-day training class...
Anyway, so you want to modify your AR to make it more reliable, right? Since mission drives the gear train, the first thing I'd do is look at what you want to use the gun for. If you're going to take your Del-Ton to the range three or four times a year and run 100 or so rounds through it, well, I wouldn't do anything to it. Save your money. The stock Del-Ton will probably run just fine given such a modest firing schedule. Just remember to keep it lubed.
If, on the other hand, you plan on doing some serious training, there are a couple of things you can do to improve your rifle's odds:
- Get a milspec M16 bolt carrier group from
www.bravocompanyusa.com, and swap it in. Keep your old BCG as a spare. You'll have a much more durable bolt, properly staked gas key, and correct carrier weight, all for about $140.
- Some ARs have a .223 Remington chamber, which is tighter than the 5.56 NATO spec. This can cause extraction trouble, especially when the rifle gets hot. You might see if anyone local to you has a 5.56 NATO chamber reamer. With the right tool, it's about a ten minute job to team the chamber to NATO specs.
- Get good magazines and keep them clean. Magpul PMAGS, Lancer Systems L5s, or USGI aluminum magazines with Magpul followers. Promags, Tapco mags, USA mags, throw all that junk into the recycle bin.
- Lube. A fairly heavy coating of quality lube on the bolt carrier rails, cam pin, bolt body, and ejector is the quickest way to turn a balky AR into a smooth-running lead hose.
Hope this all helps.
-C