mauiblue,
I really wish I would've seen this thread earlier... as the first thing I would've recommended is PISTON POWERED and not the gas-impingement system that many of my fellow Soldiers are struggling with right now.
It doesn't matter to me how great the gas-impingement can be, but how it does jam so easily. It's so finicky, and I'm waiting for the first person to tell me that, "If you clean it, it won't jam," HA... that's awesome! I really love cleaning my rifle ALL THE TIME and EVERYTIME just because Stoner designed all the carbon to go back through the chamber! WHAT! Not when there's a better alternative...
The gas-impingement system is one of the most absurd designs for the M-16, AR-15, M-4 there is. And believe me, I'm not talking about the whole weapon, because Patriot Ordinance Factory (POF), Leitner-Wise Rifle Company (LWRC), Heckler&Koch (HK), Robinson Arms and I believe Bushmaster all make a piston-powered alternative.
The POF P-415 with the Corrosion Resistant Operating System (C.R.O.S.) is an amazing step in the advancement of the Black Rifle. Having a piston-powered Black Rifle means attaining a level of reliability once only had with an AK, but also retaining the accuracy of one of the worlds most accurate rifles... the Black Rifle. It's THE BEST of both worlds. As I've said, in the regular gas-impingement system, the gas following the bullet - which is contaminated with carbon - travels through the gas tube to push the bolt back to cycle, which then exits through the chamber. The heat wear and carbon build-up over time is impossible to prevent and almost impossible to clean short of taking apart the entire weapon (time lost).
With a piston-powered system, taking the POF as example... 15,000 ROUNDS went through the weapon on multiple testing of different reviewers and a person could only tell by the usual remnants of carbon in the barrel! No carbon around the bolt or in the bolt! NONE! And after 15,000 rounds, three times the amount that the M4 is capable of handling, and that's stretching it in the M4's favor. The POF never needs lubrication because the parts are plated with silicone nickel and therefore lube themselves.
Follow this link to compare the differences... it's an illustrated working diagram...
http://www.armytimes.com/projects/flash/2007_02_20_carbine/
The link shows you how the M4 vs. the HK 416 works. The gas that follows the bullet pushes a piston to cycle the bolt, instead of the gas physically working to push the bolt.
Here are other links for other manufacturers of piston-powered systems...
POF -
http://www.pof-usa.com/P-415/p-415gaspistonrifles.htm[
/URL]
LWRC - [URL="http://www.lwrifles.com/"]http://www.lwrifles.com/
H&K -
http://www.hk-usa.com/le_hk416_general.html
Robinson Arms -
http://www.robarm.com/
Also, I think it's a shame that our government does not promote the use of silencers like they should. Owning a silencer is the same thing as owning a muffler for your car or motorcycle. It's keeping things quiet and protecting and preserving your hearing. Another advantage of the piston-powered systems are that they are more suppressor friendly than their gas-impingement counterparts.
In regard to the sight... you've got one more vote for the EOTech and ACOG. I see that you already ordered the ACOG so congrats. Now, if you can only send the rifle back and get a piston powered.
If the 6.5 Grendal was more popular, I would buy that one, as that is the mean cartridge of everything. More punch than the .223, but more velocity than a 7.62 and at greater distances.
I really liked the Smith and Wesson M&P Tactical version, but it still suffers from gas-impingement.
I'm pretty passionate about this subject, and I've researched it a lot and have had experience with the M-16, etc... I would urge you to look at the, "Book of the AR-15" 2007 that Guns&Ammo put out. You should be able to get one at a newstand somewhere. But, it features a LOT of articles testing piston-powered systems and EVERY review I've read that features a piston system is good, no matter what the brand (brand isn't as important as the system).
A little more than my .02,
Ryan