I went to the range today to test out my self-built AR15 (24" NM Bushmaster HBar, RRA Upper, etc...) with a brand new RRA bolt carrier group.
I read up on some of the AR15's extraction problems (not a mainstream problem, but it interested me nonetheless) and decided to just slap in a Wolff XP Extractor spring and a Wolff XP action spring (I bought a brand new RRA A2 buttstock kit off of eBay and the spring felt lazy).
I was using Federal LC XM193 (Lot 075, 01-04 brass). The shells fell in the same spot each time, which was about 6' to the right and 6' to the back of me (about 8.5' from me in a straight diagonal).
Out of 100 rounds, I did not have a single failure to extract/eject/feed/fire. The RRA bolt came with a black plastic insert and the stock extractor spring was ground off at the ends and had only a few coils.
The Wolff spring had a few more coils and wasn't ground off. I'm not sure if I would have a problem with the extractor, but the range officer came over and told me to use the range provided wooden shell shields so that other shooters wouldn't get hit! I told him this was an AR-15, the shells go in one direction and its not an AK (My VEPR spits out the shells as far as 20' to the right). but I guess the extraction was very strong on my rifle.
I did not see a straight mark on my shell deflector (the built in deflector on the upper) but rather a mark at the start of the angle and at the very end of the deflector. I saw pics of others AR15s and they usually have a straight line.
Another product addressing the exact same issues, as good or better than the Wolf is the SAW Sales "green" extractor spring used with the black insert. This spring was developed to solve the extraction problems for short barreled, full auto carbines in hard, life or death use - it is more than equal to any challenge a semi-auto can throw at it.
SAW - Specialized Armament Warehouse - www.sawlesales.com - is Colt's full auto/LE/Military civilian distributor. Ken Elmore, the owner, teaches Colt Law Enforcement Armorer Schools - and you will learn more about ARs from him than anybody - except maybe Tweak!
The "Green" extractor spring and his "Red" Magazine springs were developed to maximize full (and semi) AR reliability based on a LOT of knowledge developed working with Colt, the US military and police armorer communities.
Some don't like Ken for his somewhat more stringent ordering/restock policies and his "No BS" attitude, but his stuff is first rate. And Trina, his wife, is great to deal with.
Either product is an improvement from the stock extractor springs, particularly important on 16" and shorter guns that have more violent extraction.
Warmly, Col. Colt
I've heard nothing but good things about Wolff springs and their lifetime warranty, which is why I went with their extractor and action spring.
Firing my AR15 brought back a lot of fond memories