I see alot of folks encouraging the use of heavy power extractor springs, the black extractor inserts, and black crane O rings to increase extractor tension, as well as encouraging the use of H buffers. These recommendations are usually for 14.5" carbines with CAR gas systems, and are done to ensure positive extraction and to help slow the very fast bolt carrier velocity experienced with short barrels and a CAR gas system.
I am currently running a Bushmaster 14.5" barreled M4, CAR gas system, with a standard CAR buffer, standard extractor spring and insert. I have not experienced extraction issues but I am always looking for ways to make my carbine as reliable as possible. I am thinking of making the above mentioned upgrades to my carbine, but then I got to thinking - I don’t shoot 5.56 spec ammo exclusively. I often times shoot .223 spec ammo. I also shoot alot of steel cased Wolf, Barnaul, and Monarch. The extractor upgrades would probably be a good idea, but should I go with the H buffer?
Has anyone experienced problems with short stroking, not having the bolt lock back on the last round, etc with a 14.5" carbine with CAR gas system, an H buffer, and .223 spec ammo or Russian/Eastern European steel cased ammo?
Maybe Bushmaster assembles these guns with standard extractor springs, inserts, and standard buffers because the majority of their customers will be shooting .223 spec ammo? Or maybe they use these parts becuase they are readily available and less expensive?
Your 14.5 should run fine with .223 and 5.56 ammo with a simple Colt Black insert/spring combo from Brownells. I don’t run that o ring in any carbines I own. It’s not necessary on any guns I’ve had.
A simple black insert/spring combo should be the baseline. Start there, and if you don’t have any problems, you’re good.
I usually subscribe to the old saying “If it ain’t broke, don’t fix it.” I say usually because the times that I don’t follow that wisdom, I sometimes screw things up worst by dicking around with something that already works.
In this case, it wouldn’t hurt a bit to start out with something very basic and inexpensive. Upgrade the extractor spring to a Heavy Duty one like the one mentioned above, Wolff, or BCM’s extractor upgrade. All of these run under $6.
However, you won’t really understand what your carbine is capable of, or NOT capable of until you stress it, really… like say in a tactical carbine class that forces you to shoot 1000-1500 rounds within two days. My 16" Middy ran all day when I was bench shooting, but when I took it to train with some LEO buddies and had to stress it with multiple quick shots, with a suppressor, I started getting double feeds. After trying out a few remedies, I finally diagnosed the problem to a tight chamber.
The stronger extractor spring and black insert are all you may need. Have several to replace as needed if you shoot a bunch.
An H buffer is not very expensive (Bravo Company), but changing parts out will change how your rifle functions. That H buffer may slow the bolt carrier a little and soften the repeated hammering of 5.56mm ammo, but you will be doing ok with the buffer it came with.
If you shoot the rifle enough, you will see what parts my help you, but for recreational shooting, leave it as is…having spare parts on hand.