in theory, reduced recoil
Less moving mass = less muzzle lift and felt recoil.
ah i see. that energy has to go somewhere though…
This is why JP recommends the adjustable gas block…that way you can adjust it so that it gets enough gas to run reliably but not so much that the carrier is beating the s*** out of the end of the receiver extension. I’ve found that using a lighter than M16 carrier and a muzzle brake/comp that the recoil move more linear, but the muzzle lift is less. This is the ‘first step’ down the path to the ‘way’, I think. 
also, just so we’re clear, these parts are for games.
Exactly. don’t use these on a ‘social’ rifle. For ‘social’ rifles use a full weight carrier, like a LMT or BCM M16 carrier.
Does having an M16 bolt carrier make that much of a difference in a semi auto?
I have been thinking about replacing my BCG in my Rock River but am not sure if just getting it properly staked would work just as good. I dont know but am starting to wonder if the MP testing on the bolt, barrel, ect pertains more to guys who run full auto guns as opposed to semi auto. Let me know if I am way off base.
I wouldn’t just swap out a carrier if you’re is presently working. I would stake it better and just get a H buffer to make up the difference in weight. I would get a BCM MP tested bolt to keep as a spare and the BCM SOPMOD upgrade kit for your current bolt. You should always have a spare bolt handy. Everyone should use MP tested bolts for semi and full auto guns.
I’ve read bolt and barrels wear together, perhaps analogous to a chain and sprocket. If so, would it be wise to rotate after x,000 rounds so the back-up fits as well as the original?
Just check each bolt with the USGI Field gauge every few thousand rounds as part of your PM schedule. As long as it won’t close on that gauge you’ll be fine.
Not to hijack but I have a couple questions. What is the BCM SOPMOD upgrade and would using an h2 or h3 buffer work better than the regular h buffer. What about replacing the sping with an ISMI spring or the one La Rue sells any advantage there?
BCM SOPMOD bolt upgrade kit from www.bravocompanyusa.com
You can use too heavy of a buffer so that why I recommend the H. If you’ll be using an ISMI spring I recommend the standard buffer. Using the H and a ISMI or TacticalSprings.com buffer spring can cause short stroking if you’re shooting .223 pressure ammo instead of 5.56 NATO pressure ammo.
I love this site and all of the great information:D
However, it never fails to make me worry about my ARs. :eek:
Now I’m worried that maybe…just maybe my 20" AR with a rifle gas systyem, A2 stock and a .2 oz lighter (lighter than the M16 bolt carrier) LMT semi BCG is battering my A2 tube too hard.
I’m crazy, I know.
I also know that I could add a stronger buffer spring or try to modify the buffer to add the .2 oz, but I’ll probally just keep a close eye on the rifle and adjust it in the future if anything is wearing out.
Has anyone ever seen a buffer tube “wear” out? I’ve seen broken ones, but they were from hitting things etc. never worn out from shooting.
I don’t use my ARs for real “social” work, but I like to think that if SHTF I have one of the most durable battle rifles possible.
Thanks again for all the great info!
Completely irrational worry.
My oldest AR is an A2 setup with the fully neutered half circle colt bolt carrier. Never a problem.
Thanks Demigod!
I feel better now:D
Hi JC - you bring up 2 issues: Weight (16 carrier) and Quality (MP testing & shot peening).
- MP testing & shot peening: I have seen many photos of broken AR bolts. Virtually all were in semi-auto guns.
In my estimation, a number of these failures were caused by putting many rounds of 5.56 mm NATO pressure ammo through an AR with a lower-quality bolt - particularly one with a harsh carbine-length gas system. MP testing is just that - testing. Its just QC. But, it rules out harline cracks from heat treating. Shot peening takes away the sharp edges where cracks can develope. The part is actually stronger and unlikely to crack after peening. These features are valuable in ANY AR, and I agree with GotM4? that you should use a quality MP/peened bolt like BCM or if you can find/afford one, a colt.
- Weight: carrier weight in semi-auto is not really noticeable in slow fire. 99% of the AR-owning community only shoots thier ARs slow fire anyway, so you are correct: weight does not matter; the carrier you have is right one. A heavier carrier is also a reliable carrier.
Things speed up in many carbine classes or if you use your AR in “games” (as they are snidely referred to above). In that scenario, the extra carrier weight upsets the weapon and moves the dot off the target momentarily after every shot.
How long is the dot off target? - a fraction of a second.
But, on a 30 to 50 round string, those fractions add up. Timed excercises are just that - timed - and competitions are judged by time divided by accuracy. Both count. If your goal is to place aimed rounds on target as fast possible and the targets dont shoot back (ie reliability is not life or death) then there are benefits to a competition AR set up (including a lighter carrier).
My advice? Invest in a quality bolt with upgraded parts & don’t worry about the carrier.
Thanks for the replies guys it cleared up alot of my questions.
So this is my course of action. Get the carrier staked correctly, buy a MP tested bolt and replace the buffer spring with the La Rue tactical spring and leave the buffer the same?
P.S I mostly shoot lake city XM193 so I would like it if the gun recoiled less with the NATO ammo. Along those same lines I am thinking of getting a DNTC Compensator to help in this area as well.
(as they are snidely referred to above)
fwiw, my warning was not in any way meant to be disparaging toward games. I love games.
Sorry, my bad. let the games begin! Its all good.