Sorry to post this, I am sure its been talked about before but I searched the site and scanned post before posting this.

So why use one for better cycle rates?  I've been using AIM Surplus's regular mil spec BCG for awhile now and was looking at their site and saw the light weight ones and figured I would try and see what they are best used for and what purpose over Gi.

Thanks!!!!

Thanks AIM for the Quick Response.  Sending a order in today!!

I have been running one of the AIM lightweight BCGs since they were first introduced.
I recently built up a new rifle using their newest version, combined with an SLR Sentry adjustable gas block and a TACCOM reduced power recoil spring/buffer system.
The rifle shoots amazingly flat. Recoil feels like a 22lr.
When you combine all those parts, the results are amazing.

Fast forward to about 0:25 in this video of my first run with this build to see what I'm talking about. All 21 shots were hits with about a 2" spread.

LW Build First Run

Love my AIM BCGs. I have 2 LW and several of their other BCGs.

If you have to ask why you would want to use one... You shouldn't use one...


AIM said, 95% of people should stick with standard, and you go and place an order?


Unless you are prepared to tune the gun properly using an adjustable gas block, and possibly different buffers and buffer springs... You will gain nothing from the light weight buffer... But you are likely to damage the rifle.


Do as you want and all, but unless you are using an adjustable gas block (properly) you are going to over drive your rifle and damage parts over time.

Marine6680    Yes I did place an order but I didn't say for what. I ordered a AIM Nitride BCG not a lightweight bcg.   I was just asking a question about the lightweight BCG.

Ok.. yeah, that was not clear in your reply.

I hear good things about the AIM BCGs.


And you got me thinking about building a lightish low recoil AR... So thanks for making me more broke.

I use them for bump guns.

Keeps my cycle rate where I like it and reliability up.


In this video I'm transitioning between four gongs between each burst.


Of course it can also just unload the mag if I want it to.

Low mass systems, combined with light triggers/short locktime systems...combined with light ammo, and give you improved split times and more rapid shot strings/less dispersion.

It is game centric.  

Generally, it is not tollerant of variations in ammo compared to full mass/strength systems.

So would a standard or light weight bcg be prefered for a .300 Blackout pistol with a 7-10 in barrel? I'm thinking of running a adjustable gas block anyway due to intending on running super sonics. I don't want it to be over gassed and damage anything.

If reliability is your priority---standard.

Thanks!

HOW LOW MASS OPERATING SYSTEMS (LMOS) WORK AND HOW TO MAKE ONE

I believe a properly built lightweight operating SYSTEM can be reliable over all reasonable ammo choices on a semi-auto only weapon. The results can be fantastic --Incredibly light shooting. Before the he-men say that 5.56 is not hard recoiling, let me say that it's NOT about recoil really; It's about getting rid of muzzle jump. This is done by reducing the mass of the reciprocating components slaming around inside the rifle and cleverly redirecting the gas jetting out of the muzzle so it works for you instead of against you.

Forget gaming. A guy who can put twice as many shots on target per unit time, has a significant advantage in a gunfight, especially up close.  It can be done.

It's not quite dead simple to do this right, but if you're a tinkerer, the following guide should get you there. First remember that the AR works as a SYSTEM.  Make a big change to one thing and you really should change some others. The good news is that the Stoner system is incredibly forgiving and will tolerate a lot. But if you want good reliability and long term wear, treat it as a system.  

HERE IS THE HOW-TO BREAKDOWN:

Bolt Carrier -- The first and easiest component to change is the bolt carrier. Aluminum bolt carriers are the ultimate but they haven't built one yet that will hold up long term. Aluminum carriers are also said to be more "finicky".  TOO light, perhaps. I went with a V7 Ti carrier. Ti carriers are the second lightest and much more durable than aluminum. A good, skeletonized steel carrier is also a good choice. They're stronger and, some are almost as light as Ti.

Gas Length -- For best results a mid-length or rifle length gas system is reccomended. For barrel lengths under 18 inches a middy is best. My 14.5 is a middy.

Adjustable gas -- This should be mandatory though some people successfully run slightly lighter carriers without them. Most ARs are already over-gassed. If you significantly lighten the moving parts without reducing the gas that drives them, you will probably OVER drive them.  You can buy adjustable gas TUBES, adjustable gas KEYS for your carrier, adjustable gas CARRIERS, and even an adjustable gas upper RECEIVER. The most common and best solution IMO is the adjustable GAS BLOCK. One of the best and most trusted names is SLR. I went with their lightweight Ti Sentry Premium.

Buffer tube -- It is well known that a rifle length buffer system with its longer spring is the softest and smoothest shooting. If you're doing an m4-ish build, this isn't so practical unless you like a fixed rifle stock. So most go with the standard carbine length buffer tube and spring. But wait! There's a compromise solution. The Vltor A5 buffer tube (AKA receiver extension) system was developed for the Marine Corps to give rifle-like smoothness and reliability for collapsible stock carbines. Its length is in between that of the standard rifle buffer tube and the standard carbine tube. It uses a rifle length spring and a proprietary buffer. The longer A5 provides extra smoothness and some reliability insurance against the faster, more finicky cycling of a lightweight operating system. I went with a Vltor A5 and highly recommend them.

Buffers weights --  For the very best results you can reduce the buffer weights and work with different springs. Some people completely strip out the weights inside their buffers and run them hollow. I don't recconend this. Buffer weights act like a deadblow hammer to reduce bolt bounce. Retaining some deadblow effect is wise. It's not as important in a semi-auto as a FA gun, but still best to have IMO. There's also polymer buffers with no deadblow weights in them. Fine for a purely fun gun. Not for me. I went with Vltor's lightest buffer, 3 oz IIRC.

Buffer springs -- The next to last piece of the hardware end of the puzzle is the lowly buffer spring. Here's where it becomes almost black magic with people proclaiming this or that spring to be the hot deal. They sell reduced power springs, extra power springs, and standard power springs. Some people even clip coils. JP Enterprises sells a unique "Silent Captured Spring" setup with special springs and weights, all tunable for weight and spring rates. They say it makes your AR cycle extremely quiet and smooth. Confused yet? Too little power in your buffer spring and your bufffer will slam against the end of your buffer tube, and you might not have enough return force to strip the next round and chamber it. Too stiff a spring might cause short-stroking or excessive bolt bounce, or make your carrier return stroke so fast that it fails to strip the next round from the mag. I found this part of the puzzle to be the trickiest, but there IS an easy solution, so don't despair.  The easy solution is the more-or-less, one-size-fits-all, CS flat wire springs. They smooth up the action, have better compression characteristics, and last forever. I went with the very popular Tubbs.  It's working like a champ for me. Maybe I'll get brave someday and try clipping some coils.

Muzzle Device -- I probably should have listed this as the first item. Everyone knows that a muzzle device can dramatically reduce recoil and muzzle jump. In fact, this part can probably have as much effect as all the rest put together. For fun guns there's tons of good "comps." The most effective ones are obnoxiously loud and "blasty". They redirect the expanding gasses exiting the muzzle to push the gun away from you and partially cancel recoil,  which can dramatically reduce muzzle jump. Recoil mitigation by as much as almost 80% according to TTAG's superb testing (Which should be required reading. Google it.).  For guns that might be used for social purposes, flash suppression is needed. But few, pure, flash suppressors provide any recoil compensation. This is where the "combo" devices come in -- muzzle devices that provide BOTH flash suppression AND compensation. Despite their bold claims, most combo devices fail badly at one or both functions. Again, see TTAG to get the scoop. One of the few combo devices that does a fair job at both flash suppression AND recoil reduction is the Precision Armament AFAB. It was my choice hands down.

Setting the Gas Block -- This last critical step must be mentioned. Some gamers dial their gas block down to the razor's edge with JUST enough gas to run the action on their chosen load.  This gives them the very smoothest shooting and the lowest muzzle jump for the fastest split times.  This is a bad idea for anything you might use in a defensive role.

A big key to more robust reliability with a LMOS is to set your adjustable gas as follows:

1, Find the wimpiest .223 load you can ever imagine using and load one round in the mag.
2. Chamber and fire it while intentionally  *limpwristing* the gun one-handed (To create a relatively worst case for cycling.).
3. If the bolt locks back as it should, turn the gas down one notch and repeat.
4. When the bolt finally fails to lock back, turn the gas UP two notches. You should be good. Go three if you're really concerned, but it won't be as soft.
5. Now run a full mag of the wimpy stuff *limpwristed* just to be sure everything works.
6. Run hot, 5.56 mil pressure 77 grain loads and check for function.
7. Run your chosen load and check for function.
8. Train with it, and get it hot and dirty. If all is well, you should be GTG.

It's a lot to do but the reward is an almost unbelievably soft and fast shooting weapon. By avoiding the extremes and using good parts, I have a system that  I feel I could trust with my life.  It's been 100% for me so far. There's no doubt that a standard, over-gassed, heavy operating system AR would be more reliable. So would a bolt action. It's about how far you're willing to go to have a faster, smoother, higher-volume weapon. The very highest reliability or a higher effective rate of fire. It's your choice.

But sometimes quantity really does have a quality all its own.