This is an interesting look at Bolt Carrier Groups and why and how they work. Changing the mass of the BCG according to the creator can have negative and unintended consequences. Anyway, if you have time I recommend watching the video.
Bolt Carrier Mass - A Nerdy Theoretical Discussion
- Thread starter ut755ln
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Best video I've seen. The aftermarket has come a long way; we have adjustable carrier mass, adjustable buffer mass, adjustable spring rate, and adjustable gas regulation. Jim Sullivan's opinion is based on military requirements which holds almost all of those variables static while requiring reliability from arctic to desert environments. Civilians don't generally have those requirements.
Great video. It also lends to why tuning of the buffer and buffer springs is more common now, as it has a less exponential effect on the whole system, but instead changes more minor variables. AT least I think I got that right lol
Eh.. beyond the physics calculations it was mostly just a guy stating what is common knowledge at this point.
Despite being known I wouldn't go so far as to say it's common knowledge. How many times is it recommended in this forum to use super heavy buffers with adjustable gas systems? There is a large contingency of users that still think more weight is somehow always better.
I think people only suggest "super heavy buffers" when they are actually able to realize that the end user is outside the "adjustment" range of a gas block or combo of parts, and or, the mass of the bcg is lower than a standard because they end user decided to get a low mass carrier and shoot suppressed with a can that's not flow through(run-on). For instance, one AR10 bcg weighs 17 oz while another standard weight one is 20 oz. A user with a 17 oz bcg starts in a deficit when a specific combination of parts and accessories is combined. In some cases you can change a spring, in some cases you can not, the same goes for the buffer weights.
Excessive buffer weight will have little to no effect on a properly weighted bcg/spring combo. It won't slam forward as it wouldn't be over accelerated to start. But if you pair a heavy buffer with a heavy spring you get bad results.
You are the only one saying "always"
Show us your pile of springs and buffers again.
Excessive buffer weight will have little to no effect on a properly weighted bcg/spring combo. It won't slam forward as it wouldn't be over accelerated to start. But if you pair a heavy buffer with a heavy spring you get bad results.
You are the only one saying "always"
Show us your pile of springs and buffers again.
Yeah I suppose. In my mind I still believe most people can put on a spare tire and operate a wood stove, so I guess my version of common knowledge is actually fantasy land.
I've definitely seen plenty of forum replies over the years where the go to bandaid for any and all possible rifle maladies was "MOAR HEVY BUFFER!"
I haven't seen that approach in a while, but it's out there.
I was talking to a buddy and going through troubleshooting issues on an AR10. SA gas block set to bleed but still having overspeed issues. I suggested turning the gas block in to 12 turns out and it solved the majority of the problems. I would not have initially though that 12 turns would be less gas than bleed off but it was. Off topic, but in the end this combination of parts still benefitted from a heavy buffer even after gas was set correctly.
Sure, I would agree that the majority of situations that increasing the operating assembly mass just increases the amount of gas needed to cycle. Decreasing the operating assembly mass decreases the amount of gas needed to cycle.
There could be some situations where the distance between the gas port and muzzle is short which causes the gas tube to be pressurized for a shorter than normal time. If the goal was to attempt to delay unlocking of the bolt then maybe a heavy buffer and strong spring could help in that situation
Many large frame ARs have reciprocating mass that is too light. Sure they can be adjusted to work in many cases, but the window of proper operation will be too narrow and limited to one type of ammo. When gas is adjusted to work, the bolt speed will be too high. One click down on the gas and you lose reliability. This is where a combination of more weight and a good AGB make for the best combunation. IMO
Like many things in the gun community...probably just regurgitated info inertia from back in the day when we had far less knowledge and no alternatives where the best fix for over-gassed bullshit was "Throw an H2 and a black donut in it".
This is a question based on ignorance (my ignorance). If you have a rifle 16" mid length gas system. You install an adjustable gas block. You pick a lighter BCG, skelotonized stainless so lets say -4 ounces off of milspec. You have a H1 buffer weight and spring. Isn't the play here to adjust the operation via the gas block? Why would you go to a heavier buffer?
Yup, I just sent back a 6ARC bbl for them to look at. When I first mentioned the accuracy issues (not the reason it went back), they basically said that I should be running as heavy a buffer as possible…even with adjustable gas
The only thing I believe that would cause what I saw out the the first barrel in 400rds and the second in 20rds would be a soft barrel extention. Especially when considering the old bolt still passed the headspace test for the new barrel. The new barrel was actually tighter .005 when resetting my dies, but I would suspect that is because I set up my die at 100 rounds for the first barrel.
They have been assuring me I am the only one. And accusing me of being the problem when the second one did it.Yup, I just sent back a 6ARC bbl for them to look at. When I first mentioned the accuracy issues (not the reason it went back), they basically said that I should be running as heavy a buffer as possible…even with adjustable gas
And I was running an h3 buffer for the first barrel.
Mine went back because I often couldn’t get ammo to full chamber unless I inserted the round into the chamber by hand (which caused a few slamfires when dropping the bolt…). It did this with two different BCGs/bolts.
