AR-10 Buffer Tube internals-

[Quicksilver]

Got bored today and started looking up a few random things via google and came across a couple of articles about buffer tube weight when running hot loads/suppressor/other items and got curious-

So I took my buffer tube apart to find 6 steel rolled "slugs" with rubber pads stacked inbetween.
Weighs in right over 5 ounces.

I see that some companies offer a 10 oz buffer tube which sounds kinda heavy compared to the factory buffer tube weight.

What advantages does a buffer tube with twice the weight really offer, and why would it help with a suppressor or hot load?

I ask because I was thinking of machining some tungsten to the same dimensions as whats in there to double the weight.

 

[LRRPF52]

A heavier buffer will keep the bolt locked longer, which is good for gas guns because we're ripping the case out of the chamber while it's still hot and rebounding back to memory as best as it can. Hot loads tend to cause earlier unlocking because the expanding gas dynamics are more pronounced at the gas port location, which means we get more rapid and hot gas back into the system.

A similar thing happens with a suppressor, only dwell time past the port is increased because of the baffle arrays and the extended length of bore space. Because of that, there is more violent action of the gas into the BCG.

Heavy buffers fight these dynamics with mass.

The other issue that needs to be addressed with a self-loader is the return stroke and carrier bounce, where the increased mass of a carrier during the return stroke impacts the barrel extension harder, or the bolt catch harder, causing bolt catches to break in the AR10.

This is why an adjustable gas block is a popular component used to mitigate the different gas dynamics of a higher pressure load or suppressed AR10, often in conjunction with a heavier buffer. The JP Captive Spring recoil system is another excellent option for you in this regard, and will replace your buffer and recoil spring.

 

[Quicksilver]

Excellent answer. Thank you.

As I did a ladder test today, I had several FTF's where I would load 5 rounds (all of the same charge weight) and once I got above 43g of powder, I had failure to feed problems where I would fire a round, and pull the trigger on an empty chamber the next. Had to use the charge handle on every load. Went back to a known good load from another box and had zero problems. Guessing that might have something to do with it. Best accuracy was with a 42.8, at 43 everything went to shit. Ironically at 43.2, pattern tightened back up and spread vertical after that. Went all the way to 43.8 and had no signs of overpressure on cases, about to hit the garage and start measuring case stretch between all of them and the loads (I mark all my cases with load amounts). 43.8 felt like it was trying to pound on the rifle as hard as possible, but had piss poor results on paper.

 

[rg1911]

Interesting. I was testing some new loads for an AR15 and had similar results. That is, as the loads got hotter, the bolt apparently did not go back far enough to catch the mag and lock back.

Richard