"Best" BCG

[Pasta123]

Is it possible to forge the bolt in the traditional "transverse" position, though?

An AR bolt is not a crankshaft, a connecting rod, or a piston. Different applications, different loads, different geometries, yield different optimal designs.

Second, The cycle time for a nine-axis machining center to make one AR bolt, ready for deburring and heat treating is nine minutes, with no human intervention.

https://www.youtube.com/watch?v=Nkn3P2Z5m5U

To forge, you would have to cut the stock into billets, load the billets into the oven, then someone would have to remove the heated billet from the oven, put in a die, twice, (with another person to handle the steam spray), and then someone to load the forging into a machine center, where it still has to make almost all the same cuts. All that is not going to add up to less than nine minutes. Yes, there will be more chips, but they can be recycled and the cost of the extra material, minus recycling, is far less than the cost of one or two people's labor. (Don't forget "labor" includes health benefits, pension, taxes, vacation, sick leave, and hourly wage.)

As stated before, nothing in nature is free, if you gain in one place you loose in another. Forging is no different. Some properties improve in the longitudinal direction, but drop in the transverse





As to what Geissele claims, they can claim anything they want, but I will take a skeptical eye on their claims until I see one of their bolts last 50,000 to 75,000 rounds. As the standard MIL-SPEC bolt has a expected life of 10,000 to 15,000 rounds, as far as the Army is concerned.

[lysander]

I’m not sure the gas channel through the key could be machined if it was integral with the carrier.

You can do it from the bottom, then plug the hole.

[lysander]

Is it possible to forge the bolt in the traditional "transverse" position, though?

Transverse is by definition at right angles to the primary grain flow.

[xFREDx]

overall i think the best is the LMT Enhanced Bolt Carrier and their enhanced Bolt just based on design. However each BCG is different watching SOTAR for a few years i have learned a lot especially after buying my own gauge kit. Just because they maybe from a certain brand doesn't mean they are the best. Now, my LMT BCG doesn't gauge the best compared to others i have tested. surprisingly enough the best BCG i have gauged and worst one i have gauged has been a BCM. I have probably checked around 20 of them for friends and family so my experience is better with them. I have checked around 5 different SOLGW and around 5 different Aero Precision ones. 1 YMF BCG too. the SOLGW was the most consistent between them. i actually bought three different BCM BCG and gauged them to move the bolts into the best carrier for them. a little excessive but it opens up a whole new door.

[Pasta123]

Transverse is by definition at right angles to the primary grain flow.

Right. What I mean is that is it possible to forge the bolt in a different direction to make it handle the load?

[lysander]

Right. What I mean is that is it possible to forge the bolt in a different direction to make it handle the load?

The standard bolt is made from cold dawn bar stock. That means the longitudinal grain structure is long strings in line with the long axis of the bolt. That is the preferred direction for the primary loads. The secondary loads are the lateral twisting and flexing of the lugs, these are in the transverse direction.

The only forging method I can see that would have any value would be bumping a mushroom head, which, after machining won't make much different in the grain.

[Pasta123]

The standard bolt is made from cold dawn bar stock. That means the longitudinal grain structure is long strings in line with the long axis of the bolt. That is the preferred direction for the primary loads. The secondary loads are the lateral twisting and flexing of the lugs, these are in the transverse direction.

The only forging method I can see that would have any value would be bumping a mushroom head, which, after machining won't make much different in the grain.

Huh, so I guess if there's any improvement made to these lugs, it's pretty much by the material alone (what they done to the C158). I guess it's just a clever marketing then.

[lysander]

Huh, so I guess if there's any improvement made to these lugs, it's pretty much by the material alone (what they done to the C158). I guess it's just a clever marketing then.

Or geometry change, or surface treatment, or cold working.

There are a few roads from here to there that are a lot less expensive than forging or super alloys.

[Pasta123]

Or geometry change, or surface treatment, or cold working.

There are a few roads from here to there that are a lot less expensive than forging or super alloys.

My bad, I was talking about the Geissele bolt there.

I dig through one of their older videos to find more info about them, about 18:25 mark: https://youtu.be/oYCgqIvpr84

To summarize:
Extended upper rails on the bolt carrier,
Cam pin made out of Aermet 100,
Extractor made out of Carpenter 465,
Chrome-lined gas key,
A properly sourced firing pin.

It didn’t mention their forging process & the improvements over the material, though. Supposedly it’s just a better 158.

[DG23]

watching SOTAR for a few years i have learned a lot especially after buying my own gauge kit.

SNIP...

and gauged them to move the bolts into the best carrier for them. a little excessive but it opens up a whole new door.

You fell for the hype hook, line and sinker.

You got it almost as bad as the guy stressing out over .001 worth of firing pin protrusion.

.001 that will never be noticed and was not worth messing with in the first place...