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Thread: "Best" BCG

  1. #21
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    I certainly like and use BCM. I also find PSA premium BCG to be reliable. I have one PSA premium (toolcraft carrier) that has the Diamond Like Coating (DLC). The coating has held up great (no flaking or damage) after 3,000 rounds. JP Enterprises makes great BCG's as well, but spendy.

  2. #22
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    Quote Originally Posted by lysander View Post
    Forging, in this case, won't do a whole lot due to the geometry of an AR bolt.
    Forging pretty much helps everything. Of course the heat treat is equally important.

    Well, I guess it comes down to if you want a coating on your bolt/carrier and if it really helps. I can see the potential benefits of lubricity and easier clean, but always the question is durability. I will say, if true as some advertise, easier clean is a major plus for me.

  3. #23
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    Quote Originally Posted by juliet9 View Post
    I will say, if true as some advertise, easier clean is a major plus for me.
    The problem is easier clean often means lube doesn't stay put. The only finish I've tried that BOTH seems easier to clean, AND keep lube where you put it is NP3. And keeping lube where it's supposed to be is WAY more important than clean up ease.
    "What would a $2,000 Geissele Super Duty do that a $500 PSA door buster on Black Friday couldn't do?" - Stopsign32v

  4. #24
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    There are lots of good BCGs, particularly those mentioned.

    If I had to settle for 1 for all future builds, it would be a Sionics NP3.

  5. #25
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    Quote Originally Posted by juliet9 View Post
    Forging pretty much helps everything. Of course the heat treat is equally important.

    Well, I guess it comes down to if you want a coating on your bolt/carrier and if it really helps. I can see the potential benefits of lubricity and easier clean, but always the question is durability. I will say, if true as some advertise, easier clean is a major plus for me.
    Not really.

    The improvements gained from forging are due to the grain distribution and grain flow. For something shaped like an AR bolt, any improvements would come from upsetting the head. But, due to the size of the bolt, the allowable radii and other forging considerations, machining the bolt from the resulting forging will reduce the grain flow to pretty much the same as in bar stock.

    Second, you don't get something for nothing. In forging you gain in one direction, but loose in the direction perpendicular. In an AR bolt if forge so you gain the fore-and-aft direction, you will loose in the transverse, or twisting. Bolt lugs are subject to considerable twisting loads.

    I do not see any benefit from forging that would justify the increased cost.

  6. #26
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    Having raced cars and boats for years, there is a reason crankshafts, connecting rods, pistons, etc. are forged. The stresses induced, particularly in high rpm engines, are profound, thus forging.

    While you point is taken, is forging necessary? Of course not, otherwise it would have been the standard, but I am suspect to your analysis of the machining of the bolt post forging would reduce it to bar stock composition. Throwing a flag on that one. As you probably know, forging generally and vastly reduces the amount of machining necessary to get to the final result as say for example machining from bar stock.

    The forging benefits aside, if that almost doubles the cost of a BCG, you gotta ask yourself what are the benefits. Geissele claims 5 times the life expectancy versus a mil-spec bolt. Why is that? Is it because of the C158+ steel? The forged bolt? Both? Which I suspect. I find the claim interesting.

  7. #27
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    Speaking of BCGs... this just came out in Bravo's email blast

    "What would a $2,000 Geissele Super Duty do that a $500 PSA door buster on Black Friday couldn't do?" - Stopsign32v

  8. #28
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    Quote Originally Posted by juliet9 View Post
    Forging pretty much helps everything. Of course the heat treat is equally important.

    Well, I guess it comes down to if you want a coating on your bolt/carrier and if it really helps. I can see the potential benefits of lubricity and easier clean, but always the question is durability. I will say, if true as some advertise, easier clean is a major plus for me.
    While pretty damned expensive, the Cryptic Coatings "Mystic Black" BCG is hard to beat for cleaning. It also checks all the boxes for "The List". Member here VIP3R 237 had one he ran with 20K+ rounds before he retired it. Cleaning is really easy, even the infamous bolt tail. Again, it ain't cheap but is definitely a good product.

    You can also buy components from Cryptic Coatings, like a bolt only. One of those Mystic Black bolts coupled with an LMT-E carrier would be sweet for a carbine.
    11C2P '83-'87
    Airborne Infantry
    F**k China!

  9. #29
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    Quote Originally Posted by juliet9 View Post
    Historically, I have always used Colt BCG's.

    I understand there are some "better" ones out there, mainly I suppose in the coatings on them, but perhaps lug geometry as well.


    Can a couple of you give say a list of the recognized top 3 or so and I can do a bit of research?
    No such thing.

  10. #30
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    Quote Originally Posted by juliet9 View Post
    Having raced cars and boats for years, there is a reason crankshafts, connecting rods, pistons, etc. are forged. The stresses induced, particularly in high rpm engines, are profound, thus forging.

    While you point is taken, is forging necessary? Of course not, otherwise it would have been the standard, but I am suspect to your analysis of the machining of the bolt post forging would reduce it to bar stock composition. Throwing a flag on that one. As you probably know, forging generally and vastly reduces the amount of machining necessary to get to the final result as say for example machining from bar stock.

    The forging benefits aside, if that almost doubles the cost of a BCG, you gotta ask yourself what are the benefits. Geissele claims 5 times the life expectancy versus a mil-spec bolt. Why is that? Is it because of the C158+ steel? The forged bolt? Both? Which I suspect. I find the claim interesting.
    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




    Geissele claims 5 times the life expectancy versus a mil-spec bolt.
    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.

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