Supported Bolt Carrier Group Hype of Not?
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Is BCG tilt really a thing or just something that companies are making up to try and justify their high prices? Personally I think it's them trying to justify their high prices. But I could be wrong.
Oh wait, I heard BCG tilt is a massive issue that needs to be fixed and fixed right now. I heard it on the internet so it is true.
Oh wait, I heard BCG tilt is a massive issue that needs to be fixed and fixed right now. I heard it on the internet so it is true.
Sound like someone who knows next to nothing about accurizing an AR. If you did you might see what issue this may fix or help.
Interesting to see this; as I understand it, carrier tilt is more of an issue in piston-driven guns than DI guns, which makes sense given that a piston gun (especially a short stroke design) would have to give the carrier a pretty solid smack in order to ensure a full stroke. That solid smack, delivered by a metal rod (albeit one driven by gas pressure) is said to essentially tilt the top of the carrier towards the rear of the rifle, which in tun tilts the ass end of the carrier down. On DI guns, I could see, due to the compressibility of the gas, the "shove" delivered to the carrier being somewhat more gentle/less abrupt in nature.
POF has a buffer tube that kind of cradles the ass end of the carrier when the BCG is in the full forward position (it's basically longer on the bottom than it is on the top and sides) as a method of mitigating carrier tilt. I don't run any piston driven ARs, but I do tend to use the POF buffer tube in my lower builds (which are all, obviously, DI), as it seems like cheap insurance to preserve the dimension/shape of the carrier bore within the upper.
POF has a buffer tube that kind of cradles the ass end of the carrier when the BCG is in the full forward position (it's basically longer on the bottom than it is on the top and sides) as a method of mitigating carrier tilt. I don't run any piston driven ARs, but I do tend to use the POF buffer tube in my lower builds (which are all, obviously, DI), as it seems like cheap insurance to preserve the dimension/shape of the carrier bore within the upper.
This place is getting as bad as arfcom with the whole anti accurizing camp. Only there the same people that say accurizing an AR is hogwash also call BS whenever anyone says they have an AR that shoots sub MOA. “An AR15 can’t shoot sub MOA all day”, “sub MOA AR’s don’t exist”.
Coincidence? I think not.
Accurizing methods work, plain and simple.
I’m not looking at this as a since to fix carrier tilt in that manner, IMO that’s more an issue of wear on setups like this.
There is merit to keeping the BCG centered as well as possible (not sagging in the rear) to keep the round as centered on the chamber or sitting as consistently in the chamber as possible.
There’s writeups on this stuff by some dudes that know more than myself about it.
Joe Carlos and Robert Whitley probably know more about accurizing AR15's than everybody on this website combined, and they both think it's important.
If you want results non typical of the norm then you have to think outside of the box and the original design. Several people are and they're building wickedly accurate AR's.
There is absolutely a market for this type of BCG if it actually works and keeps the BCG in the same place every time, which is the issue.
The Ultra-Accurate AR — Secrets of AR Accuracy Revealed « Daily Bulletin
In our Shooters' Forum, one member recently asked: What makes an AR accurate? What parts on an AR can really affect accuracy -- such as free-floating handguards, barrels, bolts, bolt carriers? He wanted an honest, well-informed answer, not just sales pitches.
Minimizing Carrier tilt is more about consistent and repeatable accuracy. Several companies have/are addressing this issue with lower receiver or receiver extension that work like a cradle.
The only issues with this thought process is when you start minimizing tolerances especially on a semi auto DI system you increase the potential for stoppages, so basically it's a fine line between optimal performance and reliability.
The only issues with this thought process is when you start minimizing tolerances especially on a semi auto DI system you increase the potential for stoppages, so basically it's a fine line between optimal performance and reliability.
Also do a little searching back on the forum, it’s come up numerous times where guys have had accuracy issues or POI shifts on the last round when the mag is empty, or depending on whether the next round is sitting on the left or right of the mag.
That issue is directly related to how the carrier is sitting.
There’s a lot of documentation that supports carrier position and sag being an issue.
In a perfect world a carrier would get fitted to its individual upper for a precision build, and it’s feasible but would be kind of hard logistically since the receiver and carrier would need to be made basically proprietary to one another and any fitting done before coatings and coatings taken into consideration as well. Not impossible but not the easiest and how many people would pay for that.
It would be slick AF though.
That issue is directly related to how the carrier is sitting.
There’s a lot of documentation that supports carrier position and sag being an issue.
In a perfect world a carrier would get fitted to its individual upper for a precision build, and it’s feasible but would be kind of hard logistically since the receiver and carrier would need to be made basically proprietary to one another and any fitting done before coatings and coatings taken into consideration as well. Not impossible but not the easiest and how many people would pay for that.
It would be slick AF though.
First I’ve heard of such things, just like this BCG. Care to reference some products?
I'm also of the belief that this is where having tight fitting components come into play. Like either a super tight fitting upper to lower, or ideally the receivers bedded together so nothing can shift to eliminate that tolerance.
If the upper is coming to rest in the same place every time and cannot shift from slop, then a good buffer to buffer tube fit and a little bit of spring pressure (most BCG's I've found have play before contacting the buffer face with the detent installed) will help hold the rear of the carrier in a more consistent position. Then the only tolerance you have there is the consistency of the face of the buffer and rear of the carrier.
The carrier still needs to fit well on the contact points in the front or any slop there will cause it not to come to rest in the same place, o magazine and round position can also stress it.
This is also why I believe low mass carriers seem to help consistency a bit. Most of the weight reducing is done towards the rear of the carrier which is only going to help minimize carrier tilt. But low mass bolts are marketed as creating a softer/smoother shooting rifles and this is never mentioned, or at least I have not seen it mentioned by any of the makers.
If the upper is coming to rest in the same place every time and cannot shift from slop, then a good buffer to buffer tube fit and a little bit of spring pressure (most BCG's I've found have play before contacting the buffer face with the detent installed) will help hold the rear of the carrier in a more consistent position. Then the only tolerance you have there is the consistency of the face of the buffer and rear of the carrier.
The carrier still needs to fit well on the contact points in the front or any slop there will cause it not to come to rest in the same place, o magazine and round position can also stress it.
This is also why I believe low mass carriers seem to help consistency a bit. Most of the weight reducing is done towards the rear of the carrier which is only going to help minimize carrier tilt. But low mass bolts are marketed as creating a softer/smoother shooting rifles and this is never mentioned, or at least I have not seen it mentioned by any of the makers.
It's a gimmick and doesn't help nor detract from the way your rifle groups. This carrier was specifically built with a tail flare to center it in the upper.
If you want precision then you have to start with quality components from the start and that means putting money into the build. Will an enhanced bcg help accuracy? I don't know but I do doubt it but I'm sure it won't hurt anything. For someone like Padom who is searching for the ultimate in precision I could certainly see the reasoning behind trying something like this.
But one thing I've noticed is when people say something like "in all of my testing" they never mention anything about how it was tested and they are trying to sell you something. If they don't give the testing methodology then I have a hard time believing what they're saying and what they're trying to sell you. Always be weary of sales and famous people trying to sell you something. That video thst was posted reminded me of an infomercial lol
But one thing I've noticed is when people say something like "in all of my testing" they never mention anything about how it was tested and they are trying to sell you something. If they don't give the testing methodology then I have a hard time believing what they're saying and what they're trying to sell you. Always be weary of sales and famous people trying to sell you something. That video thst was posted reminded me of an infomercial lol
LMT and Falkor have the lowers with the added support for the carrier. it's easy to find out if carrier tilt is affecting your rifle just look at the wear marks that the end of the BCG make on the face of the buffer.
...except that the guy gave away the details of his "trick" without any of the ...if I told ya, I have to kill ya, heh, heh bullshit. Basically, he told anyone with even a touch of machining skill his method to accomplish carrier alignment within the upper.
Not really. Carrier tilt with piston guns is not about how hard the piston pushes, but where it pushes. In a DI gun, the bolt does the pushing, and is aligned with the carrier. On a piston gun, the force is applied above the carrier at what is normally the gas key. That causes tilt.
What's being discussed in this thread is a different thing, that is more about how a loosely fitting carrier sits in an upper.
I don’t know if it affects accuracy. I do know that if it affects reliability, I’ll skip it. If the fix gives you .1 moa tighter groups but makes your rifle 25% less reliable it’s a loss. Most ar’s aren’t being shot from rests on a concrete bench and you’d likely never see the accuracy gain in the field.
Tolerance stacking. If you increase accuracy by .1moa five times you just increased your accuracy by .5moa. Regardless though, why would you NOT want as accurate of a rifle as possible and know that you’re the limiting factor and not the gun? I can’t think of a single reason.
Doing an AR build you need a BCG anyway and most people doing a quality build aren’t buying some crappy $50 BCG to drop in their rifle that has $400 in billet receivers, a $200 trigger, a $200-$300 handguard, and a $200-$500 barrel. Lantac makes high quality stuff, I’m familiar with their rifles although I wasn’t familiar with this BCG and this thing can be found for $160 online which is half the cost of a JP that is the go to for a lot of people building precision gassers and is half the cost of my go to which is a LMT FA enhanced carrier with their enhanced bolt.
What gives you the impression it would be unreliable and how would it be 25% less reliable? A gun or part is reliable or it isn’t. It’s full mass so no operating issues there, it’s available nickel boron or nitride both of which have been around for years on BCG and is proven. Yes some manufacturers had issues with nickel boron flaking off but those were pretty much all with cheap shitty parts.
I did some researching the other day when I first saw this thread and it seems they’ve been on the market since at least 2015 so it’s not a brand new product that just dropped, and after reading probably two dozen different threads on various forums I didn’t find a single person saying they had an issue with one and if there was an issue then someone would come to the internet to bitch.
Knowing the issue that this claims to fix, knowing Lantacs quality, and seeing zero complaints about it I have enough confidence in it to give it a try. I’ll know within 30 minutes of dropping it in a rifle and playing with some feeler gauges, watching for the carrier to move when inserting a full mag, and taking taking some measurements if it does anything or not.
So because one company made one that didn’t get it right to fix the issue that means another company can’t do it and get it right?
I just don’t understand people’s stubbornness to innovate. Or negative foresight just because they don’t understand something.
Barrel extension bedding/shimming is a prime example. Do you know how many people will swear up and down that this doesn’t make a diddly damn of difference that have never even fucking tried it? Do you know how many people will also claim an AR15 will not consistently shoot sub MOA no matter how good of a barrel and components you use? Yet there are people who have tested this and know 100% without a doubt that it makes a difference and are pushing the boundaries of what the AR platform is capable of when enhanced.
People think because “this is how an AR15 bolts together, I’m an AR builder” thatthe very simple process of *assembling* and AR15 cannot be done better. It’s no different than the individual parts being made better, it’s all about tolerances and eliminating as many as you can.
You hit the nail on the head there... and I am very much on the same page with you regarding the difference between "building" and "assembling". Taking a pile of parts and combining them correctly is assembling, while (to me) building implies a greater degree of care and skill, with care taken to check/set tolerances, etc...
I bet you that less than 1% of people who have assembled AR15’s even know what headspace is, that part tolerances vary, and that it should be verified. Even if you’re buying an assembled upper and dropping a BCG in that should be done. Yet it’s very rare that anyone does.
What does that even mean? with a go/nogo guage?
I cant imagine how someone would fix something like that?
On the contrary. Joe Silvia is one of the US Army Reserve's service rifle mad scientists. If any of the improvements relative to time and money investment per weapon helps them win they'd do it.
Winning and bragging points saying your particular service won the National Championships and is the reigning annual, five-years, ten-years, etc. champions ... priceless.
The service teams try all kinds of wizardry to gain more points. If it gives you an aggregate five to ten points per soldier advantage over the next guy's score you win. If it doesn't, it's wasted effort. Each AMU, Guard, and Reserve Soldier has to manage two lowers and a number of uppers. If it doesn't work they won't do it -- considering a small team of gunsmiths and armorers have to make sure a winning fleet of competitive weapons is always performing at its best.
Individual wins are great. It's team wins (four, six, eight, and ten-man teams) where your collective talent and hard equipment have to be leading edge. When you're shooting against the best teams each service fields (especially the Marines, Guard, Reserve, and Navy) an edge is an edge.
The Army won for three or four years straight against the Marines who laughed that we went to the M16. The AMU Commander had ordered the AMU Shop give the Marines copies of our rifles, assembly books, standards, and ammunition loads for Camp Perry M16s and M9s and they still stuck with their own. Until one day they decided winning trumps tradition.
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So because one guy doesn't do it, it means it doesn't do anything? I'm assuming you're talking about service rifle/highpower, is that correct? If so I guess optical sights are pointless too since they don't use those. Free float hand guards must not do anything either because they're not using those either. Or thick walled uppers.
Are the Marines doing it and that's what is making the Army win? If Army is winning without it, would it make any difference to do it?
Your example is honestly laughable. At ISC some of the best mil and le snipers compete with issued sniper rifles, does that mean that whatever system the winning team uses is the best? No, it means they're using whats required by the rule book. Take those same rifles to a PRS event and an equal shooter is going to walk all over them.
Other than HS, remediating the barrel extension fit to the upper, & maybe lapping the upper, what other parts & tolerances are you able to control?
Do you have an unlimited supply of various parts to try?
Which other parts do you believe affect accuracy & have data available to support it? What tolerances are you going to eliminate? Do you have the tolerance specs on all the component parts?
MM
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This is something most guys won't really get into unless they're building their own barrels. I've machined a number of my own (working on 2 more right now) so I've got some experience here. This is a different thing than headspace, but can affect headspace between brass and chamber.
- In a tightly fitted barrel, .003-.004" clearance for the bolt (with no case) is good.
- In looser production barrels, or just building for reliability, .010" or so is common, some do more than that.
I've built them both ways, and owned commercial barrels all over that clearance range and even more. Generally, it doesn't matter too much, with a couple exceptions:
- Measure base to shoulder on a sized case (zero your caliper there), drop it in the chamber, and then drop the bolt from full lock back. Measure that dimension again. If a barrel is cut on the looser side, some brass will be "sized" back, same as if the reloading sizer die was set too deep. If you can measure this with a bullet seated and feed from the magazine, that's more realistic, but I've found the results are about the same. I've had barrels with .010" clearance bump shoulders back .007-.008" when a cartridge is chambered. I did have one that bumped the shoulders back over .010" and caused mysterious headspace problems.
- On a tight barrel with minimum bolt clearance, a small piece of brass shaving, copper brush bristle, etc can jam the bolt, locking it pretty solidly into the barrel extension. That's uncommon, but possible.
You missed my point. Gunsmiths are seeking advantage. If they've already tried something and abandoned it, doesn't mean it doesn't have value. It may mean the juice isn't worth the squeeze for larger groups of shooters for the time and money invested.
A sponsored PRS shooter might invest as much as a new truck in their individual rig. That doesn't necessarily meet return-on-investment for working stiffs and organizations who pay for their own stuff.
If a specific gadget or technique gives an affordable advantage others will copy. Individual turned and chambered barrels; glass-bedding or chassis; triggers; specific brand-type bullets; scopes with certain speed or consistency features or durability, etc.
Depends on the discipline I want to use the rifle for.
If it's one I'm wrenching together myself, start with a quality barrel. I've seen a lot of bargain barrels at $80 and $90 I don't expect anyone to have success with, but work for blasters where 100 yards might be the longest it'll ever reasonably be required to shoot.
All my ARs are free-floated and have either Geissele or Milazzo-Krieger triggers. Float tubes don't have to be expensive, and Geissele has Black Friday sales (just got another trigger for $90). I expect handloads to win National Championships.
If I want to win, I go to a gunsmith-turned barrel from a quality blank. Even then I've had a few disappointments -- either from a blank that was just "Meh," or a gunsmith I had higher expectations from (given recommendations from others). Some off-the-rack barrels have truly astounded me with the precision and life you get out of them for a modest price.
My kid just shot a 195-5X standing practice at 200 yards with an off-the-shelf Steve Satern Service Rifle barrel in a garage-smithed match-grade M16.
If it's one I'm wrenching together myself, start with a quality barrel. I've seen a lot of bargain barrels at $80 and $90 I don't expect anyone to have success with, but work for blasters where 100 yards might be the longest it'll ever reasonably be required to shoot.
All my ARs are free-floated and have either Geissele or Milazzo-Krieger triggers. Float tubes don't have to be expensive, and Geissele has Black Friday sales (just got another trigger for $90). I expect handloads to win National Championships.
If I want to win, I go to a gunsmith-turned barrel from a quality blank. Even then I've had a few disappointments -- either from a blank that was just "Meh," or a gunsmith I had higher expectations from (given recommendations from others). Some off-the-rack barrels have truly astounded me with the precision and life you get out of them for a modest price.
My kid just shot a 195-5X standing practice at 200 yards with an off-the-shelf Steve Satern Service Rifle barrel in a garage-smithed match-grade M16.
So after all of this thread, the only positive input you have is "buy a good barrel" and basic stuff like free float handguards and handloads? That doesn't seem particularly insightful or useful, especially in light of your earlier comments in this thread.
Or maybe he was saying that a quality barrel, free float handguard, quality trigger, and hand-loaded ammunition are about the only consistently quantified improvements.
There are tons of references in those legacy things people don't use any more called "Books."
There are a few other web sites you can sift through (try Brian Enos for three-gun, and nationalmatch for highpower rifle).
John Feamster (author of Black Magic and one the USAMU loaders in the Custom Ammo Shop) holds a few National Bench Rest Shooter Association (NBRSA) and International Benchrest Shooter (IBS) "Official Screamer" groups (five shots in .099 at 100, or ten shots in .199 inches; five in .250 at 200, or ten in .449 fired in verified, scored competition) using ARs 'smithed by Bill Wylde. Zediker, Tubb, Sweeny, and McKee all have good books your library can get you for free.
There are lots of things you can do -- like bedding uppers to lowers; truing upper receiver faces and bolt faces; using forcing bolts from the bottom; using split pins; heating uppers and force-fitting extensions into the upper, etc. Expensive to do (billable gunsmith-time wise) that may or may not give significant improvement for a team of four to sixteen guys to maintain across five uppers each.
My advice is good for exactly what you paid for it. Whether or not you use it is absolutely and completely up to you. More than a few on this site say I'm full of chicken feathers.
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Just a suggestion... make sure your gas tube has no contact through the upper or barrel nut contact, and has free and ready travel into the gas key. And have your gas block off the barrels shoulder slightly.
Not looking to start another anti-accuracy slant... just saying try it and check.
After finally reading all of this thread... I am a little surprised by the lack of "give it a try" spirit.
No one has conclusive evidence that any of these tricks will work every time with everyone's various parts and builds.... to many variables involved... right down to how the upper was assembled.
BUT... I have seen a lot of tricks work well on various builds. Enough so that I use lapping, loctiting, snug upper to lower fit , ... basically all of tricks I can do at home.
And that has allowed me to take advantage of a barrels potential. And that has helped almost every time, out of a dozen or so upper builds.
Point is .. the potential benefits out weight the time used ....none of the tricks will make your rifle shoot worse, provided you use quality tools and common sense while DIY.
Both sides have great points... and so far it has been the sum of all the tricks that worked best.
So saying it did or didn't work is gonna be hard to quantify. ... Unless you have access to a dozen similar test samples
If you don't try... you will never know.
Anyway... It is ultimately the rifles owner... do they think it is worthwhile to try. That's what I did... and will continue to do.
redneckbmxer24 I am right there with you.
No one has conclusive evidence that any of these tricks will work every time with everyone's various parts and builds.... to many variables involved... right down to how the upper was assembled.
BUT... I have seen a lot of tricks work well on various builds. Enough so that I use lapping, loctiting, snug upper to lower fit , ... basically all of tricks I can do at home.
And that has allowed me to take advantage of a barrels potential. And that has helped almost every time, out of a dozen or so upper builds.
Point is .. the potential benefits out weight the time used ....none of the tricks will make your rifle shoot worse, provided you use quality tools and common sense while DIY.
Both sides have great points... and so far it has been the sum of all the tricks that worked best.
So saying it did or didn't work is gonna be hard to quantify. ... Unless you have access to a dozen similar test samples
If you don't try... you will never know.
Anyway... It is ultimately the rifles owner... do they think it is worthwhile to try. That's what I did... and will continue to do.
redneckbmxer24 I am right there with you.
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Fella, I don't know who you are or what you've done, so all I can go by is what you're posting here, and you'll have to count me in the group that thinks your full of chicken something. I'm not seeing any useful contribution here from you, I'm just seeing an arrogant guy with a chip on his shoulder against gunsmiths.
Your assumption that anyone who disagrees with you must not read books makes you sound like an arrogant fool. I read 2-3 books a week on average, but that has little or nothing to do with the topic. There is plenty of information in books that completely counters your assertions as well. There's also plenty of good info online, like the Accurate Shooter link above. If you prefer to disregard guys like that who're actually building accurate rifles, that's your issue, personally I'll choose to try their tricks and see what works for me.
Claiming that things like shimming/bonding or thermofitting a barrel to an upper doesn't improve accuracy is silly; it's easily provable that it can, to anyone willing to try it. Obviously that doesn't help on every rifle; if you start with one that's already tight, it won't give the same improvement as comparing to a common "mil spec" upper and barrel extension. That's just one example of many tricks that CAN improve a rifle that needs it.
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