Here is a sneak preview of the AIC as well as some tech info.  These are impingement carriers that have alot upgrades for smoother action, reliability and easy maintenence that were designed into the LW piston carriers.   Since the design and engineering was done for the piston carriers already, Paul Leitner-Wise decided to offer these upgrades in an Impingement carrier.  

If you wonder why I am posting it, LW and Grenadier Precision are merging and bringing products and minds together under one roof while manufacturing is pressed to a higher lever.  We at Grenadier still want to support the impingement side of things as some people don't want to make the change to the short stroke piston, so high end AR's offered with functional and engineering improvements will be offered.

The Advanced Impingement Carriers come in hard chrome or standard park.  They are available paired with the ACB (advanced combat bolt) at a discounted package price.  The ACB's are available in 5.56, 6.8 SPC, 7.62*39.





In the following picture, you will note a front taper.  To my mind, this is the best part of the whole thing. It virtually eliminates a "double feed" or more accurately, if you have a poor extraction related to an underpowered cartridge.  What it does is it prevents a second round from being pushed out of the magazine. What this means is the immediate action on this type of stoppage is simply pulling back the cocking handle, shaking the casing loose of the ejection port and letting go of the handle to chamber a new round. A double feed as is is inaccurately termed normally requires you remove the mag then clear the stoppage, and reload.




The following picture shows the boss base at the back of the carrier.  Many on the forums are advocating the use of M16 carriers in their SA guns for the exact same reason this boss is there.  That is redistribution of mass to the ass end.  It keeps the carrier center of gravity where it was supposed to be when designed by stoner for the M16.  It stabalizes the carrier stroke.  
More importantly it is tapered on the back end to guide it into the tube reliably and the increased OD also stabalizes the carrier.  One thing that happens is when a carrier and buffer bottoms out in the tube on the recoil stroke, the carrier can tilt a bit.  Not a big issue, but one that is addressed by the boss.  To cut alot of BS out of this paragraph, it essentially eliminates up and down play in the carrier throughout the recoil and return stroke.







Some info on the Advanced Combat Bolt.  The ACB is the result of a systematic front to back dynamic analysis of the standard bolt. Nothing is there that doesn't need to be; it's designed and engineered to outlast the host weapon. It is being evaluated by a number of government and commercial enterprises.  The steel is actually EN36 BS970 655M13 or 3312 AISI/SAE. It's a nickel chromium case hardening steel. It gives a very hard surface with a strong core and retains a high degree of toughness. There is enough nickel in the steel to give it the same corrosion resistant properties as stainless steel. This still is primarily used in the manufacture of gearing for mining equipment that comes under great sudden load much like an M4 bolt does.  Please note the lugs have proper stress releif I beam cuts.  These do just that, relieve the lugs of metallurgic stress and thus preventing fractures forming.  They also decrease the bolt face mass making unlocking quicker.  If you noticed on the LMT Enhanced further generations of EB's had smaller and smaller stress relief cuts to the point where they are ornamental.  The problem is they did not choose a suited material to manufacture the bolts.

When you get the technical drawing for the M4 bolt, you note there are tolerences on it.  These tolerences are an acceptable range in which the dimension can measure and still be acceptable from a QI perspective.  Some tolerences are extremely critical on the lugs as they can effect headspace.  These bolts are held to a much tighter tolerence range as LW wanted the lugs to be run to maximum dimension for strength and integrity as well as very consistent headspace lockup.  What we have found are some accurracy benefits with the ACB that would equate to running a tight or match chamber without the disadvantage of the decrease in reliable extraction related to a tight chamber.  So out of a standard 5.56 Nato chamber, we are getting results similar to a match chamber.  Of course there are other factors involved making a match chamber accurate, and this bolt only addresses one of these, but the biggest seems to be consistent headspace lock up from round to round.  The additional QI of ensuring each lug is run very close to the max acceptable tolerence but no larger.

Note the dual extractor spring extractor.  Unlike the LMT, the springs are put into straight pockets.  Both springs are widened at the base so they are captured in the bolt.  The springs themselves are rated for millions of cycles.  Unlike the LMT, the springs both contain synthetic buffers eliminating extractor bounce or skip.  



If you look at the following picture, you will see a standard bolt 1st, then a ACB with the 1st Generation extractor, and the last is an ACB with the Raptor extractor.  Note on the standard bolt, the lugs adjacent to the extractor are undercut to accomodate the extractor.  Because there is no lug where the extractor is on a standard bolt, the 2 lugs adjacent are subject to increased load.  These 2 lugs being undercut are weaker.  Does that make sense to you?  Nope.  That is why LW engineered the lugs adjacent to the locking lugs without an undercut.  If you look at the raptor extractor, no surface area is lost in the extractor claw by wrapping the extractor corners around the lugs.  



Look at the web between the locking lugs.  It is radiused as opposed to straight cut.  This adds signifcant structural integrity to the lugs and the bolt body.  Straight ground lugs leave a weak point where fractures can form.  A web redistributes load across the structure.

As most of you know, it was a long process to pefect these and get them to market.  There were engineering  and manufacturing challenges at every step in the process.  After almost 2 years of development we finally have a lifetime AR bolt.   They have been tested relentlessly in terms of the amount of rounds fired, and over powered proof loads.  They work beautifully with 6.8 which has a far higher bolt thrust than 5.56.

Since LW is in the process of redesign of their website and webstore, we will put these in the GP webstore tonight or tomorrow as they are available for immediate delivery from LW.  The prices for these are posted in the LW forum and will be posted in the EE by LWRC.

LWRC did 1 run on these  carriers to offer folks for their DI Semi-Auto's.  I do not know if it will be a product we will continue to offer with the focus being primarily on piston operated carbines.

Awesome.  So these are going up for sale starting tonight?

Are you gong to offer Gen extractors to those who already have an ACB bolt?

How much less does this carrier weigh than a standard M16 carrier?

Are the ACB bolts offered in hard chrome as well?

I have to build them into the web store.  I will post when it is done.

TAG.

tag for later

Ok....so when are these and your lower receivers going to be available for purchase?  Have you thought about a package price for a AIC, ACB and GP stripper lower

Thanks

Cool stuff there.  What's the pricing going to be like?

I picked up a couple of the bolts in 6.8.  They look awesome.  Fit and finish is perfect.  Though I only have a few shots down range with one it functioned perfectly.

Quoted: Cool stuff there.  What's the pricing going like?

.

The tapered front on the carrier is interesting, but I'm having a hard time figuring out what is "advanced" about the rest of the carrier. Why not just make it like a regular M16 carrier?

Quoted: The tapered front on the carrier is interesting, but I'm having a hard time figuring out what is "advanced" about the rest of the carrier. Why not just make it like a regular M16 carrier?

+1

Because we already manufacture the carrier with the improvements for the piston gun.  We have no reason to make standard M16 carriers.  It would take more to modify them than to make from round stock.

Quoted: Quoted: Cool stuff there.  What's the pricing going like? .

Quoted: Prices are as follows: $149 parked with staked key $179 Hard Chrome staked key If you want to add the ACB complete add $130. $150 for the ACB a la carte. These are available for immediate delivery. I really mean it.

www.ar15.com/forums/topic.html?b=2&f=171&t=150207

Sooo, any possibility that you will be making a mirror-image version of these things for the left-handed Stag crowd?

Quoted: Because we already manufacture the carrier with the improvements for the piston gun.  We have no reason to make standard M16 carriers.  It would take more to modify them than to make from round stock.

OK, but that doesn't answer the question as to what makes it "advanced".

The same thing that makes the LMT enhanced.    Only the use of the word enhanced seems to be in use.

There have been improvements made to the carrier that make it work better.  Does not shoot laser beams or anything, but advancements have been made.  

Did I tell you about the gas filter we retrofit to the vents?  We are working hard along side the phillip morris people on that one.  

Will the 7,62x29 bolts break just like other brands, or is this so touch that it won't? I have broken two so far in under 500 rounds.

Quoted: The tapered front on the carrier is interesting, but I'm having a hard time figuring out what is "advanced" about the rest of the carrier. Why not just make it like a regular M16 carrier?

The ring at the rear should, theoretically at least, smooth out cycling, which may not help reliability as much as controllability.

The 7.62x39 bolt was designed to handle the thrust from the .499LWR cartridge pushing out a 300 grain bullet at 22,00 fps.

Simon

DAMN NICE JOB!!!

I may have to try one of these on one of my C7+ guns!!!

Thanks, also, for support the Direct Impingement folks like me.  Personally, if I wanted a piston I'd grab my M14.

Keep up the good work.

I put them on the GP store for LW.  

I really want to buy one of these bolts and BCs, but I'm patiently waiting on your matched receivers.  

How about auto carriers??

Quoted: How about auto carriers??

+1

So I know you guys have been testing the hell out of these bolts.  How are these bolts eventually failing  -- breakage due to super high round counts, finally failing headspacing, other?  Are they lasting 20k rounds in direct impingement carbines (16" and shorter carbine length gas system) and at what rate (ex. 65% last 20k or more, etc.)?  And since the extractor springs are rated for way more cycles you never have to replace them?  What about the ejector spring, is that just a standard spring?  What did you shoot for in the way of extractor spring tension?  How does the extractor tension compare to others such as the gold M4 spring, SAW spring, or Wolff spring?  Being made of hardened mining steel, do they wear out the inside of a chrome carrier?  Very excited about your product, would like to hear more.  Thank you for your help.

Some damn good questions from wyv3rn.  I'm also highly interested in the answers to his questions..in the market for a bolt carrier group and want to know a bit more about the LW product before I pull the trigger.  

tag for later reading

I like it, however.

Will you be offering them that are SP1 spec/Lightning Link compatable?

Will the radiused web betwwen the lugs work in a regular extension?

How are these bolts eventually failing -- breakage due to super high round counts, finally failing headspacing, other?

We have not had one fail yet.  ARDEC has some and so does Colt for their LAR.  Neither have reported failures.  80000 rounds on the one we are testing and still going.  On examination, it shows no signs of fatigue.  Of course we have more chalking up round counts in demo guns.  Lifetime bolt.  Lifetime Guarantee.

Are they lasting 20k rounds in direct impingement carbines (16" and shorter carbine length gas system) and at what rate (ex. 65% last 20k or more, etc.)? And since the extractor springs are rated for way more cycles you never have to replace them? What about the ejector spring, is that just a standard spring?

When these were demonstrated to the USMC their comment was if the extractor springs are rated for the lifetime of the weapon we had to either make them unaccessable to the troops or make them captured springs.  We made them captured springs.  

In piston carbines the ejector spring has held up beyond what LW expected, this because the springs do not get hot as they do in impingement carbines under sustained full auto fire.  We have not had any problems with the extractor springs in the impingement guns.  The ejector spring is a standard spring on the ACB.  There were was nothing compelling LW to change it as they did not have issues with it in piston guns which is the focus.  The ejector spring would need to be replaced on the same schedule as a standard bolts ejector spring as these are standard items.

What did you shoot for in the way of extractor spring tension? How does the extractor tension compare to others such as the gold M4 spring, SAW spring, or Wolff spring?

I will get numbers for you.  I don't have them.  No comparison has been made to the other products that I know of.  LW titrated the tension to where it was found to be functionally ideal in both tension, and buffering.  With 2 springs alone, the extractor can bounce or skip over the rim regardless of tension.  Therefore you have to buffer the springs so they are like shock absorbers as opposed to simple springs.  The extractor spring and buffers seem like a small deal, but this took far longer to perfect than all other issues.

Being made of hardened mining steel, do they wear out the inside of a chrome carrier? Very excited about your product, would like to hear more. Thank you for your help.

This is not bit steel but gear steel.  If you shoot for a steel that is uber hard, you end up with a brittle bolt.  This steel has a hard surface and a tough core.  They do not wear the barrel extension.  Only the gas rings are in contact with the carrier and these are standard rings.  Of course all of the carriers are chrome lined.

Will the radiused web betwwen the lugs work in a regular extension?

Yes.  Note that they have a very tight radius.

Will you be offering them that are SP1 spec/Lightning Link compatable?

I don't think so.

How about auto carriers??

Auto carriers are likely and those that shoot auto will gain the most benefit.  This is sort of an experiment to see if people even want an improved carrier.  I will encourage LW to support impingement but the short stroke piston is their priority and manufacturing time for the piston components will always get priority.

They are what they are.  Very nice top end AR parts.

Why don't you only make auto carriers? They are legal in a semi. Then you can have one part for everyone.

I am glad you are doing this. If you can make lifetime extractor springs, that would be amazing. I am not sure how you can do that -- and I have the feeling that a few Beta-mag dumps in an impingement system will cook your springs. I also bet if you sent me a 7.62x39 one it would break in my rifle within 200 rounds. I broke two bolts already and I have less than 500 rounds in the gun.

Oh, on the 80K gun the headspace did grow, but it was marginal as measured by the incrimental HS guages from day 1 XXX round.  I don't know where it ended up but never closed on field.  Since that gun did its duty almost completely in full auto, the barrel throat was completely eroded and allthough it did still shoot safely, in the end it didn't shoot as straight.  The barrel was replaced.  The bolt was put in the gun with the new barrel and it headspaced fine.  So I am not sure when headspace would have completely dumped.  This particular gun was a piston gun, and piston guns unlock unopposed which also reduces bolt stress.

Robert, the whole start of the ACB was to design a bolt that could deal with the bolt thrust of the .499 which is significantly higher than 7.62 by 39.

I would like to send you one to use in your 7.62 by 39 to see if it breaks.

quote:

"Lifetime bolt. Lifetime Guarantee"

So if this bolt fails for ANY reason, in it's lifetime,  it will be replaced no questions asked??

what are the terms of the lifetime guarentee??

48thHighlander, I appreciate your forthcoming answers.  I have a few follow ups if you don't mind.

Lifetime bolt.  Lifetime Guarantee.

This applies in direct impingement guns as well?

When these were demonstrated to the USMC their comment was if the extractor springs are rated for the lifetime of the weapon we had to either make them unaccessable to the troops or make them captured springs.  We made them captured springs.

Is it possible to obtain replacement springs & buffers if necessary?  Will their life be shortened significantly in a direct impingement gun or are they made to stand up to high heat (chrome silicon or some other material)?  Are they user replaceable?  Can we see some pics of the new design?

In piston carbines the ejector spring has held up beyond what LW expected, this because the springs do not get hot as they do in impingement carbines under sustained full auto fire.  We have not had any problems with the extractor springs in the impingement guns.  The ejector spring is a standard spring on the ACB.  There were was nothing compelling LW to change it as they did not have issues with it in piston guns which is the focus.  The ejector spring would need to be replaced on the same schedule as a standard bolts ejector spring as these are standard items.

Exactly what I wanted to know, thank you.

What did you shoot for in the way of extractor spring tension? How does the extractor tension compare to others such as the gold M4 spring, SAW spring, or Wolff spring? I will get numbers for you.  I don't have them.  No comparison has been made to the other products that I know of.  LW titrated the tension to where it was found to be functionally ideal in both tension, and buffering.  With 2 springs alone, the extractor can bounce or skip over the rim regardless of tension.  Therefore you have to buffer the springs so they are like shock absorbers as opposed to simple springs.  The extractor spring and buffers seem like a small deal, but this took far longer to perfect than all other issues.

I appreciate you looking into this for me.  Extractor spring tension was the downfall of the LMT Enhanced bolt IMO.  Far too low, far to easy to cause it to fail to extract.

Being made of hardened mining steel, do they wear out the inside of a chrome carrier? Very excited about your product, would like to hear more. Thank you for your help. This is not bit steel but gear steel.  If you shoot for a steel that is uber hard, you end up with a brittle bolt.  This steel has a hard surface and a tough core.  They do not wear the barrel extension.  Only the gas rings are in contact with the carrier and these are standard rings.  Of course all of the carriers are chrome lined.

I thought that raised ring around the bolt also contacted the inside of the carrier.  Either way, good to know they are not wearing out chrome lined carriers.

Have you tried McFarland one-piece gas rings with this bolt?  If so, do you believe they last longer, or are more durable than the standard 3pc gas rings?  There is no problem with the 3pc of course but products can always be improved!

48th,

I noticed you mentioned that ACB were prof load tested.  Will the also be MP inspected and marked as so?

Quoted: I appreciate you looking into this for me.  Extractor spring tension was the downfall of the LMT Enhanced bolt IMO.  Far too low, far to easy to cause it to fail to extract.

This is true. I have an LMT enhanced in my LMT 10.5 and it failed to extract once this week. My previous Colt bolt with a Wolff never did that.

48thHighlander,
Is the gas key attachment different?
I would like a key where the load bearing points are not the screws holding it to the carrier.
The only part I have broken was the key screw.  It was not obvious and it took a long time to figure out why my rifle was short stroking.  I have thought of welding the key inplace.

Quoted: quote: "Lifetime bolt. Lifetime Guarantee" So if this bolt fails for ANY reason, in it's lifetime,  it will be replaced no questions asked?? what are the terms of the lifetime guarentee??

I want to know also.  Please.

Theoretically this will cause even more issues with uppers. (i.e. there is more lee way for the inside specs with a standard carrier.).  Unless the big fat part is the same size as a standard carrier and the rest is thinned down, but I didnt get that from reading your specs.

On the piston guns the key is dovetailed and fits into a dovetail in the carrier.  On impingement guns they are standard keys except they are staked properly.  The key on an impingement gun is not subject to the same shearing forces as are present on a piston gun.  An impingement key is very soft compared to the ones we make for the piston guns.  Impingement keys are subject  only to stress of cocking and to the violent movement of the carrier.  Thus if the key was not staked properly the screws could walk out causing problems.  Of all the recent factory guns we have messed with, not many have had a manly carrier key screw staking job.  I find it wierd because its not like it takes any longer to do it properly.

The dovetail on the piston carrier is Wire EDM cut to ensure a tight repeatable fit.  It is very expensive to do, and would be mass overkill on an impingement carrier.  If someone desired a welded key, it would be very easy for us to do.

I noticed you mentioned that ACB were prof load tested. Will the also be MP inspected and marked as so?

Samples were proof tested to look at a worst case scenario.  Each individual one is not.  This is a different material with a high nickle content.  In other words magnetic particle testing would not yeild accurate results as the steel magnetizes more like stainless than carbon steel.  LWRC does have an MP machine though it is a moot point with the material.  This steel and its design may render that step obsolete if adopted in any type of military contract.  

Have you tried McFarland one-piece gas rings with this bolt? If so, do you believe they last longer, or are more durable than the standard 3pc gas rings? There is no problem with the 3pc of course but products can always be improved

We have had no need for the McFarland rings.  The gas rings on the piston gun stabalize the bolt and that is it.  In my years as a weapons tech in the CF, I never had an issue with standard rings.  That is not to say the McFarland rings are not better, just that there have been no issues with standard rings.  We can look into the McFarland as an option.

On all LW products, the lifetime guarantee applies.  Impingement or piston.  Even the springs.

Paul is in a log cabin this weekend, but when he gets back I will ask him to post the legal stuff.

They way it works is, you send it back and it is replaced.

..

Am I correct in reading your post on the first page where you say you are only making this one run of direct gas impingement carriers, then will be shifting to piston carriers? So these will no longer be supported in the future?

You want to be able to replace the carrier.  Trust me.  Pics will be online in a few days.

Quoted: You want to be able to replace the carrier.  Trust me.  Pics will be online in a few days.

Please explain.

Impingement carriers will be supported but LW will not be making them monthly unless demand dictates.  When speaking with the CEO and PLW, they support impingement  but did not want it effect deliveries of piston weapons.  

thats really sexy..I want one in chrome ha ha
However whats the address for the store so I can mark it for later?

What is going to be the minimum barrel length you can use the enhanced bolt with when used in an M16?  I believe that it has been said before that the guns with short barrels, such as the 10.5 inch barreled upper mentioned earlier in this thread, have problems with extraction.  I believe that the LW bolts before could not be used in weapons with a barrel shorter than 14.5 inches.  Let me know what length of barrels we could use these new bolts with.

Charles Tatum
Alamo Professional Arms