Bolt Carrier

Jim - I'm also guessing you don't really mean "bolt carrier".

The carrier itself almost never fails. I suspect you mean bolt carrier group.

Right??

If it were my gun and I regularly shot 600 yards with my reloads. I'd keep the old bolt carrier and send upper to someone who can sell you a bolt and headspace it for optimum accuracy with the barrel.

That should help you burn through a little cash.
 
Jim - I'm also guessing you don't really mean "bolt carrier".

The carrier itself almost never fails. I suspect you mean bolt carrier group.

Right??

If it were my gun and I regularly shot 600 yards with my reloads. I'd keep the old bolt carrier and send upper to someone who can sell you a bolt and headspace it for optimum accuracy with the barrel.

That should help you burn through a little cash.
Headspace on an AR is the interplay between the bolt and barrel extension. If those two parts are within industry spec. then headspace is good. There's really no way to tweak it to get better headspace for accuracy. The parts are either in spec or not. If headspace is off, you have bad parts. I've never headspaced an AR. Put new barrel or bolt on and go.
 
Pat,

Thank you for your reply. You are one of the people I know on this group whose opinions re accuracy I highly value. I put together an service rifle AR for someone roughly 3 years ago. The had a Kreiger barrel and said they sent the bolt out for them to "match" with the barrel. I understand that the bolt interfaces with the barrel extension.

Is that snake oil??

One other question. This one personal. I have a very high quality barrel (the brand is escaping me. One of their claims to fame is that their barrels are hand lapped to a high degree of finish) that has a great rep for excellent accuracy on an AR10 that I built.

I confirmed headspace is within spec, but the gun is not shooting nearly as well as I thought it should. I'm aware of the whole concept of free bore and just out of curiosity loaded a round very long and chambered it, which set the barrel back to a point where it was just engraving the rifling.

This was a couple of years ago and I haven't really played with the rifle lately, but I remember that I thought the freebore was excessive if loaded with rounds that would fit in a magazine. Do you have any thoughts on what a reasonable amount of "jump"is for a semi-auto rifle with a focus on accuracy??
 
I think CDNN still has Bushmaster BCG's for $60.

Toolcraft BCGs are absolutely top notch and amazing quality for the money. Heck, they’re great quality regardless. If someone wants a fancy, improved BCG, I’d send them to LMT. But my new standard for normal BCG recommendations is Toolcraft.

My personal preference is a DLC coated Toolcraft with a 9130 steel bolt instead of Carpenter 158. But the nitride one will probably last just as long.

Really, BCM and others will do just as well, but why not save money?
 
Pat,

Thank you for your reply. You are one of the people I know on this group whose opinions re accuracy I highly value. I put together an service rifle AR for someone roughly 3 years ago. The had a Kreiger barrel and said they sent the bolt out for them to "match" with the barrel. I understand that the bolt interfaces with the barrel extension.

Is that snake oil??
It’s not snake oil, but it also has nothing to do with precision of the gun. It just means the company is doing the headspace check for you. Though, I bet the vast majority of barrel/bolt combos they “match” are the first bolt or barrel they pick up. It’s pretty rare to have a new bolt with bad headspacing.

This was a couple of years ago and I haven't really played with the rifle lately, but I remember that I thought the freebore was excessive if loaded with rounds that would fit in a magazine. Do you have any thoughts on what a reasonable amount of "jump"is for a semi-auto rifle with a focus on accuracy??

What is reasonable is what the ammunition likes. Mag length is mag length and not a whole lot you can do with that. I’ve found that secant ogive bullets like the Hornady A-Max are really particular about jump, so they’re probably not the best option if you can even fit them at mag length. Sierra SMKs and TMKs and similar are more forgiving.

But if you’re interested in hand loading the rounds, play around with some different jumps until you find one your ammo likes in that barrel. I generally stop at the lands and don’t really play around with jamming the bullet into the rifling. It increases case pressure and I just don’t feel like testing the limits there. But some people do.

I can’t speak for 7.62, but for 5.56, I’ve had very good luck with Hornady ELD bullets at mag length. They’re similar shape to A-max, but the 73gr ELDs do 3/4 MOA in my Service Rifle. I don’t know why the ELDs May be more forgiving about jump than A-max bullets, but they seem to be. It could be that they just really like the extra jump found in mag-length loading.
 
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Toolcraft BCGs are absolutely top notch and amazing quality for the money. Heck, they’re great quality regardless. If someone wants a fancy, improved BCG, I’d send them to LMT. But my new standard for normal BCG recommendations is Toolcraft.

My personal preference is a DLC coated Toolcraft with a 9130 steel bolt instead of Carpenter 158. But the nitride one will probably last just as long.

Really, BCM and others will do just as well, but why not save money?

I have a LMT "lobster claw" improved bolt on my highest round count AR. Its pretty cool. But the problem is that because of its proprietary nature (it uses 2 springs) you can't install the Crane O ring upgrade in it. It really doesn't need it. But I guess what I'm getting at is that its proprietary. Although it did run to 11,000 rounds before I started having failures to extract. That's good, but I had to get the replacement springs directly from LMT.

While a regular bolt, you can buy 3 of these kits for a total investment of $15 and keep one in your range bag, another in your AR parts box, and another in your bug out box.

 
While a regular bolt, you can buy 3 of these kits for a total investment of $15 and keep one in your range bag, another in your AR parts box, and another in your bug out box.


I started using those overseas. They are consistently used in every AR bolt I have. :)

As a Company armorer, aside from bad magazines, the number one cause of M4/M16 malfunctions were worn extractors. I ensured the arms room was stocked with spares. I replaced them prior to deployment, regardless of state, and checked them at intervals sooner than mandated while deployed. But those little o-rings seemed to have helped extend extractor life before malfunctions.
 
The bolt is the wear item that needs periodic replacing. Not often, but every couple of barrels or so. The carrier doesn't really see any wear at all.

I just drive over to Windham Weaponry whenever I get a sale notice that they have complete BCG's for $100. Nothing special; just mill spec parts.

I have Windham Weaponry BCGs in every AR (15 or 10) have except one upper for LR-308. They always work fine. Usually have a black friday sale and I pick up new ones then for new uppers. havent had to replace yet
 
Pat,

Thank you for your reply. You are one of the people I know on this group whose opinions re accuracy I highly value. I put together an service rifle AR for someone roughly 3 years ago. The had a Kreiger barrel and said they sent the bolt out for them to "match" with the barrel. I understand that the bolt interfaces with the barrel extension.

Is that snake oil??

One other question. This one personal. I have a very high quality barrel (the brand is escaping me. One of their claims to fame is that their barrels are hand lapped to a high degree of finish) that has a great rep for excellent accuracy on an AR10 that I built.

I confirmed headspace is within spec, but the gun is not shooting nearly as well as I thought it should. I'm aware of the whole concept of free bore and just out of curiosity loaded a round very long and chambered it, which set the barrel back to a point where it was just engraving the rifling.

This was a couple of years ago and I haven't really played with the rifle lately, but I remember that I thought the freebore was excessive if loaded with rounds that would fit in a magazine. Do you have any thoughts on what a reasonable amount of "jump"is for a semi-auto rifle with a focus on accuracy??
No, it's not snake oil. Like Pappy said, they are just ensuring the bolt properly headspaces on that extension. Bolts are fairly inexpensive, so it's not a bad idea to change it with each barrel, especially high-dollar barrels that typically will go 5000+ rds before they need a change.
 
Toolcraft BCGs are absolutely top notch and amazing quality for the money. Heck, they’re great quality regardless. If someone wants a fancy, improved BCG, I’d send them to LMT. But my new standard for normal BCG recommendations is Toolcraft.

My personal preference is a DLC coated Toolcraft with a 9130 steel bolt instead of Carpenter 158. But the nitride one will probably last just as long.

Really, BCM and others will do just as well, but why not save money?
No, it's not snake oil. Like Pappy said, they are just ensuring the bolt properly headspaces on that extension. Bolts are fairly inexpensive, so it's not a bad idea to change it with each barrel, especially high-dollar barrels that typically will go 5000+ rds before they need a change.

I thought it was something more like lapping the lugs on the bolt to mate with even pressure with the lugs on the extension.

Shoot. I can headspace an AR myself. Thanks.
 
I thought it was something more like lapping the lugs on the bolt to mate with even pressure with the lugs on the extension.

Shoot. I can headspace an AR myself. Thanks.
I think ideally laping the bolt to the extension would be nice. Although I see this as a bit hard to do. You have many lugs that need to be lapped evenly.
When I bought my match barrel/bolt I was told that they leave the chamber a touch short and final cut the chamber to the bolt for darn near minimum head space. ? Who knows if it was a added step that actually helped.
That was close to 10 years ago and I dont shoot much these days so any skills I have are depleting rapidly .

how far do you want to go?
I cant see going to crazy if your blasting M193/855 type fodder.

if you need a lapped bolt , did you lap your reciever?1
 
Toolcraft BCGs are absolutely top notch and amazing quality for the money. Heck, they’re great quality regardless. If someone wants a fancy, improved BCG, I’d send them to LMT. But my new standard for normal BCG recommendations is Toolcraft.

My personal preference is a DLC coated Toolcraft with a 9130 steel bolt instead of Carpenter 158. But the nitride one will probably last just as long.

Really, BCM and others will do just as well, but why not save money?

I did not know that! Good to know.

I'm still looking at the 800 different AR upper builders out there to get the best value for a 300BLK pistol upper. Optimal bbl length is 9". Everyone wants to sell you a 7.5 or a 10.5. LOL. I did notice one builder/reseller uses Toolcraft BCG's. I had no idea quality. Might make me lean that way. Although I'm tempted to wait another week and see if I can BF this Mofo.
 
I did not know that! Good to know.

I'm still looking at the 800 different AR upper builders out there to get the best value for a 300BLK pistol upper. Optimal bbl length is 9". Everyone wants to sell you a 7.5 or a 10.5. LOL. I did notice one builder/reseller uses Toolcraft BCG's. I had no idea quality. Might make me lean that way. Although I'm tempted to wait another week and see if I can BF this Mofo.

Yeah, check them out. There are plenty of capable BCGs out there, but I haven’t found a better one for the money of a Toolcraft and many equal ones cost more.

For a 9” 300BLK, is BCM out of consideration for any reason?
 
I have been pondering the thought building a 308 AR 15 and I’m thinking about possibly going AERO Precision with the billet upper and lower. This was’t going to be a simple cheap build either but something nice and expensive, well worth putting together.
If there is a better 308 matched upper and lower like to know as long as it’s a cool looking billet and not boring looking like a standard AR15.


RC

A friend has an Aero M5 combo, its sweet, can't be beat for the money. Its not billet, but resembles billet, you forget that its not billet looking at it. he also got a matching Aero handguard, looks awesome and feels robust.
He went big on the engine and transmission. Went Proof Research carbon barrel and a matching Jp bolt with Jp carrier. Proof research uses JP bolts for head spacing.
 
BCM is my go to. I mean upgrading the bcg isn't going to yield any noticeable changes to the gun. I also don't get the fascination with all the gucci coatings.
 
BCM is my go to. I mean upgrading the bcg isn't going to yield any noticeable changes to the gun. I also don't get the fascination with all the gucci coatings.

They clean easier. Not that its a game changer, but they wipe off nicely.
My LWRC has Nickel boron carrier, and its literally the smoothest cycling Ar15 i have. Manually charging the gun is noticeably smoother than my colts or spikes with ordinary BCG's. Im also wondering if it has something to do with the inside of the upper being cerakoted.
Now a days Nickel boron carriers have become cheaper, so its not like they carry a huge premium like they use to.
 
I actually do that. Its a sickness.
Nice, i get it it can be maddening!
I been lucky enough that my AR builds shoot better than I will so i dont go to crazy.
Looking for a big hole upper bushing to use on my small hole lower to try out my A1 slap together.
 
They clean easier. Not that its a game changer, but they wipe off nicely.
My LWRC has Nickel boron carrier, and its literally the smoothest cycling Ar15 i have. Manually charging the gun is noticeably smoother than my colts or spikes with ordinary BCG's. Im also wondering if it has something to do with the inside of the upper being cerakoted.
Now a days Nickel boron carriers have become cheaper, so its not like they carry a huge premium like they use to.

The thing is that all the crap wipes off with an oily rag anyway except way back inside the carrier where the gas vents into the cylinder where the bolt intercourses. That needs to be scraped no matter what the coating. (But not very often and it only tends to build up if the gun is run hot. I've never scraped the inside of the bolt carrier on my service rifle in 10+ years)

I've got an AR10 with nickel boron coating and an AR15 with NP3.

I see no benefit to either other than that they look sexy. I got deals on each of them, the premium wasn't much so I gave it a try.
 
Yeah, check them out. There are plenty of capable BCGs out there, but I haven’t found a better one for the money of a Toolcraft and many equal ones cost more.

For a 9” 300BLK, is BCM out of consideration for any reason?

Price, for one. This is a "let's see what this does" sort of thing. $600-800 for an upper is pretty steep for the amount of use. If it DOES get used, it's gonna get used at less-than-10-yards.
 
If the gun is going to be used at short distances and is going to be a range toy, then a cheapie PSA is fine.

I'd trust an AeroPrecision for a "what if" rifle. This looks reasonable.

 
If the gun is going to be used at short distances and is going to be a range toy, then a cheapie PSA is fine.

I'd trust an AeroPrecision for a "what if" rifle. This looks reasonable.


No PSA either. mASS. :(
 
A single gun-friendly person that I'd visit? No. No I don't. My liberal brother in NH. And I don't like driving up to see him. LOL.

I've been tempted to wander over the line into Tiverton and get a PO Box. I'm curious if PSA is pissy enough to not even ship OOS for MA residents. I think that More Expensive Than Dirt and Sportsmans Lack Of Guide both have issues with the purchaser AND shipping address. So now I've got to ask a buddy, give him money, have him order it, get it delivered to him, drive over there, pick it up, buy him beer.

Suddenly, that seems like a hundo or more of work. LOL
 
Post sandy hook, some other guys and I maintained a PO box in Salem,NH.

The way around your "OOS for MA residents" is very simple.

You log into your credit card's web management page and change your CC billing address ot the PO box.

Then you go onthe web site and order the stuff. Then both billing and shipping addresses are in the "free" state.

Than 3 minutes after you complete the transaction , you go back to your CC and change the address back to your home.

In my case, I usually used a card that used electronic billing, so I just left the billing address at the PO box.

Just to clarify. We used it to buy Mass LEGAL stuff that people wouldn't ship into MA. Reloading components, AR parts, etc.
 
What makes them the best? Are they better than milspec? What testing is done to bring them over an above the testing done on Milspec Bcg's?

Every LMT rifle is MP tested at 20 different points , the bolt carrier group consisting of 4 of those point over the normal 1 point of other manufacturers
 
Every LMT rifle is MP tested at 20 different points , the bolt carrier group consisting of 4 of those point over the normal 1 point of other manufacturers
So all this must be on their website somewhere to confirm?
Or you work there?

Mpi tested
Shot peaned
Test fired
What's the fourth?
 
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