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ty423
03-11-2008, 1:45 PM
I see a pretty significant price jump from a standard bolt carrier then there is a "enhanced" bolt carrier. What is the difference? Is it worth the extra dough? What other different type of bolt and bolt carriers are there? What are the advantages of each.

aplinker
03-11-2008, 1:52 PM
It means it's taken male enhancement supplements :D

It has changes to the bolt carrier in terms of mass and geometry that improve strength & reliability

The bolt itself has additional springs and gasket to improve reliability.

NSR500
03-11-2008, 2:20 PM
Enhanced, like Stallone was for the most Recent Rambo movie. ;)

kap
03-11-2008, 3:35 PM
I have an LMT Enhanced SA bolt carrier group in one of my OLLs. Basically it has minor difference with the most obvious being an extra gas port which supposedly increased the dwell time and allows for easier extraction of the spent case. This is also supposed to decrease the amount of residue buildup from the gas operated system. I would say that it is just a cool factor toy for the rifle and not worth the price unless you are going to be shooting a lot of round quickly and need your rifle to be reliable.

viras
03-11-2008, 4:00 PM
So basically, since it was made for military full-auto applications, you wouldn't need it for recreational semi-auto shooting...right?

If one were building a SHTF TEOTWAWKI rifle, would an enhanced bolt carrier group be preferred over a regular bolt carrier group?

saki302
03-11-2008, 5:02 PM
The heavier weight should dampen recoil and aid feeding. My riflesmith uses carrier weights in his competition guns- he said it's easier on the brass too.

-Dave

ty423
03-11-2008, 8:19 PM
What does different buffer weights do then?

mike452
03-11-2008, 8:53 PM
It's been enhanced! It must be better!

The price is crazy. LMT must have a patent on it.

ar15barrels
03-11-2008, 9:04 PM
I put an LMT enhanced bolt carrier in my 6.8 SPC build to see if the additional weight would lower the recoil and help accuracy.
I haven't shot it with a standard bolt, but something seems to be working right.
http://www.hunt101.com/data/500/medium/9184TA_68_Hrndy110vmx021907.jpg

The carrier does not effect group size.
That's just a good barrel. ;)

Addax
03-11-2008, 9:12 PM
The carrier does not effect group size.
That's just a good barrel. ;)

And a good shooter!

ar15barrels
03-11-2008, 9:13 PM
What does "enhanced" bolt carrier mean?

There are two basic types of features on carriers, either SP1 or M16.
M16 is the original design.
SP1 style have unshrouded firing pins and the auto-sear shelf moved back.
These are changes that Colt did to keep civilians from building illegal machineguns.
M16 carriers have a shrouded carrier and auto-sear trip.
There are hybrid carriers that have the shrouded firing pin, but no auto-sear trip and these are becoming the "standard" as companies get away from the SP1 features.
I call these hybrid carriers "AR-15 Enhanced" because they have the good features of an M16 bolt without the sear trip that makes some people question their legality as possible machine gun parts.

http://ar15barrels.com/tech/ar15carriers.jpg

LMT's "enhanced" carrier is a whole different beast.
Some of the changes were mentioned above, but the most important one has been missed by everyone.
The LMT enhanced carrier has a re-timed cam pin slot that delays unlocking.
This is a specific benefit to carbine length gas system 14.5" and 16" barrels.
This delayed unlocking is not beneficial on most other barrels and has actually caused short stroking in many cases.
LMT specifically warns against using their enhanced carriers in 10.5" uppers.

ar15barrels
03-11-2008, 9:15 PM
And a good shooter!

The inside joke is that I made that barrel. ;)

Addax
03-11-2008, 9:22 PM
The inside joke is that I made that barrel. ;)

Yeah, I pretty much presumed that one bud. :D

Btw, Nice write up on the Enhanced Bolt Carrier.

dfletcher
03-11-2008, 9:41 PM
May I piggy back the thread a bit?

Embarking on my 1st build with two uppers, one a shorty and the other a 20" to 24" heavy barrel type. I don't mind spending money where it's needed, is buying each upper with the bolt carrier group included better than buying one with and one without, swapping the bolt between the two? I presume with good quality uppers and bolts the parts interchange - or should I have a bolt dedicated to each upper? Do the bolt & upper wear in together?

aplinker
03-11-2008, 10:49 PM
Bolt Carrier Group for each upper.

The carrier is less important than the bolt itself.

oaklander
03-11-2008, 11:03 PM
I do not recognize those parts you speak of. Here is what I think of when I picture a BC:

http://www.aa-ok.com/ak29.jpg

:D

They are all enhanced.

ar15barrels
03-11-2008, 11:17 PM
Embarking on my 1st build with two uppers, one a shorty and the other a 20" to 24" heavy barrel type. I don't mind spending money where it's needed, is buying each upper with the bolt carrier group included better than buying one with and one without, swapping the bolt between the two? I presume with good quality uppers and bolts the parts interchange - or should I have a bolt dedicated to each upper? Do the bolt & upper wear in together?

Do NOT share a bolt between two or more barrels.
A bolt and barrel extension "seat" into each other within the first few hundred rounds.
It wears each time it "seats" into a barrel, but then the wear mostly stops for the life of the part.
So, each time you switch, it wears a little more.
This wear is very minute, but after a while it will stack up into enough to make the bolt and both barrels go out-of-spec.

At the bare minimum, dedicate a BOLT to each upper.
You could swap the carrier and charging handle.
In the end, it's not worth the hassle.
Just get a complete bolt carrier group for each.
You WILL eventually end up with another lower.
It's a fact that lonely uppers breed lowers and lonely lowers breed uppers.

ar15barrels
03-11-2008, 11:18 PM
I do not recognize those parts you speak of. Here is what I think of when I picture a BC:

Silly AK kids... :D

dfletcher
03-11-2008, 11:32 PM
Thanks for the info, off to Brownells for bolts.

saki302
03-11-2008, 11:49 PM
My 'smith told me you run the heaviest carrier weight that will still allow your gun to function- and it usually works well with the heaviest one.

You may also run M-16 carriers now since Colt puts them in all their semi rifles as of 06 or 07, I think- they basically told the ATF 'too bad'.. so now there is a precedence set..

ATF not wanting them to use the M16 carrier is retarded, IMO. The easiest illegal FA conversion, the 'lightning link' does NOT work with the M16 carrier, so doesn't it make it harder to illegally convert by using one?

-Dave

wolfmann
03-11-2008, 11:52 PM
This should be a sticky,thank you for such a informative post.
It helps this newbie out a lot on making decisions.

aplinker
03-12-2008, 12:20 AM
Possibly true, but then you have to swap out bolts every time you change uppers. Plus the bore in the carrier sees more wear and tear. With a dedicated BCG for each upper you also don't need to keep track of which bolt goes with which barrel.

Those are user issues, not rifle issues, but I completely agree it's far easier and the better choice. I was more referring to what is functionally an issue.

randy
03-12-2008, 1:25 AM
Saki I don't know who is building your rifles but that logic isn't used by the top builders. JP and MSTN.

They pretty much make the top of the line uppers for action shooting, I don't know about NRA hi power.

When shooting your AR your sight disturbance isn't effected as much by the BCG recoiling as it is when it returns to battery.

When it returns to battery your gun tips forward and to the right because of the mass of the BCG going forward and the bolt locking up to the right. A lighter carrier group, lighter recoil spring, buffer and adjustable gas block will give you less recoil.

ar15barrels
03-12-2008, 8:57 AM
My 'smith told me you run the heaviest carrier weight that will still allow your gun to function

This only applies to 16" carbine-gassed barrels.

saki302
03-12-2008, 4:03 PM
I see..

He did tell me with the weight system his AR-10 chews up brass much less.. but it is a carbine :D

I have an adjustable block on my JP upper'd gun, and the weight on my carbine. The JP upper is so darn heavy I don't see how any carrier would affect it much- it pretty much sits there while firing, you can watch the bullets impact at 50-100 yards easily- very easily beyond that.

-Dave