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I wanted to ask here first, I will have CWA build my semi auto M3HB for me next year. I have most of the parts except the sights, RSG, and barrel. I like the M2HB barrel, but I will have to put the barrel in everytime I take it out, I see there is a quick change barrel out. Is it a lot moe to go to that style of barrel, or just use the regular old barrel. Thanks, Jerod
 

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...a QCB...?

There are a few things that just should be left alone. After speaking with several current Army and Marine folks,mainly senior enlisted, it is prevelant among trainees that they are not taught the proper way to mount and head-space an M2HB. The QCB (quick-change-barrel) set up,engineered by Fabrique'National, is in some units already and does not require head-spacing. As such,those taught this weapon are not taught the basics of setting up the M2HB. In many instances,these troops are given the older style M2HB and they do not know how to set it up properly. Bad things have happened because of this lack of training. Personally,I would not want to have this QCB type weapon,as it may become difficult to obtain parts and can present some other problems. Just my opinion...
 

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BeltFed GURU
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WORD !!
The CQB system is headspaced with one of 20+ Breech Locks that are graduated in thickness and are depot set with the correct lock you change lot of ammo that is longer or shorter and you are screwed because you cannot re set the headspace in the field with the CQB system only the Depot can re set the head space !!

CQB uses not only a different barrel but also the barrel support ,barrel extension ,and the aforementioned breech lock set .All are Expensive ,Very Expensive :( !

Having said this it does work very well as long as your ammo is from the same lot or your reloading is Match level grade in the case resizing , too long and it will not lock up ,too short and you will destroy the barrel chamber .

A good friend destroyed the chamber in an AR-50 rifle because the rounds where resized to short "Hammer Forging" the shoulder into raising a burr right at the shoulder/neck junction that clipped the neck off a case rendering the barrel useless ! Oh he got the neck out eventually and not with a ruptured case extractor !! He removed the burr only to discover the shoulder was now lopsided :eek: .
He had the chamber reset /cut and the barrel is now a scatter gun and useless for accuracy cost him a new barrel , the chamber reset and the working of a new barrel to fit the rifle way over 1K$ spent ! The AR-50 and AR-50 NM has a mil spec chamber !!!! All in 120 rounds fired :jedicrying:!!

See my point ?
P.S. If CQB barrel is Stellite chambered you will not affect the chamber with short shouldered cases but you will rupture them with ease but is it worth $1500 for a barrel that will not lock up in battery if the shoulder is too long ?
 

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I store my M3Hb broke down, bet almost everybody does. It only takes a few seconds to head space at the range. No big deal.

Karl
 

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The QD design sucks. It just plain sucks. Ive been using the M2A1 for about 4 years now and we get 1 out of 5 running, if we are lucky. They have been checked by the depot, verified and checked again. We were told to just 'break them in' and 'run them wet'. Its an absolutely atrocious design.

PLEASE understand that properly headspacing a M2 takes all of 20 seconds. Learn how to do it right and the gun will never let you down.
 

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To headspace the weapon:

1. Raise the cover all the way up and retract the bolt.
2. Screw the barrel all the way into the gun, then back off two clicks. (To tell ya the truth, this is where most guys stop when they're in Indian Country.)
3. Charge the weapon and ride the bolt forward. Don't let it slam home; since the gun isn't loaded, if you do that you'll damage the bolt.
4. Retract the bolt about 1/16" and hold it there until you've used the gage.
5. Raise the cartridge extractor, push in the alignment guide and try to put the "go" end of the headspace gage in the slot between the face of the bolt and the rear of the barrel. There's a ring on it. If you can get the gage to go in all the way down to the ring, pull it out, turn it around and try to put the "no go" end in the same place. If the "go" gage went in and the "no go" gage didn't, you're done. If the "go" gage didn't go in, unscrew the barrel one click and try it again. If the "no go" gage went in, screw the barrel in one click. Keep doing this until the go gage goes in and the no go gage doesn't.

ANOTHER NOTE FOR M3HB

Hey Karl, I just sent you an email about sending payment for the gauges.
To answer your question:
On the barrel extension, on the right front side, there is a slot for the
barrel retaining spring. You MUST use the spring for the M2HB. The M2
spring leaf has a detent on both sides, one tooth goes into the grooves in
the barrel and the backside tooth goes against the right side plate. The M3
spring has only one "tooth" on the inside that touches the grooves on the
barrel but nothing touches the rsp. The barrel on the M3 can still be
rotated by hand when the bolt is forward. The barrel on an M2 can not be
rotated by hand with the bolt forward...in battery. With the M2 you have to
retract the charging handle until you can see the "tooth" on the backside
of the M2 spring through the hole provided for that purpose. I think the
manual has pictures that show this. The M3 was an aircraft gun and once the
headspace was set there weren't any little hands around to mistakenly turn
the barrel and ruin the headspace.
Let me know if you have any other questions. TANKER



Karl
 

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PhD in Over-Engineering
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My understanding on the QCB systems is that each manufacturer has their own distinct variation. You have FN, General Dynamics and U.S. Ordnance at least, and I don't know how different they are. Never had my hands on any of these systems.
 

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When I bought my M2HB at the end of the last century , I had the choice of an FN front and rear for $4,000 , a USGI rear and FN front for $5,000 and all USGI for $6,000 . Because of my USGI WW2 fettish , I paid $ 6,000 . Reading the above info , of which I was not totally aware of , I was lucky in my choice .

I've told the story of my nephew , US Army , sent a couple of times to the sandbox , Tank recovery during the day , artillery perimeter with thier 50s at night .
When we talked about how he liked the 50 , I found he did not know how to set the headspace nor even that he could / should . I taught him on mine , gave him a set of gauges , he set all of thiers in his unit , taught everyone how to do it , and left my gauges there for the next units when he returned home . I could not see them not training everyone to set the headspace . Training on a new system then giving them the old is a reason , I guess .

Chris
 
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