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Posted: 2/5/2006 3:04:48 PM EDT
I am building a varmint upper.
Using a RRA 20" 1/8 varmint barrel, CMT upper,free float tube.
Which of the following bolt/carriers should I use?
DPMS US GI mil-spec chrome lined, or
DPMS chrome, or
Smith chrome match bolt/carrier.

I have heared that a chromed carrier will accelerate wear on the upper is this true? the chrome will peel or the chromed carrier are more likely to break.
What I would like is an accurate rifle that will be reliable.

Best Regards,
MickeyJr.
Link Posted: 2/5/2006 3:07:56 PM EDT
Colt
CMT MPC
LMT

Those are my preferences for bolt carrier groups. DPMS bolt carrier groups suck, in my experience.
Link Posted: 2/5/2006 3:48:30 PM EDT
LMT
Link Posted: 2/5/2006 6:39:57 PM EDT
I vote for the MP inspected CMT bolt with M16 or enhanced carrier (with shrouded firing pin).

Good alternate choices would be LMT with M16 or enhanced carrier and also the Colt M16 BCG.

I'm using all the ones that I mentioned except the CMT M16 carrier which I'll get for my next build.
Link Posted: 2/5/2006 8:32:49 PM EDT
+1 for cmt m16
Link Posted: 2/5/2006 8:55:31 PM EDT

read this over on the archive server -- great info...
archive.ar15.com/forums/topic.html?b=3&f=12&t=256488

ar-jedi

MSTN writes:

DAN YOUNG OF YOUNG MFG HAS LONG MADE THE BEST BOLT CARRIERS IN THE INDUSTRY. THAT'S BECAUSE HE DOES IT THE RIGHT WAY, THE HARD WAY. ALL FINAL TOLERANCES ARE ACHIEVED AFTER HEAT TREATING, NOT BEFORE. DAN YOUNG PATENTED HIS SEMI-AUTO "NATIONAL MATCH" DESIGN. HERE'S A PICTURE OF ONE I'VE HAD FOR SOME TIME:



IT'S PRACTICALLY WORN OUT, AS YOU CAN SEE. (JUST KIDDING.) YES, THAT'S AN LMT ENHANCED BOLT. YES, IT WORKS JUST FINE, THANK YOU.



LES BAER CUSTOM BOUGHT THE RIGHTS TO THIS DESIGN. YOUNG MFG STILL MAKES THEM, BUT THEY NOW CARRY THE "LBC" LOGO:



AS YOU CAN SEE BELOW, BOTH CARRY THE SAME PATENT NUMBER:



HERE'S DAN YOUNG'S NEWEST DESIGN:



HERE'S HOW DAN YOUNG FEELS THAT HE HAS, IN THEORY, IMPROVED ON HIS PREVIOUS DESIGN:



THE ORIGINAL PATENTED DESIGN IS ON THE LEFT. THE NEWER STYLE IS ON THE RIGHT. BOTH ARE LARGER IN DIAMETER THAN A STANDARD CARRIER. NOTE THE LARGER FLAT BEARING SURFACE AND SMALLER RADIUS ON THE CORNERS OF THE NEW DESIGN ON THE RIGHT. THIS PROVIDES IN THEORY AN EVEN TIGHTER, STRAIGHTER LOCK-UP.

M.S.T.N. STARTED OUT OFFERING THE YOUNG MFG N/M BOLT CARRIER IN OUR CUSTOM PRECISION UPPERS. WHEN LES BAER BOUGHT THE DESIGN, WE SWITCHED. WE NOW USE THE NEW YOUNG MFG N/M DESIGN IN OUR CUSTOM PRECISION UPPERS, AS WELL.

NEXT - STAND BY FOR THE USUAL SUSPECTS TO CHARGE THAT A STANDARD, RUN-OF-THE-MILL CARRIER IS JUST FINE, THAT THEIR COUSIN SHOT A 5-SHOT ONE INCH GROUP AT 300 YARDS WITH AN UPPER USING A BOLT CARRIER GROUP UNCLE HARRY HAD IN HIS M-16 IN VIETNAM, ETC.

THE RETURN ON THE INVESTMENT MAY NOT BE THERE FOR EVERYONE, I FREELY ADMIT. WE'RE JUST TRYING TO BUILD THE BEST PRECISION UPPERS WE CAN, USING ALL OF THE BEST COMPONENTS AVAILABLE.

HERE IS A PIC OF THE COMPETITION CARRIER PAUL HAD DAN YOUNG MAKE FOR US:



AS YOU CAN SEE, IT IS OF CONVENTIONAL DESIGN, BUT CUT AWAY TO REDUCE WEIGHT. AS WITH ALL OF YOUNG MFG BOLT CARRIERS, IT IS HEAT TREATED FIRST AND THEN RECEIVES ITS FINAL MACHINING. AS YOU CAN SEE, IT IS ALSO HARD CHROMED. IT THE COMPETITION CARRIER TIPS THE SCALE AT A SVELDT 8.2 OZ.

WHY A LIGHTWEIGHT CARRIER? IN COMPETITION SHOOTING, A SMOOTH RUNNING, FAST CYCLING GUN IS WHAT YOU WANT. MINIMIZING RECIPROCATING MASS MINIMIZES APPARENT RECOIL. THE RIGHT BALANCE FOR RELIABILITY IS ACHIEVED VIA CAREFUL TUNING OF THE ADJUSTABLE GAS PORT, BUFFER WEIGHT, RECOIL SPRING WEIGHT AND LENGTH, AND OBVIOUSLY BUFFER WEIGHT.

WES GRANT
M.S.T.N.




from a followup post:

EXCELLENT QUESTION.

THE BETTER YOU CONTROL MATERIAL, TOLERANCES, AND FINISH, THE BETTER YOU CONTROL THE END RESULTS. IF A DESIGN IMPROVEMENT HAPPENS TO WORK ITS WAY INTO THE EQUATION, ALL THE BETTER.

WILL YOU BE ABLE TO MEASURE THE DIFFERENCE IN ACCURACY WHEN SHOOTING WOLF AMMO OR BRAND-X RELOADS OUT OF AN UPPER YOU BOUGHT USED OFF A TABLE AT A GUN SHOW? PROBABLY NOT. RELIABILITY? POSSIBLY. BUT, YES, IT WILL BE EASIER TO CLEAN.

THE PERFORMANCE OF PRECISION UPPERS I BREAK DOWN AS FOLLOWS:

40% BARREL, I.E., THE BARREL BLANK

40% BARRELMAKER, I.E., THE GUY WHO CONTOURS, CROWNS, AND CHAMBERS

10% BUILDER

10% OTHER COMPONENTS USED

THE BOLT CARRIER FALLS INTO THIS LAST RATHER ARBITRARY 10%. WILL YOU BE ABLE TO SCIENTIFICALLY MEASURE THE DIFFERENCE IT MAKES WITH ONE UPPER? OF COURSE NOT. HOWEVER, WOULD THE CUMULATIVE EFFECT OF USING THE BEST GEAR WE CAN GET, E.G., BEST QUALITY BOLT CARRIERS, FITTED BOLTS, CRANE O-RING MOD, PRI GAS BUSTER, STAG OR LMT UPPERS, LARUE FORENDS, ETC., MAKE A MEASURABLE DIFFERENCE? I FEEL THE ANSWER IS YES.

THAT'S WHY OUR GOAL IS TO USE THE BEST COMPONENTS AVAILABLE IN OUR PRECISION UPPERS. I SIMPLY DO NOT CARE WHAT THEY COST. SOME OF THESE PARTS COST QUITE A BIT MORE THAN GENERIC EQUIVALENTS.

FOR EXAMPLE, A PRECISION REFLEX GAS BUSTER CHARGING HANDLE LIKE WE USE COSTS ABOUT FOUR TIMES AS MUCH AS A STANDARD ONE. IS IT GOING TO MAKE A DIFFERENCE IN ACCURACY OR RELIABILITY? PROBABLY NOT. IS IT GOING TO HELP KEEP GAS OUT OF YOUR PEEPERS? MOST DEFINITELY. WILL THAT BE WORTH THE PRICE DIFFERENCE?

IT'S YOUR MONEY. SPEND IT AS YOU SEE FIT.

WES GRANT
M.S.T.N.

Link Posted: 2/6/2006 6:25:45 AM EDT
:: drool :: Well that's a very nice carrier but what ever shall I put inside there?
Link Posted: 2/6/2006 6:47:24 AM EDT

Originally Posted By TheMocoMan:
:: drool :: Well that's a very nice carrier but what ever shall I put inside there?



and then what to wrap around it...

ar-jedi









Link Posted: 2/6/2006 6:54:28 AM EDT
The CMT MPT bolt carrier groups are available for $130 shipped, and are probably one of the best buys available right now.
Link Posted: 2/6/2006 8:05:30 AM EDT
Do you need an FFL for M16 carriers? Some sites say you need an FFL (or class III or whatever), and some sites dont.
?
Link Posted: 2/6/2006 8:07:43 AM EDT
CMT M16 MP

In fact I have one for sale in the EE
Link Posted: 2/6/2006 8:08:59 AM EDT

Originally Posted By dangerdan:
Do you need an FFL for M16 carriers? Some sites say you need an FFL (or class III or whatever), and some sites dont.
?



No.

Colt's been shipping complete rifles with m16 BCG.

I've bought them from Bravo and G&R with no problems.
Link Posted: 2/6/2006 8:09:39 AM EDT
+1 for CMT, just as good as LMT w/o the price jump
Link Posted: 2/6/2006 2:18:03 PM EDT

Originally Posted By dangerdan:
Do you need an FFL for M16 carriers? Some sites say you need an FFL (or class III or whatever), and some sites dont.
?



FFL, no that's for the transfer of a lower.

the deal with the M16 carrier is that the ATF has long stipulated "ANY machine gun part installed in a weapon makes it a machine gun, and therefore NFA Title II rules apply". hence, the issue of using an M16 carrier in an AR15. whether anyone has actually been hoisted up for it is another matter.

example,
www.bushmaster.com/shopping/uppers/8448507-s.asp

Does not include key. M16 Carriers must be used in Title II Receiver for legality.

and the fine print at the bottom:

M16 carriers must be used in Title II Receivers for legality. FFL or Tax Stamp required for purchase. M16 parts NOT legal for Sale in California.


right, wrong, stupid, you decide. it's your 20 years in federal pound-me-in-the-ass prison.

ar-jedi
Link Posted: 2/6/2006 3:28:40 PM EDT
uh oh......
Link Posted: 2/6/2006 3:33:29 PM EDT

Originally Posted By Stickman:
The CMT MPT bolt carrier groups are available for $130 shipped, and are probably one of the best buys available right now.



+1
That is what I am using on mine.
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