Accept the premise that you can have just one...

If you had to choose between the two semi-auto M14s
pictured here, which one would you choose and why?

The M21 A5 Crazy Horse EBR or the CQB-16?

For where I live and my BOL, I would take the M21 because I can stretch it's legs so to speak.   I have open areas that could be covered better with the magnified optic and longer range.  If I am at work in the city or driving, the CQB would work better for me.

For me, it would depend on what I was doing, or planned to do.

The M21A5 as it was built for the US Army 2nd Infantry Division including the Phase II upgrade is what I would choose.  From there, install a SEI radius groove piston and a Gen 6 Vortex flash hider and have the barrel hand lapped.

This M21A5 has the grooved piston and Gen 6 Vortex.

What are the 2nd ID Phase II upgrades?

What is involved with hand lapping the barrel?

Thank you.

There were 110 M14 NM and XM21 rifles rebuilt for the US Army 2nd Infantry Division between September 2004 and August 2005.  This configuration of M14 variant was classified as the M21A5/CIED by July 2007.  The Phase II upgrades were available by the spring of 2005.  The upgrades included S-7 alloy steel connector lock and trigger and hammer pins, slightly enlarged barrel gas port, chromium silicon alloy steel operating rod and hammer springs, and operating rod guides sized to fit the M21A5 barrels.  The M14 G6A3 flash hider and the M14 radius groove gas piston did not exist until 2012.  The Gen 6 flash hider has an exterior groove cut into the flash hider body at a pitch of 10 TPI.  The exterior groove facilitates removal of a sound suppressor after extended use due to carbon buildup.  The radius groove gas piston differs from the original M21A5 thin dense chromium plated gas piston by polishing the plated surface to a finish of 9 microinches, holding the internal hole dimensions to within 0.001 " tolerance, and making a full radius cut to form each circumferential groove vice a flat bottom cut.

Per the moderator unclenick's 02-18-2010 post on shootersforum,

"For true lapping you have basically two alternatives: hand lapping and firelapping. The first normally uses a lapping slug on the end of a cleaning rod that is cast into the muzzle of the bore by plugging the bore back an inch or two with patches or paper and pouring molten lead into it. Grooves similar to lead bullet lube grooves are cut into the cast slug with a knife or a gouge to hold abrasive compound. The lap is loaded (the grooves filled) with abrasive and run back and forth in the bore by hand. It's s common to use something like 320 grit silicone carbide lapping compound (Clover compound, for example). The slug is usually pure lead so that when it encounters a constriction it is narrowed and does not spring back out after passing through it. In this way all abrading on subsequent strokes is only in the tight spots. When you feel it stop cutting tight spots, you can bump the lap back up with a brass rod and hammer, and go at it some more. You keep repeating until the bore has no more tight spots and the lap feels smooth down the length of the bore.

The other method is firelapping. This involves shooting abrasive embedded bullets through the bore with very light loads that get low airgun velocities (300-500 fps). The lapping bullets are usually cast bullets in the hardness range of 10 to 12 BHN. This number range is a compromise. It doesn't limit itself to cutting constrictions as completely as pure lead laps on a rod, but it is malleable enough that it doesn't lap the wide places nearly as hard as the narrow ones. The reason it isn't pure lead is that where a pure lead hand lap can be pushed through a constriction by rod without bumping up, when you have even firelapping load pressures on the base of a pure lead bullet it will bump up to rub the wide spots as well as the narrow ones. At the other extreme, an alloy bullet of higher BHN is surprisingly elastic and will go tightly into the bore and stay tight all the way down its length, thorough narrow places and wide ones. That tends to remove material evenly everywhere. You don't want that because, while it widens tight spots, it widens wide places equally, so you don't level off major irregularities; you just smooth those shorter than the length of the slug. When you are done firelapping, irregularities are gone and it leaves the bore very slightly tapered down toward the muzzle. Maybe a half thousandth or so. This is considered desirable for accuracy, especially when the bore is to shoot lead bullets.

Either lapping method will reduce metal fouling, making the bore easier to clean. Firelapping has the advantage that in addition to introducing the slight taper, it also cleans the throat up. Hand lapping does not normally clean the tool marks off the throat because the rifling is cast into the slug when you pour the lap."

It is my understanding, note that I am not a gunsmith, hand lapping a barrel can achieve greater accuracy than by fire lapping.  YMMV

H2O_MAN that is a tough question, it would probably depend on what else I had in my armory and intended use.
I'm at a similar dilemma having a M1A standard and an EBR chassis on hand but considering a shorter 762 rifle to compliment it if I put the M1A in the chassis.

The draw back I see to the Crazy Horse is limited use in CQ due to its length and heft but it does offer stand off ability, remember distance is your friend.
The 16" M14 would be more practical if it had a magnified optic and use of irons as backup but would suffer velocity loss and accuracy due to shorter barrel and stock choice.
With a suppressor mounted the 16" wins hands down unless you're gonna keep the Crazy Horse on a bipod.

Hope you ain't losing sleep over this, LOL

Old Marine

Different, I appreciate the detailed response.
I know mine has all of the Phase II upgrades & more, but I will have to check with SEI about the lapping.



SSgt82-02, thank you for your comments... no sleep is being lost

Just as a FYI, the 2nd Infantry Division contract specified a minimum accuracy of 1 " at 100 yards for a three shot group using factory ammunition for the M14SE (later M21A5) rifles.   The accuracy test range target was shipped with each rifle back to the division.  The 22 " long 1:10 right hand twist four groove medium weight barrels were supplied by Wilson Arms and cryogenically treated per the contract.

Lee, you never fail to amaze me with your wealth of knowledge.

Thank you for sharing.

Yes, the missions & capabilities of the two rifles are very different.
The M21A5 is meant for a longer range, DMR, SASS mission.
The CQB-16 is meant for targets inside 300 yards or so as configured,
and yes, the irons do co-witness through the Aimpoint Micro T-1 RDS.

The 1-6 optic on the M21A5 matches the 600+ yard capabilities of the CQB-16
much better than the long range "reach out and touch" capabilities of the M21A5.

I will probably reconfigure these rifles later this year.

disposable income - what's that?

I'd go with the shorter one. I tried to like the SAGE chassis but it's to heavy for just a semi auto rifle. Spending some time on with the irons its not hard to get confidence with an M14 out to (or at least very near) four digit yard lines.

No, I'm not saying I can shoot as good with irons as someone else can with a scope.

Between the two, I would use the M21A5. I have an AR for "CQB" type stuff, so a 308 with a Micro isn't super practical IMHO. I would much prefer the bedding of the EBR paired with a magnified optic, which would let me make hits from 50-600/800m depending on the magnification and the shooter's ability.

HOWEVER,

An 18" bbl in an EBR with a magnified optic would be the best of both worlds.

I appreciate everyones comments, you are helping me sort things out

My first builds were 18" MK14s, and I still say that the 18" barreled action is the best compromise for general purpose use.
I sold both of mine, so I'm working with what I have; 16.25" & 22.00"

As the discussion moves forward, I'm thinking the CQB-16 may end up in a Blackfeather "RS" with their new LSP top rail.
Move the 1-6 glass to the "RS", and add BUIS... the M21A5 deserves glass that better matches the rifles capabilities.

I think this is the ticket. 6x on the 16.25" will definitelu make hits to 600m provided you do your part. Get some nice German glass with solid tracking, greater magnification, turret adjustments that match your reticle (mil/mil or moa/moa) and push that M21A5 out to 1km.

The German glass will have to wait... it's iron sights for now.

Blackfeather CQB-16 / M21 A5 Crazy Horse EBR



SuperSized Image

I've been drooling over that build with all the pics you've posted on FB recently. It is VERY well done.

I would think with the 16" you could easily hit at 300 on torso and further without too much problems.  Not sure if the aimpoint becomes a detriment too far out.  For me it's the simpler and sleeker the better.  Those big ole stocks just seem, I don't know cumbersome.  Yeah, if you were in the 2nd ID and in tip top shape and wanted to reach out and touch someone in a fairly competent manner each time, the other one is the better.  But you asked what WE would do and that wouldn't be me (choosing the larger one).

I agree, the full length EBR is better suited to the young warrior that's  in tip top shape... that ain't me

The lighter, more compact Blackfeather CQB-16 is better suited to me.

Weight is also a factor.

The most common EBRs use the heaviest variant of the tried & true EBR chassis, the M14ALCS.
My M21 A5 EBR started out as an M14ALCS. I upgraded to the lighter PMRI/PRS2 butt stock.

The NSG "Dot Matrix" EBR pictured here with nothing but iron sights remains 7.2 oz. heavier than the Blackfeather CQB-16.
The FDE Blackfeather CQB-16 is fitted with the LSP monolithic top rail, and a rather heavy optic/ring combo, plus a spacer.

It's not an apples to apples comparison, but you get my point.




Weight as pictured below

Blackfeather CQB-16: 10 1/2 lbs.

M21 A5 Crazy Horse EBR: 13 lbs.

If weight is a deciding factor, why not go with an ACOG and MRDS over the Vortex? with a direct mount like the GDI.

That was the configuration i was going for to minimize weight and offer CQB to mid range with the instant transition of sight rather than to re-adjust your magnification and excess weight.

End users can set it up any way they want... the Vortex is my only scope.
I plan to shoot it scoped for a while, and then return to the Aimpoint Comp M4s.

The Vortex is back on the M21 A5 EBR, and I'm in the process of reconfiguring the CQB-16 Blackfeather for Aimpoint use.

A range report with images ~ soon.

Back to basics.






My quick change muzzle device solution.

lapping a barrel

Thank you xviperx420

B.U.I.S. are possible on the Blackfeather RS fitted with the SHG.
Lower 3rd co-witness through the EXPS3-0