MK12 Long term...9800+ ROUNDS

[Asm1]

By asm1 at 2011-06-09


It is allways with me 24/7 I can reach it now from this key board..
I built the upper and it has been together the whole 9800 rounds never taken apart(other than normal cleaning) nor has anything came loose as the ones crane built did (I heard).Blue loktite is your friend on the outer tube nut..



I built My version of an MK12 MOD-0...I call it the MK12 MOD 0.5,I have 9800+ rounds down range useing 77mk and 75BTHP, hand throw 24.5gr of RL15 In LC/wcc/ case's and some MK262 test ammo for SUMMIT ,Accuracy has allways been very good with the weapon .5MOA to MOA and worst 1.5 MOA on the rough days cold/hot,The days I should be in the Heat,AC or Dry.. I use this weapon in a harsh way,realy The whole kit is one tuff SOB and I trust it with my life..

I used a LMT m16 enhance Bolt carrier less the LMT enhance bolt,These have a 3rd gas exhaust port and dump more preasur,I installed Tub's CARRIER Weight Systeme with the heavy tungsten insert,The 3rd port LMT carrier and the weight along with the rifle length gas systeme on WOA 18" barrel make the Impulse long slow and smooth.

Went threw a Couple Pin retainers The aftermarket one peace cool one's Last 3000 rounds and brrke in half,But they allways held the Fireing pin in and fell out when I took the carrier out of the upper to clean it,I have went back to the normal carter style pin..

I Replaced the CAM 3 times,its a Wear Item,Never broke just looked like a beaver was working on it..
I Use a AAC CAN 50/50,I ran 900 rounds threw and it was so dirty I didnt even want to try and clean it.I Used the local Car wash on the MK and it cleaned up great fast and easy!,I was shooting 30 feet stream out the barrel with soapy water,I also cleaned the lower and bolt/carrier the same way,I then did my barrel cleaning as normal and it was little effort to clean anything left.

I Remounted the mk4 with Larue rings on the PRI RECCE rail and went to 564 Yards lased,Ran my dope dent 5 rounds downrange as normal it was under MOA Center of AR400 Perfect !

I had No malfunctions or any problems with the weapon,I have used alot of Diffrent scope's trying to find the end scope that does it all, other than that its the same Kit I put together almost 10,000 rounds AGO...

I could make myself look bad if I told you how I beat this gun so I will not tell you,But I will tell you It didnt brake it,so its a tough Sum Bitch.

Parts I used to build this MK.

Bushmaster M4 lower was complete from the factory I installed these parts.
CTR magpul
2 stage RockRiver trigger
Magpul alloy trigger guard
Tango down standard Grip
Rest is factory bushmaster parts Buffer tube,spring/buffer and lower parts
Painted to match the AO of the Time.

Upper
Daniel Defence M4 UPPER RECIEVER.
PRI rifle lenght GEN2 RAIL TUBE with Lugged upper rail.
PRI RECCE Rail ties with bolt to the lugged upper rail. .400 thick.
PRI front Barrel mounted clamp on BUIS/gas block.
PRI GAS BUSTER charging handle.
Swan 40L Dual plane rear BUIS.
Rifle gas tube from WOA.
WOA 18" SPR contour Rifle gas 1-7 twist SS Bonded black.
WOA/MPI Bolt.
LMT Enhance carrier.
Standard MILSPEC parts in carrier group.Fir pin/cam bolt/key.
AAC 18T phanton flash hide Can Mount.
LARUE hybrid Bipod.
LARUE 1.25 tall Rings(with RECCE RAIL 1.65" tall from deck to center). works with PVS22 and PVS24 clip on..
Leupold MARK4 MR/T 2.5X8X36 M1 mildot.(Current scope)
Vickers Blue force sling.
Daniel Defence rail mounted QD sling mount.
AAC-7.62SD CAN.


I used the following scopes on the MK at one time.


USO SN4 1-4
USO SN4 1.8X10X44
PMII 1-4 SHORT DOT CQB/Locking turrets.
HORUS TALON 1-4(2 diffrent ones)Circle goes round and round
ELCAN specter dr 1-4
ELCAN 4x fixed
Vortex 1-4
ACOG TAO1 NSN (USED 2)
ACOG TA31F
ACOG TA11
ACOG TA47
MINI RED DOT/Buis all over the place
Eotech 3 diffrent models
AIMPOINT M2,M3,M4
EOTECH 4X mag
Aimpoint 3x mag with all kinds on mounts
PVS14
LEUPOLD MK4 3.5x10x40 M1(2 diffrent ones)Circle goes round and round
LEUPOLD MK4 3.5X10X40 M2
LEUPOLD MK4 1.5-5 M2 SPR (Used 1st gen and 2nd gen)
Leupold MK4 2.5X8X36 M1 MILDOT(current scope)
Leupold MK4 4.5x15x50 M1 PR genII Mildot
Leupold MK4 6.5X20X50 m1 TMR
NIGHT FORCE 1-4 FC2 2 diffrent scopes 1st closed cap 2nd Zero stop
Night Force 2.5x10x32 FC2 ZERO STOP
Night Force 3.5x10x50
NIGHT force 5.5x22x50
D740
Raptor 4x
Raptor 6x
PVS24 clip on

I know there was a few more I will add them As They come to mind..

By asm1 at 2011-06-09

 

[jackinfl]

Re: MK12 Long term...9800+ ROUNDS

Interesting. Have you noticed any loss of accuracy as the round count has grew?
Any plans to replace the barrel?

 

[Asm1]

Re: MK12 Long term...9800+ ROUNDS

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jackinfl</div><div class="ubbcode-body">Interesting. Have you noticed any loss of accuracy as the round count has grew?
Any plans to replace the barrel?

</div></div>

When it groups MOA+ I clean it shoot it at 500+ yards for accuracy,if my dope still match up its back in the ready.
Untill it Gets to MOA+ on average,starts throwing rounds or lose velocity I will stay with it.

I have a RECCE on stand by just in case..I have a MOD1 built and Ready, If the Mod1 pass all the test over the next few months it will replace the MK mod0.5 and I will retire it to light duty.

 

[sinister]

Re: MK12 Long term...9800+ ROUNDS

Beauty.

Try a chrome-plated cam pin -- hard chrome protects the shaft from galling and gives it a little more lubricity. I think Brownells carries DPMS and Smith's for somewhere around $20 (which would have paid for the first three you used up).