Description
Bolt B4 MK12 MOD 1 with Silencer DMR (Semi-Auto Only, Heavy Recoil, Retractable Stock, Black, 400 FPS)
The Bolt B4 MK12 MOD 1 is an electric airsoft designated marksman rifle (DMR) styled on the MK12 Mod 1 special purpose rifle, finished in black with a retractable stock and an over-barrel silencer. Our listing describes this version as semi-automatic only, with Bolt’s heavy recoil system, at 400 FPS.
Bolt Airsoft is best known for its B.R.S.S. (Bolt Recoil Shock System), which gives its electric rifles a strong, realistic kick with every shot. On a DMR, where every shot is deliberate, that recoil adds a satisfying sense of weight and realism, and the MK12’s long handguard and silencer give the rifle a purposeful marksman’s profile.
Build and design
A UK retailer listing for the fixed-stock MK12 MOD 1 SD Heavy Recoil (in tan) describes metal outer barrel, silencer, handguard, receiver, sights and trim, with a polymer pistol grip and stock, and an RIS front end for tactical accessories. The over-barrel silencer slides back over the outer barrel, so it gives the MK12 its distinctive look without adding as much length as a muzzle-mounted silencer.
This version has a retractable stock, so you can adjust the length of pull to suit your build, body armour or chest rig, and shorten the rifle for moving through buildings or for transport. Lock the stock in a consistent position when taking aimed shots so your cheek weld and eye relief stay the same.
Recoil system and internals
The same listing describes a full metal Version 2 gearbox that is fully upgradeable and reinforced with heavy-duty parts, a long-type high-torque motor, Bolt’s patented B.R.S.S. recoil system and a mock bolt with blowback action. It gives a 6.01mm aluminium tight-bore inner barrel and an adjustable hop-up, which together help a DMR place shots consistently.
Our version is listed as semi-automatic only, which suits the DMR role and the rules many sites apply to marksman rifles. Please check your site’s rules for DMRs, including minimum engagement distances, and have the rifle chronographed before play.
Battery and magazine
The UK listing gives a 300-round high-capacity magazine and recommends a 9.6V small butterfly-type battery or a LiPo of similar size, connected with a small Tamiya plug; a 7.4V LiPo stick is also listed as compatible. These details are from the fixed-stock version; battery space in a retractable stock can differ, so please check the manual or ask us before buying a battery for this version.
Key features
- MK12 MOD 1-style DMR from Bolt Airsoft
- Semi-automatic only (as listed)
- Heavy recoil B.R.S.S. system
- Over-barrel silencer
- Retractable stock
- Full metal Version 2 gearbox (as listed)
- 6.01mm aluminium tight-bore inner barrel (as listed)
- Adjustable hop-up
- RIS front end for accessories (as listed)
- Listed at 400 FPS
What’s in the box
- Bolt B4 MK12 MOD 1 rifle (listed for the fixed-stock SD version)
- Over-barrel silencer (listed)
- 300-round high-capacity magazine (listed)
- Instruction manual (listed)
Compatibility
The MK12 is an M4-pattern AEG, so it is designed around M4/M16-style AEG magazines; magwell tolerances vary, so try one spare before buying several. The RIS front end takes standard 20mm accessories, and the listing gives a 14mm negative thread.
Version 2 gearbox parts are the upgrade standard, but recoil rifles use some specific parts, so confirm compatibility with us or a technician before ordering upgrades. Use high-quality seamless BBs; many DMR users prefer 0.25g or heavier once the hop-up is set.
Care and maintenance
Take the battery out after every game and store it separately at a sensible storage charge, rather than leaving it connected inside the replica. Charge LiPo batteries with a proper balance charger, keep them in a LiPo-safe bag and never leave them charging unattended; NiMH packs should be charged with a smart charger that stops when the pack is full.
Run a cleaning rod with a lightly dampened patch through the inner barrel from time to time to clear dirt and residue, which keeps the hop-up consistent. Use good-quality seamless BBs, never reuse BBs that have been on the ground, and wipe the outside over after damp or muddy games. Leave gearbox work, shimming and spring changes to a competent technician.
Recoil systems add movement inside the rifle, so check external screws, the silencer and any optic mounts regularly, and use a recoil-rated optic.
Who is it for?
The Bolt MK12 MOD 1 suits players who want a realistic, hard-kicking DMR with a classic special purpose rifle look, and anyone moving into the marksman role at sites that require semi-auto-only rifles.
Please note: Battery, charger and BBs are not listed as included. Always wear suitable eye protection, and full-face protection where your site requires it, when using or testing any airsoft replica.
