M42A1 Self-propelled Anti-Aircraft Gun Late Type (V.N.War)
DUSTER
AFV Club 1:35 Kit No. AF 35042
Review by Terry Ashley

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The twin 40mm self-propelled gun T141 was developed using the M41 tank chassis as basis with a large gun mounting housing the twin 40mm Bofors M2A1 cannon with full 360 degree traverse. The first T141 was delivered in April 1952 and redesignated twin 40mm self-propelled gun M42 in October 1953 and commonly referred to as the “Duster”.

With the upgrading to the fuel injected AOSI-895-5 engine it was reclassified as the M42A1, there were several smaller features that changed during production, most noticeable the early two hatches between the top crew hatches were replaced but a single flat plate on later vehicles and the head light array of later vehicles included the horn and black out driving light with redesigned brush guard.

It should be noted that as this was classified as a self-propelled gun it did not have a turret as commonly referred to with a tank but instead a “gun mounting” housing the two 40mm cannon, a small technical point for those wishing to know. I will refer to the “gun mounting” in the review as this is the correct description after all.

This long awaited kit from AFV Club of the M42A1 Duster has finally started hitting the shelves and represents a later model M42A1 as typically used in Vietnam and incorporates all the later M42A1 features such as the solid plate between the crew hatches, the later style headlight array, APU exhaust muffler mounted above the right main muffler, field telephone box and main exhaust deflectors. The kit also includes two styles of three pronged flash suppressors and there are also parts for the early production Duster lurking on the sprues which probably indicates this version to come?

The kit consists of:

• 442 parts in olive drab plastic
• 3 etched brass parts
• 2 aluminium barrel tubes
• 2 small springs
• 18 vinyl washers for holding the wheels in place
• 1 short length of twine
• 2 runs of vinyl track
• 1 decal sheet and the
• 1 instruction booklet. Note; included is a small error sheet with 4 updates for the instructions and it's best to mark the main instructions with these before proceeding so you don't forget at the time of assembly. Unfortunately there are other bloopers in the instructions that will be pointed out below.

Metal and other parts

The standard of moulding is excellent throughout with very well done surface details including extensive subtle welds on the hull and gun mounting parts, there are virtually no pin marks in places that will be visible after assembly, the only ones I noticed were inside the upper gun shields and hatches which should be easy to remove. There a little fine flash on some parts again easily removed and as with most kits the main clean-up is the mould seam lines and the many plastic nodes on the parts. Some of the smaller parts will also need care removing from the sprues and cleaning up the seams but nothing out of the ordinary.

One area that will need a bit of attention is the many large pin marks on the inside of the some parts; these don’t show after assembly but will need to be removed to allow proper fit of the parts but as mentioned most others are hidden after assembly.

The kit includes some sprues from the earlier Skybow/AFV Club M41A3 Walker Bulldog; these are for the running gear (wheels/suspension) and rear engine deck, head light clusters and tools  with all other parts new for this kit including new drive sprockets with the three cut-outs in the hubs for good detail. The only interior parts are for the gun mounting and while the large front entry door has inside detail there is nothing inside the hull if the door is shown open.

I don’t have any actual 1:35 scale plans but there are smaller scale plans in both the Hunnicutt Sheridan book and the Squadron Signal Duster Walk Around and extrapolating these shows the model to be okay dimensionally give or take a fraction due to the enlargement and printing processes involved.

This is a conventional tub that includes the hull sides and upper curved gun mounting sides as well as incorporating the bulge on the left front with the first two suspension mountings (this can be seen when looking head on a the real vehicle). Just a quick explanation on this bulge which on the later M42A1 hull was larger than on the early M42 and M41 hulls, these early bulges have a flat bottom profile when viewed from the front but an angled profile on the later hulls as  depicted correctly on the kit hull.

There are also excellent weld seams on the tub as well as small port covers and nicely detailed axle mountings. A notable feature is the central cut-out for the shell ejection chute, this also has the internal chute housing but the fit of this is not precise allowing a bit of movement when fitting. It is very important to fit this exactly centrally inside the locating ridges on the hull bottom as the gun mounting traverse ring is attached to the top of the chute housing and if not in the right spot will compromise the fit of the gun mounting tub later, so take care.

The suspension is nicely done with good detail on the axle arms and mountings with the front idler and first road wheel station are moulded in one piece for a simple assembly with the axle arms fitting very snugly into the hull mountings for quick easy assembly. The return roller mounting posts don’t have the small curved rod attachment as they should and the two part return rollers are attached by way of separate hub pin allowing the roller to rotate if desired.

There are also separate bump stops added for each axle station as well as separate shock absorbers for the first two and last axle stations and overall the suspension provided in the kit is quite acceptable and robust bearing in mind most is hidden behind the wheels after assembly in any case.

The road wheels/idlers (both the same for the M42A1) have nicely done rims bolts and hub details and are in two separate wheels that trap a vinyl washer between them for easy fitting to the axles to allow these to be added or removed easily at any time.

The suspension as mentioned is from the earlier Skybow/AFV Club M41A3 kits and available separately in set #AF 35045 if still available and as there had been some discussion on upgrading the kit with this suspension I’ll briefly mention the differences.

Moving on to the drive sprockets, the instructions incorrectly point you to use the old sprockets (parts E14, E15) that don't have the three cut-outs in the outer sprocket hub. The correct sprockets are included in the kit so you should use these; they are parts B1, B2, B3. To make matters more confusing the instruction illustrations also show the old sprue E parts so take note.

The final drive mounting plate is a separate part and the final drive housings include the underside drain plugs for good detail with the sprockets attached to the axles by way of the vinyl washers trapped between the sprocket halves during assembly allowing these to be easily added and removed.

Other items added to the lower hull are the front and rear tow shackles, the taillights and battery box cover along with the large lifting eyes, all parts fitted without any problems or trimming required.

The track is full length vinyl which has very good details for the medium including the pad retaining bolt on the inside of each link as well as a small gap between links, there is some minor flash at the end of each track run but the tracks should look good when painted and fitted to the model. The track also has the correct 75 links per side as does the real M42 track.

The tracks can’t be glued with normal plastic cement but will hold together using thicker cyanoacrylate providing you don’t flex the join while fitting to the running gear.

The upper panels such as the glacis, top plate, gun mount sides and the three part engine deck are all separate parts added to the lower hull, the two side fenders are also separate parts to complete the hull. The additional parts added to the glacis, top plate and fenders can all be built as sub-assemblies before fitting to the hull, this makes assembly easier as one sub-assembly can be worked on while the glue dries on another, it also makes them easier to handle while separate from the main hull.

The large entry hatch on the glacis is a separate part with interior detail, there are also some fairly large inner pin marks to remove if you plan to show the door open but as there is no hull interior there isn’t much point having the door open anyway. One the outside there is a separate grab handle and six part hinge assembly for a very good appearance, the hinge actually works if you are careful with the glue should you wish.

The head light arrays are quite well done but need the wiring added to add more detail, these fit to the glacis mountings with front armour covers added, these actually should have two small drain holes at the lower edge that you may want to also add. The brush guards are horrendously thick and should be thinned down for a better appearance but will probably be included in the inevitable etched detail sets to come for this kit. It’s best not to fit the glacis until after you have added the top hatch plate.

The top plate is the later flat plate that includes the fire extinguisher handle on the rear edge and has the crew hatches separate with working hinges, again there are a couple of pin marks on the inside hatch surfaces that are a little tricky to remove due to the lip around the hatches but need to be removed if you are showing the hatches open? Added to the hatches are separate full pericopes with top flap and separate brush guards, these are a little thick but give a good appearance in any case and the grab handles and securing hook are also separate for good representations of the hatches. One small omission on the left driver’s hatch is the small lock bracket on the top plate that corresponds with the bracket on the hatch, this is a very small addition and is probably for those who want to really detail up the kit.

The fit of the top plate to the lower hull is very good and once attached the front gun mount wall can be added, this is also a good fit with the top plate but the side joins to the gun mount side included with the lower hull will need to be smoothed out for a better finish.

Once the top plate has been added the glacis can then be fitted and again the fit is good, just ensure this is fitted level on both sides as there isn’t any actual locating lugs on the inside of the plate, not a big deal really.

There is a potential fit issue with the rear gun mount wall if not careful due to the way the instructions would have you assemble the parts. You are directed to glue the rear wall (part L35) to the deck part (L6) before attaching this sub-assembly to the hull but even if it seems you have the two parts lined up evenly at the sides when it comes to fitting gaps can result. The better way of assembly is to firmly glue the deck part (L6) to the hull and when dry then fit the rear wall, part L35, this way you can get both sides to fit better. In any case there is some work needed to smooth out the joins on panel joins both front and rear but these are partially hidden by the supports for the fender mounted storage boxes when these are attached.

Image showing the rear well plate joins needing attention and to a lesser extent on the front plate join.
these are partially covered with the fender storage box supports when fitted.

The three separate engine deck parts fit perfectly without any trimming needed for a quick and easy assembly of the deck. On the right rear corner of the deck is mounted the telephone box but this isn't mentioned in the instructions unfortunately but is included in the kit as parts L7, L8, L25. You will need to trim the moulded on grab handle on the rear deck to fit the box mountings which can be done with a sharp blade and the handle folded up sitting against the box mounting as it does on the actual vehicle.

Each fender can be assembled as a separate sub-assembly and added to the hull as a unit, this makes assembly handling easier with everything fitting without any problems. On the left fender are the two spare barrels with the springs provided added to the plastic barrels for good detail along with the threaded ends that hold the springs in place. The large storage boxes go together okay but care is needed aligning the ends and front panel to get the best fit. The air cleaners and rear mounted exhaust mufflers all go together without any problems. The only thing to watch on the right fender storage boxes is the rearmost door is numbered incorrectly in the instructions, this should be part O31 and not O33 as indicated, O33 being the forward door.

Also included in the kit but again not mentioned in the instructions are the exhaust deflectors often fitted to Dusters in Vietnam, these are parts B26 and B31 and the deflectors can be fitted at any angle in theory but the clearance between the exhaust pipe and the fenders isn’t enough to fit the retaining clip (part B31) if fitting the deflector at an angle, this may be due to the clip being slightly oversized but it limits the angle the deflectors can be fitted, not a big deal really. The steel tow cable provided as thread should be cut to a length of 72mm to fit properly to the right storage boxes but the three cable clips along box side should be curved and not flat as moulded, a small point that will probably be fixed with the etched sets to come?

The assembled fender sub-assemblies have a very positive fit to the hull and the upper braces are also glued to the hull sides to provide more support, the front fender supports (parts O5, O6) can then be added noting these overlap the head light guards.

Added to the rear right fender is the APU exhaust muffler and drilling out the end of the exhaust pipe will give a better appearance and the muffler should be fitted as close to the inner edge of the rack as possible to allow room for the tools to be fitted. The exhaust pipe outlet guard on the hull has a plastic part and an etched part which when bent to shape replicates the guard very nicely just take care fitting the etched guard to get this at the right angle and the two large air cleaner pipes either side of the hull can be added.

The twin 40mm gun mounting is extensively detailed and includes all the major equipment items with the guns able to elevate after assembly in unison with the delicate Computing Sight M38. Some of the parts can be built as sub-assemblies and bought together for the final assembly and this makes things easier than fitting everything directly into the gun mounting along the way, these sub-assemblies are basically the tub interior, twin cannon/trunnions, main sights and front armour shield assemblies.

The lower gun tub is a single impressive moulding with a central cut-out for the recessed gun base plate, the tub has rib and other details on the underside which is completely hidden after assembly, the only blemish is a long sink mark on the tub floor corresponding to an underside rib but this is completely hidden after assembly so of no concern.

Fitting the lower gun base plate requires part of the plate to be slotted under the lower tub ring and this is quite a task, it is far easier to cut-away the section of the ring and just fit the base plate, you can’t see the section of ring cut-away as this on the underside of the tub so again no problems.

Fitting of all the supplementary items inside the tub is very straightforward without any fit problems, the only thing to watch is the placement of the rear armour wall that is fitted in conjunction with the two shell ejector chutes, it is very important to locate the wall (part D19) perfectly centrally on the tub sill as this will directly affect the fit of the side armour plates when fitted later. You can align the armour section with the moulded on beams just inboard of the folded seats on the rear of the tub sides to ensure the correct alignment as there are no actual locating pins for the armour wall section. The two crew seats are made up of three parts and are glued to the tub floor, the loader’s seats are provided folded against the rear tub wall because these automatically retract when not in use. There are a couple of items missing such as the loader’s foot firing pedal and the traverse locking bracket on the floor but both are basically hidden from view after everything else is fitted so probably not a big deal unless you want to know they are there.

The instructions would have you glue the left gun trunnion (part C61) and cross beam (part C41) to the floor at this stage but I found it easier to assembly the guns and trunnions away for the base as a separate sub-assembly to be fitted later, this is partly due to when fitting the guns to the trunnions you have to fit the elevation arc into a recess in the cross beam which is quite tricky with the trunnions glued inside the tub leaving little room to work. When assembling the guns/trunnions sub-assembly it’s advisable to temporarily fit the trunnions into the base locating slots to ensure when the glue dries they will fit without any problems when glued in place permanently.

40mm guns:
The twin 40mm cannon are obviously the centre piece of the gun mountings and the whole kit to a certain degree and these build into a highly detailed sub-assembly that includes the recoil cylinders under the barrels and separate parts for the top mounted auto loading mechanisms, the separate mechanism parts (C39, C40) need care aligning to the sections included with the guns as they can be out of alignment if you fit them deep into the recess on the guns.

When fitting the two gun receivers together a bit of trimming is needed on the mating surfaces and I also had to trim the ends of the cross pins on the elevation arc and front receiver to allow the two guns to fit together properly. The proper width of the guns is determined by the separate top and bottom plates (parts C37, C38) so test fit till these parts line up properly.

When fitting the small inner parts (C47, C48) to the rear shell guides (part C36) the mating surface on the guides have to be trimmed smooth as there is some minor excess plastic that will prevent the small parts fitting properly, also the instructions have transposed the parts numbers for the hand operating levers, part C58 should read C59 and C59, C58, this is fairly obvious when you come to fit the levers to the side of the guns in any case.  The other parts all fit without any problems as per the instructions.

The two 40mm barrel tubes are provided in tuned aluminium and fit very snugly into the recuperator spring housings on the guns and I didn’t need any glue to hold the barrels in place. The kit gives you the early style three pronged flash suppressors; these were prone to cracking with prolonged use and often removed altogether on Dusters in Vietnam. The barrels only have a very small indentation in the muzzle without any rifling and drilling this out further will improve the appearance especially if not using the flash suppressors, no screw thread is included on the barrel either if depicting them without the flash suppressors.

A new revised three pronged flash suppressor with reinforcing rings were introduced on later model Dusters and this is also included in the kit but not shown on the instructions as it’s really not applicable to Vietnam Dusters. If you want to use the later flash suppressor they are parts B17 and B44.

The two equilibrators located under the guns fit neatly into their support bracket but there should be two small holes added to the ends of the equilibrators, these are only visible when the guns are in high elevation so could probably be overlooked as it’s just a small point. The separate equilibrator pistons fit over pins on the elevation arc but are very loose and can easily pop off at any time, simply heat compressing the ends of the pins slightly using a small screwdriver head or similar will prevent the pistons coming adrift.

The trunnions have separate delicate firing solenoids (parts B30) that need care removing from the sprues but add excellent detail to parts and just a small note for those who want to know, the fire selector switches on the sides of the guns are moulded in the auto fire position. You did want to know that didn’t you?

If you want to load the guns with the 4 round ammo clips provided you will need to widen the gap between the top loading mechanism brackets as they are not wide enough for the ammo as they come, also the real mechanisms have small inner notches that fold back to allow the rounds to feed and prevent them for bouncing back out but these notches are not included on the kit mechanisms.

The assembled guns/trunnions can be fitted into the tub and have a good positive fit with large locating lugs to ensure the mounting won’t be going anywhere. The two elevation/traverse motors can also then be added and again the fit is good to the tub floor and trunnions sides and take note that the small ribbed cylinders have separate halves to be added but these are not shown in the instructions, they are parts C49 so be sure to add these before fitting the motors to the tub. You should also note that the hand crank levers are not fitted in electrical power mode so can be left off if you wish as they were not always fitted.

The main gun computing sight M38 is an extremely delicate sub-assembly and allows you to assembly the ball shaped devise with separate flight direction indicator (part C60) so that this will move in unison with the gun elevation, the mountings for this (parts C14, C52) are a little tricky to fit if you want them to move but worth the effort.

Also included is the M24C reflector sight (part C30) and etched parts for the speed ring sights for an excellent appearance, these are held in place with small butterfly screws that are not included but again will probably be included in the etched sets to come.

The assembled sights are easily fitted to the gun receivers; you should add the small right side sight arm first and the then the larger sight assembly to the top of the receivers and finally the link rod (part C18) from the ball sight mount to the trunnions side, it is this link arm that moves the sight with the gun elevation. The pin just sits into the locating hole in the trunnions side and can pop out but should stay in place providing the gun mounting isn’t tipper sideways during fitting to the hull.

Armoured shields:
The gun mounting has armoured shields around the entire tub and large front shields and again these can be built as sub-assemblies in the kit to make final fitting to the mounting easier if you wish. The many tie-down cleats on the armour panels are all moulded solid in place and those wanting to replace these with thin wire would improve the appearance.

The front armour panels have separate side plates that fit neatly into place and note the inner join line is actually on the real shields so don’t be tempted to eliminate this join, the same goes for what appears to be mould lines on the outside edges of the top armour plates as these should be there as depiction on the parts. An interesting note on the upper shields is there is a small square waffle pattern on the armour surfaces when viewed in close-up but from any distance and from a scale perspective this is very difficult to see with the armour appearing smooth as does the kit armour and is acceptable in this regard IMHO.

The lower front shields are in two parts, the side and top plates and fit was not good on the right side parts (D11, D13) and required about 1mm to be trimmed from the bottom of the rear inner plate for a good fit, this is easy to do with the parts then fitting perfectly with the fit of the front armour also fitting neatly to the side sections although you must ensue to align these properly.

Added inside the left side lower armour panel is the Drive Controller box (parts C24) with hand grips to control the gun mount rotation and gun elevation when in electrical power mode, the box can be fitted in the retracted stowed position or extended active position as you wish. If shown in the raised position the hand crank levers should not be fitted to the trunnions as both were not used at the same time, basically the hand cranks can be used in case of power failure etc.

The side curved armour plates fit precisely to the front armour section due to the neat locking brackets on the parts and make for a solid fit which does allow these to be assembled prior to final fitting the gun mounting. Once the armoured shields have been assembled the fit to the gun mounting rim was good but a little trimming was needed at the lower front but test fitting will determine if this is needed. Note the rear fit to the previously added armour section is good providing you positioned the armour perfectly centrally as mentioned earlier, any miss-alignment back then will show up when fitting the full armoured shields so take care.

With the armour in place the rear mounted ammo bins and the rear and side pintle mounts can be added with the kit providing a single M60 GPMG, this is nicely done with additional parts for the bipod and cradle mounting. You can position this on either pintle mount but many Dusters in Vietman often carried two M60’s on the mounts for maximum firepower and you would need to acquire another M60 should you wish this configuration.  

With the gun mounting assembled this can then be fitted to the hull and there are attachment tabs on the top of the shell ejection chute in the lower hull that fit into slots in the bottom of the gun mounting to lock and hold the gun mounting in place to allow rotation, so the theory goes. The fit of the gun mounting tub into the hull well is very snug and you must ensure the inside faces of the hull well as perfectly smooth or the mounting tub simply won’t fit.

As mentioned above there is scope for the shell ejection chute to be slightly out of position and if this is the case you will be pushing it up hill with a sharp stick to get the two locking parts to fit together, this was the case on my kit as it only takes a fraction on miss-alignment to stop things happening. To fix this I simply trimmed off the hull bracket locating tabs and enlarged the opening in the gun mounting base (part D7), this allowed the gun mounting to slip precisely into place and fit is snug enough that it’s not going to come adrift unless I turn the model upside down give it a good shake. This also makes it easier to remove the gun mounting at any stage for painting etc. and the mounting will still rotate in the well if required.

The instruction booklet has the usual exploded view assembly illustrations that are fairly easy to follow although there are a few bloopers to take note of, AFV Club include a small error sheet with some updates but there are other lurking as pointed out above as well as some parts not getting a mention at all (correct drive sprockets, telephone box and exhaust deflectors) so take note.

Some of the assembly sequences are a little complicated due to the number of small parts and the usual care of carefully studying the sequences before any gluing of cutting will reduce the likelihood of disasters.

The decal sheet has markings for five vehicles, four from Vietnam and one with the 4 colour MERDC cam scheme and includes extensive unit and vehicle serial numbers as well as white stars and the artwork on the large front door for option B and D.

None of the vehicles are identified in the instructions but are from the units listed below and also none of the four Vietnam marking option vehicles had flash suppressors fitted based on available period photos.

A: 1-44th Artillery Vietnam 1967 - Overall Olive Drab. Not fitted with flash suppressors. B: 4-60th Artillery (George of the Jungle) Vietnam - Overall Olive Drab Not fitted with flash suppressors. C: 4-60th Artillery Vietnam - Overall Olive Drab Not fitted with flash suppressors. D: 5-2nd Artillery Vietnam - Overall Olive Drab. Not fitted with flash suppressors. E: Unidentified Unit - MERDC cam scheme. Enhanced to show the white bits

Put simply this is an outstanding kit but definitely not for the inexperienced modeller due to the many small parts and intricate sub-assemblies. The level of detail both in the correct late features provided and surface details such as the weld beads etc. are very well done and the inclusion of optional items like the flash suppressors, telephone box and exhaust deflectors allows many variations in final configuration.

The highly detailed gun mounting with the twin 40mm cannon and intricate main sight are standout features of the kit but there are some areas that need attention with the thick head light brush guards being high on the list and the numerous pin marks on the inside of parts that need removing for a good fit, although that’s more in construction that actual kit detail.

The fit of the parts overall is good but given the complexity of some areas there is potential for ill-fitting parts if you are not careful at all steps during assembly and some minor trimming was needed here and there, but overall the kit will build into an excellent model of the Late M42A1 Duster. And as with any kit there is scope for adding additional detail and tweaking what’s there to produce an even better model.

Rating 9/10

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Sprue detail images





Build detail images

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I will make comment when researching the kit of the lack of Duster photos in many general "Armour in Vietnam" type books. Squadron Signal have a series of general Vietnam armour books and there are numberous other titles from other publishers (I know as I have many of them) but the Duster is very thin on the ground so to speak in the photo coverage with most of it going to the M113s, M48s, V100s and other types.

M42 Duster Walk Around #5705 Squadron Signal Publications	M41 Walker Bulldog in action #2029 Squadron Signal Publications
SHERIDAN A History of the American Light Tank Volume 2 R.P.Hunnicutt. Presidio Books	U.S. Tech manual TM 9-7218 Twin 40-mm SPG M42 Duster Easy 1 Productions CD T069

• Jerzy Krzemiński's albums (Has some excellent albums on Dusters in Vietnam)
• Prime Portal Walk Around 1
• Prime Portal Walk Around 2
• Prime Portal Walk Around 3
• Prime Portal Walk Around 4
• Tanks and Things FB Album

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Thanks to my credit card, and for the review kits.