Article by Doug Chaltry; last updated 9 March 2017

The M3 75mm cannon was the standard main armament of the M4 Sherman at the start of the war. Although the Sherman was upgraded with the M1 76mm cannon (in the T23 turret) in the final years of the war, 75mm-armed Shermans served on all fronts through to the end. The gun mount came in two basic versions, the early M34 with a narrow rotor shield (with or without armored side plates to protect the base of the gun barrel), and the later M34A1, which had a much wider rotor shield that provided better armor protection to the entire front of the turret.

The two terms in the photo below I believe are the official Army terms. I have frequently seen these terms confused in the modeling community, and even within some technical reference books as well. The 'gun shield' is often referred to as the 'gun mantlet' or the 'rotor', and the rotor shield is sometimes referred to as the 'gun shield' or 'mantlet shield'. In this article, I use the terms shown below. Sorry that I am not consistent throughout the remainder of the site.

This article is intended to show side-by-side comparisons of all the 75mm gun and rotor shields available to us modelers in both plastic and resin. Below the shield comparison scans, I provide additional scans of the 75mm gun barrels for comparison as well.

M34 Gun Shield

The M34 gun shield had a perforated rim (flange) around the outer edge which was screwed to the front of the turret face. All of the kits below, with the exception of ExtraTech, chose to mold that rim integral with the shield, as it should be. ExtraTech has that rim molded onto the face of their turret, thereby complicating matters if one wishes to swap parts between kits or aftermarket accessories.

The dimensions for the gun shield are difficult to determine, due to imprecise drawings in my references. The most common measurements show that the shield, with the rim, should be 13.5mm side-to-side, and between 7.7-8.3mm tall in 1/72nd scale (I'm leaning towards the larger number). I have seen an on-line discussion by one of the authors of the Son of Sherman book state that the dimensions should be 13.4mm x 8.1mm, so these are the measurements that I will use as a reference for the following comparison.

Although you see minor variations in the measurements below, they are all within an acceptable error in my eyes. More important than the precise scale is the amount and quality of detail, such as the screws and lift rings.

Lift rings: all M34 gun shields had a pair of lift rings attached to the top as seen on a couple of the examples below. Very early examples had them closer to the centerline, where they could interfere with the rotor shield (I think this style was very rare). Hence they were moved outward.

Should the rim be flush with the front face of the turret? Not entirely. It sits just a little bit above the turret face. In this scale, I don't think it would look bad if it was flush, but it really should stand out a little bit.

Picture	Manufacturer	Size	Comments
	Dragon	13.2mm x8.0mm	Lift rings are included as separate parts to attach at your descretion.
	ExtraTech	13.8mm x7.9mm	These measurements are of the rim that is molded onto the front face of the turret. Lift rings are included as separate parts to attach at your descretion.
	Heller	14.1mm x8.3mm	Lift rings are included as separate parts to attach at their outer location.
	Italeri	13.0mm x8.5mm	This is about the one piece in this comparison that looks a little off due to each dimension being off in a different direction. But even so, it doesn't look too bad when mounted. The lift rings are located towards the inside, which is likely not correct.
	UM	13.4mm x8.1mm	Although the dimensions on this piece are very good, the rim is a little narrow, making the rounded part of the shield a little too bulbuous. Lift rings are included as separate parts to attach at your descretion.
	ARMO	13.5mm x7.5mm	Modified from the ESCI M34A1 shield.
	CMK	13.5mm x7.5mm	Lift rings are located a bit too interior.
	Iron Division	13.0mm x8.0mm	This is a copy of the Dragon piece. Lift rings will need to be sourced from a donor kit.
	MR Models	13.6mm x8.0mm	The raised ridges along the edge of the gun opening is perfectly represented here. Although the others will hardly be seen when the rotor shield is mounted. No lift rings are included.

M34 Rotor Shield

Due to the curve on these parts, I was able to measure only the lateral dimension, which should be 5.0mm wide. For those pieces that have the side armor to protect the gun barrel, longer and thinner is more accurate, such as seen on the Dragon or resin examples.

Picture	Manufacturer	Size	Comments
	Dragon	5.0mm	Nice cast texture, but is it over done or even needed?
	Dragon	5.0mm	Nice cast texture, but is it over done or even needed? Nice side armor plates.
	ExtraTech	4.6mm	Unlike the Dragon parts, this one is very polished. Something in between these two extremes I think would be most realistic.
	Heller	5.9mm	A little wide, but nothing some sandpaper can't fix. Poor side armor plates.
	Italeri	5.0mm	Very poor side armor plates.
	UM	5.2mm	Mediocre side armor plates. Careful sanding should help. Lacking screw holes.
	ARMO	6.0mm
	CMK	5.0mm	Lacking screw holes.
	Iron Division	5.0mm	Molding integral with the gun barrel obviously has its limitations, but it may not look too bad when painted.
	MR Models	5.0mm	Screw holes are a little deep, but not too bad.
	MR Models	5.0mm	Screw holes are a little deep, but not too bad.

M34A1 Gun Shield

Although my reference drawings are inconsistent and show this gun shield to be a little smaller than the M34 gun shield above, that is incorrect. The opening in the turret face was the same for all M4 turrets, and these gun mounts (including the 105mm and 17pdr gun mounts) were interchangeable. Therefore the dimensions should be 13.4mm x 8.1mm.

The four, oblong openings in the gun shield are for the gun sight, coaxial .30cal machinegun, and two connectors to the rotor shield. Some kits represent these much better than others, but with the rotor shields mounted, they will not be visible. I guess these would be important only for those building a diorama with the rotor shield removed for maintenance.

There were two versions of this shield:

• The early version had two lift rings on the top edge of the shield, and the rim with the screw holes was visible only on the top, bottom and right side. The screws on the left side were made internal so there is no rim on that side.

• On the later version of the shield, the lift rings were dropped, and the screws on the right side were also made internal, so that the rim is exposed only along the top and bottom. This did not change the overall width.

Picture	Manufacturer	Size	Comments
	Dragon	13.2mm x8.0mm	This is an early example, with the rim on the right side, and two lift rings at the top.
	ESCI	14.0mm x7.5mm	Rim should not be exposed on the left side. Considering that there are no lift rings, this is likely a late shield, and therefore the rim should also not be exposed on the right side either.
	ExtraTech	13.8mm x7.9mm	These measurements are of the rim that is molded onto the front face of the turret.
	Heller	14.5mm x8.4mm	Early version with the rim on the right side. This version should have the lift rings, which you can add with parts included in the kit, although no locator holes are present.
	Trumpeter	13.5mm x8.2mm	Later version with no rim on either side (only on the top and bottom).
	UM	14.0mm x8.1mm	Early version with the rim on the right side, albeit a very narrow one. (Looks like there might be a very narrow strip on the left side, which shouldn't be there.) This version should have the lift rings, which you can add with parts included in the kit.
	Zvezda	13.1mm x8.2mm	Later version with no rim on either side (only on the top and bottom).
	Leva	13.5mm x8.0mm	Early version with the rim on the right side. This version should have the lift rings.
	MR Models	13.8mm x8.0mm	Early version with the rim on the right side. This version should have the lift rings.
	Fine Scale Factory		I failed to scan the parts of the OOP Fine Scale Factory kits. They are copies of the ESCI parts, and therefore fully compatible with them.

M34A1 Rotor Shield

Due to the curved shape of the rotor shield, it's difficult to measure anything other than the lateral dimension. Although my references give a range of dimensions, the measurement should be 14.2mm (with the left side being slightly longer than the right - 7.2mm vs. 7.0mm). This means that most of the pieces below are just a bit too wide, though not noticably so.

There were actually two different rotor shields - one for each type of the gun shield. The right side of the shield was lengthened a small bit for the late version of the gun shield, since that one was widened to cover the rim. The way to identify them is by looking at the distance between the gunsight aperture and the edge of the shield. You can see the upper two scans in the table below show this difference, with the Dragon kit having the earlier style, and the ESCI kit the later. I don't know what the difference in width would be for the model parts, but it's likely less than a millimeter.

Picture	Manufacturer	Size	Comments
	Dragon	13.7mm	Exaggerated cast texture; overly thick gun barrel side armor plates. Smallest piece in this review.
	ESCI	14.9mm	Lacking coax mg opening.
	ExtraTech	14.5mm	I never noticed until looking at these scans next to each other, but this piece certainly looks to be an improved version of the ESCI part. Or is it a coincidence?
	Heller	15.1mm	As much as I love the Heller Sherman kits, this piece does not fare well against many of the others in this comparison.
	Trumpeter	14.9mm	Despite not being able to measure the height, this part seems a little too tall relative to the others. The proportions of the raised central segment also seem to be off.
	UM	14.5mm	Lacks the opening for the gun sight. Seems a little short, top to bottom.
	Zvezda	14.1mm	One of the best shields made. Coax mg is poorly molded onto the shield, and should be replaced. Thinnest gun barrel side armor of any of these pieces.
	CMK	14.9mm	Similar to the Trumpter piece, this one seems to have some proportions off. The gun sight opening is clogged.
	MR Models	??	I actually don't have one of these in my collection. Harrumph.

I measured the lengths of the gun barrels from the base where it emerges from the rotor shield to the tip. Once again, my references differ. (You can tell when a reference isn't very reliable when several similar drawings within the same book have different numbers for the same measurement!) After converting to 1/72nd scale, the measurements I came up with varied from a low of 23.3mm (Son of Sherman) to a high of 24.3mm (Codename Swallow). I used a middle number of 23.7mm (shown in both Hunnicutt and Militaria i Fakty) as a standard for comparison of the following parts. I think that any part that falls within this 1mm range (23.3-24.3) is acceptable. For the plastic parts shown below, I assembled the pieces per instructions before measuring.

Picture	Manufacturer	Size	Comments
	Dragon	24.4mm	Just a hair long.
	ESCI	22.5mm	Horrible ejection pin mark on back side of barrel. Difficult to attach tip without locator hole. A little short.
	ExtraTech	24.5mm	Very nice piece.
	Heller	21.8mm	Adding the tip was uncool. Completed barrel is very short, even with the tip attached.
	Italeri	24.5mm	Very nice piece after sanding the tip back a hair.
	Trumpeter	24.4mm	A little stouter than the others, but looks good.
	UM	24.6mm	A little narrower than the others, but not a bad piece.
	Zvezda	25.0mm	Measurement is from the tip to the portion that I think is hidden within the rotor shield. Once built, it may prove to be perfect length.
	Iron Division	25.6mm	A bit long. Multiple air bubbles in the resin.
	Aber	22.8mm	A little short, which makes it difficult to improve, being a metal piece.
	ARMO	23.6mm	Perfect length, but no attachment peg at the rear, so may be difficult to mount with a strong bond.
	CMK	24.1mm
	MR Models	25.6mm	Quite long, so you'll have to hide much of the base of the barrel within the rotor shield. May require drilling, depending on which it's being mounted on.
	RB Models	23.2mm	Marred by grooves in the barrel from the lathe.

As with all of these comparison articles of very small parts, the great magnification of the scans emphasizes the minor differences between parts. As I've mentioned before, I feel that the overall look of the pieces, which is affected by proportional dimensions and quality of detail, is far more important to me than the precise measurements. Considering the variation in my reference drawings (not having exact measurements), and again, the small size we're dealing with here, the vast majority of the parts shown above fall well within an acceptable range of error for 1/72nd scale. The primary reason I prepared this comparison review was to help modelers judge the compatibility between kits when swapping parts or using aftermarket pieces.