I recently purchased this book:
Messerschmitt Bf 110 / Me 210 / Me 410, by Heinz Mankau and Peter Petrick, translated from the German by Don Johnston, Schiffer Military Publishing, Atglen PA, 2003, ISBN 0-7643-1784-9.
This book traces the history of the planes in its title, plus a few of their competitors such as the Ar 240 to show the context. All information is pulled from official German documents, such as RLM staff meeting minutes, correspondence between the principal players, manuals, acceptance and loss reports, logbooks, etc. It then describes all versions of each plane.
All in all, it seems pretty authoritative on the designations of the various models. The authors compare their research results to what's already been published by folks like Herrmann and Nowarra, and where there is conflict they cite their evidence in detail to show why they think they're right. Not having seen the source documents myself (which are listed in the extensive bibliography), I'm not in a position to say for sure whether Petrick and Mankau are correct. However, they do present a strong case

. It's as good as any lawyers could present a technical subject to a jury of laymen, let's say.
Anyway, for the rest of this post, I'm going to assume that Mankau and Petrick are correct. So let's examine the 110s we have in AH to see what changes, if any, should be made to them in light of this new book.
AH's Bf-110C-4bProposed changes:- Designation: Bf-110C-7
- Guns: 2xMG FF M, otherwise the same
- Ord: choice of 1x1000kg or 2x250kg
Evidence for Proposed Changes:According to Mankau and Petrick, there was no such thing as a "C-4b", but there was a "C-4/B". Only 4 of these were ever built, however (by Gotha in July 1940), and they were redesignated as "C-7" towards the end of 1940.
Originally, when the LW wanted to put bombs on 110s, they figured they could just have field units attach bomb racks to existing planes. This resulted in the C-1/B and the C-2/B. However, it was soon discovered that the original landing gear was too weak for the extra load so this project terminated quickly. Thereafter, bomb rack installation was done at repair depots because it included new legs as well, and a few new planes were built by the factories with these features as original equipment. The new planes up to July 1940 included a single C-2/B and the four C-4/Bs noted above.
Then in Aug-Sep 1940, Miag built 35 new planes called "C-7". These were identical to the C-4/B, apparently. Thus, in late-1940, the LW paperwork had C-1/B, C-2/B, C-4/B, and C-7. Towards the end of the year, they lumped all bomb-carrying 110Cs into the "C-7" designation and did away with all the "/B" names. Thus, "C-7" came to mean any 110C capable of carrying bombs, regardless as to what subtype it started as. Mankau and Petrick don't give a total for the C-7 beyond the 39 built new (35 built as such and 4 renamed), but there were apparently quite a few "C-7s" created at repair depots. In any case, there were way more "C-7s", than there were "C-4/Bs", so IMHO (assuming all the above is true), "C-7" would be a better name for our AH plane and "C-4b".
But some "C-7s" started out as "C-1s" and "C-2s", perhaps even "C-3s". The only difference between the -1 and -2 was the radio, so that has no game effect. The C-4 and later types had a different type of tailgun mount than earlier versions. Mankau and Petrick say the new tailgun mount was retrofitted to earlier types, and the AH version as the new design, so no problem there, either. However, both the -1 and -2 had the original MG FF 20mm, whereas the C-3 and later types had the MG FF M, which was better in some unspecified way. That might make a difference in the game. OTOH, it's probably safe to assume that the "C-7s" created at the repair depots got retrofitted with the new 20mm as well, because the old type required a bulge on the lower fuselage that would have interfered with the bomb racks. Anyway, I wonder whether what the game shows as "MG FF" is the MG FF M or the original version? NOTE: the 3D model in the game doesn't have the original MG FF bulge.
Finally, there's the subject of ordnance. The bomb-carrying 110Cs got the ETC 500/IX bomb rack, which was capable of mounting the following bombs:
- 1x SC 1000, or;
- 1x SD 1000, or;
- 2x SD 500, or;
- 2x SC 250.
- no mention made of SC 500s
The SD bombs were low-capacity AP bombs of slim profile, whereas the SC bombs were HE. Apparently the SC 500s were too fat to put 2 of them side-by-side on the rack, but you'd think they'd have been able to carry 1 of them, like they did with the SC 1000. Anyway, we apparently only have HE bombs in AH, so I propose adding an SC 1000 bomb to the 110C's ord list.
AH's Bf-110G-2Proposed change:- Designation: Bf-110G-2/R3
- Ord: add 1x1000kg bomb as above
Evidence for Changes:According to Mankau and Petrick, the standard armament for the G-2 was 2xMG 151/20 and 4x MG 17. This was deemed insufficient for dealing with heavy bombers, so field units often replaced the 4xMG 17s with 2x MG 151/20s. The RLM agreed but also noted that 4x20mm wasn't enough, either, based on experience with the standard 2x20mm belly pod. So instead of adopting the 20mm nose field mod, they went for 2xMK 108s.
The 30mm installation was tested on the five 110G-4/U9 testbeds during 1943. It was then approved for production for both the G-2 dayfighter and the G-4 nightfighter, in both cases resulting in the /R3 suffix. These planes were not modified in the field, but were built new with the 2x30mm at the factory. That seems to have been the case with most of the /R types--the work was too extensive to be done in the field, either to install or remove.
In terms of ord, the G-2 had the some bomb rack as the C-7, so could also carry the 1000kg bomb.
As an aside. the 3D model in AH has the large rudders (compare to the 110C model). According to Mankau and Petrick, the large rudders were only fitted to 110s that needed them to overcome stability problems caused by external equipment. As a result, they were almost exclusively seen on G-4 nightfighters, due to the problems with the antennae. However, the G-2/R1, with the 37mm gunpod, was found to need them as well.