The M43 Field Jacket entered production in the Summer of 1943 with the first contracts being the specification 370B. Several minor improvements were made by October, at which point the specification number was updated to 370C.
At some point late that Fall, it was decided to enlarge the circumference of the chest and upper arms to permit a better fit when the pile liner was worn underneath.
The QMC referred to the the enlarged design as “Pattern B”. Why didn’t they call this a “370D”? Likely so that quartermasters could easily identify which cut of jacket they had on hand rather than expecting them to remember specification numbers.
When compared, Pattern B jackets are clearly larger than their earlier counterparts. The photo above shows two 370C jackets, both size 42. The top one is a Pattern B and the bottom one is the earlier cut.
As first designed, the M43 Field Jacket had a chest circumference that was 8″ larger than the stated size. (Typically, the chests of men’s jackets are 6″-8″ larger than marked.) Thus, a size 40 had a chest measure of 48″.
For pattern B Jackets, this was increased to 10″, so a size 40 will now measure 50″. (Of note, HBT jackets are also 10″ oversized.)
In addition, the circumference of the upper arm was increased by 2″ compared to the initial design.
Today one finds a roughly equal number of authentic 370C jackets in both the initial cut and the Pattern B.
All subsequent WWII M43 Field Jackets types, the 370D and 370E, are Pattern B. Likewise, the later M50, M51, and M65 Field Jackets retain this same overly large cut.
For collectors this isn’t much of an issue, but with reenactors and modern wearers of these jackets there can be some controversy. Since the vast majority of people do not wear a pile liner with the jacket, complaints of them being too large, “effing yuge”, totally cut wrong, fitting like a garbage bag, and so forth are common. The earlier jackets are notably less baggy and thus have a preferable fit to many people.
370B Markings
Of minor interest, some manufacturers, usually on 370C’s, added the “Pattern B” to the labels in their jackets with hand stamps rather than printing it with the rest of the information. This was likely due to the labels having already been made prior to the change. The one above is stamped at the top.
This one is stamped at the bottom….
Or, take the lazy way out and just whack a large “B” on it. The B was also stamped next to the size mark below the neck. Occasionally, one can find this done on the regular spec labels as well.
All 370D and 370E Jackets were Pattern B’s. A 370D label shown above. Contracts for 370D’s were issued from April 1944 until early February 1945.
On jackets made from the Fall of 1944, one often sees “Pattern B dated 1 August, 1944”. I have been unable to find any further alterations to the pattern on these compared to those made earlier.
Label for a 370E from the first contract of this model. If any of these jackets reached troops before VE Day it would have to have been only a handful. As with the 370D’s, all of these were Pattern B.