45-70 Line Throwing Blank Mk1 & Mk32


What are the differences between an M1 and a M32 Line Throwing Blank. Do the Mk-1 and Mk-32 refer to the cartridge or to the gun?



Without doing any research I took a quick look at my GI Spam Can of blanks and it is marked

  10 Cartridges

Cal.45 Blank Line
Throwing M32
Gun, Line Throwing, MK 1




I should add - the blanks I have are from my period of service (1950s). The only guns I ever used were cut off Trapdoors and H&R type shotguns. I know that there were others, such as modified Springfield M1903s and, later, a Mossberg type shotgun. I have no idea what cartridge they were chambered for. My military mind tells me they didn’t start with M32 so there may well be at least 31 other cartridges out there.



Ray–Both the M1 & M32 designations are on .45-70 blanks. Headstamps are WCC 45-70 MK1 -1943- and WCC 56 45 M32.


The Mk1 is loaded with black powder and has one fiber wad; the M32 is a smokeless load, and has three fiber wads. I imagine the M32 primer is non-corrosive, whereas the Mk 1 is not. Heres a picture of the sectioned blanks.

Here’s the Mk1 box:


Guy–Thanks for the sectioned round pictures and explination of the differences.


I goofed. The box pictured above is for the 1943 dated MK 1 cartridges. Sorry about that.


Guy–I had already figured that out based on the “43” date on the box. I went back and edited your caption so it is correct for future reference.



Great photos and great info as per usual from you.

A couple of observations on my part.

Notice the heavy roll crimp on the M43. That is because the brass bolt (rod) was NOT supposed to enter the case mouth but was supposed to fit on top of it. The MK I appears to be made so that the bolt enters the case.

MK I are headstamped 45-70. Since most of the WW II line throwing guns were Trapdoors with original chambers and bores I suppose it seemed natural to headstamp them thus. Later guns like the H&R had special made barrels and I don’t recall them being marked for caliber.