Question on 155mm Projectile Fuzing


I just picked up a nice 155mm projectile (as an aside its amazing how it dwarfs a 105 in both size and weight!!)…but it has no fuze…

My question is, I have read a few things about a brazed in fuze adapter…did these use the same fuzes as a 105? I tried a 105 fuze, and it is way small to fit the 155 unless there is some sort of adapter. Or could/does the 155 go both ways…its own fuzes or 105 fuzes with an adapter?

Next question, are the fuze adapters, or 155 fuzes readily available somewhere, or is it hit and miss?

Not sure as to country of origin, as there is no paint on it, just some misc. stamps in the steel. I haven’t had a chance to ghet any pics yet…


Could you show us some images of your 105 and of your 155?

Sounds like your 105 is a smoke or illum shell.


OK, here are some pics…the single 105 is a 1968 dated 105, definitely HE, as it is marked 105MM HE M1…the one next to the 155 is a 1945 dated HE 105…the fuze in the single 105 is a 1945 dated fuze…I trued it in the 155, its definitely to small for the 155…it might work with an adapter, thats why I asked about this brazed in fuze adapter I have read about in a quick google search…



Generally, in chemical and illuminating shells, and HE shells of large caliber, openings in the nose are larger than required for a standard fuze, to facilitate manufacture and/or filling. An adapter is used for these types but I’ve never heard of it being brazed in. All that I’m familiar with are screw in. You’d either have to find a suitable adaptor, or have one made. I have made them myself, on a lathe, and any machinist can make one in an hour or two.

Also, your 155mm could have been made for a VT fuze which generally had a larger thread diameter. Most of the older, large, US VT fuzes have a thread diameter of 2.3", whereas smaller fuzes have a thread diameter of only 2.0" Can you measure yours to see what size they are?

Good Luck



Ray-Here are a few places I found mention of the brazed in place fuze adapter…

"The M107 is the Army’s standard high explosive (HE) projectile used principally for fragmentation and blast effects. The body of this 155mm projectile consists of a hollow steel shell containing high explosive. A fuze adapter is screwed into the body and brazed in place. "

“The body consists of a hollow steel shell containing high explosive (either TNT or Composition B) painted olive drab with yellow markings. A fuze adapter is screwed into the body and brazed in place. An eyebolt lifting plug is screwed into the fuze well to assist in transportation, it is removed and replaced with a fuze for firing. The complete projectile weighs 43.2 kg, is 800 mm long and contains 15.8% explosive by weight. It is a separate-loading projectile - propellant bags or MAC charges are loaded separately.”

In any case, it appears that this projectile is missing the fuze adapter, so I will have to start looking for one of those, and a nice fuze to add…I was pretty happy to get it!

ETA I will measure the opening…



Now I understand. On US Navy shells the adapter was screwed in and then staked in place.

BTW, the dimensions I gave were for US Navy projectiles. The Army fuzes and adapters may have different threads. But, either way, it’s important to take measurements since some of our big ordnance forum members may have what you need.




Here are some details. The fuze list should prove helpful. I’ll check to see if I have a spare, but I don’t recall having one in the lot.

(click on pics for bigger)



I’m not up to speed on Army jargon, but could the “supplementary charge” be what pzjgr is calling an adapter? On the USN projectiles the adapter is removed when using a VT but it looks like the Army removes the supplementary charge when using a VT. If this is the case, it may be easier for him to find a VT fuze rather than looking for an aluminum liner and a PD fuze.



Of the fuzes at hand, an M577, M565 and M500, here are the thread ODs.

M577 50.4mm
M565 50.4mm
M500 43.0mm

None of which are listed but are for comparison.



I’m not up to speed on Army jargon, but could the “supplementary charge” be what pzjgr is calling an adapter? On the USN projectiles the adapter is removed when using a VT but it looks like the Army removes the supplementary charge when using a VT. If this is the case, it may be easier for him to find a VT fuze rather than looking for an aluminum liner and a PD fuze.


I think it’s what lots of those in the know call a gaine. I think we discussed this previously. Regardless, my fuze manuals are all VERY thick tomes, so the options and variety are near endless. I’d just be looking for something that fit, ignoring the official list. At least 'til a good example surfaced.


Another reference, more closely dated for your projectile, lists the PD M51A3 and MT M67A1 fuzes.


I would agree with Rick, the “supplementary charge” is a gaine…as it states it is used in the deep cavity shells…

I know the German rounds worked in the same manner, if it had a deep cavity and/or in the larger diameter rounds, the gaine helped ensure even and complete detonation of the entire filler train…

Thanks for all the great information guys…I will have to compare the fuze list to a similiar list to 105’s…my thought was possibly the is “fuze adapter” screwed into the larger diameter fuze opening in the 155 to allow the smaller diameter 105 fuzes to be used…

If the 155’s can use two different sized fuzes, then I would look for the 155mm specific fuze rather than hoping to come across the adapter to use 105 fuzes…

Ok, now even I am confused! ;)



Yeah, I seem to recall that we discussed that before.

Turn of Century (20th that is) it was called a head, then (my time) an adapter, and now I think everyone calls it a gaine. I think gaine is actually the ancient term, so maybe we are regressing rather than advancing??

A couple of years ago I was talking to a young artilleryman and he kept referring to a gaine and I didn’t have the slightest idea what he was talking about. I mentioned an adapter and he was lost. We then realized we were talking about the same gizmo. Maybe that’s a better word anyway - a gizmo- the part that screws into a projectile to change the thread opening. ;)



And all this time I thought it was called a thigamajig.

Or was that a doohickie.


A few of the optional 105mm fuzes:


WW2 vintage:


OK, I grabbed a quick measurement on each, and this is rough…I should break out my calipers…

But the diameter of the opening of the 105 is roughly 1 7/8", while the 155 is roughly 2 1/4"…and judging by the list of 105 fuzes from Rick, it seems that the, say, M557 and M78 fuzes are used by both…so I am guessing there is indeed an adapter that will screw into the 155 nose to allow the smaller diamater fuzes to be used…


Also, look for an adapter ring(expander?) that goes on the fuze itself vs one(reducer) that goes into the nose of the projectile.


I have a buddy who sells a lot 155MM inert projectiles, restored and in demilled condition. If you have a hard time finding the proper fuze and or adapters for this, let me know I will try hunting the INERT parts down for you.



Just to wade in on this topic. The sup charge is also the gaine, and is re-moveable. If you look on the bottom of the round there should be a base plate held in by either stamping, welding or calking. if there is no base plate, the round should be a White Phosphorous round and would be missing the Burster Tube. The Burster Tube fits in the mouth and is about the full length inside of the round. It has a charge to open up the round (burst it) and spread the WP around as a screening smoke. The reason that your standard fuze will not fit is that the Burster Tube is threaded to accept the standard fuzes in use, be they Point Detonating (PD), Mechanical Time (MT), Electrical Time (ET) or Proximity (VT). To have a fuze fit, you’re going to have to have a piece machined that is approximately 3/4" long and will be the same contour of the round and the fuze combined. I can’t seem to get my pubs to attach to any media, but the gentleman that posted the M107 might have the WP round in his book. You could also look in TM 43-0001-27. Hope this helps, Bruce A. Carnal, MSgt USMC EOD, (ret).


I’m sorry, that would be TM 43-0001-28, not 27. Bruce.