OHF marking on butt

[Peter Laidler]

Had a PM recently regarding an OHF marking on a butt
/butt slide from a Mk3 or L4 Bren. What is it. Good question.

The OHF stands for OVERHEAD FIRE. These were selected Bren or L4 guns that were gauged to a tighter criteria, according to the EMER specification that deals with 'preparation for special function'. That being for live overhead firing of troops on the ground.

The gauging covered the fit of the gun on the tripod, the barrel chamber depth and bore to prevent any 'drop-shorts' due to gas passing the bullets in the bore. It also meant that the gun had a 'log-book' attached and serially numbered to the gun, certified by the Armourer Sergeant prior to each days shooting. This usually meant the Armourers staying in late to inspect the guns after a full days firing.

Occasionally you'll see a date painted after the OHF mark. This was the last 'signing-off' and certification date.

So if you've got one of these guns so marked, that's the answer!

At the Infantry Training Centre, we had some of these guns (and the last Vickers for the same purpose) and we kept them separate from the others just to make our life easier - as you do!

[Sapper740]

That displays a concern for the troops that would be under the flight of the bullets during the exercise. In the CF we held a Crack-Thump training exercise where we were taught to gauge the distance of the incoming fire from a regular, run of the mill C6 (FN MAG) that was pulled out of the armoury with no concern for gauging. It was placed on a berm and held in place by sandbags while we retrieved a 'casualty' who wandered into a minefield, Sketchy as heck in my opinion but we all survived.

[browningautorifle]

In the CF we held a Crack-Thump training exercise

"Locating the enemy by his fire"... Was usually done either at a gallery range and the shooting was done overhead or an area range where the firers were located in hidden spots in the field. Then they shot wide of the troops by a given safety margin.

We had overhead firing guns once we got the C6(MAG 58) and used the same rules as Warminster. We never used the old family of MG or LAR for overhead as they were wrong for it. Those excersises were reserved for battle inoculation such as Yugoslavia or later Afghanistan. Then during live fire the guns would be engaging targets distant while you moved under the shots. Lots of safety rules on that one.

[Sapper740]

"Locating the enemy by his fire"... Was usually done either at a gallery range and the shooting was done overhead or an area range where the firers were located in hidden spots in the field. Then they shot wide of the troops by a given safety margin.

We had overhead firing guns once we got the C6(MAG 58) and used the same rules as Warminster. We never used the old family of MG or LAR for overhead as they were wrong for it. Those excersises were reserved for battle inoculation such as Yugoslavia or later Afghanistan. Then during live fire the guns would be engaging targets distant while you moved under the shots. Lots of safety rules on that one.

I guess things were different with the Engineers left on the West Coast, especially after CFB Chilliwack was closed and access to the Vokes range became problematic so we did our live fire training exercises at Ft. Lewis Wa. We kept our sole C6 and sole M2 HBAR QCB at the Area Support Unit which was all that was left at Chilliwack. I can't speak to the right or wrong of the safety practices we trained under as junior ranks had no say in the matter. I personally questioned the sergeant running the C6 as to safety and was told "You have nothing to worry about".

[browningautorifle]

I guess things were different with the Engineers

Yes...

[Peter Laidler]

Ironic that you mention the GPMG/FN MAG58 in the OHF role BAR. I was one of the Armourers on the team investigating its suitability to replace the Vickers guns. We didn't know too much about the wear patterns of the GPMG's or the tripods at the time. So there was nothing to compare it with really. Our first GPMG's were all BL 64 or 65....., Belgium Liege, 1964 or 65 made guns. Some of the later ones were designated L7A1 made in Belgium before full production got underway at Enfield. Some of the old BL64 and 5 guns were still in service, upgraded to later spec several times in the 2000's

The buffered tripod was deemed to be a bit of a problem as were the mounting pin holes in the gun and tripod. I left the team part way through but it seems to have been acceptable. But as a result of the trials, the tighter barrel nut (the No2 barrel nut) was introduced to tighten up perfect 0- but loose - barrels.

What a magnificent bit of kit the GPMG turned out to be. I'm sure that it'll take the crown away from the Bren, at 66 years service, for length of service in the UK military. I THINK, as someone said to me recently, that the prize must go to Bedford trucks..... But that's not comparing like for like!

We also had a Saracen APC painted in large yellow and black stripes plus an old up-armoured Centurion tank that would drive into the 'troop zone' and up to the fall of shot area to ascertain the new safety areas for the 762 ammo. The drivers, signalers and commanders would hear the clang of bullet strikes as they got into the troop zones. I bet that they wouldn't do that now...... I wonder if there's a 5.56mm LMG in the OHF role anywhere........?

[Sapper740]

What a magnificent bit of kit the GPMG turned out to be. I'm sure that it'll take the crown away from the Bren, at 66 years service, for length of service in the UK military.

My nephew is a USMC 0331 Machine Gunner who was trained on and still uses the M240B although the U.S. Army is looking to replace their GPMG's with the XM250 which fires that crazy hot new round: the 6.8 X 51 SIG Fury. As the USMC is the red-haired bastard step-child of the U.S. military, I'm sure we'll see their use of the M240 for some years to come.

[Lee Enfield]

My nephew is a USMC 0331 Machine Gunner who was trained on and still uses the M240B although the U.S. Army is looking to replace their GPMG's with the XM250 which fires that crazy hot new round: the 6.8 X 51 SIG Fury. As the USMC is the red-haired bastard step-child of the U.S. military, I'm sure we'll see their use of the M240 for some years to come.

I've read that in testing the Mag58/M240 gets the desired velocity out of the "training standard pressure" "Fury" round without the super high pressure 2 part case.

Something about the MAG having a normal length barrel.

The US Mil has been sold on "free lunch" yet again...

You need the multi part exotic case because you need super high pressures to get the velocity out of the super short barrel that you need because of the large can that you need with the super high velocity blast that you need with the super short barrel that.....ect ect....

resulting in exotic alloys for the parts to minimize breakages and wear resulting from the super high pressures that you need because of the super short barrel that you need because of the can that you need because of the super blast from the super short barrel that you need because of the...."free lunch"...

Just a thought, maybe a 19" barrel with a telescoped can could get the desired velocities without all the exotics...? but then you wouldn't need to "invest" in all the specialty ammo manufacturing (someone is getting patent rights for sure), and all the exotic alloys (maybe ask the Germans why they switched from the MG34 to the MG42, right in the middle of a "minor" conflict...)

[Sapper740]

I've read that in testing the Mag58/M240 gets the desired velocity out of the "training standard pressure" "Fury" round without the super high pressure 2 part case.

Something about the MAG having a normal length barrel.

The US Mil has been sold on "free lunch" yet again...

You need the multi part exotic case because you need super high pressures to get the velocity out of the super short barrel that you need because of the large can that you need with the super high velocity blast that you need with the super short barrel that.....ect ect....

resulting in exotic alloys for the parts to minimize breakages and wear resulting from the super high pressures that you need because of the super short barrel that you need because of the can that you need because of the super blast from the super short barrel that you need because of the...."free lunch"...

Who knows what the thought process was that came to the conclusion that the new SIG round was the way to go although I'm sure we can agree that cost to the taxpayer wasn't part of the conversation. Whatever the cost, the improved penetration of body armor and greater 'point blank' range will be appreciated by the men at the tip of the spear.

[Peter Laidler]

If I had to choose between a 762 - 54R PKM and a GPMG, it'd be a hard choice Mike. The PKM is just so wonderfully simple, built like a brick sh......., er....., out-house. Just look at the claws that drag the rounds from the belt as a good example. Barrel changes too. Niot that the Soviets worry too much about barrel change discipline.

But the GPMG has a place in my heart too..... Next to the L4