Chatting About Cannons & Tanks with Glenn Fleming

When I arrived at down in Texas, I was happily surprised to find my old acquaintance Glenn Fleming working there as lead gunsmith. Glenn and I first met on the set of a certain TV show many years back, and he is a great guy – in marked distinction from the rest of the show’s cast. Anyway, Glenn left the show shortly after my appearance (coincidence?) and has been working as a gunsmith since. For a while he ran a Youtube channel call the Gunner’s Vault. Anyway, Glenn is now the head gunsmith for DriveTanks, doing fun and interesting things with machine guns and artillery, like rebuilding a 14.5mm KPV from a parts kit. He took a few minutes to chat with me about some aspects of shooting and working with tanks and artillery…


  1. Really stupid question: it is known that having a tank fire its main gun at a high angle relative to the horizon like a field-howitzer is generally not a good idea, but if it must be done, what is the best method for doing such an action?

    Even dumber question: are towed heavy field guns or gun-howitzers (both intended for long-range fire) a realistic threat to a tank at spitting distance, even if the tank somehow failed to notice the guns?

    • I do not think breech pressures get much bigger at higher elevation angles, but what is probably determining factor (specifically in tank) more than anything else, is recoil clearance. This is more-less area of self-propelled howitzers, I’d think.

      • Also, tank gun systems do not generally have indirect fire sights, which are an entirely different matter than direct fire sights. So IF with a tank gun is going to be approximate at best.

        “Approximate” is not a word your own frontline troops like to hear coming from divisional fire support. Especially when calling fire on somebody right in front of them.

        It’s especially unwelcome when heard in conjunction with “Danger Close”.



    • Even dumber question: are towed heavy field guns or gun-howitzers (both intended for long-range fire) a realistic threat to a tank at spitting distance, even if the tank somehow failed to notice the guns?

      Probably the sheer mass of a heavy duty artillery round hitting a tank will do damage, with HE affect added. A 155 round is about 100lbs, moving supersonic. If it hits a tank, even an MBT of recent vintage, it’s going to do damage. Might not penetrate, probably wont, but the dent is going to break everything inside the tank and plenty of stuff outside.

      Recall that one of the ways the US Army had to deal with a Tiger in NW Europe (besides call in artillery or air support) was to smother it with 75MM HE rounds. But that is almost internet lore so take it with a grain of salt.

      • Generally, the most effective fire from support artillery on tanks is going to be indirect fire. The roof of a tank turret or SP gun is generally the part with the thinnest armor. So even a theoretically non-armor-piercing HE round from something like a 155mm howitzer has entirely too good a chance of penetrating.

        In direct or indirect fire, most modern 155mm or similar guns have dedicated guided CLGPs (Cannon-Launched Guided Projectiles) for “tank plinking”. The M712 Copperhead being one of the earliest examples still in service;

        Copperhead is now being supplemented and in the end will probably be replaced by M982 Excalibur;

        The SADARM carrier round for M982 has been proven to be especially effective at killing tanks, even on the move.

        Note that during WW2 in Europe, the U.S. Army answer to the field gun vs. Panzer problem was to add a four-gun battery of M3 3 inch anti-tank guns to each 105mm artillery unit.

        Since the M3 was built on the M1A1 105mm carriage to begin with, gun crews used to the 105 had no trouble learning to use it, and being attached to the 105 units meant that there were always dedicated anti-tank guns available to handle an unexpected Panzer visitation.

        Also, being an integral part of the field artillery units meant that there were always adequate numbers of prime movers available when it was time to move the guns. Thus avoiding one of the recurring problems of AT guns attached to infantry units.



    • With respect to using towed field guns in an anti-tank role, in the period before, during, and after WWII it was common for field pieces to have a few AP, HESH, or shaped-charge anti-tank rounds for self-defence purposes in case enemy tanks showed up unexpectedly. If using an AP round they were often fired using a super-charge (the largest powder charge the gun was rated for).

      I’ve no idea when or if that sort of thing fell out of common practice once anti-tank missiles became common enough to equip artillery units with some for self-defence.

    • “(…)are towed heavy field guns or gun-howitzers (both intended for long-range fire) a realistic threat to a tank at spitting distance, even if the tank somehow failed to notice the guns?(…)”
      I assume that under gun-howitzers you are understanding what is called гаубица-пушка in Russian. If this does not hold true ignore this post entirely.
      During Great Patriotic War Soviet guns of this kind were furnished with anti-armour ammunition. Take for example ML-20 ammunition suite:
      penetration of armour are given in table below it.
      Cold War-era D-20 which replaced ML-20:
      has HEAT shell available and is also able to fire (developed several years after D-20 itself) guided shell Краснополь-М
      it can be used against tank both moving and stationary, thus giving good chance of scoring hit from beyond tank’s armament range, however it relies on artillery observer which must have unobstructed Line-of-View at target.

      • Assuming enemy tank cannot snipe artillery spotter, result is: “You can run, but you can’t hide from THIS!” KABOOM!!

      • Interesting post Daweo. The 152 had roughly the same AP ability as the US 3″ gun. Two totally different guns for different roles.

        However, gotta believe the 152MM hitting with an HE round is going to do a lot more damage than a 3″ HE. Matter of fact, probably fatal damage.

        But found the AP numbers interesting.

    • At a “mad minute” at Fort Riley, summer of 1984, I saw an M110A2 8″ SP howitzer in direct fire mode score a bullseye on an older Soviet tank (probably a T-55, but I’m not certain).

      They hit it directly at the turret/hull joint, and the entire turret went up. And up. And up. And up. It was almost slow motion, spinning end over end, at least 300 feet into the air before tumbling back to earth.

      It was amazing. And then the A-10s came over. 😀

    • Usually tanks have thinner armor on top. While some of the more exotic munitions have been mentioned already, the most common (at least for 155MM at least) munition to take out tanks is DPICM (, a shell that disperses many bomblets that right themselves to point downward with a streamer. When the bomblets make contact with a tank they fire a shaped charge that can punch small holes in armor. Beyond the damage the shaped charge does … the resulting spalling can also take out tank crews and causes secondary explosions etc.

  2. I wish Glen showed his projects, instead of pointing his thumb into space. 🙂

    To restore cannons/ field pieces is a territory with many risks with almost zero chance to “reproduce” certain parts. I am certain that real “heads” were working on them in past and those pieces were optimised after several runs of calculations and physical tests (e.g. German field guns had higher safety factor that the Russian ones – hence their higher mass). As for breech rings you better have quality forgings from a specific steel – something which is not normally available to enthusiasts.

    For this and for red-tape to deal with we ought to be thankful to people like Glen.

  3. After WWII was was the German 88 not retained and used by other militaries like other German equipment? Seeing how dreaded the 88 was during the war, I would have expected the 88 to be utilized by other militaries or even copied and put into service like the MG42 was.

    • The heavy 8.8 cm flak guns at that point were almost totally outclassed by new developments, but several preserved examples were fired during the Yugoslav wars. As the local armored forces were hardly top-notch, the 8.8 cm guns were more than enough to make hostile tanks miserable. I could be wrong.

      • Certainly in Finland–neutral, low on resources to lavish on its armed forces, and having to negotiate the Cold War as the USSR’s only non-proxy bordering nation state (see “Finlandization”), the 88mm German flak gun was used into the late 1970s.

        Similarly, Franco’s Spanish State retained the German 88 throughout Spain’s ostensibly “neutral” period, although when the nation officially joined Nato, I think these were scrapped. Certainly I’ve seen a few there that look as if they could be made operational relatively easily?

        Meanwhile, the rest of the world obtained arms from either the U.S. “free world” or the USSR Socialist Bloc for the most part. The U.S. had its 90mm gun, and various recoilless rifles and tanks and bazookas for anti-armor use, and the Soviets had the 85mm gun and much else besides.

    • A nice book on FLAK/PAK 8.8cm by Chris Ellis w/ Peter Chamberlain; quote from pg.8:

      “While there is no doubt that the 8.8cm gun was a classic design, superbly engineered and of typical German quality, continuously developed and adapted with Teutonic thoroughness, it must also be said that some of its formidable reputation in WW2 was achieved by the inflexible attitude to its deployment shown by the Allies. The Germans themselves found that the most modern comparable Russian guns they captured were actually superior to the 88 and that he 88 was overengineered for its task.”

      • In part, the Germans were willing to commit to using a gun as big as the (various) 88 mms into the front line. The U.S. 90mm, the 17 pounder, and some of the Soviet guns were at least comparable in anti-tank performance. But in the late war, the Germans were on the defensive, and had ever shortening supply lines so putting an 88, or a large self-propelled gun into anti tank service wasn’t as impractical as it would have been for the advancing allies.

      • The Finnish military retained the 8.8cm as a field weapon until 1977, and it was still in use as a coast defense gun in turreted emplacements in both Finland and Sweden until the early 2000s;

        Ironically, the coast defense turrets bore a remarkable resemblance to the French turret emplacements of the Maginot Line of 1940.

        But of course torpedo boats and etc. could not do an “end run” around the coast guns, because something called “the shoreline” was in the way.



        • Torpedo boats would have to ask for naval airpower to get past the coastal guns. And even then, good luck, it’s not like the coastal batteries would have no flak cover either!

  4. Also, lovely reference book book on big bores I recommend is Artillery by Chris Chant. It covers most of developments from beginning of 20th century to late 80s. Subtitle is “Over 300 of the world’s finest artillery pieces from 1914 to present day”. I find it one of best for on-fly enthusiast.

    • Sounds good! I have Brassey’s Artillery of the World–or whatever it is called. Not much on the earlier stuff except for the “classics” like the “soixante-quinze” and “Big Bertha” and so on.

    • Also this one with the same title;

      Hogg was a Master Gunner, Royal Artillery, and what he didn’t know about the history of his profession probably didn’t exist. Also, the book is extensively illustrated by John Batchelor, the dean of military hardware artists.

      I have two copies; one for archive, the other so heavily used since 1973 that its spine is coming off. I highly recommend the book, as well as anything else written by Hogg.



  5. From an old tanker (74-99)

    1) Use of tank main guns in the indirect fire role was part of US doctrine and training until the last M60 series vehicle was retired. The tank had an azimuth indicator (see second photo)

    again second photo

    to set direction of fire and a surface was machined on the breach to use a gunner’s quadrant to set elevation

    In action


    Tank destroyers spent almost all their time firing direct missions, the amount of HE expended being immensely more than AP. By December 1943 the four TD battalions in Italy were averaging 15,000 HE rounds per month and the wearing out barrels so rapidly that getting replacements was a problem. I doubt if the entire TD force fired 15,000 AP in the entire war. BTW, many TD officers were converted artillerymen, so adapted easily to indirect fire.

    After the first several months in Korea, tanks were used almost exclusively as indirect fire missions and also did so in Vietnam


    2. US 75mm and 105mm Howitzers were issued HEAT. US doctrine in WW Twice was for 4.6-inch, 155mm and 8-inch to fire at tanks using the common HE round with the nose plug still in, not the fuse. Kinetic energy would tear the turret off or cave in the bow or sides. &diety knows what an 8-inch gun or 240mm howitzer round would do to a tank, but I don’t think their carriages had enough depression to allow direct fire.

  6. A W W 11 vet I knew had his 90MM antiaircraft battery (they had been shooting down buzz bombs on the Normandy coast) thrown into the Battle of the Bulge to, hopefully, knock out Tiger tanks. He and his crew dueled with a Tiger in the December night. Unable to stop it, being surrounded by German S.S. troops, they were forced to abandon their gun and made their way to Bastonge.

    • Not so fun fact;

      The 90mm gun on the M36 tank destroyer and the M26 Pershing was developed from the 90mm AA gun; essentially, the slightly-shortened 90mm tube installed in a concentric recoil system, using the same cartridge case but with APCBC and APCR shot.

      The muzzle brake on both was vitally necessary to prevent the recoil force of the 90mm (roughly 1.6X that of the 76.2mm in the M4A1) from wrecking the recoil system and probably the inside of the turret as well.

      The punch line is that the 90mm was not noticeably more effective vs. German Panzer armor than the 76.2mm. Neither one could penetrate the front armor of the Panther at 30 deg. incidence beyond 600 meters.

      Vs. the Tiger II, both guns failed at 250 meters.

      Interestingly, both guns showed consistently better performance vs. the T-34/85 in Korea. And the Russian D-5T 85mm gun on same was shown to be no more effective vs. the M4A3E8 Sherman and M46 Patton’s front armor that the German 7.5cm KwK 40 L/43 gun on the Panzer IV had been five years earlier.

      Granted, this still made the T-34/85 a nasty opponent, but the Russian gun was considerably less effective than either of the two German 8.8cm tank and tank destroyer guns.

      U.S. tank main gun development from the 1930s to the 1950s was a history of “too little, too late”. The shortcomings were finally solved by the adoption of the British Royal Ordnance L7 105mm gun, originally developed for the Centurion, as the M68 gun for the M60 in 1960, and later the M48A5 in 1966.



      • “(…)The shortcomings were finally solved by the adoption of the British Royal Ordnance L7 105mm gun, originally developed for the Centurion, as the M68 gun for the M60 in 1960, and later the M48A5 in 1966.(…)”
        I found it interesting that they did not that earlier. Apparently U.S. Navy had nothing again using British-designed U.S.-made jet engines during 1950s in their carrier-based aeroplanes (see F9F-5)

        • The L7 gun was developed by Royal Ordnance Enfield beginning in 1954, and made its debut on the Centurion MK V in 1958, replacing the earlier 84mm 20-pounder which dated to 1946. It was chosen for the new M60 tank (basically an improved M48A3) in May 1959, with production beginning in the U.S. in early 1960. So really, it was one of the faster peacetime decision-making procedures in U.S. Army Ordnance history.

          The major impetus from the U.S. Army’s POV, contrary to myth, was not the 100mm gun on the T-55. The 100mm was fairly well understood, as it had been in service as an AT gun as early as 1944 (SU-100), and had been “acquired” from various sources (notably Israel) due to the various Arab armies (notably Syria’s) perpetually losing intact vehicles due to fuel exhaustion and abandonment in situ.

          The actual reason was intelligence reports on the new 115mm smoothbore gun of the T-62. It was supposed to be able to penetrate the M48 over most of its armor from 900 meters.

          In fact, like the T-62, the 115mm gun wasn’t as great as advertised. Ironically, its main influence was keeping the T-55 in production.

          Today, Norinco, the arms export side of the Red Chinese PLA, does a considerable business offering “kits” to refit existing T-55 tanks with the PLA’s copy of the L7/M68 105mm gun. While the L7 is only a moderate threat to such tanks as the M1 or Leopard II series, it can still destroy tanks of the previous generations with efficiency, and such tanks still account for over 80% of the MBTs in service worldwide.

          Also, there are many things to shoot at on a battlefield other than MBTs, and the L7 105mm rifled gun is perfectly capable of dealing with them with ordinary HE rounds, saving the APFSDS “long rods” for when an enemy MBT is making a nuisance of itself



  7. Jane Defense Magazine had an article on postwar British Army comparison on german 88mm
    gun to equivalent soviet AT gun, concluding that only from the 100mm gun there was an effective match to the 88mm.

  8. Actually, Sweden had a fairly sophisticated 12cm coastal artillery system the ERSTA 12cm/70. Finland’s–which unless I’m mistaken–was the 130mm/53 TK supplemented by a handful of T54/55 turrets here and there with its 100mm gun.

    True story: After almost falling to my death from a dilapidated 19th Century British-made bridge into the Paraquacu river in Northeastern Brazil, I found a bunker guarding the beach near Cachoeira with a couple Brazilian army soldiers napping inside… Next door, so to speak, was an enormous WWI British-made Armstrong 4.7-in. QF gun on a WWII-vintage U.S. artillery carriage with rubber tires. It was one of the coastal defense weapons gifted to the Getulio Vargas regime to keep the Axis from jumping over from one or another of the Vichy sub-Saharan African colonies to the Americas… Provided in exchange for U.S. airbases and overflight rights to jump from Brazil to Tunisia and North Africa during Operation Torch. Gun was still very well maintained and in service!

  9. Returning to Cherndog’s first question about using tank guns for high elevation artillery fire … I vaguely remember seeing a photo of four Shermans firing high-elevation during fighting in Italy (1943 – 1945) or Korea (early 1950s). If it was in Italy, they were probably 75 mm guns which were developed from the excellent WW 1 French 75 mm gun.
    If in Korea, they were probably the later 76 mm gun installed in Sherman M4A2E8.

    They were parked on extra-long railway ties that were laid on a small hill that was already steep. I doubt if they were as accurate as dedicated artillery and suspect that they were used more for “area suppressive fire.”
    Hopefully some one else can find that photo.

  10. Having used both the 90mm gun M41 and the 105mm L7 (M68) I will state my preference for the 90mm because of the wide variety of ammunition available for it. M377 canister and HE M71 were effective, reliable and versatile, particularly with additional fuzing available. By contrast M494 APERS was miserably erratic in function and HEP M393 was excellent, the M68 gun could have benefited from a convention HE round as well. There was a HEP round in the ammo catalog for the 90mm but I never saw one in real life.

    Put me down as a fan of a rifled gun and for a tank that can deal with more than other tanks. I maintain that the best time to have a tank is when the other guy doesn’t.

  11. In Germany in the early 70s my unit condicted a direct fire shoot off. M60A1 vs M551 Sheridan (conventional round) vs M109 Howitzer (long tube). Targets M47 tanks at 1000 meters. All rounds fired hit the targets. The Howitzer’s second shot broke the target’s turret ring and the turret slid off to the ground. But by then the Sheridan had put 4 shots into its target and the M60 8.

  12. Upthread there was some discussion about using tanks in the indirect role. The last tank remotely capable was the M60 series. The last gunnery manual to cover topics like figuring mask clearance or laying a tank platoon’s guns parallel was the 1968 version of FM17-12. The instruments like an azimuth indicator or an elevation quadrant were never installed on any production version of the Abrams. Any tank platoon sergeant that has set his platoon into a “lazy W” formation would be a contemporary, long retired and in his mid seventies or older.

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