303 flame tracer G MK 2


#1

nickel steel jacket, copper cup, brass washer nozzle, 154 gr, flame trace 1000yds, coridite


#2

Thats a really good section and one I find particularly interesting. Thank you for that.
I can’t read the headstamp, I tried clicking on the picture to enlarge it but still couldn’t read it.

Two seperate observations for that round that I would like to make. The first one is only of general interest regarding .303 cartridges. For people who don’t know much about .303s, notice how clearly it shows that the propellent (cordite) part of the case is parallel inside despite the case being tapered on the outside. This is done intentionally because the cordite is like sticks of uncooked spagetti and the case is formed to its final shape after the cordite has been inserted. That way the cordite is held snugly but is not crushed and neither is there any unwanted free space.

The second observation concerns the projectile. The 1000yds is the burn distance but by the time that bullet had reached 1000yds and all the compound has burnt off it would have lost so much of its weight that it would be flying at a much lower trajectory, and slowing down much more quickly, than the ball rounds with which it was interspersed. Also because all the residual weight was so far forward it would probably be spinning erratically (ie wobbling) too. adding to the deceleration.

This has always been a problem with tracer and can lead to a machinegunner spraying an enemy position with tracers at 1000yds while the “real” bullets are going over their heads.
That section shows very clearly how much of the space (and hence weight) is lost to the tracer mixture and illustrates how the problem can occour. For that it is again very interesting. Thanks again.

I notice you come from Hilton Head, a lovely part of the world, I’ve been there and liked it very much. Its a shame I didn’t know you were there when I went, I would have liked to have seen your collection.


#3

BE/43/gii suprized to see diff kinds of metals. Orginal box had half the cart with split necks. HHI is nice but the summer heat is comming! Cobia r in as well. Got private 300yd range that catches fire alot from all the tracers, API, spotters, etc… Could always use company


#4

I have problems seeing cordite in the picture.


#5

[quote=“VinceGreen”]Thats a really good section and one I find particularly interesting. Thank you for that.
Two seperate observations for that round that I would like to make. The first one is only of general interest regarding .303 cartridges. For people who don’t know much about .303s, notice how clearly it shows that the propellent (cordite) part of the case is parallel inside despite the case being tapered on the outside. This is done intentionally because the cordite is like sticks of uncooked spagetti and the case is formed to its final shape after the cordite has been inserted. That way the cordite is held snugly but is not crushed and neither is there any unwanted free space.

The second observation concerns the projectile. The 1000yds is the burn distance but by the time that bullet had reached 1000yds and all the compound has burnt off it would have lost so much of its weight that it would be flying at a much lower trajectory, and slowing down much more quickly, than the ball rounds with which it was interspersed. Also because all the residual weight was so far forward it would probably be spinning erratically (ie wobbling) too. adding to the deceleration.

This has always been a problem with tracer and can lead to a machinegunner spraying an enemy position with tracers at 1000yds while the “real” bullets are going over their heads.
That section shows very clearly how much of the space (and hence weight) is lost to the tracer mixture and illustrates how the problem can occour. For that it is again very interesting. Thanks again.[/quote]

I would like to add a couple of points to those observations Vince.

The shape of the .303 case was settled before cordite was available as a propellant. The first two marks of .303 ball were black powder and were loaded with a solid BP pellet, rounded at both ends with a central logitudinal hole to aid ignition. When cordite was adopted in 1891 the shape of the case remained the same. Most cartridge cases have internal dimensions that are approximately cylindrical.

With respect to the ballistics of tracer rounds, matching the trajectory with that of ball bullets has always been a problem, but the weight loss caused by the burning tracer element is relatively insignificant. In the case of the GII round in question, bullet weight was 154 grains and the weight of the tracer composition was only 10 grns plus 6 grns of priming composition. Thus the total weight of the tracer element was 16 grns or about 10% of the total bullet weight. This means that even when the tracer is all burnt, the bullet retains 90% of its original weight. Whilst this is enough to mismatch trajectory with the 174 grn ball round at long range, it will not induce the yaw that you mention.

Later tracers had a shorter range as most were air service rounds where ranges tended to be shorter. The final Land and Naval service tracer, the G8, retained even more of its weight when all burnt at 1,000 yards. Bullet weight was 169 grans, much closer to the ball bullet weight and the tracer element only weighed 14 grns. leaving the bullet with about 92% of its original weight.

Regards
TonyE


#6

Tony,

One thing I have found with the “Parallel” nature of the inside of a (British) .303 case (Cordite)—and the “z” type as well, is that when making “Extended Neck Blanks” for Movie use, we expand the current shoulder and neck to about 10mm ID (.40) to allow a 3/8ths (.375) Tube to be slipped in all the way to the Web. THis is then held in place by “re-sizing” the case expanded case back to .303 Specifications, and then further reducing the “Bullet” Profile to about 7,5mm Diameter.( to feed into the throat of the chamber)

The entire combination makes a solid, excellently chambering and firing Blank,. especially suited for Lewis, Bren and Vickers-GO guns ( all guns requiring a full length blank ( either brass or wood bulleted) for reliable feeding and functioning.

The pre-cut tube ( .375 x .014 WT) is supplied by K&S Brass Tube of Illinois, USA ( See “The Model Engineer”(UK) or “Model Railroader” (USA) and similar Magazines…also their web page).

WE use thousands of these pre-cut tubes for “making” brass FL blanks for Movies this way ( .30/06, 7,9mm, 7,7 Japanese (all types) .303, 6,5 Italian, 6,5 Dutch, etc.etc. Adjustng the length of the pre-cut tubes for each calibre as required.

Whilst “Short” blanks ( crimped Ball cases) do work in “Pull out” belts (such as Maxim,Vickers, Browning, Swarzlose, St.Etienne, etc, those guns with iether “Push thru” belts or trays or Strips, all require the extra “projectile” profile to feed properly into the mechanism without costly ( and destructive) modifications to Gun or magazines or both.

With other cases, where the insides actually “taper” (at least towards the Web, area of the Body…there is somne “paralleL” section of the body,… the tube is “formed” to the inner body dimensions by the Resizing process and by actual “fire forming”…In any case, in any Blank, the tube is perfectly “Locked in” by the Shoulder and neck of the case, and can’t “shoot downrange” even when fired in a normal Rifle.

THis has been a “Structural disquisition” on the nature of Movie Blanks and the “Internal Engineering” of same and NOT a “Reloading” Article.

Anybody with collateral “re-enactment” interests regarding Blanks can contact us directly via our Email address. (Information only)

Regards,
Doc AV
AV Ballistics Film Ordnance Services
Brisbane
Australia.