Lee Enfields and Boat Tailed Bullets

[smelly sam]

Remember that there was a change in ammunition going from the 215gn (Mk VI) to the 174gn (Mk VII) along with the introduction of Cordite replacing black powder. To get the best out of the new shorter Mk VII ammunition the chamber was redesigned, reducing the throat length / leede, the 'cone', so that there was less distance for the projectile to travel before engaging the lands, which is why (along with canting / yaw shown by Parashooter) that most MLE, Mk. I / II shoot like crap using 147 - 174gn boat tail / flat base spitzers. Using 180 - 200 gn flat base seated very long in the neck of the case helps get over this, but won't load from the magazine, thus it is a targeteers single shot solution, you can forget rapid fire).

The new barrels came into service late in 1916, with the 19th Bn AIF being the first Australians to receive the new Mk. III* rifles which had HV SC (High Velocity, Short Cone) stamped on the barrel to indicate it was set up for Mk. VII ammunition which soldiers immediately took to as they knew they could kill more Germans more accurately than during the transition where they had the older technology barrels using the newer technology ammunition that shot all over the place. They were very pleased by this.

Looking at the pictures one can clearly see that the bearing surface of the 215gn round nose is significantly more than the 174gn spitzer, as well as the distance from the case mouth to where taper commences on the projectile. The bearing surface for a flat base projectile with the cannula / canular / cannelure (the crimp groove) is obviously greater than that of a boat tail, but in reality this often proves not to be the case as the tapered end is noticed on pulled military projectiles from WWII as well. Go work that out.

The throat of the MLE and Mk I / II was specific to the 215gn round nose, which meant that the rifling started at a point that would allow for some freebore to exist. This freebore would obviously be excessive for the new 174gn spitzer being shorter in length, which accounts for the accuracy problems owners of the older Marks experience (in most cases). Again, the amount of wear to the bore is another significant contributing factor which is why to slug the bore is a wise thing to do and then think about swapping over to cast projectiles sized one or two thousandths of inch over the groove size measured. Gas checks also make the world of difference to performance as well. Be careful about the velocity to hardness, as the softer lead will coat the bore if pushed too fast along it. If into casting, like all things Enfield, there will be a unique set of characteristics suited to each rifle, as no two by now (because of use and abuse) can be expected to perform the same.

The photos show the three 215gn projectiles in use before the soft and hollow point Mk. VI designs were banned because they were considered too inhumane and were replaced in the Mk. VII by a 174gn spitzer, which with its light tip proved to be vastly more effective than the previous Mk. VI at being inhumane. To make it even more humane, the replacement tips in pressed wood pulp / fiber were autoclaved so as to prevent infection, another great advance from the English command mindset of the time.

In summary, if shooting any Mark previous to the Mk. III* then consider longer projectiles - heavier or cast. The barrels _do not_ have 'HV SC' on them instead (I think) you will find many have 'Nitro Proofed' to indicate Cordite use with the newer Enfield rifling design and as all rifles are generous in chamber and throat dimensioning you do well to slug them out to exactly determine which fodder is best to feed them for maximum accuracy and pleasure.

Safety Note: Do not use Mk. VI ammunition in a Mk. III* rifle as the projectile will most likely jam up into the lands preventing the necessary initial free movement on firing. This in turn can dangerously increase chamber pressure, which is not good for the rifle or the shooter as at some stage something will give and when it does it will not be pretty. Also, the Mk. VI ammunition is worth more $$ to a collector than it is to shoot it off.

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[enfield303t]

Went to the range today and used the 174 BT's with 40 and 41 gr of RX15.

Both shot well, and I think I will stick with 41gr. for now.

The No4 is sure a "shooter" and I am very happy with it. Will do lots of little things to keep it consistent and am looking at a different custom made butt as it is impossible to get a cheek weld with the scope mounts I am using even though I have a lace on to raise the comb.

I won't drill into the stock using a No4 sniper cheek piece and have found a CGN member that is making a high comb custom stock for his Lee Enfield and for a reasonable price will make one for me.

It will look a little strange but should solve aiming problems.

Thanks again for all the hints on BT's

[Bindi2]

Make your own cheeck pad out of wadding or very dense foam rubber be very nice to a sewing person much better and easier than mucking around with the butt.

[RobD]

To have a cheekpiece without drilling the stock, I recommend use a repro cheekpiece stuck on with some of that (phenomenally strong) double-sided tape.

---------- Post added at 09:28 PM ---------- Previous post was at 09:25 PM ----------

Is it correct that the light tip of the Mk VII was put there so it would be less humane (i.e. turn sideways on impact)? I have heard this factoid several times. But I have also heard that it was to move the point of balance rearward so as to stabilise the bullet in flight. Does anybody know the truth?

[vintage hunter]

Careful with the tape, the chemicals can cause permanent staining in a very short time, especially on light color wood. If your going for function over form there's several good cheek pieces on the market that use straps to secure them and the height is adjustable. I've had one on my M1A for 12 years and it really does the trick. I've never read anything that said the tip filler of the mk.VII bullet was there for any other reason than to increase the length, but, the filler in the 7.35 Carcano bullet IS there for the sole purpose of making it yaw on impact.

[Bruce_in_Oz]

The filler in the Mk7 bullet has an interesting technical origin.

When the Germans threw the small arms world into a tizz with their spitzer bullet in the early 20th Century, there was a frenzy of research to catch up.The Swiss ended up with the magnificent GP 11 cartridge, the US had to rejig their new rifle and come up with the .30-'06. The Brit's answer was the Mk7.

The trick was to get the muzzle velocity and down-range trajectory and performance without having to totally redesign their entire small arms suite. Note also that at the same time they were cooking up the outrageous P-13 with its "magnum" sized .276" cartridge.

A complete Mk7 cartridge is essentially the same length as the Mk6 that it replaced. This meant that the basic designs of rifle magazines and machine gun feed mechanisms did not have to be re-engineered. Small detour:

In your trusty SMLE magazine there should be an “extra” bit of metal clipped onto the front wall of the box. This is the “auxiliary spring” As a wee lad I was mystified by this, even after the instructors told us that it could be clipped onto the standard “W” job for some extra lift.

Not too sure about that explanation. The magazine of the Lee Enfield Rifles (long ones) had a strange “U” shaped follower spring that clipped to the front of the magazine case. The spring was pretty much flattened against the front wall of the mag when 10 cartridges were inserted. Being spring steel it would also have been harder and smoother than the actual mag case..When something better (the “W” shaped spring) came along, BUT the same EXTERNAL case dimensions and cartridge length had to be retained, that little auxiliary spring was fitted, both to take up the space and to provide a tough but smooth surface against which projectile meplats could bear. The front lips of the magazine for the Mk6 ammo did not retain the Mk7 projectile very well; hence another redesign.

The "Short Cone" was an issue, but optimising it for the Mk7 round was not quite as good an idea as it sounded, as the Mk6 was still in use at the end of WW1, hence there had to be a compromise in that area.Then of course, there was a serious need to have sights with increments that bore some relationship the cartridge du jour.

Thus, for quite a while, the general production barrel for SMLEs had a “universal” short cone. Note also that the twist stayed at 1:10” because the bullets were the same LENGTH, despite the weight difference: See Greenhill’s formula.

Back to the Mk7 bullet:

The bullet had to be 174 gn or less to allow it to be driven at the velocity required to achieve the trajectory and range that the ballisticians wanted. A solid lead, or even a lead alloy core would not allow this. Making it a “super-slinky, VLD shape” was probably too much of a technical ask, not to mention being a retention and feed-control nightmare. The solution was to insert a filler of light material in front of the lead core. This had the “interesting” side effect of greatly increasing the tendency of the bullet to tumble upon striking anything much harder than relaxed muscle tissue, especially at short ranges whilst it was still precessing to some degree.

[Peter Laidler]

Phew................ You can see and understand why Armourers never touch ammo and Ammunition technical bods never touch firearms now!