@ CORNBINDER 49:
Obturation.
The flat-base bullet of the Mark VII sets up to fill the bore much better than any boat-tail design. The Mark VIII, if properly made (and see Big Ed's original military drawings on this), has LESS TROUBLE THAN OTHER TYPES in obturating, but even it is not ideal. Remember, roughly 95% of all Lee-Enfield rifles were built during wartime or something approaching it: conditions of great stress, cheapest bucks for the bang, relaxed tolerances and so forth. Many of them have been shot a lot with Cordite, which burns very rapidly and with a VERY high flame temperature. NC powder burns cooler but erodes the Leades quicker; the 2 types of ammunition were never mixed in Service where it was possible to keep them separate. Mark VIII for the Vickers gun was factory-packed in belts and shipped in sealed Spam cans, 2 in a crate; Mark VII was packed generally in boxes of 48, 26 to the crate.
Now we consider RIFLING. The Lee-Enfield rifl gnerally uses ENFIELD rifling: 5 lands, 5 grooves, grooves deep, lands and grooves of EQUAL width. It is the prototype for the now-fashionable "5R" rifling which is said to last so very well, just turning Left instad of Right. This rifling was developed by Mr. William Metford, a celebrated 19th-Century target shot and replaced the earlier Metford rifling (also developed by Metford) when it became apparent that the Cordite Mark I of the early Marks of Ball ammunition were burning-out barrels at a fearsome rate. Metford rifling originally was developed in Black Powder days as a long-range rifling form which afforded easy cleaning; the later form called ENFIELD was developed to make a barrel LAST with Cordite. With Enfield rifling, the bullet has a lot of deforming to do just to fill the barrel completely but, once it has done this, the barrels can be made to shoot splendidly. The secret, of course, it to FILL the barrel so that gas cannot bleed around th bullet and destabilise it at the muzzle. I have been playing with Lee-Enfields for over 50 years now and have been experimenting with them seriously for close to 30 years. Any time I want the BEST accuracy from an Enfield barrel, I go to a FLATBASE bullet, generally the Sierra 180 Pro-Hunter.
Bullets are filled with LEAD and lead is a DEAD METAL: it has no spring-back, no elasticity at all. When you have a thin jacket filled with lead, the pressure of firing all goes onto the BASE of the bullet. The JACKET starts to move but the lead core does not. The core is PLASTIC and deforms quite easily so, when the back end starts moving and the core is not rigid enough to keep up, the lead core squishes sideways, deforming the jacket and FILLING the core completely, preventing any gas from escaping around it. This is one of the REASONS that Lead is used in bullet cores; a steel or iron or zinc core will not obturate properly, nor will any of them have the DENSITY of the lead core to keep the bullet stable and carry it on its way to a very distant target.
Boat-tail bullets are fine with Mauser-type rifling (pretty much the world's standard) or with the special rifling of a Ross Rifle. In these rifles, boat-tailed bullets will have superior performance at ranges over 900 yards but, for anything closer, there is very little difference. Remember that boat-tailed bullets originally were developed to afford Machine Guns a longer range... and for no other reason. And a final point: the SIGHTS on a Lee-Enfield rifle were designed and set for use with a flatbase bullet at 2440 ft/sec MV.
*****
I have taken down some of the Partizan (PPY .303Mk8Z) amunition and it does NOT conform to the Mark 8 standard. For one thing, the bullet is 192 grains rather than 174 and there is no REBATE: the bullet is a standard boat-tail design. Likely it is wonderful stuff in a Bren or a Vickers Gun, but I really think you will get a better target with a flatbased bullet. The Partizan Mark 8 also is a VERY hot load. My favourite rifle now is 106 years old; this stuff doesn't get anywhere near it. Remember, the locking parts of a Lee-Enfield weigh about an ounce, as compared to the POUND or so of the lock-up in a Vickers.
Hope this helps.
Obturation.
The flat-base bullet of the Mark VII sets up to fill the bore much better than any boat-tail design. The Mark VIII, if properly made (and see Big Ed's original military drawings on this), has LESS TROUBLE THAN OTHER TYPES in obturating, but even it is not ideal. Remember, roughly 95% of all Lee-Enfield rifles were built during wartime or something approaching it: conditions of great stress, cheapest bucks for the bang, relaxed tolerances and so forth. Many of them have been shot a lot with Cordite, which burns very rapidly and with a VERY high flame temperature. NC powder burns cooler but erodes the Leades quicker; the 2 types of ammunition were never mixed in Service where it was possible to keep them separate. Mark VIII for the Vickers gun was factory-packed in belts and shipped in sealed Spam cans, 2 in a crate; Mark VII was packed generally in boxes of 48, 26 to the crate.
Now we consider RIFLING. The Lee-Enfield rifl gnerally uses ENFIELD rifling: 5 lands, 5 grooves, grooves deep, lands and grooves of EQUAL width. It is the prototype for the now-fashionable "5R" rifling which is said to last so very well, just turning Left instad of Right. This rifling was developed by Mr. William Metford, a celebrated 19th-Century target shot and replaced the earlier Metford rifling (also developed by Metford) when it became apparent that the Cordite Mark I of the early Marks of Ball ammunition were burning-out barrels at a fearsome rate. Metford rifling originally was developed in Black Powder days as a long-range rifling form which afforded easy cleaning; the later form called ENFIELD was developed to make a barrel LAST with Cordite. With Enfield rifling, the bullet has a lot of deforming to do just to fill the barrel completely but, once it has done this, the barrels can be made to shoot splendidly. The secret, of course, it to FILL the barrel so that gas cannot bleed around th bullet and destabilise it at the muzzle. I have been playing with Lee-Enfields for over 50 years now and have been experimenting with them seriously for close to 30 years. Any time I want the BEST accuracy from an Enfield barrel, I go to a FLATBASE bullet, generally the Sierra 180 Pro-Hunter.
Bullets are filled with LEAD and lead is a DEAD METAL: it has no spring-back, no elasticity at all. When you have a thin jacket filled with lead, the pressure of firing all goes onto the BASE of the bullet. The JACKET starts to move but the lead core does not. The core is PLASTIC and deforms quite easily so, when the back end starts moving and the core is not rigid enough to keep up, the lead core squishes sideways, deforming the jacket and FILLING the core completely, preventing any gas from escaping around it. This is one of the REASONS that Lead is used in bullet cores; a steel or iron or zinc core will not obturate properly, nor will any of them have the DENSITY of the lead core to keep the bullet stable and carry it on its way to a very distant target.
Boat-tail bullets are fine with Mauser-type rifling (pretty much the world's standard) or with the special rifling of a Ross Rifle. In these rifles, boat-tailed bullets will have superior performance at ranges over 900 yards but, for anything closer, there is very little difference. Remember that boat-tailed bullets originally were developed to afford Machine Guns a longer range... and for no other reason. And a final point: the SIGHTS on a Lee-Enfield rifle were designed and set for use with a flatbase bullet at 2440 ft/sec MV.
*****
I have taken down some of the Partizan (PPY .303Mk8Z) amunition and it does NOT conform to the Mark 8 standard. For one thing, the bullet is 192 grains rather than 174 and there is no REBATE: the bullet is a standard boat-tail design. Likely it is wonderful stuff in a Bren or a Vickers Gun, but I really think you will get a better target with a flatbased bullet. The Partizan Mark 8 also is a VERY hot load. My favourite rifle now is 106 years old; this stuff doesn't get anywhere near it. Remember, the locking parts of a Lee-Enfield weigh about an ounce, as compared to the POUND or so of the lock-up in a Vickers.
Hope this helps.
