High velocity rounds

[David Filsell]

A question on a subject about which I am ignorant.

Does a high velocity round - higher than the 'original round - increase the accuracy of using a short barrelled weapon - a carbine - or is the accuracy dependent upon (amongst other things) barrel length?

[sw63]

Higher velocity simply means a faster speed, therefore greater impact energy but not accuracy. At least that is my understanding of the term.

[Beerhunter]

Unfortunately, high velocity can mean almost anything; it often depends on context.

[David Filsell]

Thank you. The Us M1 carbine is claimed to have been accurate to 200 yards. I wondered if a high velocity would affect accuracy and/or increase it.

[MikB]

If a higher velocity can be achieved, it flattens the trajectory. That means the round travels further before accurate range estimation becomes critical to scoring a hit.

The volley sights fitted to British rifles, for example, were graduated out to 2,700 yards - but at that distance the bullet's flightpath is descending at more than 15 degrees, which in turn means that only about 10 yards rangefinding error would make the difference between striking the dirt in front of the enemy's feet and missing over the top of his head; and that disregarding ordinary variations in velocity and the manufacturing tolerances in the setup of rifle and sights. But a general purpose 'battle' sight, or a simple adjustable rearsight, would cope with the trajectory path up to normal fighting ranges of 100 to 400 yards to the extent that an error of 100 yards or more in range setting would make a much smaller difference to point of impact.

Physics, metallurgy, propellant chemistry and practical portability of the firearm impose limits on what can be achieved. The M1 carbine does around 2000 fps, but achieves this with a lightweight bullet with a rather poor ballistic coefficient - which means it loses velocity quite quickly. To try to improve on this would require a larger, faster-burning propellant charge (so as to produce as much velocity as possible in a shorter barrel) generating higher breech pressure, and that would substantially increase the weight of both firearm and ammunition - ultimately defeating the purpose of developing the carbine in the first place.

Humanity's interest in weapons is such that the ballistics achieved in most well-known military smallarms are about as good as is practically possible with the technology - which has basically remained unchanged for about a century. We can't make steels much better, or propellants much more controlled in their burning, than we could in WW1. Efforts to improve firearms have had to concentrate largely on other aspects of their design than basic ballistics.

Regards,

MikB

[David Filsell]

MikB

Thank you for that. Most helpful.

My understanding is that high velocity rounds are available I wouldn't think 15 rounds would crucially affect the weight of the weapon though -would it?

[MikB]

MikB

Thank you for that. Most helpful.

My understanding is that high velocity rounds are available I wouldn't think 15 rounds would crucially affect the weight of the weapon though -would it?

I can see that a current US manufacturer is selling HV ammunition, but he's doing it by using even lighter lead-free bullets to stay within pressure limits. I think they'll lose that velocity advantage before they get to 200 yards because of reduced sectional density, and there'll be no effective range advantage at all.

This is getting way off-topic, and I don't think I should comment further.

[David Filsell]

MikB

Thank you again I guess I was pushing the Forum limit a tad.

Your information has answered my question very effectively though.

Most grateful

David

[nigelfe]

Accuracy has several components, you can start with the quality control arrangements during manufacture, which will determine the extent of differences between each round (and the firing weapon). For individual weapons the 'skill of the user' is the main determinant of accuracy, and the range to which it is accurate. Some people shoot more accurately than others, that's why there are shooting competitions.

[Chasemuseum]

Keeping within a Great War context, the British .303 rifles were transitioning between the Mk Vi and Mk VII cartridges during the war. While the Western Front saw almost exclusive use of MkVII as a rife cartridge, the ANZAC troops at Gallipoli used Mk VI with the rifles having the sight beds replaced for HV ammunition in 1916 while in transition from Gallipoli to the Western Front. I would be interested if anyone can answer were the British troops at Gallipoli using Mk VI or Mk VII ?

Then for the Vickers gun the Mk VIII round head an even higher velocity but this cartridge was never considered as safe for use in a rifle.

Cheers

RT

[Guest]

At Gallipoli the regulars had the SMLE and Mark VII ammunition whereas the RND had the long rifle and Mark VI ammunition. This caused resupply challenges during the landings in April. The TF formations* also had the long Lee Enfield and I think Mark VI ammunition. The first TF formation landed only two weeks after the initial landings.

On the Western Front if memory serves the initial TF units had longs and Mark VI ammunition but at some stage the longs were converted to take Mark VII. The first TF units arrived in Sep 1914 and by The end of Dec 1914 there were 23 TF battalions in theatre of which 17 were embedded with regular Brigades. Given the short time I suspect the TF in 1914 were using longs and Mark VI. I assume this caused problems of resupply.

In terms of ammunition and rifles I think there is little doubt that the SMLE was considered preferable.

MG

* at Gallipoli there were five TF Divisions and enough TF units by way of reinforcements to have formed at least another. There was one regular Division (which included a single TF battalion) and three New Army divisions in the British Army. The 29th Indian Inf and the RND were also present in the British forces in addition to the Australian and New Zealanders.

[MikB]

MikB

Thank you again I guess I was pushing the Forum limit a tad.

Your information has answered my question very effectively though.

Most grateful

David

Recognising that it's off-topic, it's worth pointing out that SMLE and M1 carbine were both essays in trying to produce a lighter, handier general purpose personal weapon.

Comrade Kalashnikov travelled the same road a bit later. Compared to the M1 Carbine, he managed about a 12% heavier bullet at 15% higher velocity, and maybe 35% more effective range - but he had to pay for that with about 80% more loaded weight. The world has voted with its cash on which solution it thought better.

[Guest]

Recognising that it's off-topic, it's worth pointing out that SMLE and M1 carbine were both essays in trying to produce a lighter, handier general purpose personal weapon.

Comrade Kalashnikov travelled the same road a bit later. Compared to the M1 Carbine, he managed about a 12% heavier bullet at 15% higher velocity, and maybe 35% more effective range - but he had to pay for that with about 80% more loaded weight. The world has voted with its cash on which solution it thought better.

I suspect it voted with its cash on which one was cheaper and which one was simpler to maintain. The differences in design complexity are quite profound.

On topic there is plenty of evidence in the war diaries that the transition to the HV Mark VII ammunition caused the BEF some considerable problems. The most famous example being the London Scottish at Messines who had received Mark I rifles converted to take Mark VII ammunition only the day before leaving for France. According to their published history:

"The new rifle served out the day before leaving Abbot's Langley proved to be defective. There had been no opportunity for rifle practice after landing in France and not a man in the Battalion had ever fired a shot from his new rifle until he used it in battle. The rifles were Mark I converted to take Mark VII ammunition. Not till the Battalion was in action was it discovered that the magazine had too weak a spring and its front stop clips were of the wrong shape for the Mark VII bullet. This caused refusal of the cartridge to entre the chamber of the barrel, for either the point of the bullet came too low and hit the lower part of the breech entrance and jammed there, or it jumped and hit the top of the breech entrance, sometimes breaking off the point of the bullet. It was certainly a serious matter for men opening fire in their first battle to find their rifles jamming and the magazines failing to act. The magazines were useless and the rifles had to be used as single loaders. All the same, steady shooting beat off the attacks"

MG

[RodB]

At Gallipoli the regulars had the SMLE and Mark VII ammunition whereas the RND had the long rifle and Mark VI ammunition. This caused resupply challenges during the landings in April. The TF formations* also had the long Lee Enfield and I think Mark VI ammunition. The first TF formation landed only two weeks after the initial landings.

On the Western Front if memory serves the initial TF units had longs and Mark VI ammunition but at some stage the longs were converted to take Mark VII. The first TF units arrived in Sep 1914 and by The end of Dec 1914 there were 23 TF battalions in theatre of which 17 were embedded with regular Brigades. Given the short time I suspect the TF in 1914 were using longs and Mark VI. I assume this caused problems of resupply.

In terms of ammunition and rifles I think there is little doubt that the SMLE was considered preferable.

MG

* at Gallipoli there were five TF Divisions and enough TF units by way of reinforcements to have formed at least another. There was one regular Division (which included a single TF battalion) and three New Army divisions in the British Army. The 29th Indian Inf and the RND were also present in the British forces in addition to the Australian and New Zealanders.

It amazes me how mainstream historians ignore this sort of stuff in their narratives... when it could be a matter of life and death that correct ammo was supplied; logistics just doesn't exist to them. Seems to show up more in unit histories. I can only imagine the comments when QF 15 pounder rather than BLC 15 pounder cartridges arrived at Gallipoli..