Thread: New Defence Force rifles need firing pins replaced

Also you need to see if those 50 and 55 gr bullets were flat base vs a 62gr + bullet that is likely to be a boattail. The latter is going to stay more accurate the further out it goes compared to the flatbase in general terms. The flatbase will also loose velocity and energy a lot quicker too.

Originally Posted by Cowboy06

Also you need to see if those 50 and 55 gr bullets were flat base vs a 62gr + bullet that is likely to be a boattail. The latter is going to stay more accurate the further out it goes compared to the flatbase in general terms. The flatbase will also loose velocity and energy a lot quicker too.

@Cowboy06

Correct, but only at the end of the bullet's useful flight path, therefore it is not quite correct to state that a flat base spitzer will lose velocity and energy 'a lot quicker' than a boat tail.

There is no advantage from boat tail bullets at ethical hunting distances, only disadvantage, if you never need to shoot animals more than half a K away. (OK, boat tails are easier to seat when reloading, but really!)

At supersonic speeds the front ogive is what matters in reducing velocity loss. The lead and copper going into forming the boat tail is better used for forming a longer ogive at the front of the bullet when hunting distances are involved. To increase your supersonic range, you need a long slender spitzer more than a boat tail.

Boat tail spitzers only have significantly lower drag than flat bottom spitzers once they both have slowed to transsonic/subsonic velocity. Only at that point do boat tails really start showing significantly less velocity drop than the equivalent weight spitzers. But note, the boat tail only helps conserve trans/subsonic velocity, a bit like a coffee mug that is only insulated at the bottom third to keep the dregs warm. The boat tail is thus for target bullets or for long range sniper bullets (where instant kill vs wounding vs slow kill is less important) but making an accurate long distance hole is everything.

For subsonic / transsonic loads however, a long boat tail is useful right from the muzzle, and a round nose better as it keeps centre of gravity forwards, something that is hard to do with a spitzer shaped for supersonic flight. The "ideal" subsonic hunting projectile is thus similar in shape to a Berger VLD flying backwards!

Re our new Army "Guns", didnt we see a similar thing with the Steyr ? They demonstrated a well-made (..ish) German one, then supplied us with crap made elsewhere. I'll bet the demo-models were well-crafted, In-House,in The States, not Mexico

Steyr is austrian not german

Originally Posted by systolic

Holy Grail

@systolic
Either the only one who got it or the only one who felt like responding.
Good job and the knights of Ni salute you.

Smart warfare is to wound not kill. It ties up more resources, an inaccurate gun is more likely to Wound not KILL

Originally Posted by gonetropo

Steyr is Austrian not German

@gonetropo

So was Herr Hitler. Austria is a Germanic country, just as Sweden is a Scandinavian country. The central point is basically accurate: you should expect German quality from Austria.

yes and no...... wounded guys can still shoot back. if youve ever seen what a tumbling .223 round does when it hits flesh (as the origonal design called for them to do) it sort of blows that whole theory out of the water...... the yellow packet norinco .223 make a hell of a mess of wallaby sized game...can see the resistance level being much more. Ive skinned out wallabies with holes big enough to stick your whole arm in using them.... and if you watch the way some people shoot it would be just as dangerous to not be what they were aiming at.... accurate is only as good as the plonker pointing the thing LOL.

I once talked to a guy who was ex British army, must've left around the time they were changing from SLR to L85. He had his doubts about the power of the 5.56 round.

His verdict:"I don't like this idea of shooting people gently"

Originally Posted by Cordite

@Cowboy06

Correct, but only at the end of the bullet's useful flight path, therefore it is not quite correct to state that a flat base spitzer will lose velocity and energy 'a lot quicker' than a boat tail.

There is no advantage from boat tail bullets at ethical hunting distances, only disadvantage, if you never need to shoot animals more than half a K away. (OK, boat tails are easier to seat when reloading, but really!)

At supersonic speeds the front ogive is what matters in reducing velocity loss. The lead and copper going into forming the boat tail is better used for forming a longer ogive at the front of the bullet when hunting distances are involved. To increase your supersonic range, you need a long slender spitzer more than a boat tail.

Boat tail spitzers only have significantly lower drag than flat bottom spitzers once they both have slowed to transsonic/subsonic velocity. Only at that point do boat tails really start showing significantly less velocity drop than the equivalent weight spitzers. But note, the boat tail only helps conserve trans/subsonic velocity, a bit like a coffee mug that is only insulated at the bottom third to keep the dregs warm. The boat tail is thus for target bullets or for long range sniper bullets (where instant kill vs wounding vs slow kill is less important) but making an accurate long distance hole is everything.

For subsonic / transsonic loads however, a long boat tail is useful right from the muzzle, and a round nose better as it keeps centre of gravity forwards, something that is hard to do with a spitzer shaped for supersonic flight. The "ideal" subsonic hunting projectile is thus similar in shape to a Berger VLD flying backwards!

I thought a boat tail design can improve your BC over all velocities. Not a big issue at very short range but a low bc will sap bullet energy from the muzle. Have a look at the BCs for identically weighted projectiles of different design... However nothing is free, unfortunately making light projectiles with a spire point and boat tail can leave little bearing surface, I think that's some rifles hate Berger projectiles.

Originally Posted by rewa

Re our new Army "Guns", didnt we see a similar thing with the Steyr ? They demonstrated a well-made (..ish) German one, then supplied us with crap made elsewhere. I'll bet the demo-models were well-crafted, In-House,in The States, not Mexico

The trials rifles and the first batches delivered to NZ were Austrian made by Steyr.

The rest were made in Australia, as was always intended as the Australians were making them for their military. Some plastic parts were made in New Zealand. Wanganui possibly. NZ was always going to get the vast majority of the Steyr rifles from Australia.

Originally Posted by Max Headroom

I once talked to a guy who was ex British army, must've left around the time they were changing from SLR to L85. He had his doubts about the power of the 5.56 round.

His verdict:"I don't like this idea of shooting people gently"

nobody in thier right mind would claim the 5.56 is BETTER than the 7.62 (.223 Vs .308) and the SLR is a proven preformer....you could say same thing of the .303 brit the preceded it too. 100rounds of .223 is easy to carry as its small and light....... the other two,not so much.

Originally Posted by csmiffy

@systolic
Either the only one who got it or the only one who felt like responding.
Good job and the knights of Ni salute you.

The Knights of Ni... huh, indeed.

Originally Posted by 300CALMAN

I thought a boat tail design can improve your BC over all velocities. Not a big issue at very short range but a low bc will sap bullet energy from the muzle. Have a look at the BCs for identically weighted projectiles of different design... However nothing is free, unfortunately making light projectiles with a spire point and boat tail can leave little bearing surface, I think that's some rifles hate Berger projectiles.

@300CALMAN

Yes, agree BT helps at all velocities, less at the beginning.

The berger VLD reminds me of the .303 mk VIIIz bullet, which was designed for extended range MG fire. Less bearing surface (look below at the narrow parralel portion, and cannelure further forwards - they would be far off the rifling when chambered) lovely spire, boat tail to boot. Hate to think of how it did in variable-throated variable headspaced LE rifles - but accuracy is no concern with MGs if you get an extra Km max range!

Originally Posted by Cordite

@Cowboy06

Correct, but only at the end of the bullet's useful flight path, therefore it is not quite correct to state that a flat base spitzer will lose velocity and energy 'a lot quicker' than a boat tail.

There is no advantage from boat tail bullets at ethical hunting distances, only disadvantage, if you never need to shoot animals more than half a K away. (OK, boat tails are easier to seat when reloading, but really!)

At supersonic speeds the front ogive is what matters in reducing velocity loss. The lead and copper going into forming the boat tail is better used for forming a longer ogive at the front of the bullet when hunting distances are involved. To increase your supersonic range, you need a long slender spitzer more than a boat tail.

Boat tail spitzers only have significantly lower drag than flat bottom spitzers once they both have slowed to transsonic/subsonic velocity. Only at that point do boat tails really start showing significantly less velocity drop than the equivalent weight spitzers. But note, the boat tail only helps conserve trans/subsonic velocity, a bit like a coffee mug that is only insulated at the bottom third to keep the dregs warm. The boat tail is thus for target bullets or for long range sniper bullets (where instant kill vs wounding vs slow kill is less important) but making an accurate long distance hole is everything.

For subsonic / transsonic loads however, a long boat tail is useful right from the muzzle, and a round nose better as it keeps centre of gravity forwards, something that is hard to do with a spitzer shaped for supersonic flight. The "ideal" subsonic hunting projectile is thus similar in shape to a Berger VLD flying backwards!

I’m not sure your understanding of BC is as strong as you think it is.

Drag is drag so it’s entirely accurate to state that a flat base spitzer will lose velocity and energy faster than a boat tail.