6.5 Bmg?

Ok, here's my thought.
Since any army would love to only have to deal with one diameter bullet in all small arms (simplifies manufacturing, thus lowering per unit cost), wouldn't it make sense to have an exceptionally heave and long bullet in something the likes of a .50BMG case? Make it heavy and long - for added range and hitting power.

C'mon experts, let's hear it!

I advocate putting the 6.5 grendal in all are rifles, light machine guns(m249 saw) and medium machine guns (M240g). The 6.5 out performs 5.56 NATO and 7.62 NATO and could easily be used in all 3 weapons.the bullet weight would be the one with the highest bc. .50 bmg is a hevy machine gun . I believe the projectile in that weapon does what it is supposed to do very very well. I would like to see a new and improved .50 machine gun. I believe the U.S. military is currently doing that as we speak. :D :D

You could probably shoot a 6.5 from a .300 win-mag case and get flight characteristics similar to the .50 BMG. The 50 BMG case would be overkill for a 6.5mm round in my opinion.

I hope there isn't a thread necromancy issue here but 6.5 bullets from a necked down .50 BMG casing would lead to a weapon that would need its barrel replaced every 200 shots or so, if not even more often.

Read up on the Polish Model 35 or the Panzerbusche weapons; they were somewhat similar oversize cartridges firing the 7.92 caliber and suffered very short barrel life.

I hope there isn't a thread necromancy issue here but 6.5 bullets from a necked down .50 BMG casing would lead to a weapon that would need its barrel replaced every 200 shots or so, if not even more often.

Read up on the Polish Model 35 or the Panzerbusche weapons; they were somewhat similar oversize cartridges firing the 7.92 caliber and suffered very short barrel life.
First, welcome to the boards! Glad to see a new member.

Dragging up old threads once in a while keeps us on our toes.

It WOULD be interesting to see the velocity on a 6.5-.50, I'm guessing somewhere in the 5-6000 fpm range, and that WOULD definitely shoot flat and burn barrels at a horrific rate. Rifling at even 1-12 would give rotational velocities of something like 360,00 RPM. I'm not sure we have bullets, even solids, that will stabilize at that velocity! Back it off to 1-24 and you get 180,000 RPM, soemthing that I don't think the current jacketed bullets could handle, but maybe some of the tougher ones could.

But that sucker would shoot flat! Especially if you came up with a LONG 6.5, about the length of the current .50 bullets, but at less than 1/3 their weight.

Bill

wouldn't it make sense to have an exceptionally heave and long bullet in something the likes of a .50BMG case? Make it heavy and long - for added range and hitting power.

C'mon experts, let's hear it!


Surely you are not expecting to shoot this out of a 26" barrel.

On the surface it would seem like a great idea, but the real world of reality it would have a very poor tangible outcome. If we talk about effciency, grain for grain; selecting the smallest case that will deliver the ballistics that you are after without pressure issues will always be the best choice. This has been my personal experience in wildcats from .14 to .338, the smaller is better. The 50BMG case holds about 413 grains of water, with some loads as much as 270 grains of powder.

The 6.5mm bore only has so much volume so lets talk about expansion ratio. The expansion ratio is the ratio between the total volume of the bore and
the total volume of the case. The number of times the gas will expand by the time it reaches the muzzle is the expansion ratio. Let's not forget by necking the case down from almost 13mm to 6.5mm we have drastically changed the pressure curve of the case. If we choose one of the slowest powers available such as US869 or 20N29 you would be looking at a load of around 230-250 grains of powder.

Here's my mild 140 grain VLD long range 6.5-284 load: 29" barrel- 52.5 grs N165 for avg velocity of 2945 fps. Here's a known load from an even larger overbore 6.5mm, a 6.5/300 Weatherby:32" barrel-92 grs Retumbo, 3425 fps.


Using the same 140 grain bullet, I would be willing to bet money that one would be hard pressed to obtain 4000 fps in a barrel as long as 36" with a twist as slow as 1-19".


So the question is why...............unless you like pissing into the wind, uphill.

Mike, I've heard that there are some people who do enjoy "golden showers." :eek: :p :D

Mike, can I use a sabot round? :D

Joe

Surely you are not expecting to shoot this out of a 26" barrel.

On the surface it would seem like a great idea, but the real world of reality it would have a very poor tangible outcome. If we talk about effciency, grain for grain; selecting the smallest case that will deliver the ballistics that you are after without pressure issues will always be the best choice. This has been my personal experience in wildcats from .14 to .338, the smaller is better. The 50BMG case holds about 413 grains of water, with some loads as much as 270 grains of powder.

The 6.5mm bore only has so much volume so lets talk about expansion ratio. The expansion ratio is the ratio between the total volume of the bore and
the total volume of the case. The number of times the gas will expand by the time it reaches the muzzle is the expansion ratio. Let's not forget by necking the case down from almost 13mm to 6.5mm we have drastically changed the pressure curve of the case. If we choose one of the slowest powers available such as US869 or 20N29 you would be looking at a load of around 230-250 grains of powder.

Here's my mild 140 grain VLD long range 6.5-284 load: 29" barrel- 52.5 grs N165 for avg velocity of 2945 fps. Here's a known load from an even larger overbore 6.5mm, a 6.5/300 Weatherby:32" barrel-92 grs Retumbo, 3425 fps.


Using the same 140 grain bullet, I would be willing to bet money that one would be hard pressed to obtain 4000 fps in a barrel as long as 36" with a twist as slow as 1-19".


So the question is why...............unless you like pissing into the wind, uphill.


Just curious, what is water?

Mike, can I use a sabot round? :D

Joe

Joe, with the 17 Jet, I've sent some moly coated 15 gr Bergers with 17.8 grs Tu2000 just shy of 4600fps in an 1-10" twist barrel, this equates to about 259fps per grain of powder. However, the primer pockets are toast. I bet if I had a 1-14" twist, that 4650-4700 fps wouldn't far off.

I have some lathe turned 10.3 gr solid copper .14 bullets. They really don't shoot that well, I think they would make a fine candidate as a sabot. :D

Hey, IIRC there was an article(may have been by Robert Rinker) back around 95-96" in Precision Shooting that stated that velocities over 5500-6000 fps are pretty much theorectically impossible with conventional lands and groove small arms cartridges.

Mike

Mike, I've heard that there are some people who do enjoy "golden showers." :eek: :p :D

Some exercises are closer to "Scat" :eek:

Mike,

I sent you a question in pm.

Joe

Aaron, water is that stuff known as H2O in the scientific world and it comes out of taps in your home and is in lakes, oceans, and rivers. Snow when it melts makes water. Really cool to watch, unless you live up here in Maine and it becomes mud in the spring, which of course is when water mixes with dirt. Children sometimes like to play in this "mud" stuff and they get horribly dirty. Sometimes scantily clad women wrestle in mud which gets the spectators all riled up. :D ;)

Sorry. I had to. Anyways, case volume is often measured in how much water will fit in a case, as water is a finite measurement. It gives you an idea of case volume is all. Every powder will fill a given case a different amount because every powder is shaped differently so it packs in the case different. Like if you look at LilGun next to IMR4320, it is TOTALLY different and you can fit WAY more LilGun in a particular case than you could 4320. That answer the question? I liked my first response better though...