.223 Bullet Weight

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maynard

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The DCRA may consider changing the bullet weight limit for .223 from 81 grains max. 90 grain bullets and rumour that a 100 gr .223 bullet could be on the market in the future has the DCRA thinking about doing away with the weight limit for .223 altogether. This will of course be for TR and F(F) class.
Now how fast of a twist will you need to launch a 100 gr .223 bullet 1000 yards accurately?
 
Agree, but I would think it would be longer with maybe a slightlt longer bearing surface without having to change the core material to something other than lead. Sierra lists their 90 gr .223 bullets with a BC of .5 or better, while the 80gr run around .4 BC. Anybody try any of these 90 gr .223?
 
It seems to me that you are running out of case capacity when you start playing w/ a 90 gr. pill in the .223. I'm going to play with the 80 gr. JLKs I just got...
 
"...running out of case capacity when you..." And feeding issues. Unless you're using a single shot, the OAL will be limited to what the mag will hold.
 
sunray said:
"...running out of case capacity when you..." And feeding issues. Unless you're using a single shot, the OAL will be limited to what the mag will hold.
Click to expand...

Most target rifles and F Class rifles used for fullbore competition are single shot anyway so that really isn't an issue. Case capacity and powder burn rate is something that may need some experimenting, along with longer throat chambers.
 
would be able to push it what 2500-2600fps?

what advantage would that give over an 80gr at 2900?

Would make the 223 a mean lookin round though :)
 
Like the 6BR, we are rapidly hitting the point of diminishing returns. Some are pushing these heavies to high velocities but that has to be at spooky pressures. Plus not all barrels will shoot well at elevated pressures.

I think bullet manf can modify the bullet planform to increase BC without increasing mass. Why this has not really taken off is a surprise. The shining example is the 308 155gr Lapua Scenar.

I think the ideal bullet right now is the 80gr Amax. Secant ogive, poly tip all add up to a streamlined bullet. This is easily pushed to 2900fps by most 223's. Hornady QC has been really good of late too.

Comparing bullets, the 80gr Amax is as long/similar in shape to many 90gr VLD slugs. I have seen many Amax bullets fly better then their printed numbers suggest. I feel these 22cal amax fly better in the real world - 75 and 80gr Amax.

The 90's usually get to 2700fps but many barrels/rifles have a hard time with the super long for cal bullets. Going heavier isn't going to resolve much.

I will try some Bergers to see if these can squeeze my groups down a bit more.

Jerry
 
I've got 1k of 80 bergers, and 500 80 JLKs to play with. We'll see which one comes out on top out at 900m at Batouche. My money is on the JLK's... The really interesting thing will be what sort of velocities I can get out of the 22" 1-8" L-W tube.

Untill Lapua starts making a .223 version of the 155 Scenar, as Jerry suggests, I think the berger and jlks will stomp the 80 amax.
 
It takes more energy to push a bullet through a rifled tube than it does a smooth tube, and the faster the twist the more energy is required to drive that same bullet down the barrel. This is the only disadvantage I can see in choosing a heavy for caliber bullet that requires a fast twist barrel. There is no reason why heavy bullets need to be loaded to dangerous pressure levels; they do not require the high velocity that the light bullet does to get the job done. If we consider an arbitrary pressure of 50,0000 psi that drives a 50 gr bullet at 3500, it will also drive an 80 gr bullet at 2900, and perhaps a 100 gr bullet at 2500, there should be no mystery here. The key is to choose a propellant that produces good load density. Compressed loads, I have found, produce erratic results, therefore the ideal powder will not be too slow. Conversely, powder charges with excessive air space don't produce as consistent results as do charges which fill the available space in the cartridge, so there must be a proper balance between the bullet weight and the burning rate of the propellant. The rifle should have it's chamber cut to match the length of the bullet. Try to avoid the practice of seating a heavy bullet into the powder space of the cartridge. By keeping the bullet in the neck of the case we optimize the powder density of your load, and takes away from the compressed load bogeyman.

I believe there can be some real advantages to using a heavy bullet. For example, the heavy bullet uses substantially less powder. The lighter the powder charge, the more consistent the ignition will be with minimal priming. The often cited increase in recoil for a heavy bullet load fails to materialize due to the reduced powder charge. The 380 gr bullets pushed by 84 grs of powder in my .375 have less apparent recoil than the 270 gr bullets pushed by 95 grs of the same powder.

The big advantage of heavy bullets for the long range accuracy bug, is that a heavy bullet will shed it's velocity at a slower rate than does the lighter bullet. If a bullet that has a MV of 2500 fps remains supersonic at 1000 yards, then it has shed less velocity than the lighter bullet that crosses the 1000 yard mark at the same velocity, but begins it's journey 1000 fps faster. I believe that a bullet which crosses into transonic velocity with a slower rate of velocity decay is less likely to destabilize. The faster the spin the more difficult it is to destabilize the bullet and a light 50 gr bullet with a MV of 3500 fps is spinning 3500 ### from a 1:12 barrel compared to a 100 gr bullet at 2500 fps from a 1:5 barrel producing 6000 ###. Now if we consider a slower rate of decay combined with a faster spin, it follows that the bullet will be very stable at extreme range.
 
If you go here, you can see a side by side comparison of all the common 22cal LR match bullets. The 80gr Amax is listed a bit lower compared to the 75gr Amax.

http://www.6mmbr.com/223Rem.html

As you will note, the 75gr Amax is near identical in length and basic shape to the 80gr VLDs. The 80gr Amax comes dangerously close to the 90gr Bergers and JLK's. Better then the 90gr MK's.

We know the poly tip does reduce drag in flight compared to a HP, and the Amax shares the secant ogive planform (more slippery then a tangent ogive). I would say real world shooting will put all of these bullets close together as any reduction in BC of the Amax is quickly made up for by the higher muzzle velocity.

Big bonus, the costs of the Amax is up to 1/2 that of the Berger and JLK's and readily available. Can't always say that for the Bergers and certainly the JLK's - limited production bullet.

More importantly, some are reporting these super long heavy 90gr bullets are not the easiest to dial in for accuracy. Of course, every barrel has its own quirks but there is a common truth that the longer a bullet gets, the more finicky it is to set up.

I have shot both the 75 and 80gr Amax and can say they set up dead easy.

For me, my bullet choice boils down to wind drift at distance. I want as little as possible so the highest BC bullet going the fastest is always my goal. With a small case like the 223, that becomes a balancing act between bullet weight/BC/muzzle velocity/LR accuracy.

Ultimately, the barrel becomes the deciding factor.

Jerry
 
Sierra made a 100gr .224 SMk for the US Mil
BH pushed it to 2200fps out of a 18" Mk12 in mag loading configuration - - rainbowed badly - but it was impressive terminally.

Sierra also make a 88gr SMK for the US Mil - mag lengh @ 2400 from the SPR/MK
I beleive it was in the 2300's from a 16" Mk12 Recce rifle.

As far as I know they were never civilian released.

Powell River Labs made (makes?) a 87gr Powdered Tungsten "Green Bullet" that was loaded by BH again for the AMU and USNSWC Crane - however it suffered from both impressive price and unreliable performance.

None of these bullets (save the PRL) had much application outside the mil sector -- the PRL was being offered as a Green Option as it was lead free
 
RePete,
That I don't know. I do know some testing will be done this winter down south and there should be a full report in the spring Canadian Marksman.
I am sure several different powders will be use to find the right balance.
 
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