We have seen the increase in the available bullet weight for the 223 over the years, the 69, 75, 77, 80 and now we have 90 grain 223 bullets available. With the increase in bullet weight we have seen improvements in BC which combined with achievable velocity result in improvements in wind drift. It seems that at some point the maximum safe working pressure will result in a loss in improvement in wind drift as safe achievable velocities drop with the lower muzzle velocities of heavier and heavier bullets. So where is the peak in performance, 80 grain bullets? 90 grain bullets? or will we get even more improvement above the 90s?
Max Bullet Weight for the 223?
- Thread starter chkunz
- Start date
My guess is a hybrid but it will be in the 80/82 grn weight.
JRS Thanks for letting me know that the question has been asked and answered by Bryan Litz and a simple search will yield the answer to my question. I often see the same questions asked that I know have already been answered and agree that it is best to search first before repeating the question. I did try to search out the answer as you recommended but did not find the answer to my question. I would like to know if we have reached the minimum wind drift with the 80s or 90s in the 223 within safe pressures or is there something yet to be gained with a bullet heavier than 90?JRS said:The question has been asked, and answered by Bryan Litz. With a simple search, you'll find the discussion right hereT-REX said:
Thanks, the link got me to some good discussion on the subject. It did not answer my question directly but it sounds like the general consensus is that 90 grains or below is the useful 223 bullet weight limit and the Sierra Match King is easier to work with but the Burger 90 has more potential if a person wants to put more effort into development. Also, it appears the F Class folks are still doing a lot of research in this area and it is not settled science yet. We could see more development in this area over the next few years. Bryan Litz makes a good point that one should not expect to make a 6mm out of the 223 and I certainly understand his point. I am considering building a dedicated Mid Range gun to shoot on the conventional target (sling) and want to stay with 223 and am just trying to get the most I can out of it but not go to extremes with pressure, barrel length, etc. Thanks again for your help in pointing me to the information. Someone yet may jump in with more on this topic since it looks like others are interested in where the practical boundaries are with the 223 bullet weight.JRS said:
Considering the limitation, due to case capacity, I think it comes down to bullet configuration, and the necessary velocity to drive the bullet. Heavier is not necessarily the component that delivers accuracy. The shorter the length of time the bullet is in the air, wind doesn't have as much time to affect it's flight.
That didn't answer your question ??? My personal belief would be 75-80 grains.
That didn't answer your question ??? My personal belief would be 75-80 grains.
Two factors combine to give a bullet's BC value - form factor and sectional density (SD). SD is fixed by the calibre and bullet weight, so a 224 80 always has an SD value of 0.228 and a 90 is always 0.256.
The form factor is the more interesting value in many respects as it's a numeric value put on the bullet shape, ie its aerodynamic efficiency. The factor is always a comparison to the 'reference projectile' which in our case is best met by the G7 model and as it's drag based, the lower the value the better. The 'reference projectile' is always given a value of 1.000, so if a bullet has that value it's equally efficient as the G7 model, if less it's more efficient (and gives a higher BC when combined with the SD), if higher it's poorer and produces a lower BC value.
The benefit of form factor values is that you can compare different calibre / different weight bullets and it gives an idea as to how clever the designer has been and also an indication as to whether there is more to be wrung out of the calibre with better designs - albeit you can't get equally good form factors across all calibres as the larger calibres might need way too long and heavy designs to match the best 6.5s for instance.
The very best (lowest) FF values have been found in the 6.5s in modern designs. The 140gn Berger Hybrid at 0.905 a shade less than 10% more efficient than the already effective G7 reference is a good example, but there are a very few that slip down into the high 0.8s, such values found in no other calibre for traditional jacketed / lead core designs. The best of the 7s are slightly higher in the 0.920s and that's where the new heavy (>200gn) .30 Hybrids are.
So, we can compare the 0.224 80s and 90s against them. Remember this isn't BC as you have to add in the bullet weight / calibre bit too and equivalent different calibre bullets can be driven at diferent MVs within the same maximum pressure ceilings.
So (source Bryan Litz) we get form factors for the heavier 224s of:
80gn Sierra MK ............ 1.048
80gn Berger VLD .......... 1.001
80.5gn Berger BT ......... 0.979
80gn AMAX .................. 0.987
90gn Sierra MK ............ 0.999
90gn Berger LRBT ........ 0.979
90gn Berger VLD .......... 0.911
What this tells us is that the existing and been around for a few years 90gn VLD is an outstanding design both in relation to newer designs in other calibres (marginally lower than the new 105gn 6mm Hybrid) and in relation to its fellow 22s.
So you wonder why Berger isn't pushing / developing the model. In past email correspondence with Bryan Litz, he has been cautious, almost cool, on the subject of new ultra-heavy (ie 90gn) 224s. I suspect that's because the bullet is at the limits of overall length in relation to calibre and is likely pushing the boundaries of good bullet design. It works very well for some, not at all for others in optimally specified L-R 223s for FTR and similar. Even where it works, the occasional unexplained 1,000 yard elevation flier appears and it's not just that every factor of the rest of the 223 package has to be 100% right and consistent that explains this.
So, from Bryan's comments elsewhere on the forum, it looks like a Hybrid weighing in the low 80s will appear in due course. Given how well the 80.5gn Fullbore has worked out in practice, that is likely a very sensible move. I cannot see how a workable lead core HPBT 224 with a lower FF value than the current VLD's 90 can be sensibly achieved, so my conclusion FWIW (which is likely not a lot) is that .224 calibre bullet design has peaked in simple ballistics terms (which is a different thing from practicality, useability, and precision).
We won't see anything heavier than 90s either as if you do a scaling exercise as Bryan L and Berger have no doubt done when it comes to what are the practical limits on bullet lengths and designs, the same optimal shape scaled up and down gives you 90gn for 22, 115gn for 6mm, 142gn for 6.5mm 185gn for 7mm, 225gn for .30 (working from memory here on this bit of Bryan's book Applied Ballistics for Long Range Shooting) Some would say that the 90gn VLD form in .224 and the 115gn ditto in 6mm are a scale-step too far as neither works as well for them as some lighter / shorter designs in these calibres.
There are of course other ways of skinning a cat and a notable recent development is the very short bearing surfaces on many recent introductions in all calibres. This allows higher MVs through reduced friction in the bore and also less heat induced stress placed on the bullet. I've no idea if there is any opportunity in this design aspect for the putative 224 Hybrid, but here's hoping.
The form factor is the more interesting value in many respects as it's a numeric value put on the bullet shape, ie its aerodynamic efficiency. The factor is always a comparison to the 'reference projectile' which in our case is best met by the G7 model and as it's drag based, the lower the value the better. The 'reference projectile' is always given a value of 1.000, so if a bullet has that value it's equally efficient as the G7 model, if less it's more efficient (and gives a higher BC when combined with the SD), if higher it's poorer and produces a lower BC value.
The benefit of form factor values is that you can compare different calibre / different weight bullets and it gives an idea as to how clever the designer has been and also an indication as to whether there is more to be wrung out of the calibre with better designs - albeit you can't get equally good form factors across all calibres as the larger calibres might need way too long and heavy designs to match the best 6.5s for instance.
The very best (lowest) FF values have been found in the 6.5s in modern designs. The 140gn Berger Hybrid at 0.905 a shade less than 10% more efficient than the already effective G7 reference is a good example, but there are a very few that slip down into the high 0.8s, such values found in no other calibre for traditional jacketed / lead core designs. The best of the 7s are slightly higher in the 0.920s and that's where the new heavy (>200gn) .30 Hybrids are.
So, we can compare the 0.224 80s and 90s against them. Remember this isn't BC as you have to add in the bullet weight / calibre bit too and equivalent different calibre bullets can be driven at diferent MVs within the same maximum pressure ceilings.
So (source Bryan Litz) we get form factors for the heavier 224s of:
80gn Sierra MK ............ 1.048
80gn Berger VLD .......... 1.001
80.5gn Berger BT ......... 0.979
80gn AMAX .................. 0.987
90gn Sierra MK ............ 0.999
90gn Berger LRBT ........ 0.979
90gn Berger VLD .......... 0.911
What this tells us is that the existing and been around for a few years 90gn VLD is an outstanding design both in relation to newer designs in other calibres (marginally lower than the new 105gn 6mm Hybrid) and in relation to its fellow 22s.
So you wonder why Berger isn't pushing / developing the model. In past email correspondence with Bryan Litz, he has been cautious, almost cool, on the subject of new ultra-heavy (ie 90gn) 224s. I suspect that's because the bullet is at the limits of overall length in relation to calibre and is likely pushing the boundaries of good bullet design. It works very well for some, not at all for others in optimally specified L-R 223s for FTR and similar. Even where it works, the occasional unexplained 1,000 yard elevation flier appears and it's not just that every factor of the rest of the 223 package has to be 100% right and consistent that explains this.
So, from Bryan's comments elsewhere on the forum, it looks like a Hybrid weighing in the low 80s will appear in due course. Given how well the 80.5gn Fullbore has worked out in practice, that is likely a very sensible move. I cannot see how a workable lead core HPBT 224 with a lower FF value than the current VLD's 90 can be sensibly achieved, so my conclusion FWIW (which is likely not a lot) is that .224 calibre bullet design has peaked in simple ballistics terms (which is a different thing from practicality, useability, and precision).
We won't see anything heavier than 90s either as if you do a scaling exercise as Bryan L and Berger have no doubt done when it comes to what are the practical limits on bullet lengths and designs, the same optimal shape scaled up and down gives you 90gn for 22, 115gn for 6mm, 142gn for 6.5mm 185gn for 7mm, 225gn for .30 (working from memory here on this bit of Bryan's book Applied Ballistics for Long Range Shooting) Some would say that the 90gn VLD form in .224 and the 115gn ditto in 6mm are a scale-step too far as neither works as well for them as some lighter / shorter designs in these calibres.
There are of course other ways of skinning a cat and a notable recent development is the very short bearing surfaces on many recent introductions in all calibres. This allows higher MVs through reduced friction in the bore and also less heat induced stress placed on the bullet. I've no idea if there is any opportunity in this design aspect for the putative 224 Hybrid, but here's hoping.
I've not played with my 223s seriously for maybe three years now, but will see if I can get them back to the 2,900 fps node using a new powder we've just got in the UK - Reload Swiss (Nitrochemie) RS52, a high-energy small kernel product with Nitrochemie's Ei deterrent infusion process and with a burning speed close to that of VarGet / Re15. (Think Alliant Re17 but with Re15's burn speed.)
I don't expect to get above the 2,910 fps node, but if I can get back there with acceptable case life and good groups, the 90gn VLDs should perform well again. I've managed to gather together enough 90s both VLD and the discontinued LRBT to see me out for the rest of my days I reckon especially as I share my range time with the 308 I had built for the FCWCs at Raton in FTR and with various 6.5s and 7s in F-Open these days.
If and when Berger does get around to an 82-85gn Hybrid, I'll definitely give it a try.
I agree with you there on both points. As I said in my earler post, Bryan Litz has always been noticeably cool on doing anything more with 90s without specifying exactly what his doubts are about this weight in the calibre. I think it significant that the scaled equivalent in the next largest calibre up, the 115s in 6mm have never been wildly popular and widely successful except for a relatively few competitors such as John Whidden.
I did try 'heavies' in 308 when the heavier Hybrids appeared, but nothing above 185gn worked for me in FTR. As you rightly say gstaylorg, it's a rifle management issue. Although I have some Juggernauts and 185/190gn VLDs, I shoot little other than 155s and the 168gn Berger Hybrid in 308 FTR these days. Some people do just fine with the heavies although most of my fellow Brits seem to prefer the 210gn Berger LRBT to any of the Hybrids. Paul Crosbie, the 2013/14 GB FTR league champion and big Steve Donaldson the current GB champion like them though, although Steve won the title mostly with the 210gn BT.
I don't expect to get above the 2,910 fps node, but if I can get back there with acceptable case life and good groups, the 90gn VLDs should perform well again. I've managed to gather together enough 90s both VLD and the discontinued LRBT to see me out for the rest of my days I reckon especially as I share my range time with the 308 I had built for the FCWCs at Raton in FTR and with various 6.5s and 7s in F-Open these days.
If and when Berger does get around to an 82-85gn Hybrid, I'll definitely give it a try.
I agree with you there on both points. As I said in my earler post, Bryan Litz has always been noticeably cool on doing anything more with 90s without specifying exactly what his doubts are about this weight in the calibre. I think it significant that the scaled equivalent in the next largest calibre up, the 115s in 6mm have never been wildly popular and widely successful except for a relatively few competitors such as John Whidden.
I did try 'heavies' in 308 when the heavier Hybrids appeared, but nothing above 185gn worked for me in FTR. As you rightly say gstaylorg, it's a rifle management issue. Although I have some Juggernauts and 185/190gn VLDs, I shoot little other than 155s and the 168gn Berger Hybrid in 308 FTR these days. Some people do just fine with the heavies although most of my fellow Brits seem to prefer the 210gn Berger LRBT to any of the Hybrids. Paul Crosbie, the 2013/14 GB FTR league champion and big Steve Donaldson the current GB champion like them though, although Steve won the title mostly with the 210gn BT.
CharlieNC
Gold $$ Contributor
Running a range of weights, bc, calibers, and velocities through JBM I see a near unique correlation between wind drift and the product of muzzle velocity x BC which helps to simplify the thought process. I have found CFE223 gives much higher velocities without pressure issues vs a number of other powders. With this my 75 A max node is at 3150fps so you may be able to push 2900 with the 90 gr.
Case heads are our Achilles Heal. Palma brass in the .308 killed the 223 for anything other than midrange. I still shoot mine and love it though.
THIS WOULD BE AWESOME, PRETTY PLEASE!!!Laurie said:
I also have to say the 223 is great, I love it for F-TR. And something between the 80 vld and the 90's would be even better for midrange! Hell I'd even shoot them at 1000. If I wasn't so lazy I'd put the effort into the 90's haha.
Bryan Litz Ballistics
Site $$ Sponsor
Not much I can add to the discussion on this topic.
But, consider...
When we talk about .224 caliber bullet performance, we're usually talking about the 223 Rem case because that's the only alternative to the 308 Win in FULLBORE and F-TR competition, and it's a very common round. I'm a little surprised we don't see more competition rifles chambered for 220 Swift or .22-250 with fast twist barrels, throated for 80-90 grain class bullets. The 223 Rem is typically the fast twist option from the factory so it's what we think of for heavy bullets (ironic considering the case capacity). The 22 cal hotrods (Swift) are typically built to push light bullets in the 40-50 grain class to 4000+ fps, and so the barrels are typically much slower twist and won't stabilize anything much heavier than 60 grains.
A cartridge that can push a 55 grain bullet 3900 fps should be able to push a 90 grain bullet to 3000+ fps. Run the ballistics on that and you'll see it's no slouch. Forget comparisons to 308 Win because we're outside of TR rules with a non 223 Rem cartridge, but look how it compares to a .243 Win, .260 Rem, etc.
I'm guessing you'll still have the pressure and fouling issues due to the long bearing surface, but I don't know of enough people who've tried this to ask how it's worked.
Anyone done this?
-Bryan
But, consider...
When we talk about .224 caliber bullet performance, we're usually talking about the 223 Rem case because that's the only alternative to the 308 Win in FULLBORE and F-TR competition, and it's a very common round. I'm a little surprised we don't see more competition rifles chambered for 220 Swift or .22-250 with fast twist barrels, throated for 80-90 grain class bullets. The 223 Rem is typically the fast twist option from the factory so it's what we think of for heavy bullets (ironic considering the case capacity). The 22 cal hotrods (Swift) are typically built to push light bullets in the 40-50 grain class to 4000+ fps, and so the barrels are typically much slower twist and won't stabilize anything much heavier than 60 grains.
A cartridge that can push a 55 grain bullet 3900 fps should be able to push a 90 grain bullet to 3000+ fps. Run the ballistics on that and you'll see it's no slouch. Forget comparisons to 308 Win because we're outside of TR rules with a non 223 Rem cartridge, but look how it compares to a .243 Win, .260 Rem, etc.
I'm guessing you'll still have the pressure and fouling issues due to the long bearing surface, but I don't know of enough people who've tried this to ask how it's worked.
Anyone done this?
-Bryan
Yes, a few years ago I was playing around with numerous different fast twist .224s. Once I got above 22BRX in 7" twist barrels, the rotational speed started bullets to blow up prematurely. My 22BRX with 7" twist barrel was awesome, but once its throat got rough, bullets started to blow up. I intended to cut it back to 22BR to reduce bullet RPM and freshen the throat, but for F Open there were better choices. After seeing how my 22BR went, I am keen to try a 223 for mid range F classBryan Litz said:
Steve Dunn won the UKBRA 1,000 yard BR match at Diggle in northern England last Sunday with a .22BR, 4-group agg 6.619". I'm pretty sure he loads 80s, not 90s though.
Results here:
https://www.dropbox.com/s/w7upbcllz3go3ig/UKBRA%201000BR%2016th%20August%202015.pdf?dl=0
Oddly enough, I've just acquired a bench gun in 6mm Super LR, but it also came with a .22-250 AI barrel in 7-inch twist. I hadn't been wildly enthusiastic to do much with this to be honest, but it may well be worth a play with 90s in due course as a light F-Open / BR Light Gun to see what you can do.
Results here:
https://www.dropbox.com/s/w7upbcllz3go3ig/UKBRA%201000BR%2016th%20August%202015.pdf?dl=0
Oddly enough, I've just acquired a bench gun in 6mm Super LR, but it also came with a .22-250 AI barrel in 7-inch twist. I hadn't been wildly enthusiastic to do much with this to be honest, but it may well be worth a play with 90s in due course as a light F-Open / BR Light Gun to see what you can do.
I think immike on here is using a 22br with the 90's now.
Upgrades & Donations
This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.