80g Amax in a 1:8?

[Si-Snipe]

Hi guys. Looking to fit a .223 barrel. Looking at 1:7 or 1:8. The plan is to shoot 75 or 80g Amax but still be able to shoot 50-55's if poss.

Can anyone advise on this please?

Thanks

Si

[Barrelsniffer]

I've used the 75 and 50-55 in my 1/8 tikka 223 I did find the 75 were not stabilising at 100 but were past 100 could of been my load but never used the 75 after that.

[Brillo]

Hi guys. Looking to fit a .223 barrel. Looking at 1:7 or 1:8. The plan is to shoot 75 or 80g Amax but still be able to shoot 50-55's if poss.

Can anyone advise on this please?

Thanks

Si

 

Hi Si,

 

My .223 barrel is a 1:8 twist Lilja on a Remington 700 action. Although throated for 50-55's it shoots Berger 73's and 80 grain VLD match pills beautifully. The long profile of these bullets makes it possible to seat these bullets not too deeply and in my .223 the COAL's are 2.302" and 2.435" respectively.

Be careful with the loads though because you will be seating a tad deeper than the 50 - 55 grainers and I saw pressure signs before recommended maximum.

I also found that the 80's grouped best at about 2650 fps.

HTH

[oaken]

I had my .223 rebarreled with a varmint weight 27" 1:8 pacnor with the intention of using the 75gr amax. Couldn't get it to shoot at all. Switched to 80gr berger vld which it shoots very well to 1000yds.

No problems with 55gr. In fact it shoots the Barnes tsx 53gr with 10x ridiculously well, Im just too tight to pay £30 for 50 again. Being a banded bullet it can be pushed to silly speeds with fast powders without pressure problems.

Rup

[dannywayoflife]

I'm hoping I can get the 75/80 Amax going out of my factory 1in8 tikka barrel. It shoots every brand of bullet and weight of factory ammo I've put through it so its un fussy.

[triggersqueezer]

my border archer 1 in 8 loves 75 amax,not tried hevier yet there is no need.im happy.

[Si-Snipe]

Hiya Si,

 

I had a .223ai with an 8 twist Kreiger on it, I managed to shoot everything from 50-80grain VLD's with it into tiny groups. Obviously you will scrub off some spead shooting the 50's through an 8 twist pipe but it will certainly generate the tiny groups for you.

 

Whats the spec of your .223 going to be ???

Hi Ronny.

Possibly AI. 23" and moderate weight like say heavy sporter. Will add a single shot loading tray for the 75+ bullets. It's to be built on my current 17 Rem which is a stainless 595 in standard synthetic stock.

ATB

Si

[Si-Snipe]

I had my .223 rebarreled with a varmint weight 27" 1:8 pacnor with the intention of using the 75gr amax. Couldn't get it to shoot at all. Switched to 80gr berger vld which it shoots very well to 1000yds.

No problems with 55gr. In fact it shoots the Barnes tsx 53gr with 10x ridiculously well, Im just too tight to pay £30 for 50 again. Being a banded bullet it can be pushed to silly speeds with fast powders without pressure problems.

Rup

Hi Rup.

Interesting to note the Pacnor didn't shoot the Amax.

Thanks

Si.

[Tony.H]

my border archer 1 in 8 loves 75 amax,not tried hevier yet there is no need.im happy.

 

what powder are you using?

[jeffo223]

Si, my sako 75 varmint loves the home loaded 75gr A max , Shoots tiny groups at all ranges also use 55gr nosler these are very good but no where near as good as the 75gr A max.

[Laurie]

Right, let's inject some facts into this discussion. The two primary determinants of stability are 1) rilfing twist rate, 2) bullet length. MV only has a marginal effect. If the other two are way out of kilter, it takes a huge MV change to put them right. So far as weight goes, a given bullet length in a given rifling twist rate has a higher stabilisation value at a greater weight than at at a lighter one. That's why all-copper Barnes etc bullets need faster twist rates than gilding metal / lead core types - they're lighter but longer.

 

We only talk weights in this issue because generally speaking a heavier bullet = a longer bullet. The key ratio is bullet length divided by bullet calibre.

 

The fourth factor that can be significant is atmospherics. The thicker the air, the more resistance on the bullet tip = the greater the " overturning motion", the thinner the air, the less resistance and the slower the rate of axial spin needed to stabilise a particular bullet of so many calibres' length. By that I mean a bullet has to be spinning a LOT faster at low-lying Bisley on a cold January morning in anti-cyclonic conditions with say 0-deg C / 32-deg F temperature and 30-inches + of mercury atmosheric pressure compared to a high summer afternoon at the US NRA Whittington Centre Ranges, Raton New Mexico, 6,500 ft ASL and 80-90-degrees F.

 

The 80gn 0.224" cal A-Max ~1.160-inches length, or ~5.2 calibres, one helluva long bullet for .22. (For comparison, the 210gn 0.308" Berger 210gn VLD is 1.490-inches long = 4.83 calibres.)

 

Run it through the Millers Twist Rule spreadsheet at 2,800 fps MV in a 1-9" twist barrel under standard ballistic conditions (59-deg F, 29.92-inches Hg pressure, o% humidity) and we get:

 

Don Miller's Twist Rule Caliber 0.224 Inches Bullet Weight 80 Grains Bullet Length 1.162 Inches Barrel Twist 9 Inches/turn muzzle velocity 2800 fps Temperature 59 degrees Fahrenheit (59 is standard) Pressure 29.92 inches of mercury (29.92 is standard) Sg = 0.91 Sg shouldn't be less than 1.4. If Sg is greater than about 2.0, you may gain some accuracy by going to a slower twist barrel.

 

 

Anything under 1.0 Sg (Coefficient of Stability) is not stabilised. Research has shown that anything under ~1.25 loses a lot of its effective BC even if it produces round holes on the paper. (See the April issue of TargbetShooter online when it appears in a few days time).

 

Right .... the A-Max has a plastic tip and the effective bullet length for this purpose is rather shorter. It's also a HPBT behind the plastic tip and the lead core has an airspace above it. Let's say for the Miller twist rule that the bullet is a tenth of an inch shorter, ie ~1.06-inches. We now get:

 

Don Miller's Twist Rule Caliber 0.224 Inches Bullet Weight 80 Grains Bullet Length 1.06 Inches Barrel Twist 9 Inches/turn muzzle velocity 2800 fps Temperature 59 degrees Fahrenheit (59 is standard) Pressure 29.92 inches of mercury (29.92 is standard) Sg = 1.19 Sg shouldn't be less than 1.4. If Sg is greater than about 2.0, you may gain some accuracy by going to a slower twist barrel.

 

In theory, just stabilised - but maybe not.

 

In my own experience of loading heavy bullets in .223 Rem and shooting them to 1,224 yards, the 80gn A-Max only barely works well in a 1-8" twist barrel, and is better suited to a 1-7". 1-9" NOT A CHANCE !!!!

[Tony.H]

Right, let's inject some facts into this discussion. The two primary determinants of stability are 1) rilfing twist rate, 2) bullet length. MV only has a marginal effect. If the other two are way out of kilter, it takes a huge MV change to put them right. So far as weight goes, a given bullet length in a given rifling twist rate has a higher stabilisation value at a greater weight than at at a lighter one. That's why all-copper Barnes etc bullets need faster twist rates than gilding metal / lead core types - they're lighter but longer.

 

We only talk weights in this issue because generally speaking a heavier bullet = a longer bullet. The key ratio is bullet length divided by bullet calibre.

 

The fourth factor that can be significant is atmospherics. The thicker the air, the more resistance on the bullet tip = the greater the " overturning motion", the thinner the air, the less resistance and the slower the rate of axial spin needed to stabilise a particular bullet of so many calibres' length. By that I mean a bullet has to be spinning a LOT faster at low-lying Bisley on a cold January morning in anti-cyclonic conditions with say 0-deg C / 32-deg F temperature and 30-inches + of mercury atmosheric pressure compared to a high summer afternoon at the US NRA Whittington Centre Ranges, Raton New Mexico, 6,500 ft ASL and 80-90-degrees F.

 

The 80gn 0.224" cal A-Max ~1.160-inches length, or ~5.2 calibres, one helluva long bullet for .22. (For comparison, the 210gn 0.308" Berger 210gn VLD is 1.490-inches long = 4.83 calibres.)

 

Run it through the Millers Twist Rule spreadsheet at 2,800 fps MV in a 1-9" twist barrel under standard ballistic conditions (59-deg F, 29.92-inches Hg pressure, o% humidity) and we get:

 

Don Miller's Twist Rule Caliber 0.224 Inches Bullet Weight 80 Grains Bullet Length 1.162 Inches Barrel Twist 9 Inches/turn muzzle velocity 2800 fps Temperature 59 degrees Fahrenheit (59 is standard) Pressure 29.92 inches of mercury (29.92 is standard) Sg = 0.91 Sg shouldn't be less than 1.4. If Sg is greater than about 2.0, you may gain some accuracy by going to a slower twist barrel.

 

 

Anything under 1.0 Sg (Coefficient of Stability) is not stabilised. Research has shown that anything under ~1.25 loses a lot of its effective BC even if it produces round holes on the paper. (See the April issue of TargbetShooter online when it appears in a few days time).

 

Right .... the A-Max has a plastic tip and the effective bullet length for this purpose is rather shorter. It's also a HPBT behind the plastic tip and the lead core has an airspace above it. Let's say for the Miller twist rule that the bullet is a tenth of an inch shorter, ie ~1.06-inches. We now get:

 

Don Miller's Twist Rule Caliber 0.224 Inches Bullet Weight 80 Grains Bullet Length 1.06 Inches Barrel Twist 9 Inches/turn muzzle velocity 2800 fps Temperature 59 degrees Fahrenheit (59 is standard) Pressure 29.92 inches of mercury (29.92 is standard) Sg = 1.19 Sg shouldn't be less than 1.4. If Sg is greater than about 2.0, you may gain some accuracy by going to a slower twist barrel.

 

In theory, just stabilised - but maybe not.

 

In my own experience of loading heavy bullets in .223 Rem and shooting them to 1,224 yards, the 80gn A-Max only barely works well in a 1-8" twist barrel, and is better suited to a 1-7". 1-9" NOT A CHANCE !!!!

so would my 1:8 twist .223 shoot everything from 40gr bullets up to 80gr bullets?

[Laurie]

Tony,

 

more or less. The longest of the 80s are getting a bit marginal for having enough rotation, but most people find that the A-Max performs OK. This is the sort of situation where you might have brilliant result on a warm summer's day, but wonder why your load 'goes off' on a really cold and high-pressure day on a seaside range situated only a few metres above sea level. The 80gn Sierra MK is spot-on for the 1in8-inch twist rate. The other issue that can arise is that a nominally 1 in whatever barrel can be 'out' a bit either way. Not an issuue with a custom match barrel from any of the top barrelmakers, but it can arise with factory barrels. A nominally 1-8 that's actually 1-8.25 can affect things at the margin, or it might be the other way at 1-7.75 which sees a bullet which shouldn't work fully stabilised. This is a particular issue with factory 1-9s, where one guy tells the world the 75gn A-Max shoots a storm in his rifle and that this twist rate is therefore fine with the bullet, but when another guy takes his advice in a different make of rifle, finds he's wasted his money and time.

 

At the other weight extreme, the 40-52gn lightweight end of bullet ranges, the risk here is of bullet break-up through very high rotational speeds stressing the jacket to core fit. In the past, some very lightly constructed 224 varmint bullets designed to expand violently at .222 Rem velocities were advised as being unsuitable for twist rates faster than 1-10. Such models seem to have disappeared these days presumably because of the dominance of more powerful .22 centrefires. I did manage to get 52gn Hornady A-Maxes to blow up in a 1-8" barrel 223 Rem on a very hot summer's day some years back. In fact any .224 bullet that I had break up in this barrel was always a Hornady as they seem to have thinner jackets than other makes. There were almost certainly other issues at work though such as barrel fouling, heat, a rough well-worn throat and so on. Generally speaking this is a rare occurrence though and US bullet manufacturers are working on the basis of their bullets being likely to be fired in 1-7" twist barrels these days given the large number of models on sale in the US that use it, especially semi-auto AR-15 type rifles.

[ricky5042]

Hi i use the 52gn a-max bullet heads and i find them very accurate through my 1-12 howa 1500 223

on the box it has 1-14 twist.

 

Rick

[Tony.H]

thanks for that laurie, i have the 75 Amax too try, but was supprised that you mentioned the 80gr smk, i suppose it will all boil down to if i can chamber them.....

[Laurie]

thanks for that laurie, i have the 75 Amax too try, but was supprised that you mentioned the 80gr smk, i suppose it will all boil down to if i can chamber them.....

 

 

Exactly so Tony. People often forget it's not just twist rate but whether the chamber throat will accomodate a longer bullet OK. You can't sensibly seat any of the 80s at the standard 2.26" COAL.

 

As you're loading the 75gn A-Max though which is a long bullet for the weight, you should be able to use at least some of the 80s too.

 

FWIW, in my days with a 1-8" barrel .223 Rem, I always got better results with the 75gn A-Max than its longer 80gn brother. You can push the 75s really fast too. Bruce Lenton (Mole-e30 on this forum) is another fan of the 75 A-Max for target shooting and whacks them out at impressive velocities using H. VarGet. For longer range shooting, I always used 80s in the early days of F-Class, usually either the Sierra MK or Nosler CC. I shot them at Diggle years back at 1,000 and people used to come up and ask me if it was true that I was shooting a 223 as they had trouble believing you could actually hit a target at this distance with this cartridge. The biggest problem was I was only running at ~2,700 fps MV and the bullets were subsonic at this distance so the butts crew missed atround one shot in three or four and you spent the match shouting to the RO to get the target pulled. This combination would be hopelessly uncompetitive with today's F/TR standards I should add at any range much beyond 500 yards.

[bradders]

In a SAAMI spec .223 chamber, 80 SMK's will seat around 2.420". In a .223 Wylde the max OAL is around 2.465" (from memory)

In a NATO chamber max OAL is around 2.550"

[Laurie]

Mark,

 

you're pretty well spot on with your memory for the Wylde chamber. My blunter 80s ran somewhere ~2.455" just out of the lands in a Wylde chamber in a new barrel, rather longer by the time I scrapped it after getting on for 5,000 rounds!

[bradders]

Nobody ever considers JLK bullets..........

Their 80gn VLD has a quoted BC of .510, which is way above everyone elses and the same (allegedly) as a .30 175 SMK.

I used to use them for Highpower at 600yds and also used them once to come second at 1000yds in the long range snaps during the Practical Rifle Nationals.

That year I was using a stout load of N540 and they were clocking 2955fps from a 20" barrel.

They shot MOA

[Tony.H]

anyone tell me what powders they have used with the 75gr Amax......

[bradders]

anyone tell me what powders they have used with the 75gr Amax......

You should be looking at the following

Reloder 15, Varget, N140, N540, H4895, AA2520, Ramshot Tac.

 

They all work well

[Tony.H]

id got RL 15, varget, bl-c2, h4895 on my short list.......have you any experience with any of theses bradders?

[247sniper]

I am watching this topic with great interest. I am considering a fast twist .223 myself. Currently I use my .204 for long range vermin and varminting out to 600 yards. Will I benefit from a fast twist .223 for my needs?? I can see the benefit in a fast twist .223 in shooting competition out to 1000 yrds but that's about it, plus if I was shooting out to 1000 yards I'd choose a different caliber anyhow. Out to 600 yards my.204 load is very comparable to the likes of a fast twist .223 75/80 grain A-Max, my .204 is far flatter shooting and almost identical in the the same Windage scenario out to this range...... Is it worth to me the expense and hassle of a new rifle set up plus another new scope to benefit from a possible inch or so at 600 yards.

 

What's you views guys?

 

Cheers guys

 

Steve.

[bradders]

Mostly RL 15 and Varget.

4895 isn't as popular as it used to be as the newer powders give better performance.

I also use Tac and AA 2520 on occasions. They may actually be the same powder.

 

Personally I'm a fan of RL15 as its a good do it all powder for .223, especially the heavier bullets.

[Laurie]

Mark,

 

we don't see the new (Belgian manufactured) AA-2520 in the UK, or not under that name anyway. It seems likely that Ramshot Wild Boar which is a 'Europe only' product is the same thing as the AA-2520 sold in the US.

 

We still get the older 2520 stuff made in the Czech Republic which strictly speaking is Lovex DO73.6. I had starting results with this powder and the 75gn A-Max in my straight-pull AR several years back. Very high MVs and good groups. I wasn't a fan thouigh as it (and the other powders in the Lovex DO-73.x ball powder range) leave really, really hard carbon deposits on the outside of the case-neck. That may not be an issue now though for those who've invested in steel pin media tumbling systems.

 

I've still to try 'Wild Boar' in .223, but it looks promising. You can download a pdf file of very comprehensive loads data from the Western Powder Co. website just for this powder. It shows the 80gn SMK at 2,792 fps from 24-inches at the US 223R 55,000 psi max and a staggering 2,949 fps for this bullet in CIP 5.56X45mm PMax form, with the 90gn SMK max load at 2,467 fps all from a 24-inch barrel, Win case / WSR primer and at a totally unsuitable 2.260" COAL quoted for all loads.

 

I've just started trying Ramshot in 308W and Big Game is looking good and is the cleanest burning ball powder I've ever used. Patches are less fouled than you get with Viht or Hodgdon single-base powders.