20 practical vs 223

[Baron85]

Having the itch to build another rifle for prairie dog blasting. Typical max range for me is 350 and in. Currently running a 16” 223ai and a 26”223 both with 53 vmax.

Wondering if the extra speed will be more explosive or if it’s not a very noticeable improvement. The 223 have worked good but more pop would be good. My buddy shoots a 6br with 58vmax and it’s pretty explosive.

I do not want to step up to a bigger caliper since we shoot pretty high volume and already have a pile of 223 brass.

 

[Supersubes]

Im a big fan of the 20 P and shoot it high volume at squirrels. By the numbers, the 20P with a 40 vmax or 39 bk will out perform your 53 vmax load. Similar BC, but a fair bit faster. The 20’s do seem to be more explosive than 223 generally. In the end just do it because you want to.

 

[Baron85]

Im mostly concerned about the explosiveness. I do see running the numbers that the 20 will beat the 223 ballistics but it’s not worth it to me to setup new dies and bullets if it’s not a big improvement in explosiveness

 

[Supersubes]

Hard to say, you're not gonna get any more explosiveness in a 223 based case, thats for sure.

I used to shoot 223’s mostly, and a 6x47 lapua with 70 gr ballistic tips. I got into the 20’s after watching a friend’s 204 ruger/39 bk/3800 fps combo smoke my 6x47. The ballistic tip is kinda sturdy, so that may have played a role, but his 204 was in another league regardless of distance.

 

[jLorenzo]

I have never had a 20 but I would like to at somepoint. Maybe get a 9 or 12 twist 223 barrel and push some 40-50gr stuff. I imagine a hot 40gr would be pretty destructive.

That being said I had a 7 twist 223 wylde barrel that shot 50gr HPs the best out of everything I tried.

 

[steve123]

20x47L gives appropriate acrobatics with a light load using 40vmax at 4100 fps, just putting that out there for the fun of it.

I had a 204R using 32's and liked it for PD's.

Later on I went for a 20 based off 221 Fireball which has a lot of nice attributes.

20's are awesome!

 

[kyotekiller25]

Why not just shoot the 40g vmax at 3800 fps from a 223? It'll easily do 350+ and the 40s are a lot more explosive than a 53g vmax will ever be.

I shot a lot of the 40 vmax at 3800 with 28g Benchmark through my old Ruger Target 26" 223 out to 500 on ground squirrels and pdogs, they pretty much disintegrate into a pink mist...

 

[st1650]

Hard to say, you're not gonna get any more explosiveness in a 223 based case, thats for sure.

I used to shoot 223’s mostly, and a 6x47 lapua with 70 gr ballistic tips. I got into the 20’s after watching a friend’s 204 ruger/39 bk/3800 fps combo smoke my 6x47. The ballistic tip is kinda sturdy, so that may have played a role, but his 204 was in another league regardless of distance.

Big fan of the 204R and BK39 as well as Berger 40. Extremely accurate with XBR.
Had buyers remorse initially until I started smoking yotes.

 

[Baron85]

My concern with the 40’s was my current twist rates are 1-7 and 1-8.

I guess it doesn’t hurt to try a few and see what happens.

 

[Kiba]

My concern with the 40’s was my current twist rates are 1-7 and 1-8.

I guess it doesn’t hurt to try a few and see what happens.

Depends on the bullet and the condition of your barrel, always worth trying some.

I was able to push nosler 50gr ballistic tip lead frees up to 3475 in a 7.5 to 6.8 gain twist 223AI that was intended for heavy bullets before blowing up about 40% of them, that's 368k rpm.

Dropped them down to 3375 and zero bullet failures over the next 600 rounds.

In my 8 twist 6 dasher that I normally shoot 105s in I use the nosler 55gr lead free at 3800fps for squirrels, that's 342k rpm-- and with 2200 rounds on the barrel and a pretty rough throat they're still very accurate and no bullet failures.

Some bullets do better than others with high rpm, but the general consensus for jacketed bullets is try to stay under 300k rpm to avoid bullet failures. With 40s at 3800 you're looking at 342k rpm in an 8 twist and 391k rpm in a 7 twist; my hunch is certain bullets might hold together with the 8 twist but you're not going to have a good time with the 7 twist with any jacketed bullet, but 40gr lathe turned copper monos should hold together (a bit expensive for high volume varmint blasting though.)

I'm also thinking about a .20 practical or 20-223AI build for varmints, but in my state I have to use non lead for hunting and there aren't too many .204 non lead bullet options-- and some of those non lead .204 bullets are once a year seasonal runs at the manufacturer and typically out of stock.

 

[st1650]

I'm also thinking about a .20 practical or 20-223AI build for varmints, but in my state I have to use non lead for hunting and there aren't too many .204 non lead bullet options-- and some of those non lead .204 bullets are once a year seasonal runs at the manufacturer and typically out of stock.

Wow that’s insanely gay to force copper for varmints. That would definitely push me toward 223 AI / 22 ARC / 22-250

 

[Kiba]

Wow that’s insanely gay to force copper for varmints. That would definitely push me toward 223 AI / 22 ARC / 22-250

Yep, it sucks.

First it was non lead for big game and only in the California condor zones. Then it was non lead only for big game, but state wide. Then it was non lead for any hunting, including varmints, state wide. At least there's an exemption for hunting with lead in the air rifles...

Sucks when you have your lead loads all worked up and a huge stockpile of lead bullets on the shelf, and then when you start buying the non lead and doing load development you find out some of your twist rates aren't optimal for the non lead stuff.

I had to have lilja make a custom 7 twist barrel for my .17hmr sako quad because the standard for .17hmr 9 twist barrel wouldn't stabilize the non lead .17hmr when the DA was under about 3000'. No keyholes, but 2-3 inch groups at 50y. 7 twist makes tiny groups even at -1200' DA and shoots the lead ammo great too.

I have very accurate non lead loads worked up now, but the non lead is more expensive, often out of stock as the non lead varmint stuff is kind of a single state market and most manufacturers only run 1 batch a year, and it has a lower BC than the lead stuff.

I still want to try a .20 practical or .20-223AI, but it loses a lot of the appeal when I can't run the heavy for caliber high BC lead bullets. The most appealing non lead options to test would be the 24gr NTX, nosler 32gr BTLF, or a Lehigh 30gr CC. The 24 NTX at 4250ish looks like the winner out to 400ish, but I did not find great accuracy testing the .224 NTX's in my 223s, 22BR, and 22-250... The nosler BTLFs were far more accurate than the NTX in the 7 rifles I tested them in.

Anyways, enough sidetracking... Lol

 

[jLorenzo]

Depends on the bullet and the condition of your barrel, always worth trying some.

I was able to push nosler 50gr ballistic tip lead frees up to 3475 in a 7.5 to 6.8 gain twist 223AI that was intended for heavy bullets before blowing up about 40% of them, that's 368k rpm.

Dropped them down to 3375 and zero bullet failures over the next 600 rounds.

In my 8 twist 6 dasher that I normally shoot 105s in I use the nosler 55gr lead free at 3800fps for squirrels, that's 342k rpm-- and with 2200 rounds on the barrel and a pretty rough throat they're still very accurate and no bullet failures.

Some bullets do better than others with high rpm, but the general consensus for jacketed bullets is try to stay under 300k rpm to avoid bullet failures. With 40s at 3800 you're looking at 342k rpm in an 8 twist and 391k rpm in a 7 twist; my hunch is certain bullets might hold together with the 8 twist but you're not going to have a good time with the 7 twist with any jacketed bullet, but 40gr lathe turned copper monos should hold together (a bit expensive for high volume varmint blasting though.)

I'm also thinking about a .20 practical or 20-223AI build for varmints, but in my state I have to use non lead for hunting and there aren't too many .204 non lead bullet options-- and some of those non lead .204 bullets are once a year seasonal runs at the manufacturer and typically out of stock.

How did the lead free bullets shoot for you?

 

[Kiba]

How did the lead free bullets shoot for you?

Other than being a bit down on BC compared to the lead alternatives I was previously using, the nosler 40 BTLFs and 50 BTLFs that I switched to from the 53 vmax as well as the 72 Lehigh controlled chaos to fill in for the 75 amax were all very accurate once I worked up loads.

My own 223s being faster twist were able to switch from the 53 vmax to the nosler 50 BTLF with zero issues. My friend's slower twist 223 and 22-250 that were previously very accurate with the 53 vmax would not stabilize the 50 BTLF; no keyholes but shotgun groups at 50 and most of them off the paper at 100. Had to use the 40 BTLFs in both of those slower twist barrels and they're very accurate with the 40s.

My friends 22-250 that was chambered by Spartan Precision managed multiple 1" 5 shot groups at 500y with the 40gr nosler BTLFs at 4200 on a wind free morning... Didn't believe that a lead free flat based varmint bullet could be so accurate until I repeated it.

The nosler BTLFs being true flat based bullets are kind of a pain to load, with no boat tail you have to keep your fingers on them so they don't tip or fall out of the case mouth before you seat them.

They are very reactive bullets and blow up squirrels really well, on par with or even better than the 53 vmax.

I tried Barnes lead free varmint grandes, they didn't group worth a damn in anything I tried them in. The .224 Hornady NTX did pretty good in everything I tried them in, but were not as accurate as the nosler BTLFs. The NTX has the advantage of being available almost all the time though, whereas the noslers are usually in stock around January when they do their production run but then can go out of stock for the rest of the year depending on demand. The nosler .224 40s and 50s were damn near unavailable from 2019-2022 as nosler told me they were focusing production on high demand bullets, and the BTLFs are low demand. I actually need to get some more 6mm 55gr BTLFs, but I haven't seen any in stock since 2019, and I'm signed up for back in stock alerts everywhere.

 

[jLorenzo]

Other than being a bit down on BC compared to the lead alternatives I was previously using, the nosler 40 BTLFs and 50 BTLFs that I switched to from the 53 vmax as well as the 72 Lehigh controlled chaos to fill in for the 75 amax were all very accurate once I worked up loads.

My own 223s being faster twist were able to switch from the 53 vmax to the nosler 50 BTLF with zero issues. My friend's slower twist 223 and 22-250 that were previously very accurate with the 53 vmax would not stabilize the 50 BTLF; no keyholes but shotgun groups at 50 and most of them off the paper at 100. Had to use the 40 BTLFs in both of those slower twist barrels and they're very accurate with the 40s.

My friends 22-250 that was chambered by Spartan Precision managed multiple 1" 5 shot groups at 500y with the 40gr nosler BTLFs at 4200 on a wind free morning... Didn't believe that a lead free flat based varmint bullet could be so accurate until I repeated it.

The nosler BTLFs being true flat based bullets are kind of a pain to load, with no boat tail you have to keep your fingers on them so they don't tip or fall out of the case mouth before you seat them.

They are very reactive bullets and blow up squirrels really well, on par with or even better than the 53 vmax.

I tried Barnes lead free varmint grandes, they didn't group worth a damn in anything I tried them in. The .224 Hornady NTX did pretty good in everything I tried them in, but were not as accurate as the nosler BTLFs. The NTX has the advantage of being available almost all the time though, whereas the noslers are usually in stock around January when they do their production run but then can go out of stock for the rest of the year depending on demand. The nosler .224 40s and 50s were damn near unavailable from 2019-2022 as nosler told me they were focusing production on high demand bullets, and the BTLFs are low demand. I actually need to get some more 6mm 55gr BTLFs, but I haven't seen any in stock since 2019, and I'm signed up for back in stock alerts everywhere.

Are the lead free bullets longer per gr than the lead? Is that why the lighter LF bullets wouldn't stabilize?

 

[Kiba]

Are the lead free bullets longer per gr than the lead? Is that why the lighter LF bullets wouldn't stabilize?

Yep, copper is lower density, so a copper bullet is longer for the same weight as lead. Thus a 50gr non lead bullet will need a faster twist to stabilize than a 50gr lead bullet.

Luckily bullet manufacturers recognized this so most non lead varmint bullets are made to be slightly lighter than the lead bullets they're replacing, so they will usually stabilize in "traditional" slower twist varmint barrels that people already have.

The downside is the non lead bullets usually give up BC to comparable weight lead bullets. There are exceptions for some of the lathe turned copper monos but it gets expensive to send those $1 per bullet high BC lathe turned copper monos at squirrels. (I do from time to time, but I save the high BC monos for the really long range squirrels.)

And now thanks to this thread I'm considering building a 20 vartarg to sling the 24gr NTX at about 3950 with only about 20 grains of powder... Much easier on barrels and heating in busy squirrel colonies than the 20 practical or tactical.

 

[supercorndogs]

I kinda doubt it's going to be much easier on barrels. If it had twice the barrel life it probably still wouldn't dissuade me from 223 brass goes into the die, 20 practical comes out.

Bullet selection is important. I always felt like the 55 v max made them come apart better than the 53. The 55 seirra hpbt 223 bullet is very explosive.

For my 20 practical. I have some 34g nosler varmint bullets and they don't really do much. The 40g vmax on other hand was flopping them all over place. When I chronoed the load it was only like 3450 or 3480 pretty slow anyway.

 

[Kiba]

I kinda doubt it's going to be much easier on barrels. If it had twice the barrel life it probably still wouldn't dissuade me from 223 brass goes into the die, 20 practical comes out.

The vartarg works great, a friend has had one for years. Very low recoil, very slow barrel heating from only about 19-20gr of powder, and I think he has about 5k rounds through it now and it still shoots great and the barrel looks good. Very efficient little round provided you don't try to send bullets heavier than 32gr through it; heavier than that there just isn't enough case capacity IMO, but since I have to use non lead 32gr is going to be my upper limit.

Brass is the sticker though. Forming vartarg yourself takes time; form die, cut the necks, turn the necks. Or cheat and buy LC 223 brass already formed into 20 vartarg for about $1/ea from a couple of guys on accurate shooter and saubier.

20 practical is an easy button like you said though... Run 223 through the 20 practical die and done.

There's also the feeding issue to consider. 20 vartarg being so short can be a pain to get to feed out of magazines, and I don't want a single load only gun. 20 practical is obviously no problem out of a magazine.

Still can't make up my mind, which is why I haven't built any .20 variant yet...

 

[Baron85]

A little more researching and a few more questions.

It seems that people are having luck with single pass sizing in the 22 tactical and some say fire forming is required. It appears from the pictures that the tactical is actually pushing the shoulder back and lengthening the neck vs a 223ai that is pushing the shoulder forward?

Only reason I ask is because I prefer non bushing dies and hornady makes the tactical dies. It would also help me separate my brass from the 223’s I will also be shooting.

 

[Supersubes]

A little more researching and a few more questions.

It seems that people are having luck with single pass sizing in the 22 tactical and some say fire forming is required. It appears from the pictures that the tactical is actually pushing the shoulder back and lengthening the neck vs a 223ai that is pushing the shoulder forward?

Only reason I ask is because I prefer non bushing dies and hornady makes the tactical dies. It would also help me separate my brass from the 223’s I will also be shooting.

Do you mean 20 tactical? Never heard of of a 22 tactical. A bit like the 6 and 6.5 SLR cartridges, you're pushing the shoulder back from the neck shoulder junction. I dont shoot a 20 tactical, but my varmint duster buddy does. Just size and load.

 

[Kiba]

I believe the current preferred method for forming 20 tac is to simply run it through a non-bushing FL die, one step and done. The Hornady .20 tac FL die is usually recommended for this. Quite a few people are saying don't even mess with the .20 tac forming dies anymore.

I do think the .20 tac with the 30 degree shoulder and longer neck from slightly pushing back the shoulder does look cooler than the .20 practical, but the .20 practical lets you use your existing .223 bushing FL dies with a simple bushing change.

If you are planning on running the 40-55gr lead .204 bullets the .20 practical or tactical would be my choice. Since I'm limited to non lead which is in the 24-32gr range, both the .20 practical and tactical are a bit more powder than needed for those light bullets which is why I'm considering the vartarg. If I could use lead I'd probably skip the vartarg and do a .20 practical or tactical with the 40-55gr bullets just for the higher BC for the longer shots; the vartarg doesn't have the case capacity to send the 40-55gr bullets at the velocity I would want to send them at.

 

[Supersubes]

I kinda doubt it's going to be much easier on barrels. If it had twice the barrel life it probably still wouldn't dissuade me from 223 brass goes into the die, 20 practical comes out.

Bullet selection is important. I always felt like the 55 v max made them come apart better than the 53. The 55 seirra hpbt 223 bullet is very explosive.

For my 20 practical. I have some 34g nosler varmint bullets and they don't really do much. The 40g vmax on other hand was flopping them all over place. When I chronoed the load it was only like 3450 or 3480 pretty slow anyway.

The vartarg works great, a friend has had one for years. Very low recoil, very slow barrel heating from only about 19-20gr of powder, and I think he has about 5k rounds through it now and it still shoots great and the barrel looks good. Very efficient little round provided you don't try to send bullets heavier than 32gr through it; heavier than that there just isn't enough case capacity IMO, but since I have to use non lead 32gr is going to be my upper limit.

Brass is the sticker though. Forming vartarg yourself takes time; form die, cut the necks, turn the necks. Or cheat and buy LC 223 brass already formed into 20 vartarg for about $1/ea from a couple of guys on accurate shooter and saubier.

20 practical is an easy button like you said though... Run 223 through the 20 practical die and done.

There's also the feeding issue to consider. 20 vartarg being so short can be a pain to get to feed out of magazines, and I don't want a single load only gun. 20 practical is obviously no problem out of a magazine.

Still can't make up my mind, which is why I haven't built any .20 variant yet...

I dont shoot a vartarg, mine is a straight 221 case necked to 20. My load is 18.5 gr H4198 or RE7 under a 32 varmageddon. Barrel heat is nothing, and at a modest tempo, I can shoot continuously. Very neat cartridge. The lions share of out squirrels are inside 180 yards, and it does great there.

 

[Kiba]

I dont shoot a vartarg, mine is a straight 221 case necked to 20. My load is 18.5 gr H4198 or RE7 under a 32 varmageddon. Barrel heat is nothing, and at a modest tempo, I can shoot continuously. Very neat cartridge. The lions share of out squirrels are inside 180 yards, and it does great there.

Exactly why I'm considering a 20 vartarg. I'd say 75% of my shots on squirrels are 250 and in, 20% from 250-350, and 5% beyond 350-- not because I have to shoot that far (I can always move my shooting position farther into the field once the close ones are dealt with) but because I want a challenge of hitting a little squirrel way out there.

The vartarg with 24s, 30s, or 32s will easily handle 85% of my shots and do so while using very little powder and be easy on the barrel. For the longer shots I can grab my 223AI, 22GT, or 6 dasher.

 

[Baron85]

Oops, yea i meant 20 tactical. Sounds like that is the route I will likely go since I prefer non bushing dies and I buy a die set for each caliber anyways so I don’t have to re adjust.

 

[MarinePMI]

I believe the current preferred method for forming 20 tac is to simply run it through a non-bushing FL die, one step and done. The Hornady .20 tac FL die is usually recommended for this. Quite a few people are saying don't even mess with the .20 tac forming dies anymore.

I do think the .20 tac with the 30 degree shoulder and longer neck from slightly pushing back the shoulder does look cooler than the .20 practical, but the .20 practical lets you use your existing .223 bushing FL dies with a simple bushing change.

If you are planning on running the 40-55gr lead .204 bullets the .20 practical or tactical would be my choice. Since I'm limited to non lead which is in the 24-32gr range, both the .20 practical and tactical are a bit more powder than needed for those light bullets which is why I'm considering the vartarg. If I could use lead I'd probably skip the vartarg and do a .20 practical or tactical with the 40-55gr bullets just for the higher BC for the longer shots; the vartarg doesn't have the case capacity to send the 40-55gr bullets at the velocity I would want to send them at.

I've heard that it's actually done with seating die, though I haven't tried it.

I run a 20 Tactical, but have the form die. Been shooting it off/on for the last 20 years or so (back when Douglas was the only barrel maker that offered .20 cal barrels).

The 204R was actually originally intended to be a 20 Tac, but there were screw ups in testing that led them to go to a longer case, and so the 204R was born.

20 Practical came about because Todd Kindler (Woodchuck Den) designed and paid for the initial dies, not allowing Redding to sell dies except through him. Which were...pricey, at the time. Today (unfortunately) the 20 Tac is not that common, partially because of the 20 Practical popularity. Only downside is that you can chamber a 20 Practical in a .223. .20 Tac's shoulder is too short to do that as easily.

As bullet weights, 32gr lead bullets work fine. When the 20 Tac was designed, the only 20 cal bullet was Berger 36gr bullets (originally made for the 5mm Craig conversions that Walt enjoyed playing around with), but was soon followed by Hornady's 33gr VMAX. Eventually Hornady went to 32gr VMAX and 40gr (IIRC) VMAX bullets. Heck, I think I still have a box or two of 33gr oens on the shelf....

BTW, your name sounds familiar. Are you an old Saubier'ite?

 

[Kiba]

I've heard that it's actually done with seating die, though I haven't tried it.

I run a 20 Tactical, but have the form die. Been shooting it off/on for the last 20 years or so (back when Douglas was the only barrel maker that offered .20 cal barrels).

The 204R was actually originally intended to be a 20 Tac, but there were screw ups in testing that led them to go to a longer case, and so the 204R was born.

20 Practical came about because Todd Kindler (Woodchuck Den) designed and paid for the initial dies, not allowing Redding to sell dies except through him. Which were...pricey, at the time. Today (unfortunately) the 20 Tac is not that common, partially because of the 20 Practical popularity. Only downside is that you can chamber a 20 Practical in a .223. .20 Tac's shoulder is too short to do that as easily.

As bullet weights, 32gr lead bullets work fine. When the 20 Tac was designed, the only 20 cal bullet was Berger 36gr bullets (originally made for the 5mm Craig conversions that Walt enjoyed playing around with), but was soon followed by Hornady's 33gr VMAX. Eventually Hornady went to 32gr VMAX and 40gr (IIRC) VMAX bullets. Heck, I think I still have a box or two of 33gr oens on the shelf....

BTW, your name sounds familiar. Are you an old Saubier'ite?

There is that issue to think about accidentally mixing 20 practical with 223 and chambering it since they look very similar at a quick glance, but in my case I'm pretty sure 20 tactical would accidentally chamber in any of my 223AIs...

As I mentioned earlier I like the look of the 20 tactical with the slightly longer neck and steeper shoulder over the 20 practical and I'd probably go with the 20 tactical just for that reason, lol

And no... Not a member at saubier, even though I've read a lot of threads over there relating to various flavors of .20s.

 

[Baron85]

Pulled the trigger on an origin action to start the build. Thank for the help guys. Going 20 tactical 24” preferred barrel blanks

They offer 8.5 and 11 twist. Hoping to run the 40 vmax so thinking probably go with the 8.5 twist?

 

[supercorndogs]

I want to say my 20 practical is a 1 in 10.

 

[carbonbased]

I don’t reload. 204R is the thing for me. LOVE 204R.

Only shoot Hornady ammo. The 40gr is better in the wind…load it up in your ballistic app and you’ll be surprised. It hangs close with 6br 105gr Lapua Scenar-L out to 500yds.

For my factory 1:12 Rem and Tikka barrels, the 32gr is more accurate. Called Hornady and they said the optimal twist is 1:12. Either they are full of it or, as I’ve read, what’s stamped on the barrel can be the lie.

I’ve ordered a 1:11 twist for the Tikka as that factory barrel really dislikes the 40gr. We’ll see!

I shoot pdogs usually from 300-470yds with 204R. From 300yds on in the 204R provides lots of aerobatics lol. If it isn’t really windy, I tend to use a 17 Hornet at 300yds and in as it has even less recoil and is just a fun change of pace.

204R > 223, for me anyway.

 

[carbonbased]

And oh yeah, another consideration for pdog shooting is the amount of ammo you’re likely to plow through.

Maybe you like reloading A LOT and don’t mind loading 1000 cartridges.

I would rather kill myself lol.

People shoot 350-1000 shots easy over a five days. Some people even more.

 

[Baron85]

We do day hunts close to the house most of the time and a couple 2 day shoots through out the year.

Typically go through 150-200 most days and I load on a progressive in bulk.

 

[carbonbased]

Pulled the trigger on an origin action to start the build. Thank for the help guys. Going 20 tactical 24” preferred barrel blanks

They offer 8.5 and 11 twist. Hoping to run the 40 vmax so thinking probably go with the 8.5 twist?

8.5 twist seems awfully fast for a 40gr vmax 20cal, but like I said, I don’t reload and only have 1:12. Bugholes also said 1:11 should be enough.

My internet perusal seemed to suggest some bullets blowing up, especially at faster than 1:10.

Just throwing that out there.

 

[Supersubes]

Pulled the trigger on an origin action to start the build. Thank for the help guys. Going 20 tactical 24” preferred barrel blanks

They offer 8.5 and 11 twist. Hoping to run the 40 vmax so thinking probably go with the 8.5 twist?

Mine are all 10 twist but between your two choices, id do the 11.

 

[Kiba]

You can probably push a 40gr to 3900ish, that's 330k rpm with the 8.5 twist. Depending on the bullet used, you might experience some jacket failures.

At 3900fps a 10 twist would be 281k rpm, and an 11 twist would be 255k rpm.

If you plan on shooting 40s, I'd probably go 10 twist if you can find a blank. Depending on what 40gr you go with, an 11 twist might be marginal; it should still stabilize but you might give up some accuracy and BC. And if you choose to load a bit slower than 3900ish and especially on cold mornings with low DA the 11 twist might start to have issues with the 40s, but the 10 twist will still have plenty of stability down around 3600 even on cold mornings.

If you want a barrel ASAP and can't find a 10 twist and can only choose between the 8.5 and the 11 twist, I'd go with the 11 and keep my fingers crossed it plays nice with the 40s on cold mornings with low or negative density altitude conditions... but if you plan on shooting the 40s exclusively I'd skip both the 8.5 and 11 twist and find a 10 twist, even if I had to order a blank and wait.

 

[supercorndogs]

This has been discussed here before in someother threads. As it was explained, shooting an unstable bullet faster doesn't make it more stable because it's spinning faster. I believe they were referencing Litz's book.

 

[powdahound76]

@Baron85 - you will dig the Origin I think.

Slick to shoot .223 (or 20 Practical) and then pop on a 6.5 barrel and whack deer.

I have 3 of them now…..

 

[RTH1800]

I would consider going 20 Tac. I’ve shot .204, 20 P and 20 TAC. All are similar but the 20 Tac often makes the most sense case life wise.

No idea why “explosiveness” matters beyond that needed to hit, kill and be safe. To each his own I suppose.

The advantage of the .20 cal is trajectory and drift factors. The difference will amaze you.

 

[supercorndogs]

When they splode in 14 peices I know they aren't suffering. Dey ded.

 

[carbonbased]

I cannot deny the explosiveness entertainment factor lol

 

[264win]

Had quite a bit of experience with the 204 R
Running 39-40g bullets I’ve seen 12 twist destabilizing around 500yds. Running a 9 and a 10 twist now and they are both running great. 39 grain sierra @ 3875 is easily sub moa at 700yds in calm weather.

 

[A.sosa]

I have both 20pr and 223 and would like others have said not use the 20pr on anything bigger than a yote. The last couple of yotes that I eshot with the 20pr when I skinned them out there was alot of tissue damage just under the skin on the side that I shot them on but not much on the other side. I would be scared that if you hit bone on a deer that you would not get to where you need to. My feeling are that use the right toool for the right job. 20cal varmints only.

 

[MarinePMI]

I have both 20pr and 223 and would like others have said not use the 20pr on anything bigger than a yote. The last couple of yotes that I eshot with the 20pr when I skinned them out there was alot of tissue damage just under the skin on the side that I shot them on but not much on the other side. I would be scared that if you hit bone on a deer that you would not get to where you need to. My feeling are that use the right toool for the right job. 20cal varmints only.

It's really more about the bullet, and jacket thickness. But yeah, any varmint bullet will "splash" on bone sometimes.

As to explosiveness, the 20 Tac can still provide ample flips, cartwheels and red mist when solid hits are made, or better yet, right after a rain and the little shits have been feeding.

 

[Supersubes]

I have both 20pr and 223 and would like others have said not use the 20pr on anything bigger than a yote. The last couple of yotes that I eshot with the 20pr when I skinned them out there was alot of tissue damage just under the skin on the side that I shot them on but not much on the other side. I would be scared that if you hit bone on a deer that you would not get to where you need to. My feeling are that use the right toool for the right job. 20cal varmints only.

Like @MarinePMI said, bullets matter. My coyote bullet is the nosler ballistic tip. The heavy base and tapered jacket does coyotes just right.