AR15 with 90 grain berger at 2905 fps, impossible? Not so much.

[Mod Adahy]

Here is the story. I wanted an AR that would be capable at 1000, played around with grendels, 6woa and 6x45 but none did it for me. So the grendel was the best I could find but it has lug issues when pushed hard. I looked at the 22mmar but it has the same problems as the grendel with lugs since it is the same parent case. The .224" 90 berger and 90 smk were the obvious choice since they have a bc of .551 and .501 respectively. Barrels have been 24" but have run test to run down to 20". Lost 22 fps per inch from 27 to 20". But how to push them to needed velocities. Ended up with the 6.8spc case necked down with shoulder pushed back. The middle cartridge is the 5.68DMR. I have also run the cartridge with 70 grain barnes bullets at 3120 fps out of a 20" ar.




With the 90 berger we can get them to mid 2900's and accuracy node is at 2905 with RE15.


Here is a pic of the necking down process.


Barrel.


And gun.


It is as simple as a barrel, bolt and magazine change to convert any AR into it.

Sorry to ramble on but wanted to put it together instead of explaining it 500 times, so that is why the delay. I am not trying to sell them, but just to get the info out there. These will be available from Youngs Manufacturing in the near future. Please pm me for details and to get on the list.

 

[Morale_Gear]

Looks like a pretty decent 22cal alternative for those that don't want to move up to the 6mms.

 

[Mod Adahy]

Better bc's than you can get with 6mm ar and faster.

 

[SomeOtherGuy]

Very cool. What barrel twist do you need for those bullets?

 

[Mod Adahy]

Very cool. What barrel twist do you need for those bullets?

6.900" ish.

 

[koden]

Barrel/chamber vendors or specs to give to same?

Die sources?

I have a complete upper and lower waiting for a barrel and this is intriguing.

 

[Mod Adahy]

I have the reamer and have another coming any day. Dies are 6.8spc redding with modified bushing and I am in the process of having barrels chambered.

 

[Forgetful Coyote]

Have the 90s been giving consistent groups? Because IIRC the 90s didnt work out for the Service Rifle High Power shooters..

 

[Mod Adahy]

Have the 90s been giving consistent groups? Because IIRC the 90s didnt work out for the Service Rifle High Power shooters..

I will find other pictures. They have been great so far. Were they pushing them at 2900ish? I tried them with an 8 twist and they were no go.

 

[Mod Adahy]

Here is another 5 shot group. These are normal or good groups for me, I am not the best AR shooter and will say so upfront.



The SMK is also a good round, although the node for them is almost 100 fps slower out of my barrel. 5200'da gets me 1300fps at 1100 yards. True transition at 1335 yards.

Bergers gets you 1305 yards at 1300 fps and transition at 1510 yards.

 

[BoilerUP]

Those run at standard AR mag length?

 

[aviumvenator]

tag

 

[Mod Adahy]

Those run at standard AR mag length?

The 90's need the PRI 6.8 mags at 2.295' coal but 77, 75 or 70's will run in standard 6.8 mag.

 

[BoilerUP]

So we're basically just talking about a 22-6.8SPC? That's probably what, ~3gr of case capacity more than a 223AI in LC or Lapua brass?

90gr VLDs @ 2800fps from a 20" gas gun is DAMN tempting, probably a bit more than I could get with my 22" 223AI bolt gun.

You might not be trying to sell them, but you're doing a really good job so far

 

[346ci]

Impressive results for a 90gr bullet that has some reach.

The new CPD 6.8 mags should be able to handle 2.29-2.30" COAL, while not built as tough as a PRI, could be a cheaper mag alternative..

 

[Mod Adahy]

So we're basically just talking about a 22-6.8SPC? That's probably what, ~3gr of case capacity more than a 223AI in LC or Lapua brass?

90gr VLDs @ 2800fps from a 20" gas gun is DAMN tempting, probably a bit more than I could get with my 22" 223AI bolt gun.

You might not be trying to sell them, but you're doing a really good job so far

Essentially yes with the shoulder moved back. Case capacity is 36.3 grains of water.

 

[lwrkeysfisher]

I've been interested in this for a long time. AR15 performance made some barrels a while back, but I never ordered one.

 

[Mod Adahy]

What is the case capacity of the 223ai? I forgot that we trim the case back which when combined with the shoulder move, gets you to the 90 grain bullets and makes it different than the Harrison.

 

[ranger1183]

Who makes the reamers you are buying?

 

[SPEAK338]

This is interesting I might like one of these. I need a faster 22 cal AR

 

[Forgetful Coyote]

Sweet groups. Thats definitely a stout LR load. I cant remember the specifics but I remember hearing the AMU tried out the 90gr Bergers for Service Rifle with 1:7" twist and ended up ditching them for the 80s. Im not sure on the velocity. Yall think a 20" .223 gas gun would give enough velocity to stabilize the 90s with a 1/7?

 

[AKONA]

Very nice! I love it.

I Think after the great budget 75gr and 80gr amax, the nice 80gr berger and a couple of others the real advantage of the 6mm is that the best of the 6mm starts
where the best of the .224 ends. Specially but not restricted to medium game hunting and then some amazing long range capabilities. I am surprised the 6x45 did nothing for you with the
amazing berger 95gr VLD feeding from VLD magazines at VLD length @ 2800fps. Or the amazing 105gr at 2700fps also at VLD length.
With the largest bolt the best commercial option is the 6mmBR. But one that I really got to love A LOT is its cousin the 6.5BR. I have a couple of uppes launching 123gr Scenar, berger and amax
between 2750 2800fps from a 20" upper. With a milder accurate load we are in the 2700fps with accuracy in line with the king, the 6mm BR.

One of the advantages that I see about pumping the largest .224 bullets is for folks who want to rationalize and keep things in the same caliber. I am suffering a bit for too many calibers and I had
to spend a lot extra in equipment so I am trying to get rid of a couple of calibers in any case, shape of form.

Wildcatting around the AR15 portfolio is addictive isn't it?... so watch out!!!

NAH!!! I have been doing it for 25 years and I am not addicted!!! (Typical AA like denial comment) LOL

Great round. Please keep us posted!!

 

[SPEAK338]

Looking forward to hearing more on this.
What's the process for necking down the 6.8 brass? I haven't wild cat before

 

[1slow01z71]

Looking forward to hearing more on this.
What's the process for necking down the 6.8 brass? I haven't wild cat before

Depending on the difference in bullet diameter you essentially size down the neck with a progression of smaller and smaller bushings, in this case going from .270 to .224 with probably 3 neck sizing steps.

Im really looking for a setup to replace my 20" 223 WOA barrel, and was looking at a Grendel build. Ill be watching this once someone else jumps on it and tries this out. Id really like a capable AR15 caliber to play with on the 1000yd range while the big sticks cool down.

 

[SPEAK338]

Where would I get this 6.9 twist 24" fluted with a bolt brl combo?

 

[1slow01z71]

Any chance you could try some CFE223? Im trying to convert most of my high consumption rifle loads to a good metering powder and have had decent luck with CFE in 223 and 308 so it would make this caliber even more enticing for me.

 

[Mod Adahy]

I will try some cfe on Wednesday. Necking down is just as 1slowz71 says with 3 different bushings.

 

[flatland1]

I got really good results with an AR15 SR using JLK90VLDs back in '03 & '04 - had a PacNor 3-groove, 1:6.5tw 20" bbl from John Holliger, and was loading N550 for a velocity just a hair over 2800fps. John's reamer for the 90s had a throat that let us seat the 90s out for single-loading during 600yd slow prone, yet still shot S77MKs with fine accuracy for offhand & the rapids at 200 & 300.

Berger borrowed Jimmy Knox's 90VLD dies when they were working on their own 90 VLD design, and made some changes, as my left-over JLKs can be seated out about .045" farther than Bergers in the same bbl. But the Bergers shoot really well in a 26" Krieger 1-7tw sendero contour bbl in 223AI in a M700 I built myself, and they do it when seated to Accuracy Intnl. magazine length. So I'm thinking the 6.5tw bbls were overkill. In fact, I've gotten 1 MOA 600yd accuracy with 90VLDs out of a PacNor 1:7.5tw bbl on a M70 Stealth, and that's with some JLKs that gave rather poor accuracy out of our 6.5tw SR bbls.

If you check into the S90MK, you'll discover that Sierra designed them to work best at velocities considerably slower than either Berger or JLK 90VLDs, and they've got too much bearing surface to get much beyond 2650fps with sane pressure out of an AR15 SR's 20" bbl.

 

[Mod Adahy]

Here are some chrono results with 2 different powders. I shot 5 of my known 2810fps load and got 2804,2815,2816,2811 and 2814. Then shot with CFE and Varget with 90 grain bergers. These were loaded to mag length. Pretty eye opening.

CFE
27.2, 2807,2801,2807
27.5,2830,2824,2842
27.8,2855,2861,2855
28.1,2886,2873,2879
28.4,2917,2898,2899, had accuracy node in less than 1" at 297 yards
28.7,2930,2943,2949

Slight pressure at top load, but still pretty good. Confirmed dope at 1075 yards with 28.4 and run average at 2905fps.

Varget
26,2766,2795,2777
26.3,2795,2807,2812
26.6,2842,2841,2836
26.9,2849,2848,2867

No pressure problems with varget at all, last charge was compressed.

 

[Mod Adahy]

Just got to looking at specs for the SMK and the berger. Both have close to same bearing surface, .393 for the smk and .399 for the berger. That is from Litz's book. Wonder if one of them changed the bullet. Neither stabilized from an 8 twist but both stabilize out of a 7 twist with no sign of becoming un-stabilized. Although if you shoot a 1" mesquite branch, they will key hole in target behind it. BC is .551 for the berger and .501 for the SMK per Litz and that matches my dope.

 

[1slow01z71]

This is out of a 24" barrel? What kind of price are these barrels going for witj a headspaced bolt? Do they come threaded? How much? I wont be making any changes soon but summerish time. 1" group at 300 and 2900 for 90gr sure sounds like fun.

 

[gravityoutdoors]

I am thinking about a .224 ar to run 90 bergers. Is the brass with this rifle close to the same as 22ar(necking down 6.5 grendal brass), any additional steps for the 6.8 brass as oppose to the grendal brass? I am wanting to build a 6.9 twist for begers on a 15 platform. Looking to build with a 22" barrel. shorter if I can keep 2800fps. I don't want to fire form anything, if I did I would build a .22 ar turbo, if that makes sense. I am interested in this setup as well if anyone wants to point me in any direction. Oh one more thing I have to run mag length and for sure the 90 bergers with a .55 BC. Thanks for telling us about the rifle.

 

[ranger1183]

I am thinking about a .224 ar to run 90 bergers. Is the brass with this rifle close to the same as 22ar(necking down 6.5 grendal brass), any additional steps for the 6.8 brass as oppose to the grendal brass? I am wanting to build a 6.9 twist for begers on a 15 platform. Looking to build with a 22" barrel. shorter if I can keep 2800fps. I don't want to fire form anything, if I did I would build a .22 ar turbo, if that makes sense. I am interested in this setup as well if anyone wants to point me in any direction. Oh one more thing I have to run mag length and for sure the 90 bergers with a .55 BC. Thanks for telling us about the rifle.

Hey everybody head's up!
Just because it is possible to make this (the .220 Thunderbolt) out of 6.8 SPC brass does NOT mean that is how "The Pro's" are doing it.

They are instead using 6mm HAGAR brass as their starting point. Use this link to order brass and dies: Keystone Accuracy Custom Rifles, Plymouth Meeting, PA

Use these links to get up to speed with reading and more contact information:
Keystone Accuracy Custom Rifles, Plymouth Meeting, PA
.240 Tomahawk, Keystone Accuracy Custom Rifles Contact Us

Is it possible to make the .220 Thunderbolt out of 6.8 SPC brass? Yes, it is possible. Is that the best way to go? Not by a long shot.

 

[Mod Adahy]

Not possible to run 220 thunderbolt with 90's at mag length. As someone who has a tomahawk, I disagree that the hagar brass is the way to go. Fireforming SSA brass has been way more consistent than the hagar brass. I dig the tomahawk but it just lacks velocity with the 105's, 2780 out of a 24" at mag length. I also was gonna run the 22mmAR but I did not because I had prior problems with bolts in the Grendel case. It is believed that the Grendel has less strength because of the bigger bolt face. I also talked with John at Keystone about the 220 tbolt but it is impossible to run the 90's and I have no use to run 75 grain barnes.

 

[gravityoutdoors]

Thanks for the help.

 

[Mod Adahy]

Thanks for the help.

The rifle above does run 90 grain bergers at mag length at 2900 plus out of 24". I am sending a couple loaded rounds to a guy that has one in a 20" to see what he gets. I did take a 27.5" gun and cut it down an inch at a time with 75 grain bergers down to 20.5" and got 150fps loss for that 7 inches of barrel removed. JFI

 

[SPEAK338]

Really enjoy reading this info. What is this round called?

 

[ranger1183]

Really enjoy reading this info. What is this round called?

Dude, really?

 

[Mod Adahy]

Dude, really?

Try to compare to tbolt. Here is a pic of brass that includes the 22pdk (which is the closest round to this) and a quote for John. "It is based on the 6mm Hagar case, in fact all it is is the Hagar case necked down to .22 cal in order to get .22-250 performance out of an AR platform. It retains the same shoulder angle and all dimensions with exception of the neck diameter." Other emails were very clear you can not run the 90's in the tbolt. Was not possible in the 22pdk either as the shoulder was further forward than the 6.8spc case.

Here is trim lengths for the 6mm Hagar.
Max Case and Trim Length for 6mm HAGAR Brass Cases


Max Case Length: 1.775"

Trim Length: 1.765"

If you would have read the above post, Ranger, you would have realized that the trim length on this one is way below what the 1.775" of the tbolt.

 

[ranger1183]

d'oh!

 

[AK264]

Thank you for sharing. A 90 at 2900 out of the 15 platform out of a magazine is incredible performance. Hell thats less wind drift than a 6.5x55 shooting 140s amaxes at 2800! Many things that should have popular have not been but with those numbers I cant see it (name needed) not being popular. What does it do with the frangible 80gr a-maxes?

 

[SPEAK338]

Dude, really?
Smart ass your not much help

 

[Mod Adahy]

Name will be 5.68 DMR.

 

[SPEAK338]

Azprc thankyou I will keep watching this

 

[steve123]

Name will be 5.68 DMR.

I want one!

 

[Mod Adahy]

I want one!

I should have your barrel in the next couple of weeks Steve. Bolts are no problem as I have plenty of them.

 

[steve123]

You got me covered like a fat lady sitting on a golf ball and I'm smiling like a smashed cat on the highway. Nice!

 

[BoilerUP]

Because I'm a little dense, can you confirm the recorded velocity with 90VLDs from a 20" barrel?

 

[Mod Adahy]

Because I'm a little dense, can you confirm the recorded velocity with 90VLDs from a 20" barrel?

Dont know yet on the 20". I am sending some loaded ammo to a guy in TX that has a 20" to have him shoot it over the chrono when he gets them. Mid 29's out of 24". I am hoping for mid 28's with the 20". I shot a whole bunch of ammo over this last weekend in his 20" but did not try the 90's in it since it is a 1-8 twist. I am trying to be conservative since most people exaggerate numbers. His 20" was fast, 77 noslers at 3170fps.

 

[bohem]

I have a 240 TH from John, impeccable work and with fireforming Hornady 6.8 brass I'm getting around 1/2 MOA with the 105 Hornady, mag length, 2720fps. I'm not pushing them hard during FF.

I talked to John at length about the 220 TBolt and went with the 240 TH instead because I have thousands of 105's available but nowhere near that many 77's and absolutely none of the 90's. The 22TBolt with 90's is very impressive ballistics but if you want mag-fed it's not going to run... so this approach is pretty damn cool. I'm appreciating the performance an AR can dish out more and more. I have a 6 Lapua shooting a full mil flatter at 600yd but as well all know, those medium bore 6's are awfully rough on barrels.

I'm running a 22.25" 8tw tube on my 240, I'm pretty happy with with it. If I was going to do a micro-action like a cooper I'd be on the 220 TBolt in a heart beat. I might at some point go 22 cal and think about this caliber, but for now I'm going to keep focused on the 24 calibers since I run 1 bullet for both guns.