6mm Rem AI

shortgrass

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Mar 31, 2010
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2,686
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Western Oklahoma
I built myself a 6mm Ackley on a VZ-24. My reamer has the 40* shoulder. The barrel is a Hart #4 contour with a 1-7 twist finished at 26" long. 3225fps average with 107g SMK. It'll lay one on top of the other, repeatedly...... I had the barrel nitride. Using Reloader 22, Win. brass, Fed GM LRP. I haven't tried any bullets heavier than the 107g. I have fit a couple of barrels to Rem. LA for customers. The 6mm and the AI version fit the LA better than they do the SA,,,, especially if launching VLDs is the goal. The accuracy is in the barrel...... I did one for a customer on a Rem SA. He wasn't interested in anything heavier/longer than 87g varmint bullets. Took quit a bit of extra work to make that one feed trouble free. Wasn't exactly a 'drop-in'.
 
Last edited:

just country

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Aug 6, 2014
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78154
morning I have both the 243 and 6mm AI's. 95gr berger VLD
will shoot into .500 or better. the powder for 6mm is
4831ssc. the 243 powders 4320, RL15 4064 and 4832sc.
bullet weights vary with powders. older rem. actions.
26" or more barrel lengths. gbot tum
 

2Rope

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Mar 6, 2015
Messages
55
I’m running 105 hunting vld’s 3250. They shoot in the 2’s if I do my part. The action is a long 700 with a brux 5 contour bbl. This rifle was a 25-06 and after years of great service it needed a re-barrel, the 6 AI fit the long action and I was wanting a 6mm. I shot quite a few coyotes with it this winter and am happy with it even though it’s not fur friendly...
 

AZShooter

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Dec 12, 2005
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2,577
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Tucson Az
I tried quite a few 6mms over the years. I currently own the extreme ends of performance with a 6BR and a 6mm-284. I own the reamers and do the chambering myself.

There is a wildcat I may have to try one of these days. The 6 BR reamer would be used to cut deeper to headspace as a 243. The shoulder angle would be changed to 30 degrees with less body taper. I used my 30 BR reamer to do exactly that with the 308 win. The neck does require turning but end result is a super accurate cartridge. A BR die can be used for sizing and seating.. I have gotten 10 firings of the lapua 308 brass before primer pockets loosen. (max loading with 215s)

Here is some more information on the 6mm and 22 dubbed the BRK

upload_2018-4-30_14-9-0.gif
upload_2018-4-30_14-9-0.jpg
upload_2018-4-30_14-9-0.jpg
,October 6th, 2013

Hot .243-Based Wildcats — The .243 BR-K and 6mm Super X

Gunsmith Mike Sosenko and long-time AccurateShooter Forum member John Adams have been using a modified .243 Winchester case with great success in Varmint Silhouette matches at the Pala Range in Southern California. Officially called the “.243 BR-K” (and informally dubbed the “6BR Long”), the wildcat is basically a .243 Winchester with less body taper and a 30-degree shoulder. The design essentially grafts a 6mmBR Norma “top end” to the .243 Winchester case. After fire-forming, Mike and John can reload this case using normal, unmodified 6BR neck-sizing and seater dies.

Compared to a .243 Winchester, the .243 BR-K’s body length is about .006″ longer, and the shoulder is about .0055″ wider. The main difference is the shoulder angle (30° vs. 20°), and the location of the neck-shoulder junction (“NSJ”). Based on reamer prints, the base to NSJ dimension is 1.718″ on the 6BR Long, compared to 1.804″ for the .243 Winchester. Neck length is a bit shorter because “the neck shrinks a little when the shoulder blows out” according to Sosenko. We’ve provided a mock-up diagram of the .243 BR-K, but you should check with Dave Kiff of Pacific Tool & Gauge for exact dimensions. Dave created the reamers for both the 6mm and 22-caliber versions of this wildcat. Ask for the “22 BR-K” or “.243 BR-K” reamer designs.
 

moosehunter

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Joined
Mar 19, 2002
Messages
131
Location
Prince George British Columbia
This case could be improved about 6 gr. for the neck/shoulder junction to be at the boat tail/bearing surface.
This is a 105gr vld. My accuracy load is 3370 fps with RL26. 26" bbl. For the record, I never did max out. I stopped when it started printing in the .3's.
View attachment 97146
Did you find any good nodes below 3370? I’m using Matrix 105 VLD and my powder of choice has been H1000 and H4831sc. Problem I’ve been having is going close to 3300fps I get about 3 loads and the primer pockets are done. Also I’d like to get some life out of my Shilen barrel. So far I’m getting groups in the .7 range with 51.2 gr of H1000. Haven’t chronyd this load yet. Any info and advice with this project would be appreciated.
 

tbrice23

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Dec 12, 2012
Messages
3,077
Location
Indiana
No, I run the high side and don't look back.

I'm on my 8th firing and pockets are still tight.

I formed my brass from Norma 7×57 Mauser cases, good stuff!

Otherwise the only other brass I could find was once fired RP brass... no thanks.
 

sable tireur

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Joined
Oct 8, 2010
Messages
1,552
I tried quite a few 6mms over the years. I currently own the extreme ends of performance with a 6BR and a 6mm-284. I own the reamers and do the chambering myself.

There is a wildcat I may have to try one of these days. The 6 BR reamer would be used to cut deeper to headspace as a 243. The shoulder angle would be changed to 30 degrees with less body taper. I used my 30 BR reamer to do exactly that with the 308 win. The neck does require turning but end result is a super accurate cartridge. A BR die can be used for sizing and seating.. I have gotten 10 firings of the lapua 308 brass before primer pockets loosen. (max loading with 215s)

Here is some more information on the 6mm and 22 dubbed the BRK

,October 6th, 2013

Hot .243-Based Wildcats — The .243 BR-K and 6mm Super X

Gunsmith Mike Sosenko and long-time AccurateShooter Forum member John Adams have been using a modified .243 Winchester case with great success in Varmint Silhouette matches at the Pala Range in Southern California. Officially called the “.243 BR-K” (and informally dubbed the “6BR Long”), the wildcat is basically a .243 Winchester with less body taper and a 30-degree shoulder. The design essentially grafts a 6mmBR Norma “top end” to the .243 Winchester case. After fire-forming, Mike and John can reload this case using normal, unmodified 6BR neck-sizing and seater dies.

Compared to a .243 Winchester, the .243 BR-K’s body length is about .006″ longer, and the shoulder is about .0055″ wider. The main difference is the shoulder angle (30° vs. 20°), and the location of the neck-shoulder junction (“NSJ”). Based on reamer prints, the base to NSJ dimension is 1.718″ on the 6BR Long, compared to 1.804″ for the .243 Winchester. Neck length is a bit shorter because “the neck shrinks a little when the shoulder blows out” according to Sosenko. We’ve provided a mock-up diagram of the .243 BR-K, but you should check with Dave Kiff of Pacific Tool & Gauge for exact dimensions. Dave created the reamers for both the 6mm and 22-caliber versions of this wildcat. Ask for the “22 BR-K” or “.243 BR-K” reamer designs.
This idea is similar to the 6mm Super LR from 6mmAR:




.243 Win.(left) vs. 6mm Super LR (center) vs. 6XC (right)

http://www.6mmar.com/Super_LR.html

Lots of these variations are good, solid improvements over the existing original cases. It's fun to continue on down to .22 caliber for a varmint cartridge as well. There isn't as much case capacity as with the 6mm Rem. versions but the powder selection is a little more broad. Then again there is the .22 TTH or Texas Trophy Hunter for those looking to gain a bit more from the .22 VLDs.
 

CaptnC

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Jun 21, 2017
Messages
1,426
Location
Texas
I built myself a 6mm Ackley on a VZ-24.
I did the same thing, but never like the bullet performance on game so I scrapped the caliber and rechambered to 300wm...

I shot 95gr Nosler BT out of it, but don' recall how fast...knowing me it was at book max...lol
 

waltercrouse

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Jun 18, 2013
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225
Location
SAN DIEGO,Ca.
How many have or have had a 6mm rem AI ?

A good friend just finished a really nice rifle in 6mm rem AI and it is a great looking cartridge when fire formed. The powder capacity edges out the 6mm CM by one grain + but I haven't seen the test results yet to do a good comparison.

Just wondering what powders and velocities he will get using the heavy 6mm bullets.

J E CUSTOM[/QUOTE. I had Mauser 98 in 244 ai / 6mm shot old Barnes 105 in it. Shot slot of deer , tiny entrance but big exit hole.
 

J E Custom

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Jul 29, 2004
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10,380
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Texas
Ackly called it the 244 improved,the one I had was with 1-10 twist not the 1-12 twist that Remington used.
The 1 in 12 twist Was the reason for the cartridges downfall. The 243 Winchester had a 1 in 10 and the rest is history. All of the wildcatters and Re barrels solved this and saved the cartridge.

Like other disasters, remington changed the name from 244 to 6 mm in hopes it would boost sales. It still has potential as a cartridge with the right bullets and barrel twist.

It looks like it is up to us to save some of the old cartridges from extinction instead of the potential sales priority of the manufacture.

Looking forward to hearing how well my friends 6mm AI performs.

J E CUSTOM
 

Uboatrobert

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Joined
Aug 14, 2014
Messages
28
Location
Florida
I built up a 6 AI back when, but we didn't have the bullets we have today. I put it on the Gunbroker and ended up trading it to a guy in Boise for a New 700 - 24" HB in 22-250 w/Redfield medium base and rings and shipping. He really wanted that gun.
I still have a 22-250 AI Winchester HB that still shoots into .5 @ 100, I use for prairie dogs.
 

TOM H

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Joined
Dec 24, 2001
Messages
1,214
Ackly called it the 244 improved,the one I had was with 1-10 twist not the 1-12 twist that Remington used.
Speer Wildcat manual first printing 1956 has Ackley data for the 244 Improved and he used 1/12 twist and it has 30 degree shoulder. In Ackley book the original 244 improved had 26 degree shoulders with a minimum body taper. (They don't show what that was but in Speer book they have case dimension.) Later they changed shoulder to 40. In Ackley book standard twist 1/12 and special twist was 1/10

The loads in Ackley book for the 244 Improved, some of the loads are same as in Speer Manual.

I used 1/10 in 6RemAI.
 

waltercrouse

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Joined
Jun 18, 2013
Messages
225
Location
SAN DIEGO,Ca.
Speer Wildcat manual first printing 1956 has Ackley data for the 244 Improved and he used 1/12 twist and it has 30 degree shoulder. In Ackley book the original 244 improved had 26 degree shoulders with a minimum body taper. (They don't show what that was but in Speer book they have case dimension.) Later they changed shoulder to 40. In Ackley book standard twist 1/12 and special twist was 1/10

The loads in Ackley book for the 244 Improved, some of the loads are same as in Speer Manual.

I used 1/10 in 6RemAI.
Speer Wildcat manual first printing 1956 has Ackley data for the 244 Improved and he used 1/12 twist and it has 30 degree shoulder. In Ackley book the original 244 improved had 26 degree shoulders with a minimum body taper. (They don't show what that was but in Speer book they have case dimension.) Later they changed shoulder to 40. In Ackley book standard twist 1/12 and special twist was 1/10

The loads in Ackley book for the 244 Improved, some of the loads are same as in Speer Manual.

I used 1/10 in 6RemAI.
 

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