6mm vs the .243 AI

[Greg Duerr]

Ive been told several times that a standard 6mm Remington will shoot a 105 as fast or faster than a .243AI each with a 26" Barrel and 1x8 twist barrels.................Was told that there is no practical reason to have a rifle chambered to a .243AI when you can get the same or better performance out of a Standard 6mm Remington.

I have no idea so can anyone help me out here

 

[Rich Coyle]

Ive been told several times that a standard 6mm Remington will shoot a 105 as fast or faster than a .243AI each with a 26" Barrel and 1x8 twist barrels.................Was told that there is no practical reason to have a rifle chambered to a .243AI when you can get the same or better performance out of a Standard 6mm Remington.

I have no idea so can anyone help me out here

There is another reason to go with the 6mm. That is longer barrel life.

 

[Jud96]

I don't have any experience with a .243 AI, but my cousin has a 6mm Remington built on a Remington 700 long action with a 26.5" Shilen Match 1-8 twist barrel that he bought off a shooting buddy. He pushes 105-107s at 3150fps with H1000. He took a deer with it at 600yds this year and it dropped it dead in its tracks. The only thing with the 6mm is he has trouble finding brass for it, but he is planning on rebarreling it and changes the bolt and making it a magnum since he already has a .240 Weatherby with a 28" Krieger launching 107s at 3300fps!

 

[HARPERC]

............The only thing with the 6mm is he has trouble finding brass for it,..........

I've had a 6mm Remington for over 30 years, and still believe it's about as good as it gets in that caliber, all things considered.

I've got mine when it comes to brass, but be prepared to buy factory ammo for the brass from here out. Even that isn't a reliable source.

 

[Greg Duerr]

I shoot a .243 AI with a 26" barrel and with RL 22 and a 105 berger Im getting 3300fps...............

Now can someone tell me that in a standard 6mm shooting a 105 berger that they can get 3300fps.................??

 

[d11r529]

I have a Remington 700 in 243 win, Brux 1/8 twist 26 in barrel. It's running 3150 fps with 105 A-Max. No special anything, all the factory ammo I would want and can find brass anywhere. The 163+ inch whitetail buck I shot 2 years ago maybe made it 25 yards, bullet in and out the rib cage with a tennis ball sized exit. I also have a Remington 700 in 243 win, Hart 1/7 twist 26 inch barrel. 115 Berger bullets are running just over 3100 fps, I nailed a coyote at just over 1,231 yards this last winter. My brother shoots 6mm's and isn't getting any more speed out of his then I am. Because of the brass problem he has said that he wished he would have gone with the 243

 

[HARPERC]

Now can someone tell me that in a standard 6mm shooting a 105 berger that they can get 3300fps.................??

All other things being equal, the case capacity of the AI should yield about a 2% increase in velocity over a standard 6mm.

Not a thing in the world wrong with a standard .243, or the improved version. If one is looking for velocity, the 6-284 has more capacity, and will yield a bit more velocity.

The 6mm Creedmoor, and the 6X47 also have a fan base.

 

[Dgd6mm]

My 6mm Competition Match pushes the 115 DTAC at 3153 fps out of a 27" 7.5 twist Krieger using H1000.

 

[Trickymissfit]

never owned a .243 in anything, but have shot quite a few. I've owned a couple 6mm and one 6mm improved (40 degree). I also own a 6mm/250AI. When I was shooting the 6mm Remington's (24" barrels), I also shot with a couple buddies that were in the .243AI camp. We usually shot over one of two chronographs we owned (Ohler and a Pact). The .243's were both 26" Shilen barrels, reamed with one of Pindell's reamers. My 6mm's were factory chambers, and the 6mmAI was another one belonging to Ferris. The .243AI's were very close to the factory 6mm barrels (with in 25fps), but when I shot them I also noticed quite a bit more recoil (were the loads safe?). One thing that was quite noticeable when shooting 90+ grain bullets was the bullet being seated deep into the case. We never shot an Amax, but did shoot several others in the 100 grain class. I did see several 3175fps loads in the 6mm and the .243AI using 100 grain bullets. I later worked up a 3250 fps load in one of the 6mm's (other wouldn't shoot it) that was very hot. Used some old .257 cases (they hold a couple grains more powder). I think with two inches more barrel; 3000fps is doable. The 6mm improved was good for a solid 3400fps. The 6/250 will shoot a 105 grain Amax or a 107 Sierra to right at 3100fps. A little smaller case than the .243AI, but also far more efficient. It has the same issue the .243's have in having to push the bullet into the shoulder area. But with another .05" of shoulder length in the .243 shows me 3250fps is doable.
gary

 

[tbrice23]

Trickmissfit,

Is there any way you could recall an accuracy load for your 6mm AI?
And if possible an accurate fire forming load for 6mm rem?
I'll be forming for an 8 twist 26" 6mmAI next week.
Thanks.

 

[Trickymissfit]

Trickmissfit,

Is there any way you could recall an accuracy load for your 6mm AI?
And if possible an accurate fire forming load for 6mm rem?
I'll be forming for an 8 twist 26" 6mmAI next week.
Thanks.

was before I started keeping a log book, and simply wrote on the target. I want to say 4064, but doesn't seem right at all. Probably IMR 4350 or 4831. I did shoot some 3100 as well. Loads were starting to get finicky and this shows me the case was moving into overbore. I do know I did some experimenting with 4064, but think it was with 87 grain bullets. Rock steady in the low 3300fps range. I stopped using it because the barrel got hot enough to fry an egg on it! Look for some of those old .257 cases (Winchester). They are thinner and hold a little more powder (maybe 1960ish)

I did run across a folder of 6mm targets I shot a couple months back, and most all groups were sub 3/8th". There was standard 6mm and the improved. Not much data on them except for weather and wind. Groups were measured all wrong I noticed, but all were five shot. There were also several that had me trying to shoot Berger 88's, and of course they wouldn't group even slightly. Then I ran across one target with 69 grain Bergers, but you couldn't measure it as they look like they blew up going thru the card board!
gary

 

[tbrice23]

was before I started keeping a log book, and simply wrote on the target. I want to say 4064, but doesn't seem right at all. Probably IMR 4350 or 4831. I did shoot some 3100 as well. Loads were starting to get finicky and this shows me the case was moving into overbore. I do know I did some experimenting with 4064, but think it was with 87 grain bullets. Rock steady in the low 3300fps range. I stopped using it because the barrel got hot enough to fry an egg on it! Look for some of those old .257 cases (Winchester). They are thinner and hold a little more powder (maybe 1960ish)

I did run across a folder of 6mm targets I shot a couple months back, and most all groups were sub 3/8th". There was standard 6mm and the improved. Not much data on them except for weather and wind. Groups were measured all wrong I noticed, but all were five shot. There were also several that had me trying to shoot Berger 88's, and of course they wouldn't group even slightly. Then I ran across one target with 69 grain Bergers, but you couldn't measure it as they look like they blew up going thru the card board!
gary

Thanks,
That's funny. I laugh sometimes when I look at my old targets too.
Seems I'm always getting more detailed about data.

My plan was to use rl22 and cheap hornady 105s to FF. And develop a load with rl23. I just thought that I could ask someone with previous experience.
My back up plan is imr4350 or 7828 to FF.
I'm tired of bullseye and COW , its almost like going the job half way. FF with bullets insures the cases are as straight as the chamber.

 

[LeddSlinger]

This is the 3RD thread I have seen on this pointless subject. All started by Mr. Gregg Duerr.

It really doesn't matter. A fast rifle does not win competitions and it doesn't kill animals better. Accuracy does. That's all you should be worried about.

You're not gonna have the fastest rifle or the fastest car. Someone will always have something faster or better, or at least claim to. Don't get so worked up over such a ridiculous thing. 3 threads started at the same time is crazy. Or at least that's all Ive found so far, could be more....

 

[tbrice23]

Some people believe in sustained energy and terminal ballistic efficiency.
A LOT of people.

You might want to vent by starting a thread about how sustained energy and terminal ballistics don't matter.