243AI vs. 6mmAI Help

[glider]

My itch started when i decided to sell one of my 260 imp 30*s .With Lapua brass I turn for a .295 chamber NK. After FF brass i'll re-cut with 30* cutter . For me and my time I enjoy bench work ,Anyway rifle is gettin a lot of attention but no one wants to spend time with brass .
So Im thinking to rebarrel to .243 AI or 6mm AI . with no turn nk chamber for the walmart easy peasy shooters who can just load and shoot . As for a standard .243 unless molly coating I cant see how a 115 gr will reach 3150 as stated by George Gardner.As for 6mm AI , between the two looks better.
If anyone can shed some light on a smith familiar with either and help decide for PRS matches and varminting which works best or equal. Running a 700 custom repeater. 105-115gr bullets 26" to 28" 1:8 or 1:7.5 twist.
looking forward to comments and suggestions !

 

[TAJ45]

AckleymanII has had several of each, well smithed. Maybe he'll see this and chime in.

 

[Dusty Stevens]

Damn sure wouldnt do either one of those for a prs rifle. 6mm brass selection sucks and while the 243 is the best choice for prs you wouldnt want to fireform brass to burn up there. A moly coated dtac in a regular 243 will get those numbers with h1000- i do it. Get the 8tw. The faster twists will rob you a bit of speed. Also ill throw this out there- theres a reason a dasher or straight br or bra wins more in br matches than say a 6x47 or creedmoor. You can push bullets faster than they want to go. People get blinded by wind drifts and bc numbers and dreams of bucking the wind when in reality a smaller group at 2850 beats a big group at 3150 on any day. Say what you want about missed wind calls and all the other excuses- if you miss it your bullet going at 3500 misses it just a bit faster. You can also see the light bulb going on over prs guys heads too- who woulda thunk a shitty feeding from a mag dasher would be the best prs round when the other rounds go faster by a big margin?

 

[MrMajestic]

Tell us how you really feel Dusty...

 

[Dusty Stevens]

Tell us how you really feel Dusty...

Im a huge advocate for 243 in prs actually. Feeds like butter with no mods, itll push a bullet where it wants to shoot while idling, good brass or cheap brass, and feeds like butter. The only thing it doesnt have going for it is its not the flavor of the week and thats the most important thing in prs.

 

[rafale]

Im a huge advocate for 243 in prs actually. Feeds like butter with no mods, itll push a bullet where it wants to shoot while idling, good brass or cheap brass, and feeds like butter. The only thing it doesnt have going for it is its not the flavor of the week and thats the most important thing in prs.

Hi Dusty,

It's not only in PRs that the 243 will be good but it excel at long range ! Like Mr John Whidden I found that the 243 is a very capable round with slow powder(N 160,N165) in long barrel's 30"/32".We experimented this cartridge on a BR base rifle and it came very close comparing at the 6Br with
the same rifle.Yes it's a barrel burner but with the right chamber and a quality barrel and custom bullet it will shoot very well !

Michel

 

[Dusty Stevens]

Hi Dusty,

It's not only in PRs that the 243 will be good but it excel at long range ! Like Mr John Whidden I found that the 243 is a very capable round with slow powder(N 160,N165) in long barrel's 30"/32".We experimented this cartridge on a BR base rifle and it came very close comparing at the 6Br with
the same rifle.Yes it's a barrel burner but with the right chamber and a quality barrel and custom bullet it will shoot very well !

Michel

I use h1000 myself.

 

[AckleymanII]

I have a few of both, but I was shooting coyotes and p. dogs with 70g bullets at warp speed.

Like Dusty, I would not want to shoot PRS with these two cases.

 

[MrMajestic]

Im a huge advocate for 243 in prs actually. Feeds like butter with no mods, itll push a bullet where it wants to shoot while idling, good brass or cheap brass, and feeds like butter. The only thing it doesnt have going for it is its not the flavor of the week and thats the most important thing in prs.

I'm for ya, not agin ya...If there is one thing I've learned in my 60 years on this ball of dirt is, as powder capacity increases the number of "where the hell did that come from" moments increase..

 

[onelastshot]

The only holdback with the 6mmAI is brass availability. When brass becomes scarce I neck down 7mm Mauser brass. On paper the 6mmAI beats the 243AI. What I typically do is purchase 6mm ammo and shoot it, fire forming the brass. The 6mm ammo shoots very well in my 6mmAI. There's an article on this site by Richard Franklin; 6mm Remington Ackley Varminter, https://www.accurateshooter.com/guns-of-week/gunweek042/; that provides some excellent information. In the article he describes shooting a 14-twist that drives a 75-grain V-Max at a blistering 3860 fps.

 

[ballisticxlr]

Reloader 23, 45.5.gn, 115 DTAC, F210, Hornady brass 3180fps, 26" pipe. You were doubting?

I ran that combo doing PRS for 2 years. 1500 rounds on the barrel before I pulled it. It made wind holds pretty forgiving and shot flat as heck. No big problems feeding from a mag but got only 8 rounds in 10 round mags with angled floor plates. Brass life was stunning.

 

[B23]

Although it may have a little shorter barrel life, if you want a VERY easy .243/6mm that'll push heavy for caliber bullets faster, consider building a 6-284. My 6-284 is built on a Rem 700 SA and not only is there no fireforming, but necking down Lapua 6.5-284 brass is so easy it barely can be considered a wildcat cartridge. Top notch dies are readily available, too. My 6-284 is one of my most favorite rifles I own.

 

[Zero333]

Most top PRS shooters are going with 6mm Greedmoor, 6x47 Lapua and now the 6mm Dasher is the new Shiny in the PRS Circus.

The name of the game is "Spot your own shots". So everything PRS Open class related is about enhancing your ability to spot your own shots.

 

[Racebannon3855]

I have a 6 mm AI with a 1:8, 1" diameter 27" PacNor with a neck turn chamber on a short action tang safety Ruger. I settled on the 115 gr Berger VLD Hunting and using 7828 SSC they run between 3150 fps and 3200 fps depending on temperature. Above this I get a healthy ejector mark (The bolt has been bushed by Mr. Tannel). After shooting a bunch of deer and a few coyotes with it I would not part with it. It will consistently shoot under an inch at 250, it is a hammer as far as a hunting rifle goes.

That said I would not do it again. Overall cartridge length for my Rifle is the same as that listed for a .240 Weatherby and it turns the rifle into a single shot. According to the Berger calculator, if I run a 115 much above 3250 fps in a 1:8 the bullet will have issues so extra velocity is not needed. Brass can be tough to find.

My 243 Varmint rifle has a 26" barrel and it will not approach the velocities of my 6 AI, but guys are getting impressive velocities with longer barrels. I like the 115 for hunting because it always exits, not sure if you need the 115 for target work. For varmint work a lighter bullet would get better terminal performance. I only shoot one load in each of my rifles so I use the 115 for coyotes in my 6 AI. I know it is not cutting edge, but my Ruger 77 VT really likes the Sierra 85 gr GKHP and the terminal performance is fantastic. It also works for deer if you keep it in the heart lung area. Velocity is high enough that trajectory is quite respectable. Numerous sources of great 243 brass and all the major component manufacturers publish 243 data. My 243 feeds great from PTG bottom metal and AI pattern mags. That would not happen with my 6 AI.

Another vote for the 243.

 

[Farmerboy78]

If you will be using it for prs, you WILL be shooting alot. For that reason I'm saying that a 6x47 lapua is a great round and is very flexible. I run the 107mk in mine at 2920fps and its extremely accurate at distance. I could definitely run it harder with lapua brass. But, I reform hornady 6.5 creedmoor brass to 6x47 because I have a ton of it from prs matches. And, it doesnt hurt my feelings if I lose one of those instead of a lapua.

 

[mauser284]

Damn sure wouldnt do either one of those for a prs rifle. 6mm brass selection sucks and while the 243 is the best choice for prs you wouldnt want to fireform brass to burn up there. A moly coated dtac in a regular 243 will get those numbers with h1000- i do it. Get the 8tw. The faster twists will rob you a bit of speed. Also ill throw this out there- theres a reason a dasher or straight br or bra wins more in br matches than say a 6x47 or creedmoor. You can push bullets faster than they want to go. People get blinded by wind drifts and bc numbers and dreams of bucking the wind when in reality a smaller group at 2850 beats a big group at 3150 on any day. Say what you want about missed wind calls and all the other excuses- if you miss it your bullet going at 3500 misses it just a bit faster. You can also see the light bulb going on over prs guys heads too- who woulda thunk a shitty feeding from a mag dasher would be the best prs round when the other rounds go faster by a big margin?

I agree 100%. Ackley Improved cartridges make no sense in a competition gun since the fire forming is still wear and tear on the barrel. When the AI cartridges were invented they made some sense but today they are the opposite of smart and wise! Since today we have unimaginable numbers of cartridges and brass to pick from their is no need to try and hot-rod a piece of brass when you really should just pick a better cartridge for you purpose. 150fps does not make or break a rifle in terms of accuracy or leathality since the most accurate load is seldom the hottest load.

If you learned to reload in the 1950's-1970's than your mentality or paradigm is likely stuck in that era and the AI's make perfect sense to. On the other hand anyone that learned to reload in the 1980's forward the AI's are comical and silly at best and a waste of barrel life and brass life. It is kind of like the Food Pyramid and it is not just outdated but it is wrong on every level. Just like egg's are bad for you and so is butter but margarine and trans-fats are good for you! LOL

In this case the OP has said that he enjoys benchwork so for him the bench work is more fun than shooting the rifle. Nothing wrong with that from a belief stand point or opinion on what is fun it is only when these sorts attempt to make it sound logical to do all that work for such little return that I get tweaked. The reduction in brass life and barrel life is never really mentioned or emphasized though and I think this is a disservice to all. This is not opinion or belief it is a fact. The only way you would see me buying anything chambered in an AI cartridge would be if the total price of the rifle was equal too or less than the cost of just an action or the same price as that base rifle at Walmart it being chambered in an AI cartridge reduces it's value to me greatly. It is going to ruin my brass for any standard chambering and it will need to be set back and re-chambered at the very least to be of any use to me. It is like a CB radio that has been modified for more channels it is worth less not more

Since the 243 is a barrel burner as it is an AI version is just even more of that! Unless PRS has changed it's rules 3200fps is the speed limit. 6mm and 6.5mm dominate PRS and heavier bullets are the norm. PRS is not about pushing the speed limit it is about low recoil, tight groups and decent barrel life in a light weight package since you are not sitting at a bench with a sled and or bags.

If I was going to run a 243 Win in F-Open or PRS it would not be an AI version. You can shoot inside of the more popular 6.5's with out resorting to AI so why bother? No one get's a trophy or a medal for having the fastest moving load it is not a drag race! LOL

P.S. The real limit on heavy 6mm's is the absolutely stupid twist rate that factory rifles come with for the various 6mm cartridges often 1:10 or 1:9 will not get it done for the heavy VLD's.

If you want decent barrel life bigger bores last longer. The straight 284 will out last a 6.5-284 and people have proven that the straight 284 can win in F-Open so why bother with the 6.5-284 .284 Win is a 7mm so necking it down to 6.5 just shortens the barrel life more than anything else.

https://precisionrifleblog.com/2017/02/16/long-range-calibers-cartridges-what-the-pros-use/

 

[fyrewall]

If you want a nice 6mm that produces great range results go for a .243 Win or smaller (6mm Dasher?) with 105's.

For field shooting at rodents, the dramatic, sexy looking and exciting hi-vel., 10% capacity increase, 6mm AI with 75's or 87"s is my choice. Should you have problems with fire forming go for a 6mm-.284. Somehow, I can manage to keep some 200 rounds of 6mm AI brass on hand, some of it being FF 7X57 PPU.

Being real old with vivid memories of many past happy exciting events with rounds like the .257 AI & 6mm PSP, I promptly acquired a LA Ruger M77 MKII rifle and 300 pieces of 7X57 PPU brass for a 6mm AI project (build?). That was six years and one barrel ago. The last trip to the range, 87 grain loads using my old chronograph were @ 3600 fps (plus or minus 30 fps) - much more excitement than the .243 W, sort of like a drag race where your head snaps back.

My thoughts on the .243 AI is that it is much the same as the .243 Win. Only the 20 degree slopey shoulder has been changed; the body taper is not or only slightly changed. For a smallish factory 6mm I would go for a 6mm CM.

My loyal wife just showed up with a nice snack of an ice cold micro brew, hi-grade cheddar cheese, and a small portion of cheddar cheese-sour cream, flavored potato chips - this switches my thoughts from rifles & stuff to how the beer & other stuff would comply with the Food Pyramid.

Edit: that should be .240 PSP (Page Souper Pooper) vs. 6mm PSP - designed to make the .243 Win more exciting - usually a rechamber without setting the barrel back.

 

[glider]

Thanks for such well written responses,good to have so many experienced advisers!
As for PRS matches I do not plan on getting in line , My shooting is on farm land within the Adirondacks and Green mountain ranges so I am lucky to have many acres of different terrain and 6 seasons of weather. Ranges from 0-1400 yds. Like having a private range.There a many days though when bad weather comes in so I have my crackers and cheese will doing bench work ) Over here there are not a lot of guys into hitting tomato cans at 1k yds mostly farmers carrying 30-06s and shooting of there tractors.
When I decide to experince another chamber and rifle configuration I need to sell a rifle to pay for new projects .
Selling is dead IMHO these days maybe just enough $$ to recover component costs . This is why I posted thread .
Understanding todays market from just these posts here helps .
As for .244 rem I think it is a better design ,Richard Franklin sure has done his home work .Personally 6mm AI with 115s seems better suited for a mid length or long action .
All new designs ,6mmGT for example are just that new designs . Tell me what is the difference when trying to design a completely new cartridge or improving existing ones ?
Also with .243 Win there is best of both worlds just drop in factory loads which will shoot steel good then use FF when you want .
My experience with imp cratridges has been most shoot very well with standard rounds. Ryan Pierce will confirm.
just take a look at his 300 Norma imp thread , I have shoot out to 1300yds with ABM 215 bergers with good results while FF .
Finally .243AI for short action wins. resale,ease of shooting ,reloading options .
Now I just need to find info for chamber spec to shoot 107-115s

Have a look
photos Ryan Pierce 300 Norma imp .
shooting factory ammo first three where my first three behind this set up , second three .091
second set of pics factory FF at 1300 yds

Appreciate all responses, anyone with a reamer spec for what I am tryin to build or a smith who is into .243AI
Please let me in on !