What's the real world difference between the two? Does the AI really have advantages worth the extra fuss? Will I see a significant gain over say my 6mm Rem.?

Thanks

1. None.
2. Lack of trimming - which in my book isn’t much of an advantage.
3. Same case capacity as 6mm, so no.

Real world difference is AI = no case trimming

I hate trimming and love my .22-250AI..

I wouldn't tear apart a good shooting 243 to AI it but If rebarreling I think it's a nice way to go.
A little more speed and never trimming doesn't hurt anything

There is no reason not AI if the gun is already apart.

I like the AI, but with the 6mm Creed and all the good factory ammo that will follow...I'd just go that route.

JMO. Unless you love reloading more than shooting.

Except for the added cost of new dies. Also time and money spent fire-forming.

LCD die works on AI brass. A bump die is really all a guy needs.

FF loads hit targets and critters just like any other load...

I’m aware of this, but it is something that needs done to an AI to allow full powered loads, that doesn’t need done for a regular 243. Though I will admit that fire-formed brass isn’t a bad idea for accuracy in either.

Believe I’m a dozen AI’ed rifles in at this point, so am well aware of the pros and cons. I doubt I’ll do another.

Always wanted a 6mm rem. More speed, longer neck, and no fuss.

Sounds like I might be better served by selling one of my .243's and building another 6mm Rem. Or maybe rebarrel my 70 Lightweight to 6mm. I've got a factory 70 Featherweight in 6mm but my daughter has laid claim to it. Decisions, decisions, hmmmm.

With modern bullets, the .243 or .243 A.I. with a 1 in 8 or faster barrel is pretty damn potent out to 1000 yrds and beyond, I have found the .243 A.I. very easy to get good speed and accuracy, fire forming is no big deal almost any brass will work, some brass is just better and lasts longer.

With a good hunting bullet the .243 A.I. will drop anything most of us will ever hunt, and a lot of critters most of us will never get a chance to hunt.

I heard a rumor somebody killed one of those bullet proof rocky mountain elk with a .243, must have been a lie,

I heard at the pool hall. Rio7

Just because you've killed more than one Gemsbok, plus Wildebeest and Elk, with Scenars out of your .243 AI, not to mention untold whitetails, hogs, coyotes and Bobcats, suddenly you've become an expert?

I heard that same rumor. I think someone was telling it either at the pool table in the bar or at the bar in the whorehouse...My momma told me to never hang out in pool halls, bad things happen there.

Ed

Fire forming is a non issue for me, i loaded plain jane 243 maximum loads( very accurate )and hunted till my brass was fire formed. You may tell me I'm full of it, but i actually gained velocity with the same load in the fire formed brass. I get maximum 243 velocity with less pressure. Im satisfied. Plus less trimming, and longer brass life.

You would not be the only one who has seen the exact same results. It may not turn the .243 Win into a .240 Weatherby, but it does make life better. IMHO...

Ed

Done the ackley thing on a previous build. Currently running a 1-8” 243 win. I don’t believe the minimal velocity improvement to be worth the components, barrel wear and time.

https://m.youtube.com/watch?v=ClrsRhhjJsw

Buy this if you dislike trimming. Just get a 243 win twisted and throated to take advantage of the bullets you intend to use that fit the mag well.

I wonder if the sharper shoulder of the 243AI reduces the throat wear that is endemic with the standard 243?

I doubt it. The short neck is the culprit.

Not speaking from experience, but everyone I've talked to says longer bbl life in a cartridge that otherwise has a relatively short bbl life.

I'm going to find out--I replaced my burned out 243 with a new take off SS bbl and had my gunsmith chamber it to 243 AI. I'm still deciding how much money I want to spend on a new stock for it. I should just screw it into one of the stocks I have and take it out and start fire forming.

I have a custom 243 with a match chamber. On my 5th loading my reloads won’t chamber. Apparently the brass flows forward and a guy needs to inside neck ream at a certain point, depending on your chamber dimensions. I believe blowing it out to an ackley or just doing a 6 creedmore would solve the problem. If I had to build a new rifle tomorrow given the choice of a 6mm Creedmoor, 243, or 243 ackley I would choose the Creedmoor because of case design.

Partly it is, but the shoulder angle is quite different with the AI, directing the gas into the neck instead of the throat.

6 SLR solves the shoulder angle and no fire forming...

I own 6, 243's all of them are AI's. So some of the issues are already resolved with the price of dies, which cost about the same as a box or 2 of bullets over and above the cost of SAAMI dies.

One of the points often brought up is barrel life, a good argument. What is often forgotten is that a large percentage of shooters need to forget about that issue as they would be hard pressed to put a thousand rounds down range in the next 10 years. Secondly I've yet to see any proof that SAAMI chambered cartridges are easier on barrels than AI's, some reports to the contrary.

Another issue is you have to fire form. Of the 30 - 40 AI chambered rifles I have, I have yet to find one that didn't shoot well enough fire forming brass that I wouldn't take on the most important hunt of my life. I took at very nice 180 class mule deer the day after taking delivery of a custom 280 AI after sighting in with 6 shots fire forming 145 Speer flat base bullets.

Factory ammo, kind of a moot point as AI chambers done properly will shoot just fine. Although I couldn't prove that point as I haven't shot 40 rounds of factory ammo in the last 50 years out of a center fire rifle.

Velocity issues. Hell there has been many arguments over 300 Savage, 308, 30-06 to fill all the pages of the campfire. You want a 22" 243 and want to maintain the same velocity as a 24"- 25" 243, the AI is your answer.

Lots of to do about nothing.

Now lets talk about that dreaded belt on belted magnums, and to really pizz off the anti AI folks. I don't have to trim brass.

Is the 243 SLR and 243 Imp 30 degree the same cartridge?

I just built one. Just starting to develop loads with the new Hornady eld 103 grain, RL26 and lapua brass. Part of the Ackley thing is the tinkering one does to develop brass etc. Lord knows folks turn necks, sort brass , use Vern junkie machines to check bullets etc etc, all seeking that tiny edge in performance. I can see both working just fine."....some guy came up with the term rifle looney.......man was that spot on. Goodshot

6mm Wasp, pretty much has this subject covered. Rio7

+1

Could not have said it better.

I would add that a 6 Remington is a long action cartridge.

I think a much better cartridge would be a 358 Winchester AI necked down to 243. GD

I think a .280 AI necked down to .264 would be even better.

Ed

Actually the the .270 Win. necked up to 308 would be the prefect do all cartridge.

Dang, why didn't I think of that!

Ed

I'm going to build a light weight 6mm Rem with a 7.5" twist barrel. I can't find any real measurable differences in it and the 6mm Creedmoor. I don't think an AI modification would gain me any significant velocity.

What action length are you building the 6mm Rem on?

I've owned a dozen or so rifles in 6MM over the past 50 years from Rem/Rug/Win, all short actions, have shot bullets in the 75 to 100 range and have never seen how a longer action would have made a noticeable difference.in performance.

I still have my first 6MM, a 660, and my last, a 20" 700 with the X'd out 6MM REM MAG barrel stamp.

I recently did a 7t 243ai and have been very happy! with out pressure signs I’m getting 3175 with the 105 hpbt using rl26.

Hondo, It's a custom barrel for my R8 Blaser. I'll use a 7x57 megazine insert that will give me plenty of room for stretching out the big, long ones.

No, the SLR has the shoulder/neck junction squeezed backward to make a longer neck emerge.

The Imp 30 has the shoulder blown out but maintains the short neck.

Thanks Dakota! I was wondering.....

I can trim cases after dark in my basement. I cannot fireform that way. AI chambers are a Kool-aid drinkers champagne. They create more real world problems than they solve.

Well said.

Another point with AI chambers - you gotta deal with picking up brass. Nothing quite as fun as ejecting a specially fireformed case into a snowbank while shooting at a coyote, then digging for five minutes trying to find your precious shell casing.

My next 243 will say 6 Creedmoor on the case head.

or a 6XC for me

8 grs less powder every shot over the std 243

Quit being a drama queen

My experience has been the opposite. I can fireform cases at steel and animals. I cannot trim cases that way

Putting together a 6 Creed presently, but if picking up brass and buying a set of dies are real challenges for some guys, I can understand why they’d feel so strongly about AI chambers.

I handload, so picking up my brass, regardless of chambering, is nothing new to me...

You could remove the ejector. I plan to do that on my bench gun, where I load singly anyway.

Can't remember the last time a piece of my brass hit the ground. Catch it on the way out but I can see getting excited and jacking them onto the ground. I once caught myself with a hand full of 22 Mag brass when the smoke cleared.
As they say ( Different strokes for different folks)

I am curious about the real world problems though.

I am pretty happy that folks make the AI stuff far more drama and work than it really is.....I have picked up a couple of smoking deals from guys like that.

I shoot 'em all and 6mm Rem and 6mm Rem AI,would be the last on any/all lists. Too easy to whoop in a S/A and too easy to whoop in a L/A. #4 and #3 from right,respectively.



The 243AI is a great chambering and I've shot THE fhuqk outta it,but a "sedate" 21" Kreedmire will squirt 108 ELD's at 3050fps and there's not much it won't reliably do. ES and SD are amazingly trite,Precision a given and Alpha brass has no equal. I've got a couple Custom Rifles so chambered and with .110" freebore,it's no thang to squirt same from OEM mag confines. Add throat or projectile length and an AICS DBM is a nice place to be,allowing one to retain binders for added rugged reliability. That is always a nice place to be.



While I kinda like the XC(4th from left),I much prefer the Kreedmire,both due case design and brasstitude. Though in fairness,with but a coupla steps,one can form positive headspaced XC Virgins from Alpha 6.5 Kreedmire donors. Hint. Hold the Fluff however and pass the Kreed.



It's never not interesting,to toss more than a few like bore sized rifles in different chamberings in the crummy and extrapolate 'em side by each,in like conditions. Mild manners,exceedingly modest ES/SD and unerring consistency,are literal Giant Killers. Much to be said for copious erector travel,unwavering tracking and an amazing penchant to retain zero too. All are in a hurry to overlook that,which is never not funny. Hint.




A 270,6 Grendel or 6BR will reliably blow minds(top 3 rifles above)...assuming 1-8" or more RPM(none of mine are faster than 1-7"). I'll happily take them mild manners,as they are all too happy to stretch wayyyyyyyyyy beyond the 1000yd line,if only because I do so daily. Hint.

Now and again it's fun to whoop out a Niche Toy,but the Utilitarian stuff is far more useful and forgiving.



Easy for me to say,if only because I shoot it all.

Hint.

Just saying.

Good talk.

Laughing!...............

Not always. I had a Rem 722 in .244, the 722's were short action rifles. I still have a factory 6mm Remington Model 70 Featherweight SA that I've never had any issues with. My favorite 6mm Rem. is my Ruger No. 1B. No action length to worry about.

I can understand your thinking though. With today's trend toward the >100g 6mm bullets most SA's don't have enough magazine length to accomodate them.

The magazine on a rem 788 let's you run the bullet way out there. I am shooting berger 105 s in it. Not sure if there is another standard factory mag that allows for a longer oal. I have a 8 twist barrel to spin them.

243 by the way.

Stick, are you shooting moly coated bullets exclusively in your .6mm's?

I see the un-moly'ed bullets in the upper picture with the load notes on them, but that's the way I do my "standards" loads for returning to seating die settings for a given bullet weight.

Ed

When the throat goes in my 1-7.7" .243 Number 1V, I'm thinking of going with a 6mm/06 AI rechamber to clean it up and get some more mileage out of the barrel. Otherwise, it'll get a 6mm CM tube, or maybe the Grendel version, since the dang thing's too heavy to carry up the hills. Not much need for anything over .24 caliber around here. Hell, .22 would cover most stuff if VA allowed it for deer.

Have 2 .243 std and 2 .243 A.I. all are 8 twist usually carry one of the A.I. in my jeep don't spend a lot of time at the range with my A.I.s I have a good fixed load for each rifle, that's fast, accurate and kills real well.

What a rifle and caliber does in the field is what's important to me, as I never know what will come up at any given time or how close or how far.or how big or how small or how pissed off it will be. I don't go looking for big critter's with my .243 A.I. I have other guns that will handle anything, but if they are not in my jeep when the SHTF, so I use what I have handy, I will say I am surprised at some of the big critters that have fallen with a well placed shot from my .243 A.I.s and the penetration and damage caused by 105 gr. bullet. Rio7

When are we going to have the discussions about

The real world problems caused by the AI chambered rifles
That pesky belt on belted magnums
That terrible boom associated with un-suppressed, un-civilized rifles
The superiority of the 6.5 Creed over the ugly old 270 Winchester for the non turret twister
And lastly, most importantly how life would suck without the 223 Ai thread.

Looking for the smile face but can't find it.

Hmmmmmmm.....

A belted .270 case necked down to .223..... then AI’d and shot Suppressed.

Genius Mike!