View Full Version : 6mm or 243

February 2, 2006, 11:01 PM
Interested in target shooting and was wondering what's the difference between these two calibers.

February 2, 2006, 11:21 PM

It is suposedly a little bit hotter than .243...
And it can be hand loaded even hotter than that...

I wouldn't want either one for anything bigger than small Texas white tails.:D

February 3, 2006, 06:52 AM
I have had both 243 and 6mm's.

If you reload, the 6mm really shines, you can do alot with it, as you are limited as to factory ammo choices.
If you are not a reloader the 243 is excellent, as there are alot of factory ammo choices out there.

I have taken Mule Deer, Whitetail Deer, Antolope, coyotes, and praire dogs with it, and never had a problem with the 6mm.

February 3, 2006, 07:26 AM
The 243 is based on the 308 Winchester case and the 6mm is based on the 7mm Mauser case. The 6mm holds a bit more powder. If you load you own, I say 6mm, if not then 243. You'll love either one as they are very useful rounds.

Jack O'Conner
February 3, 2006, 07:38 AM
I've never owned a 6mm, but years ago my boss hunted with one. It was a Remington 760 slide action with basketweave checkering that I found quite appealing. We often hunted together. One morning he shot a big buck at about 150 yards or so. It reared up on its hind legs and pawed the air like a stallion; then fell backwards. An impressive kill shot through the chest.

I've hunted mule deer and antelope with a .243 Remington 760 slide action since 1968. Dad bought it for my brother and me to share and it has certainly put a lot of venison in the freezer.

Many good bullets to choose from. I've had best accurasy with Sierra and Nosler Ballistic Tip. I hear Hornady's SST is also quite good.

February 3, 2006, 09:44 AM
I think I'd go .243 myself, as it is more common and easier to find ammo variety.

Have been looking at the Ruger M-77 International in this caliber. Sooo tempting. Just for a fun gun that could dispatch groundhogs and deer equally. Though my .260 Remmy will do the same work, it's more fun to have an excuse for another rifle! :cool:

February 3, 2006, 12:10 PM
Interested in target shooting

look for a 6mm PPC, ultimate target cartridge. You can buy a new Cooper for around 1k... not sure you want to spend that much.

Otherwise, I'd go with the .243

February 3, 2006, 12:30 PM
look for a 6mm PPC, ultimate target cartridge. You can buy a new Cooper for around 1k... not sure you want to spend that much.

Otherwise, I'd go with the .243

+1. Can't top that advice.

February 3, 2006, 06:41 PM

+1. Can't top that advice.

How about 25-06...?

Will that do?... :D :D :D :rolleyes:

February 3, 2006, 06:57 PM
I had a .243 my wife had a 6mm each in a Ruger 77. Hers was stocked to fit her. There wasn't enough difference to matter. The 6mm is a slightly larger case and so will accept a very little more powder but also needs a very little more powder to achieve the same velocity which the 6mm will then go on to very slightly exceed. The 6mm could be described as a slightly improved .243 or even as a .243 with an oversize chamber.

The only meaningful difference is that the .243 will fit and work better in a true .308 length action. In a short action the 6mm may require slightly shorter seating and so lose some of the extra capacity. The 6mm has a slightly longer neck. There was once a consensus this is a good thing. Some folks, Gale MacMillan for one, think necks should be as short as possible but not shorter for best accuracy.

I'd buy a .243 over a 6mm all else equal for the better availability of factory loads and brass. I'd buy a 6mm if it happened to be cheaper or in better condition that is if all were not equal.

February 3, 2006, 10:11 PM
Thanks for all the feedback. Being new to the sport of shooting there were things mentioned that I would have never considered.

I do have access to a reloader but don't currently own one so I want to learn that aspect of the sport also.

A Cooper firearm would be great but beyond the reach of my wallet.

Really didn't consider a 25-06, thought the recoil might be more than I was ready for. I'm making the transition from rimfire to centerfire so I want to continue practicing good form without developing a tendency to flinch. Also wanted a caliber that could easily reach out to 200 yds.

February 3, 2006, 10:22 PM
Yeah, I guess the .25-06 does top the 6mm ppc come to think of it Pointer. :p But yeah, the 25-06 gets a little punchy pretty quick in the recoil dept.

February 3, 2006, 11:26 PM
I'm not sure anyone but Remington even makes a rifle in 6mm anymore.

It is a better cartridge than the .243 but not by a lot. I mostly handload, and if I could find a nice 6mm I would grab it over the .243.

As per the 6 PPC, well that is another thing completely. One of the most accurate rounds ever made, but not for most people except the benchrest crowd. Cases are expensive, and case prep requires lots of extra work - in addition to being restricted to handloading only, and again, not a lot of rifles are offered in 6 PPC.

T. O'Heir
February 3, 2006, 11:36 PM
"...what's the difference between these two..." The case and about 100 fps. The 6mm Remington uses a slightly longer case and is 100 fps faster with equal weight bullets. Same bullets. It's not as readily available as the .243 Win either. If you get off on a hunt in some small place and find you left your ammo on the kitchen table, you're far more likely to be able to find .243 Win in a small town hardware store.

February 3, 2006, 11:45 PM
For casual target shooting: an off-the-rack heavy barrel .308 is probably the best bang for the buck. Accurate ammo is easy to find. Remington, Tikka, Savage, all very accurate.

February 4, 2006, 12:21 PM
The best bullet weight is 100 grains for both calibers. Although there is a 105 grainer out there. Pushing both at about 3100 fps (hornady vol II). The six performs flatter with the larger projectiles. Where you hunt should dictate what you need. Here in CA I get by even with my Ruger #1 falling block chambered in .357 Mag

If Mule Deer is the goal and heavy recoil is the avoidance. Try a throwback caliber. The .257 Roberts handles 60-120 gr bullets (120 is perfect for deer) and allows you the versatility to go from prairie dogs to prong horn. I personally dropped a Anelope with a 120gr boat-tail spitzer at 475 yds using a .257 Roberts pre-64 super grade mod 70.

There is one catch! you will have to get into reloading to get the versatility. Over the counter ammo is usually 100 grain only.

Art Eatman
February 4, 2006, 03:05 PM
One issue is the twist rate of the rifling. Many of the 6mms had a faster twist, which works great with 100-grain bullets. But, in the early days, they got a bad rep for accuracy with varmint bullets.

I have a Sako in .243, and it's the opposite. I get dime-sized groups with 70- and 85-grain bulletws, but not that good with 100-grain. Slower twist.


February 4, 2006, 03:17 PM
Good point, Art. Actually that's what killed it (the faster twist and resulting worse performance with light bullets). That and the fact that Americans prefer American-convention-named cartridge (inch designations), not dem furrin' millimeter ones. But 6mm is better for deer loadings like 100/105/107s. Most .243s nowadays are 1 in 10. Art, do you know what rate your Sako is? Did they used to make .243s 1 in 12 as standard or what back in the day? My newish Handi rifle .243 is 1 in 10 and so far it likewise does not group well with the 105s I tried. And anyone know what the twist rate is with 6mms? 1 in 9 or what?

February 5, 2006, 01:19 AM
+1 for 6mm ppc or 257 Roberts, or what happend to the .250 savage :confused:

Art Eatman
February 5, 2006, 01:00 PM
FF, sorry, but I've been too lazy to check out the Sako's twist.

(Repeat after me: "Sorry is as sorry does.")

:), Art

February 5, 2006, 01:13 PM
The twist on a 6 mm is 1 in 9. I have a Remington mod 700

February 5, 2006, 01:29 PM
OK, Art. Yeah, me credo is, lazy is as lazy does. :) I wish one of my .243s had a 1 in 9 twist, for the heavy dudes.

February 5, 2006, 02:17 PM
Whichever round you pick wil serve well for you both are more than capable of reaching out to 200 yards effectively i know a fellow who can consistently kill coyotes at 400 yards with a .243 winchester. My experiences with the .243 were also very positive and I never lost (or tracked for that matter) a single deer.

I, however, would choose the .243 because:

1. It is simply more common and you will have a greater selection of rifles and ammunition.
2. Being based on the .308 Winchester case I have heard rumors that the .243 is just more inherently accurate than the 6mm Remington.

Jim Watson
February 5, 2006, 03:19 PM
What kind of target shooting? Neither 6mm Rem nor .243 Win are usual choices for the sorts I have done, but they are accurate enough and are decent deer loads.
If you are not going game hunting, I suggest you look at a .223. It is accurate and has more selection and lower price on ammunition. But don't try to cheap out too much on ammo, the common fake surplus FMJ is fair to poor. I have read that the WWB 45 grain JHP is quite accurate, though.

February 5, 2006, 07:30 PM
The 6mm is a little hotter and I have found it to be a little more finicky to load, with 70 gr bullets the range of powder loads is narrower than the same bullet than 243 to get the peak accuracy. It could be the gun that’s for sure the 6mm is a Ruger V77 heavy barrel and the 243 is a Rem 700.
Between the two the Ruger 6 shoots larger bullets a little better. Of the two the Ruger has been introduced to a lot more ground hogs than the Rem has.
I have one that I took at over 350 yards and it was witnessed by a friend. Personally I thought it was more luck than anything else, but it did take a second shot, first over shot him.
Both are very good cal but if you don’t reload the 243 will probably work best for you, loaded ammo for the 6 is a little scarce around here.

February 6, 2006, 01:25 AM
Type of target shooting would be offhand, kneeling, seated, prone and bench.

Although the 6mm or 243 isn't the usual choice of target shooting I was trying to select something that was low recoil. Also had in my head that I needed something with a heavy barrel in the 26 inch lenght.

Originally wanted a 6.5x55 (not mil surplus) but found the rifle selection limited.

Kind of decided against the 223 because of the lighter bullet weight.

Being new to shooting I took alot of info and funneled it down to this choice.

All the help is greatly appreciated.

February 6, 2006, 12:50 PM
You could also look at a .260 remington (6.5mm) its the same case a .243 but slightly larger bullet and it is supposed to be incredibly accurate.

February 6, 2006, 02:29 PM
Remingtons VLS .243 has a 1-9 1/2 twist 26" heavy barrell<>free float, takes the 107gr bullet, kinda hard to beat especially for the price .. if you were so inclided to get one, i'd be looking for in stock on your dealers shelfs at ser#'s
a prefix letter E or F not sure which .. the action was made by Colt .. as i was told .. at 200yrds w/ a 90gr bullet holding 3/4" could put mine in a target shooter class as 243 isn't usually consider as that .. don't see the reason for a 6MM unless your gonna build a custon gun for big buck .. shooter choice .. thats why theirs so may to choose from

February 6, 2006, 02:37 PM
The .260 is another fine choice, IMO. Anything 6.5mm is pretty popular as a target round, and the .260 or 6.5-08 is fairly common among the Match Rifle shooters around here.

There are downsides however. 1) It is a reloader's cartridge, realistically. 2) Kicks more than a .243, thus requiring greater concentration to shoot well (though this isn't exactly a huge thing; most shooters can contend with the recoil of the mild 6.5s quite well). That's about all of the negatives I can think of actually.

Is this target shooting formal NRA Highpower events or just for fun? I ask because the .223 is another great target round, and if you are a reloader it has an astonishing amount of versatility. I and many others routinely fire AR-15s at 600 yards in Highpower matchs. Some people use 77gr magazine length loads, others of us use specially loaded 80gr slugs. Either bullet requires a 1-8" twist barrel as a minimum, which rules out the majority of factory bolt guns I know of.

Barrel length also only seems important if you are shooting irons. Otherwise that 26" heavy barrel is going to get, well, heavy. Shorter barrels are preferable IME, so long as velocity levels are adequate to remain supersonic all the way to the target.