6mm or 243

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by bulldurham, Feb 21, 2007.

  1. bulldurham

    bulldurham Well-Known Member

    Feb 18, 2007
    i am looking for a good coyote gun , which one would be good to use . i have been thinking 243 becuase i have the dies , but would like the 243 ai . was told to go with the 6mm. any suggestions.
  2. screech

    screech Well-Known Member

    Nov 26, 2005
    From what my short memory says, the 6mm has a longer neck. I dont know if that really makes a big difference but it might. not really sure it does but I think it does. For yotes, I really have no sugestion because every yote I have shot that was shot with a gun smaller than a 6.5x284 ran away. Ask Remington 25-06. That guy seems to be able to kill the things with a .177 cal pellet gun almost. /ubbthreads/images/graemlins/confused.gif /ubbthreads/images/graemlins/confused.gif /ubbthreads/images/graemlins/confused.gif He uses 222 loaded with 55gr. bt coyote does bang flop. I use 22-250 with 55gr. bt and I have three run away. /ubbthreads/images/graemlins/confused.gif /ubbthreads/images/graemlins/confused.gif /ubbthreads/images/graemlins/mad.gif

  3. Willys46

    Willys46 Well-Known Member

    Oct 4, 2006
    I shoot the 6mm Rem and love it. I get .5moa out to 300 with 70gr NBT @ 3476fps. The factor ammo is very limited for the 6mm, reloading is a must. Quality brass is limited aswell (REM and Win). The rem brass takes alot of prep.

    Both would be great choices if your not after pelts!
  4. mindcrime

    mindcrime Well-Known Member

    Jun 14, 2002
    I have a 6mm Ackley built by Darrell Holland (www.hollandguns.com) and my dad has a factory VS 6mm Rem with the barrel shortened to 22 inches (mine is 27" + break). Dad's routinely shoots 1/2 MOA, while mine averages between 1/8-1/4 MOA with its heavy varmint barrel contour. We have also had a .243 Win, but after shooting BOTH cartridges, we both seem to prefer the 6mm Rem. I prefer the 6mms longer neck. Just my $0.02. /ubbthreads/images/graemlins/cool.gif
  5. CatShooter

    CatShooter Well-Known Member

    May 8, 2001
    I am having a 6mm built - I first was thing of a 243 Win, but after looking at the loading data, and the case design, I went with the 6mm Rem - I got the Ackley Improved version. Of the two cases, the rem case is better designed with a sharper shoulder, it has more volume and is a faster round.

  6. remingtonman_25_06

    remingtonman_25_06 Well-Known Member

    Jun 4, 2003
    Your really splitting differences for a yote rifle. The 6mm is what about 100fps at the most 150fps faster then the 243? I dont think any coyote is gonna know the difference there. If you have the 243 brass and dies, I would go that route, the 243 AI is just as fast as the standard 6mm. I"ve killed quite a few with a 222 and 40/55g bullets out to 250 yards w/out any problems what so ever. You cant go wrong with either really, like I said, a coyote aint never gonna know the difference. I would think the perfect yote gun to be a 243 AI and shooting the 70-80g btip. I think that would be a tough combo to beat.

    BTW- Isn't a 6mm kinda middle of the road between being a short or long action??
  7. James H

    James H Well-Known Member

    Jan 15, 2006
    As Remingtonman said the 6mm Rem is not a true short action ctg.
    Lapua brass is available for the 243Win.
    I would go with the 243Win.
  8. .25AOD

    .25AOD Well-Known Member

    Feb 12, 2007
    Now me and 25-06 seem to see eye to eye on a lot of things... but I'm gonna have to say that the 6mm kicks the .243's a$$ up and down the block! Having owned a number of .243s, 6mms, and 6/284s I would have to give the 6mm the #1 spot. I've never really run into any problems with action length... sure, occasionally I'll have to seat some heavy bullets a little deeper to fit them in the magazine, but they still shoot well. Also, the velocity difference is more like 150-200 fps... not enough to make a difference to a coyote... but enough to make a difference to me!!
    I will concede the factory ammo advantage to the .243, but that's all I give it. I have a .243 for sale now... I'd keep it, but my old 6mm BDL-V is just as accurate, 200fps faster (w/2" less barrel), and has been with me since high school.
  9. bulldurham

    bulldurham Well-Known Member

    Feb 18, 2007
    thanks guys for the info.
  10. biff's reloading

    biff's reloading Well-Known Member

    Jun 12, 2006
    243 with the 55gr b-tip. the 6mm doesnt do any more than 100fps better. sure u can get 200fps more from a hot loaded 6mm than a mild 243, but its no 6-284. if absolute speed is an issue, then neither 243 or 6mm is the gun for you. u need a 6-284 or 6-06. the brass is way better for the 243. the factory loaded ammo is non existent for the 6mm. with all the work that you will put into the 6mm why not get a 6-284? it has good brass at least..... they are both good, but my vote definately goes for the 243.
  11. keithcandler

    keithcandler Well-Known Member

    Jan 30, 2005
    The biggest problem is finding a gun in 6 Remington......

    If you are having one built, the 6 Rem will shoot the 80g Sierra Blitz Bt at 3600 fps with Max loads of IMR 4064 and R#19.

    The 243 will shoot the 80g Sierra at 3500 fps with Max loads of IMR 4064.

    The 6 Rem will shoot the Sierra 60's at 4000 fps using 49.5-50g of 760 into very tiny groups, while the 243 shoots the 60's at 3800-3850 with max loads of 760.

    I Have shot out the barrels of many of each on dog towns. Cases have to be trimmed more on the 243 than the 6 Rem, and the Bonanza neck sizer used as a shoulder bumper on both will lengthen case life considerably.

    The 6mm Rem does present some problems for guys that like shooting from the magazine. The 6mm Rem is the cartridge that first got me into having zero freebore reamers made. The 6mm Rem is really a long action cartridge if you want to use the magazine and chase the lands as the leade grows. I shot out many Ruger and Remington Varmint's in 6 Rem and shot them as a single shot.

    In factory rifles, I think that it is a waste of money buying Lapua brass unless you are a long range match shooter, the chambers are so sloppy in factory rifles that you can not take advantage of the small advantage that the high quality brass gives you. Good brass does not make up for a sloppy chamber. I shoot exceptional groups in my 700 sporters with Rem, Win brass, and PMC brass. If your rifle likes Lapua brass, more power to ya, but you can't make up for a bullet that gets started crooked as it starts to obturate in the lands. I have one 243 that demands Rem brass and another that likes Winchester brand of brass or PMC. These sporter rifles shoot 1 1/2"-2" at 300 yards.

    I have had more than a dozen Match quality 243 Ai's and only two 6mm AI's and the 243 AI's win hands down in being user friendly in load development with all kinds of bullets and powders. The 6mm AI's that I have had were picky and had a shorter range of powder charges that would shoot in the Sweet Spot of accuracy.

    The 6mm AI is about 200 fps faster on the lighter bullets when compared to the 243 AI when loaded to the point to where you did not have to full length size after every firing. The gap between the two AI's shorten up as you load the 243 AI to full tilt.

    The discussion of which is better will go on forever. I would probably make the instant decision based on which one I could get at the best price, knowing that I was going to have to load the 6mm Rem single shot to get the best accuracy out of the rifle.

    Good luck!
  12. MagMan

    MagMan Well-Known Member

    Dec 20, 2002
    Re: The biggest problem is finding a gun in 6 Remington......

    Keith, what are your thoughts on the 6mm 06.
  13. blackco

    blackco Well-Known Member

    Jan 19, 2007
    I grew up on 243's; now I have 2 6mm's (all out of the box factory rifles, sorry). I think they are the "Hammer of Thor" /ubbthreads/images/graemlins/grin.gif on everything up to mule deer, including coyotes, and mine have made quite a few caribou get all loose inside also.

    Anyways, if all things such as price/availability/etc. were the same I would definatly take the 6mm for the 100-300fps advantage. But since you are already set up for the 243, if you can get one of them, take it and never look back.

    After a few long discusions with my gunsmith, I believe both of these rounds really "wake up" when they are AI'd. Both of my 6mm are heading his way as soon as I put enough in the money jar.

    To make a long story short (too late) I would pick the 6mm for its small advantage but would not feel handicaped at all with the 243; either way I would take it to the gunsmith for a reaming to AI.

    Good luck,
  14. FRANK21

    FRANK21 Well-Known Member

    Jan 16, 2004
    My vote is for the 6mm. Not that it is any "better" than a 243, but its something different that what everyone else has. In my experience, with same bbl lenghts the 6mmRem will best a 243 by 150-200 fps with any given bullet weight.