Hello Guys,
As some of you Guys know my main varmint rifle is a custom 6PPC which is incredably accurate but when the wind starts to blow out comes my SAKO 75 stainless varmint in .243, this gun shoots 87 V Max's in the 3's and around an inch at 400 yards on a good day.
I'm considering building a .243 Imporved or 6mm Rem Improved on a Remington action and a 26 inch 1 in 8" barrel to shoot 87 VM's & 105 A Max's.
Two questions:
Considering I have good Lapua .243 brass already will a 6mm IMP give me any better performance than a .243 IMP ?
As my .243 already shoots 87 VM's very well at 3180 fps am I really going to gain that much more velocity and accuracy with an Improved?

Cheers Guys.

Steve.

First off all 6PPC Varminter welcome back,
Did you have a nice time in canada ?
as for your question to 243 or 6mm rem (this is not going to help your query sorry) im am looking at the same idea,
I have also got my CZ shooting those 87grn V MAXes very accurately so im hopeing to give you a good run at pickering in september LOL
when you find out the info your after drop me a email
thanks Mark

As a guy who shoots both the 243 and the 6mm Rem, I see no advantage to the AI's especially since they provide an extras step. I don't see signifcant advantage especially with varmint weight bullets. Velocity gains are minimal if at all.

I have acquaintances who shoot both and at the chronographs we see minimal difference. both are efficient cartridges.

I do wish the 243 had a longer neck, but I do prefer the 6mm Rem, if it is in a long action that bullets can be seated out long.

A 6/284 will offer even more than the AI's but in my experience unless the bullet is 105 grains or more the difference in velocity once again is not that much, especially in ratio to the headaches involved.

Both 243 and 6mm Rem I have not experienced a lot of need to trim, which is one advantage the AI is suppose to offer.

Just my experience after walking down that road.

Good luck with the project tho.

Cheers and Good shooting
seafire

I prefer the 6mm AI (and shoot the 243, 6mm rem, 6mm AI, 6mm-284, and 240 Gibbs), but performance wise, it's not that big of a jump, really. If you want a fast 6mm for the heavy bullets, try the 6mm-284, or even quicker, the 240 Gibbs. FWIW - Dan

I had a long reply typed up but I'll shorten it to the meat of the subject......for all the trouble of fireforming vs. the velocity gains.....just leave it be!!! Mr. Ackley was a genius!!! Too bad he didn't get to design the originals!!! Now as far as the ORIGINALS go.....I guess I'd have to rate the 6mm over the .243(and for all those questioning minds, I've probabaly shot more groundhogs with a .243Win than any other round excepting the 22-250) I think the 6mm offers a bit of advantage due to the neck length and it's ability to handle the heavier(105's,107's) than the .243.....albeit and not splitting necks like the .243 is prone to do! Go ahead folks, jump in my doo-doo! hahahahahaha GHD

6PPC,

First off the as a custom rifle builder I would not recommend going with the 243 AI simply because the parent round is already pretty well maxed out except for shoulder angle and that will not give you much at all.

If the AI rounds, the ones on the 308 family provide the least amount of performance increase of the lot.

That said, the 6mm AI will give you about 150 fps over the parent 6mm and around 200-225 fps over the 243. If thats worth it to you then I would do it.

Here is another idea, I just built a 6mm-06 for a customer using a blue-printed Rem M700 BLD with I fitted with a 28.5" Kreiger 4 groove barrel with a 1-9" twist and bedded it in a H-S Precision 2000 Police/Sniper tactial stock.

I have been getting range reports ever since with the followign results:

55 gr Bal. Tip
4350 fps
groups in the high 1's low 2's

70 gr Berger HP
3980 fps
groups in the 3's

105 gr Hornady A-Max
3450 fps
groups in the 3's

These are not top loads with the 105 gr bullet either. He is going to try some slower powders to fill the case better and see what he can get.

This round is impressive as it whoots bullets from 55 gr to 105 gr all under .300".

Brass is cheap, it feeds far better then any AI round and there is a good supply of match quality brass for the parent case.

Just another option to think about.

Another one is the 22-6mm AI. Just built one of those and it shoots the 55 gr Sierra Blitzking at 4200 fps out of the Ruger factory 26" barrel on the M77VT that used to be a 220 Swift. The factory barrel still groups in the 4's with that load.

I am building on for myself on one of my tuned M700 actions and using a 30" Lilja 1-8" twist barrel. I will be using the Berger 80 gr VLD loaded to around 3600-3700 fps.

Another option to cloud your judgement with. This hot 22 runs with most 6mm rounds, except the 6mm-284 and up.

Good Shooting!!!

50

When more performance is wanted and your near bore capacity it's not a bad idea to look at a larger caliber.

The 6.5 mm's have many sleek bullets and the bore will last a lot longer.

One of the nice things about the AI you can normally varmit shoot with a fireform load as not to waste the barrel. On my AI's I normally get an average 100/150fps more plus alot better case life. If comparing a custom 243 say to a 243AI don't think you would see any improvement in accuracy but may if comparing a factory rifle. I've been shooting a 243 since the 60's still have that rifle but have done acouple 6mmremAI. On comparing my custom 243 to my 6mmrem I have found alittle better velocity and day in day out shooting the 6mmrem gives alittle better accuracy two of my 243 have a 1/10 twist barrel the other a 1/12 my 6mmrem one has a 1/14 the other 1/12 both my 6mmremAI have a 1/10. I prefer the 95 gr bullet in the 6mmAI. For PD over 500 yds I'll go to a 6x284 and will try a 6.5x284 next month. One of the problem with the 1/8 twist barrel may best performs with lvd bullet. I shot a 6x284 and 6br with a 1/8 twist barrel but never tried anything but lvd bullets so don't really know how they would do. I've always figure when I changed things with a varmit rifle it's got to have an advantage and for me with the AI there has been. I know alot say well 100/200fps isn't much but in a varmit rifle that adds yardage and I like the case life get less brass flow. I say build what you want get a long enought barrel and if it's not what you really thought it should be then rechamber it . I'm having a 6x22-250 done up with a 1/14 twist barrel and it it doesn't get the velocity I think it should well it will become something else. Well good luck.

Savage99,

The 6.5's are mighty big to be using for a varmint round, unless its a dedicated long range rig then I would agree with you.

I would not recommend overlooking the 25 calibers before jumping to the 6.5mm rounds. The 25-06 and its AI brother are very impressive varmint rounds.

Good Shooting!

50

When 6mm PPC suggests a 105 AMax then one might conclude that richocets are not a problem or considered. Also that expansion is not all that important on whatever varmint is being shot at. Having been to Northern England and having talked to gunbuilders and gameskeepers there I am guessing that the varmint is foxes. There may be something else to shoot at but I don't think they have a lot of rodents.

The foxes I am familar with are rather easy to kill and therefore an AMax bullet may do the trick.

I view the overbore 6mm AI's and wildcats as a gunsmiths money maker. If one hunts with a laser rangefinder and some data from a ballistics program one can do what long range shooters have been doing for a long time now and hold or click off the right amount. A barrel burning overbore wildcat is not going to last all that long if a load is ever developed at all for that matter.

I am not going to discourage someone from having fun with improved cartridges or wildcats but standard cartridges that have a long history of load development are much easier to live with.

If one looks at the variables that are most difficult to figure out it is wind drift. Take another look at the 6.5mm's and you will find that they have bullets that drift less. Laser in the distance and your all set trajectory wise.

The .25 cal is not very popular overseas or elsewhere for that matter so I skipped over it. Of course it's a move in the right direction.

In conclusion the first thing I would do is optimize what I already have. A 243 shooting a 87 gr VMax with a Ci of .4 is pretty good at the posted velocity. So if a laser and data is not being used that's the path of least resistance.

Savage99,

If what you say is correct about the foxes being the majority of targets, why use anythign larger then a 22 caliber round.

One could take a standard 22-250 with a fast twist barrel of 1-8" and shoot the great Berger 80 gr VLD's which have a B.C. of around .5. The 22-250 will drive these bullets just as fast as the 243 would drive the 105 gr A-Max bullet and with identical B.C. numbers.

I just am having some trouble understanding your logic.

Foxes surely do not need a 6.5mm bullet to shoot well and there are many bullets on the market today in 6mm that will rival the 6.5mm bullets in B.C. unless you get into the real heavy weight VLD's in the 6.5mm which are pretty poor varminting bullets.

Good Shooting!!!

50

Steve,

I realize this is not one of the options you listed, but I have to agree with Fiftydriver, check out the 25-06 or the 6-06. Hornady makes a 75 grain V-max that has been shooting very well out of every 25 I have been around.

FWIW, I gave my .243 varmint rifle to my Dad after I built my 25-06.

If you haven't prchased a short action yet, I would reconsider...

Later, pdhntr

Hello Guys,
Thank's for your views, it appears that the general opinion is that as my SAKO shoots so well in the first place I am not really going to gain that much velocity if I stay with the parent .308 case. 200 fps is not worth spending the �1000 on the project so I will stay with the great rig that I have and have SAKO fit a set trigger then pillar bed the action or possibly drop the action into a McMillan. I missed a Remington VSSF in 25-06 at my local gun store yesterday, sold an hour before I arrived and at a very resonable price, it would have made a great doner for a long action varmint gun project. Still there will be others.

Thanks.

Steve.

6PPC,

Most people in the USA don't have a clue how much a thousand English pounds are.

Not many people in this country would spend $1800.00 or so, just to go from a 243 to an Improved case.

I don't think we Americans realize how fortunate we are for prices for firearms in our country compared to foreign countries.

6PPC brought it home for me, once again.

ONe day this hobby will only be for the mega rich people.
Like Kathi's post on the big game forum about the Two clowns that were busted for Drugging Deer for rich clients who paid, $4k to $20K just to shoot a deer!

Amazing, simply amazing!

cheers,
seafire

I must say I like the 25-o6 as a varmint round. It was very accurate but the barrel didn't last long. A stainless barrel may have given longer barrel life. what do you think fiftydriver?

6mm Rem., it has class and not everybody has one. No need to improve. Lou