.260 AI, 6.5XC, and now 6.5 Creedmoor!!??? Which One??

[M21SNIPER]

Gentlemen,

After much thought, shooting, and throat erosion, it is time to re-barrel my venerable pre-'64 NM Model 70,currently 30/06 Caliber original barrel).

Fortunately for me, the kind folks at Bartlein Barrels are going to provide me with a 6.5mm 5r Heavy Varmint Blank for the rifle. Talking to my gunsmith, we determined that a 1:8.5 twist would stabilize the 142 SMK well, which would be the heaviest bullet shot through the barrel.

Now here is the problem: my smith' has a 260/6.5-08 AI reamer in his inventory presently. I like the 40d shoulder to a point, but was really interested in something steeper than the standard .308 20 degree shoulder, and I find out that there is indeed a .260 Remington Improved with a 30 degree shoulder available. Then, David Tubb and company spawn the 6XC which is immediately wildcatted to 6.5XC, and now 6.5 Creedmoor!!!

What is a fellow to do? The barrel of the model 70 has a cone face which will aide in chambering and feeding for 80 shot across the course matches, but the .308 feeds like a dream with the 20 degree shoulder. Is there a compromise @ 30 degrees with the 6.5 Creedmoor and the Tubb 6.5XC? Is the 40 degree shoulder on the AI cartridge reliable for 80,actually 88) rounds across the course, or will dirt and fouling lead to problems with that steep shoulder? Is 40 degrees too much for an across the course rifle? Barrel life and case life are probably amazing with a 40 degree shoulder, but will it reliably feed under dirty match or tactical conditions?

The other issues are of course $$$$$$, as my smith' has the .260 AI reamer, and long term accuracy data on the 6.5XC and now this 6.5 Creedmoor. The .260 AI appears to be time prooven in the short action category, but fire-forming brass is not something I'm looking forward too. The 6.5 Creedmoor appears to be able to be formed out of 22-250 brass????? Seems easier than buying,$$$$$!) 6XC brass to only neck up to 6.5XC. Any thoughts from an economy standpoint?

Any suggestions as to the extended use reliability and long term accuracy of the 40 degree shouldered .260 AI would be appreciated, as well as any data on 6.5XC and the new 6.5 Creedmoor rounds would be greatly appreciated. My gut says stick with the prooven .260 AI, but the stepped up 6XC to 6.5XC and the new Creedmoor cartridge are very interesting indeed.

Thank you for your time and good shooting!

Regards,

Matt

 

[rhino]

Neither of them.

6.5x55 SE and never look back

RHINOUT!

 

[Spotcheck_Billy]

Neither of them.

6.5x55 SE and never look back

RHINOUT!

I was lurking here just waiting for you to say that:lol:

 

[Spotcheck_Billy]

Now to get serious

M21SNIPER,

I once had a 260AI on an M700 repeater that wouldn't feed reliably from it's staggered magazine. It fed the un-Ackleyized short rounds very well. This was before the Badger Ordnance bottom metal that utilizes the Accuracy International center feed magazines was in existance.

I'm wondering if the claw,controlled round) extractor and the coned breech on your M70 wouldn't help to allow it to reliably feed a short AI cartridge. It might be worth the gamble to find out!

 

[mysticplayer]

I shoot a 6.5 Mystic which is my version of the 260AI and has a 40deg shoulder. No issue firing ALOT during an F class match without chambering issues. All single fed.

However, I would not recommend this steep of a shoulder angle in a controlled feed action. My orig rifle was a P17 and it wouldn't feed the sharp shoulder. Push feed actions are much more tolerant.

The new Savage center feed mags are superb and will handle a 40deg shouldered case. My short action mag would house a 3.00" rd. I hope someone will start making true 5 and 10rds mags.

So back to the 30deg shoulders wildcats. Decide which bullet you want to shoot and how fast you want to go. If the 139/142gr bullets are what you want to shoot, the 'best' case is the 6.5 Swede for both velocity and feeding in a staggered mag,similar capacity to the 260AI/Mystic).

The XC, Creedmore, 47L are not big enough to reach 2900 to 3000fps with this bullet weight. I also don't like running super high pressures in a rifle that must run quickly. One sticky bolt and it could cost you time/score.

I would use a larger case at lower pressures to reach the same velocity/accuracy.

If you want less recoil,ie shoot a lighter bullet) or can live with less velocity, then these mid sized 6.5's are just fine. Personally, I would pick one based off the 22/250 case so I never have to worry about brass availability or cost. The 6XC and Creedmore are similar enough and are based off the 22/250.

I shoot in the cold so do not like the small rifle primer of the 47L. One hang fire and my match is toast.

Wind is my big issue during competition and anything I can do to help reduce drift I take. The mid sized 6.5's simply will not keep up with the larger ones unless you really know how to drive.

Jerry

 

[chrisj]

I don't think that you really need to worry about shooting 142 bullets @ 2900-3000 fps. You can get those velocities from the smaller cases,6.5x47, 6.5xc, 6.5 IHMSA, 6.5/250 AI, 6.5 creedmoor etc. when shooting some of the newer 130 GR VLD,s from Berger, JLK etc. I shot the 130's to the same poi and windage in the smaller cases as i did with the 6.5-284 with 139's and 142's. You will get better bbl life from the smaller cases also.

Good Luck,

Chris

 

[Raptor]

Go with a 6.5x55 if you have a long action, you won't be sorry!! I have the 260 and have had 6.5x284s and with a 6.5x55 you can shoot it as a 260,Which I do) or push it up to shoot right with a 6.5x284 and it "WILL" push the 139 and 142s fast enough for you and it will feed well too. Good luck in your quest!!

 

[Ogre6br]

Neither of them.

6.5x55 SE and never look back

RHINOUT!

Times 2 for the 6.5x55- use Lapua brass and load to 308 pressure levels and enjoy. Will work a dream in you 06 magazine length and allow you to seat long and make use of all the x55 cases powder capacity. With using all the case capacity and seating long in quality brass like Lapua the performance will exceed what the .260 or .260 AI can do. Using the strong Win 70 action you don't have to worry about keeping pressure low like most reloading manuals say. laod up to .308 pressure levels and it takes the x55 into a whole new realm of performance.
In my modern Tikka 695 action using Lapua brass I'm not far behind the 6.5/284,6.5/06) in performance with 140's.



If you really want an improved shoulder version get your smith to chamber up to slightly short with a min spec 6.5x55 reamer and then clean out the shoulder and a bit of case taper with a 6mm BR reamer to 6.5x55 slight crush fit headspace.
Gives a nice 30 Degree shoulder, halves the factory taper of the factory x55 case while still having enough to ensure great feeding. Nice long neck to hold the projectile in alignment.
fire form up a couple of cases with mid level factory x55 loads and neck size em, then fire again and then send the brass to Hornady and get them to make you a custom New generation bushing die set. Hornady do great work and are less $$ and reportedly quick turn around.

later
p

 

[M21SNIPER]

Gentlemen,

Wow! Thank you all for commenting on my subject. I apologizing for not replying sooner, but my wife just gave birth to our 2nd child,a boy-safe and healthy) on November 20th, so I have been VERY busy worrying about everything else, and not my re-barrel project.

This will be my first wildcat, so I am really nervous about a 40d shoulder being capable of 100% reliable feeding/chambering in an across the course/F-Class rifle. I am also a stingy SOB,see note about 2nd child above: 2nd Child= $$$$ Money and Time Lost although he would need his own rifle eventually of course, right?) and I am really concerned about throat erosion and barrel life.

How is the 6.5 x 55 with barrel life and throat erosion? Is a 22-250 case necked up to 6.5mm and a 30 degree shoulder a named cartridge? Is it essentially a 6.5XC? The economy of necking up 22-250 brass to 6.5mm seems like a sound practice, and the 22-250 has the same head size,0.473) as the 30-06 and the .308, correct?

Is the 22-250 case necked up to 6.5mm capable in terms of powder volume and efficiency to get the 107, 120, 123, 139, 140, & 142 grain bullets up to speed for 600+ yard shooting? The reason I like the original .260,other than the shallow 20d case shoulder) is that it is a necked down .308 with decent case volume in an efficient case design. Is the 6.5 x 55 an efficient case design? It would appear to be a little long, with regards to case efficiency.

All of you comments and postings have once again started the gears turning in my head. Maybe I will just utilize the .260 Remington w/ 30d Shoulder and bite the bullet on buying the reamer outright for this particular project. I believe there is some merit in being able to produce custom wildcat dies from standard military cartridges,.308).

I will definitely take a look at the Swede and review chambering concerns with my smith'. I originally thought the cone face and controlled claw feeding would be beneficial, not a hindrance.

Thanks again gentlemen. I hope everyone had a wonderful Thanksgiving. Talk to you soon.

Regards,

Matt

 

[Raptor]

Matt,
I belive the 6.5x55 is @ 57grs of water,If memory serves me correctly) compared to a 260 case @ 54grs of water. I read somewhere that the 6.5x55 is the ideal case capacity for the 140gr 6.5 bullets.

A fellow shooter who got me on to the 6.5s years back said that in Norway they were getting 5000 to 6000rds out of their rilfes when used with factory match ammo. If you load them hotter they will not last as long but they are capable of good barrel life also.

You may want to wait for a few months to see what the Hornady 6.5creedmoor will do. Its 53grs for case capacity. I would stay away from the 22-250 case and the 6.5 bullet. My son has the 6-250 shooting 105s and he has problems with stiff bolt lift at the worst possible times.

I have a 6.5x55 and a 260 and have had several 6.5x284s and the 6.5x55 is a very nice compermise between the 260 and the 6.5x284. It feeds like a dream and can be loaded to either 260 or 6.5x284 velocities.

 

[Rust]

OK, the sweet spot for the 139 to 142 gr bullets is right around 2950 FPS, there is another up around 3150 but that is a seriously hot load in a 6.5 X 284 and past the capabilities of any of the smaller cartridges. A .260 AI and 6.5 X 55 will hit 2950. The thing is, at that velocity both of them will be hot enough to have a barrel life a little better than the 6.5 X 284 as far as gilt edged accuracy goes.

As far as feeding issues go, the Swede will feed fine, there may be some issues with a 40 degree shoulder with the .260 AI.

So I'll put it to you like this, the 6.5 X 284 and 6.5 X 55 have Lapua brass available out of the box. Neck thicknesses have been uniform enough that I went with a fairly tight no turn neck on the 6.5 X 284, basically inspect the brass, iron the necks, touch up the chamfer, load and go to a match. The Swede would be the same. And no fireforming to blow out shoulders.

I like that concept since for the last few years I haven't had just a whole lot of spare time on my hands.

 

[DesertLefty]

M21,

With a long-action gun there is absolutely no reason to choose a chopped-off little round like 6.5XC or 6.5 Creedmoor,untested) or 6.5x47 Lapua,fantastic!). All of these were designed with the primary purpose of shoehorning long, pointy bullets into a SA magazine. You don't have that worry.

You'll get better feeding, better ballistics and longer barrel life with something bigger. I too think that 6.5x55 or some variation thereof would be an excellent choice.

I had an improved version called "6.5 Vais" that served me VERY well out to 1000 yds. Only problem was that my gun was a short action. You can see a photo at: http://www.websitetoolbox.com/tool/post/6mmbr/vpost?id=2141880

 

[M21SNIPER]

DesertLefty & other 6.5 Swede fans,

Point well taken on the 6.5 x 55. It's powder capacity, flat trajectory, and suitability for the long action are without question......

BUT, that all being said, the Model 70 in 30/06 is a 0.473" bolt face, where the 6.5 x 55 is definitely NOT! I am trying to put all of my money into the barrel and action blueprinting & chambering, and I don't want to alter the bolt face of an original pre-'64 Model 70.

I do however, want to look into more of a short action cartridge with regards to OAL so as to be able to modify the bolt stop to allow a shorter throw. The intent here is to be able to hold consistent stock or cheek weld, while being able to cycle the bolt and not have to change natural point of aim/hold of the rifle while working the action. That, and the more efficient case design of the .308 short action parent case made me focus on the 6XC, .260 Remington and its wildcat successors,6.5XC, 6.5 Creedmoor, and .260 AI.

Any thoughts for this viewpoint? Any other cartridges with a standard 30/06 or .308 bolt face that can obtain the required 1000 yard velocities, with essential a Short Action bolt throw length?

I would really be interested in sticking with the 0.473" bolt face, and keeping the cartridges as short as I can, so as to focus on natural point of aim and proper position. I am a firm believer in the short, squat, efficient cartridge,6mmBR, etc.) and trying to maximize barrel life as much as possible.

Thank you all again for your valuable input. It is wonderful to see this many dedicated shooters focused so intently on their sport.

Regards,

Matt

 

[tbeasley]

M21Sniper
Since there has been alot of other calibers thrown out there, I'd might as well throw in the 260 Rogue. This caliber is much like the 260AI version, but with 37 degree shoulders. The action was a Savage long-action that was chambered in 30-06. I have a 1-8 Broughton @27" barrel on it now and shoots 139 Scenars into 2"@600yds. I can hit a quarter 4 out 5 times at 400 if the wind is calm enough. The caliber feeds great with the Savage action, not sure what it might due with your Winchester. I can get 2950 fps with the 139 and recoil is not bad at all making a fun gun to shoot matches with.

Earlier someone was comparing smaller cases and and then compared the larger ones and mentioned the 6.5-284. This is just me, but the 6.5-284 is in its own class. The cartridge takes like 51-53 grains of H4831sc and the 260AI and Rogue take 47-48 of the same powder. The 6.5-284 is like the HOT-Rod of the 6.5's and fireforming the 260 Rogue using the Cream-of-wheat method iseasy and very cost efficient and nearly zero wear on the barrel.
Hope your confused even more on which caliber to decide to go with Really it boils down to what your planning on doing with the rifle, I personally like my cartridge that I'm using and honestly didn't know of a 260 Improved, It very well may get your 139-142 to just at 2900,maybe even alittle more.
Just Have FUN !!! with IT!!

 

[Spotcheck_Billy]

M21SNIPER,
You should physically check the Swede cartridge and its relationship to the boltface on your M70 before you reject it out of hand. There isn't a heck of a lot of difference between the .473" diameter of your .30-'06 and the .476" diameter of the Swede. Given the normal production tolerances found in mass produced firearms I'd bet that you'll find that the Swede will function just fine with your unaltered '06 boltface.

I've not personally tried the Swede in an M70, but I can attest to the fact that it will work without any problems in the vast majority of M700's. Try it before you give up on the idea.

 

[M21SNIPER]

Gents,

Any improved cartridge is going to take a heck of a lot of work for me to make/fireform from virgin .260 brass. And then, unless you are necking up .243 Lapua or other good brass, you are stuck with R-P cases as the sole supplier for your brass.

I think when we look at the 30 degree shoulder of the 6.5 Creedmoor, 6 & 6XC Tubb cartridges, and even the 6.5 x 55mm, they all have steeper, but not too steep, case shoulders. I am sure the 6.5 x 55 is a more potent cartridge, although it is a little long in OAL for my preferences, but it is a factory cartridge with excellent sources of brass,Norma, Lapua, etc.).

If Hornady is making the brass, will only Hornady be the one to produce it? No one makes the .260 except Remington. Hopefully, someone else will start manufacturing the brass...competition is a good thing.

I really like the 06' bolt face, the slightly shorter case than the .308, the projected barrel life based upon the efficient 30d case shoulder, and the economy of powder while still getting the bullet supersonic to 1000+ yards.

Other than purchasing the reamer, it would seem that the 6.5 Creedmoor is a pretty solid contender for this rifle. I will keep my ears open if any additional testing is being done with this cartridge and go from there. If Dennis DeMille is using and winning with it, I can rest assured that it is an inherently accurate cartridge.

Thanks again for all of the advice and expertise fellas. Good shooting!

Regards,

Matt

 

[mysticplayer]

If you are building this off a pre 64 Model 70, then you are dealing with a CRF action.

STay away from any sharp shouldered cartridges ie over 30deg. Odds of jamming up are high.

Also, keep your OAL as close to the orig as possible. This helps ease the chambering process.

Knowing this additional info, I would suggest a 6.5-06 or a 6.5-7X57Mauser.

If you go with a short rd, you may have it jump out of the mag before you want it to. Also, mag blocking and other tweaks might be necessary.

If not attached to this rifle, consider selling it as orig factory. They tend to bring a pretty penny nowadays.

Use that money to build a center feed whatever in the action length you want.

As for 260 brass, I make all of my 6.5 Mystic from 308 Win brand brass. Superb and takes a couple of easy steps to form.

Jerry

 

[DesertLefty]

M21,

That's some seriously good advice from MysticPlayer.

So, 6.5-06 it is! Or maybe just a plain-jane 270 Win using Berger's new VLDs. Or maybe a 280 Ackley? But wait, there's tons of good match bullets in .30 caliber, so why not a .30-06? Oh shit! Now I'm confused again...

 

[treeman]

6.5 swede feeds from a long mag just fine. and i'd bet it also fits the bolt face since it's only .006" larger. i used the swede as an across the course round and it performed well. good luck and have fun!! treeman

 

[3sixbits]

You know here in America we don't give much of a damn what happens on the other side of the pond. The 6.5X55 has been winning matches for decades.

Just got to have something different, try it AI'd.

There is just a comfort factor in knowing that a cartridge that has been around for ever, still gets the job done.

I was just rereading ACKLEY's Vol II about the 6.5X55 and he says that it is just about the bore limit for 6.5mm. After 30 plus years of play with the 6.5, I think he was right.

No it's not sexy, no it's not going to cause extra work. It will however do what you want.