6mm CM...(or something like it)

[redshooter]

SOooooO, I've discovered some new things recently, my rotator cuff irritation is most likely arthritis, and even 10 lbs. of 7.62 Battle Rifle won't tame the recoil to the a point where I'm not whimpering every time I lift my arm over my head for a week after an afternoon at the range. Through some good fortune, I was in the position to replace it before I sold it (it's on the EE, nice deal if I do say so myself!). After 4 days of total focus on figuring out what I should replace it with I settled on the Savage 10T-SR in 6mm CM.

First, to the stated topic, 6mm CM (or similar). I'm a LITTLE concerned about barrel wear, so I'm hoping the 6mm shooters can pass on some wisdom. At this point I'm going to be shooting Hornady 105 HPBT Match over some kind of 4350, or H4831, any compelling reason to use something else, cost is an issue, but if something is that much better it might be worth the expense. Regarding the 105 HPBT, anything to know about them, like to jump/jam etc.. To mitigate barrel wear I'm going to get some cheap 6mm flat base projectiles, and shoot reduced loads with H4895 to train at short range, anyone doing something similar?

Stock mods; any advice as to how best to stiffen up the forend, I'm assuming Arrows/threaded rod, and epoxy? "Get a chassis", might be the ultimate advice, but you may as well be telling me to "use the force Luke".

The magazine...I'm open to ideas here, just not a chassis (unless you want to start a "Gofund Me" Page for me). I see they have a ten round mag for these rifles for roughly the same price as the flush fit 4 rd., if they function well and someone knows where there's stock I'll order one today...

So far 20 rounds down range, 5 to get zeroed, first five 1.147", next ten below. The funny/exciting part is the cold bore shot is in that five shot cluster. It was factory ammo, Hornady 103 ELD-X.

 

[rugbydave]

I'm on my 3rd 6 Creedmoor barrel so I'm starting to accrue a bit of experience with the caliber. Generally the barrel will speed up till bout 150 rds then stabilize. Expect a barrel life of 1500-2000 rds depending on what your accuracy expectations are. Accepted wisdom is that for 105-108 class bullets, H4350 is the go to, for 110s it's H4831SC and for 115s H1000. You can also run H4350 in all 3 classes (and get higher speeds) but the powders I outline will generally give you better ES/SD, or so I've been told. I ran my first 2 barrels with 110s and H4350 (around 3050fps) and am trying the 3rd with H4831SC.

I have no experience with running flat base bullets and reduced loads for close range practice, I just use a .223. I don't know that you'd really save much barrel life. You could also maybe source a second take-off barrel and use one for close range and one for long range? I say that because you could burn up a bunch of barrel life doing land dev for 2 different bullets.

I've got nothing for you with regards to the Savage stock or mags.

 

[scourge18a]

As far as barrel wear, it is what it is and I think Rugby dave is correct on round count. Probably around 2k depending on how hot you run things. It's a small bore caliber so life won't be the best but barrels are replaceable, your shoulder isn't haha.
The Savage has the advantage of prefits if you do burn the barrel out you can just get some gauges and throw a new one on. But my guess is the factory barrel will shoot well, every Savage I have had shoots lights out.
I run Berger 105 Hybrids and started playing with the Sierra 110s, Both using H4831sc and Alpha brass. I have had good luck with both in my Bartlein barrel.
Some people say the slower powder will help a barrel last longer....I don't know what truth there is to that.
As far as the Savage stock....I have a Model 10 PSR in 308 and it's a laser beam in that plastic stock. I didn't go with a chassis since it's my hunting/ beater gun but I did strip it, clean it and make sure to torque everything down. I am very happy with the accuracy from a plastic stock cheap Savage. Mine stays free floated when loading a bipod and I haven't had accuracy issues so I left it.
I am not sure who stocks the 10 round mags but the TRs are nice that they at least use metal mags, not plastic like the 110 etc.
Maybe take a look at the MDT Oryx chassis if you wanted something more budget friendly and then use the AICS or MDT mags

 

[iain.quayle]

nvm

 

[Suther]

I'm on my 3rd 6 Creedmoor barrel so I'm starting to accrue a bit of experience with the caliber. Generally the barrel will speed up till bout 150 rds then stabilize. Expect a barrel life of 1500-2000 rds depending on what your accuracy expectations are. Accepted wisdom is that for 105-108 class bullets, H4350 is the go to, for 110s it's H4831SC and for 115s H1000. You can also run H4350 in all 3 classes (and get higher speeds) but the powders I outline will generally give you better ES/SD, or so I've been told. I ran my first 2 barrels with 110s and H4350 (around 3050fps) and am trying the 3rd with H4831SC.

I have no experience with running flat base bullets and reduced loads for close range practice, I just use a .223. I don't know that you'd really save much barrel life. You could also maybe source a second take-off barrel and use one for close range and one for long range? I say that because you could burn up a bunch of barrel life doing land dev for 2 different bullets.

I've got nothing for you with regards to the Savage stock or mags.

110s at 3050fps? That's a bit faster than I thought the 6cm was? Is that a typical velocity for that bullet in 6cm?

 

[scourge18a]

110s at 3050fps? That's a bit faster than I thought the 6cm was? Is that a typical velocity for that bullet in 6cm?

Depends on node, barrel length and powder.
I was shooting 105s at 3100 with a 24" barrel. (Close to max)
I'm shooting 3020 ish out of a 22" barrel now and 110s at 2960 from the same barrel

 

[adamg]

No reason you couldn't exceed 223 barrel life with 6CM barrel. Just load them down to the 2700fps and should be good for 10k rounds I would guess.

 

[Johnny Boom]

I'm on my 3rd 6 Creedmoor barrel so I'm starting to accrue a bit of experience with the caliber. Generally the barrel will speed up till bout 150 rds then stabilize. Expect a barrel life of 1500-2000 rds depending on what your accuracy expectations are.

I'm on my 3rd 6 Creed barrel now as well and I concur. I've only been running 105 Berger Hybrids riding H4350.

Rugbydave, do you find that you lose a bit of velocity around 1100 or so rounds and have to bump up the charge slightly?

 

[rugbydave]

110s at 3050fps? That's a bit faster than I thought the 6cm was? Is that a typical velocity for that bullet in 6cm?

I've had them up at 3150 out of my 1st barrel (26" Hawkhill 7.5tw) with zero pressure signs. Backed it down to 3050 figuring on a more stable load. Lost about 50 fps at 900 rds and been stable since then (around 1800+ now). My 2nd barrel I've kept at 3080 fps (26" Hawkhill 8tw) and it's at 900 rds and is still stable (although I'm anticipating a drop off pretty quick here)

 

[rugbydave]

I'm on my 3rd 6 Creed barrel now as well and I concur. I've only been running 105 Berger Hybrids riding H4350.

Rugbydave, do you find that you lose a bit of velocity around 1100 or so rounds and have to bump up the charge slightly?

I lost 50 fps at 900 rds. I've tried increasing OAL (since I track the throat erosion) to see if that would bring back the speed and it never did. I didn't bother increasing powder charge as it still shot well so I left it as is and adjusted my dope instead.

 

[redshooter]

Thanks for the replies gents!

I've been looking for dies, and one of those factory ten round mags (Savage sells them, assuming factory) from one of our sponsors without much success. One had the dies, but what they wanted for shipping was a bit over the top. Anyone know who has one, or both?

I'll be definitely doing some reduced laods. I already shoot H4895 in my 223, and you can make really light loads with it in pretty much any cartridge. Hodgdon's web site has some ref., basically you take 60% of the max charge of H4895 for a given cartridge listed in Hogdon's online data and use 60% of that as your starting load. So for a 6mm CM using an 85 gr projectile the max load is 38.8 gr X 0.60 = 23.28 gr. I'm a bit disappointed about the fact that there doesn't appear to be any cheap bullets in the same manner as .224. That said Hornady has an 87 gr HPBT that looks like it will fit the bill. That's assuming I can find them bulk, if I can't just may as well shoot the 105's if I buy them 500 at a time. As for working up a reduced load and barrel wear, I'm assuming about 2400-2600 fps for an 87 gr. If that was all I shot that barrel would last a long time.

I noticed there isn't too many 5/8 24 6mm brakes available, any reason not to buy one for a 6.5mm?

 

[rugbydave]

I noticed there isn't too many 5/8 24 6mm brakes available, any reason not to buy one for a 6.5mm?

The loss of recoil reduction from running a muzzle brake with a larger bore size isn't noticeable. I run one of mine with a .30cal brake and the other 2 with 6.5s. Insite's new Heathen has different size end caps that you can swap in and out for different calibers.

 

[Mystic Precision]

Thanks for the replies gents!

...

I noticed there isn't too many 5/8 24 6mm brakes available, any reason not to buy one for a 6.5mm?

The size/ volume and venting style of the brake will have a larger effect on recoil reduction vs the central port diameter. Been there and tested the various bores vs bullet diameter. There was very little difference in using a 30cal brake in 22 to 7mm barrels vs a calibre specific brake. There are also muzzle brake tests on youtube to back up my experience.

Note that a brake with a calibre specific insert at the end, still has the ports THROUGH the brake very large (assume they are 30cal... maybe larger???) ... so it really doesn't change the effective porting of the brake.

Arguably, the exit port should be the largest to ensure the bullet doesn't have to thread the needle while the rifle is in recoil.

YMMV...

Jerry

 

[8 ball]

6mm Creedmoor is truly an outstanding cartridge! I do not have high round counts through my rifle yet (AI AT with an Insite barrel) so can't comment on barrel life, but I can attest to the fact that velocities, as compared to the 243 Win are impressive. This using standard book data. The ability to push a 105-108 class vld bullet at speeds as fast as or faster than nominal 100gr speeds out of a 243 Win, coupled with accuracy that is really almost beyond my ability at this this time, makes for an extremely pleasant round to shoot. My 308 Win barrel is gathering dust!

 

[Crashman]

I am running a 6XC, very similar to the 6CM. I am at about 300 rounds now on my barrel. It got faster to the 150-200 round count and has now stabilized. I am running the 115 DTacs at 2950(ish) and it is very accurate at that node in this rifle--oh yeah it is a Tikka T3 with a Benchmark 7.5 twist barrel installed by Insite Arms with one of their Heathen muzzle brakes, sitting in a McMillan A3 adjustable. I almost wish I had gone with the 6CM if for no other reason than to have factory ammo available for those times when I can't get to the reloading room. I love reloading but with work and family it is hard to spend much time there anymore.

 

[kthomas]

I really don't understand the purpose of this exercise. Why completely neuter a cartridge, to do what it wasn't designed to do?

I would sell the barrel and pick up a 6BR barrel for your gun. Excellent accuracy and easy to handload for (lots of proven recipes, easy to find a great load), excellent consistency, and great barrel life (3000+ rounds). Makes a lot more sense than completely neutering a 6 creedmoor, in the hopes of finding a good reduced accuracy node and increased barrel life, which IMO, would still pale in comparison to a 6BR.

The 6BR is an excellent cartridge, and sounds like it would serve your purposes perfectly. You should be able to recoup some money by selling the barrel (especially if it still has a low round count - I'm sure there's lots of interest in a 6 creedmoor), and you are not stuck trying to smash a square peg in a round hole.

 

[Ryan.M.Anderson]

I noticed there isn't too many 5/8 24 6mm brakes available, any reason not to buy one for a 6.5mm?

GBT has Area419 brakes with that threading and hole diameter.

I have 2 - great product.

 

[scourge18a]

I really don't understand the purpose of this exercise. Why completely neuter a cartridge, to do what it wasn't designed to do?

I would sell the barrel and pick up a 6BR barrel for your gun. Excellent accuracy and easy to handload for (lots of proven recipes, easy to find a great load), excellent consistency, and great barrel life (3000+ rounds). Makes a lot more sense than completely neutering a 6 creedmoor, in the hopes of finding a good reduced accuracy node and increased barrel life, which IMO, would still pale in comparison to a 6BR.

The 6BR is an excellent cartridge, and sounds like it would serve your purposes perfectly. You should be able to recoup some money by selling the barrel (especially if it still has a low round count - I'm sure there's lots of interest in a 6 creedmoor), and you are not stuck trying to smash a square peg in a round hole.

This.
Or just shoot the Creedmoor as intended and dont worry about barrel life. Barrels are consumables like brass and bullets. Just put a few bucks away every once in a while for a new one if you burn that one.

 

[Suther]

This.
Or just shoot the Creedmoor as intended and dont worry about barrel life. Barrels are consumables like brass and bullets. Just put a few bucks away every once in a while for a new one if you burn that one.

Except judging by the target in the first post, the OP already has a rifle in 6cm.... He could consider a 6BR, 6BRA, ect on his next barrel though.

 

[kthomas]

Except judging by the target in the first post, the OP already has a rifle in 6cm.... He could consider a 6BR, 6BRA, ect on his next barrel though.

He should be easily be able to sell his Savage 6 creedmoor barrel, especially with that low round count. Wouldn't be hard to get into a 6BR right now.