6x47 Lapua for the shorts 300-600yds/m

[DaveMc]

Now I just have to work out a similar thing for this pile of 7mm barrels I am building.

At the moment I am thinking of running 32 inch as RSAUM for around 1000 rounds then chopping back to 26-28 inch 284 and running 168's for short ranges......?????? mmmmm Perhaps even a 7-08AI????

[Brad Y]

Dave- do you grow tomatos up there at all? I imagine you have a 7shehane brass forming barrel too.

I suppose thats the good thing about the smaller 22 and 6mm cals. Theres always plenty of varmint shooters around that will jump on a used 30" target barrel and make an evil 26" varmint rig out of it.

Has anyone ever checked the value of a dead barrel with a scrap metal place? Would think being stainless it might be worth something???

[ecomeat]

I have kept both my dead 6 x 47 Lapua barrels. They work really well as a "humbling device". Any time i feel a risk of turning into a smart arse coming upon me, i can just look at either of them and get instantly "grounded" again.
Tony

[Brad Y]

Tony- put a patent on that.

I use my wind reading skills as a humbling device. And it works quite well. And often.

[Matt P]

Dave
I just rechambered a 7 x 300 wsm for Rod that had done 4-500 rounds and I had to cut 3.5" off it to find some reasonable steel , I think the RSAUM will be similar so I'd suggest rechambering earlier than 1000 rounds.
The 7 x 300WSM makes the 243AI look good !!!!!!!!!
We also rechambered Ben's 6 x 47 @ 800 rounds and once again 3" had to be cut off, we're going to run this barrel out and see if it's a viable option, it shoots just a well but I have no idea how long it will last.

Matt P

[KHGS]

Gentle People,
My thoughts for what they are worth, I believe the key to barrel life is chamber pressure/velocity/powder charge, these are all closely related. The higher the velocity of a given bullet in a given chambering & bore the shorter the barrel life will be. A lower pressure/accuracy node will give a longer barrel & brass life, this is a fact. When seeking a suitable accuracy node a point to remember if barrel life is a consideration, is that a given bullet must be driven around 300 fps faster to gain .75moa reduction in wind drift in a 10 mph right angle wind at 1000 yards. Of course these figures are approximate & a rule of thumb for illustration purposes only. So why push any cartridge to maximum pressure levels? In my humble opinion the returns are just not worth the cost.
I have had customers get 2000 rounds of accuracy from .243AI & .243 when they developed accurate loads at 2950 to 3050 fps These barrels were in suitable condition for re-chambering, however I do not believe it is cost effective to re-chamber barrels when a competent 'smith is to be paid to do it, better to put the $$$ towards a new barrel.
Keith H.

[DaveMc]

Thanks for the input Keith (with great respect) this is worth discussing. The guys I am talking about don't push the 243AI too hard either and shoot slowly and steadily (which is another barrel killer) and generally rechamber to 6BR at around 1500 rounds. They then typically get over 2000 and up to 4000 rounds out of the next chambering in 6BR. The BR chambering seems to hardly suffer from the previous rounds as these "barrel burners" seem to do most damage in the first few inches (3-6) and they typically shoot very well when rechambered. Add up the costs. Say a barrel costs you 600 and smith $300. $900 for the first chamber and $300 for the second that gets you another 2000+ rounds. Value for shooting even a new BR at $900 you would have to go 6000-12000 rounds to do as well... Of course it is shorter than a new barrel but the BR chambering seems to handle it well. This is one combination that seems to stack up. I agree with you though - not all do.

[DaveMc]

Dave
I just rechambered a 7 x 300 wsm for Rod that had done 4-500 rounds and I had to cut 3.5" off it to find some reasonable steel , I think the RSAUM will be similar so I'd suggest rechambering earlier than 1000 rounds.
The 7 x 300WSM makes the 243AI look good !!!!!!!!!
We also rechambered Ben's 6 x 47 @ 800 rounds and once again 3" had to be cut off, we're going to run this barrel out and see if it's a viable option, it shoots just a well but I have no idea how long it will last.

Matt P

Youch. But I had heard some of the WSM's going south at 500-800 rounds. The RSAUMS reportedly 800 -1500. my typical load is light and only 55.5-56 gr 2209 doing 2920-2950 fps (I have a hotter one but it rarely comes out). Most guys are pushing the WSM to around 3080-3100 fps and burning a lot more powder to do so. I guess my expectations are somewhere between the 284 and WSM on barrel life (hopefully) - fingers crossed - it sure is an accurate cartridge so hopefully we can nurse it through a few rounds - will let you know how it goes. 3 barrels chambered and running and all look good in the throat so far (touch wood) but not many rounds down yet.

[Norm]

Gentle People,
My thoughts for what they are worth, I believe the key to barrel life is chamber pressure/velocity/powder charge, these are all closely related. Keith H.

I think Keith is right on the money with his thoughts on barrel life.

I have some experience with high pressure boiler steam tubes that are made from similar Chro-molly steel to that used in some rifle barrels. With these tubes they are made to operate at a temperature of 560 degrees C. If these same tubes were run at a temperature of 600 degrees C, then their life span would be reduced by 50%.
So just a small % increase in operating temperature can have a huge effect on the life of the components.
It's not hard to see the similarity and how higher powder charges can reduce barrel life through the additional heat that they apply to the metal surface over a longer - "peak pressure curve" duration.

[Chopper]

Good on ya Norm, Like I said , if you want to burn ya chips turn up the gas a little bit , , the photos show it, Well done, Chop.

[BRETT B]

I had a good chat wil Bill Hallam on the weekend in regards to barrell life with the 6mm"s. He told me he normally gets around the 2000 rnd mark before he rechambers on a 6Br and maybe a few hundred rounds less for the BRX etc. He then would usually get another 1500 of excellent accuracy shooting before he would call the barrell Dead or not accurate enough to compete with. As you increase cartridge size like my 243AI barrell life will reduce but he would expect 1500 rds before a re chamber would be required which has been my experience with my last 2 6mm barrels. From my own experience with the hotter 6mm and 22 cals, as the throat wears powder charge and seating depth needs to be adjusted to keep it in its accuracy zone otherwise the groups will start to open up quite a lot. Some barrels are not effected by this as much or even not at all , its really just a lottery but is something worth considering. My current barrell has been the hardest to tune i have ever had and has taken many days up the farm shooting 10 shot groups @300 to find something it really likes and now it is starting to show on the mound with my scores. My old barrell loved 2209 and SMK107"s but this one will hardly hold a 3inch group @300 with a similar load!! throw some Bergers down it and it gets worse Then i ran some LAP 105 down it and got an instant improvement to around 1.5 inch but that was its best. I Threw various loads of Vit down it and nothing improved but finally when it got a dose of Reloader 19 with the LAP 105"s it came to life in a big way. It has now shot several 10 shot groups on different weekends of 22mm @300 or better and seems to do it very consistantly !! Weird since my old Maddco hated Lapua bullets and R19 !! Bullett seating depth also played a big part in finding accuracy with this barrell !! so the point i am trying to make is sometimes you may think that your barrell is dead but maybe!! not allways, it may need a retune to get the accuracy back.. This may not be the case with everyone but may be relevant to some

[AlanF]

Brett,

I believe a big part of what bullet a barrel likes is diameter. Lapuas are generally smaller in diameter then SMKs or Bergers. Bore diameters vary between barrel brands, even between barrels of the same brand.

One inexpensive way of comparing bullet diameters is to see how easily they go into the neck of a fired round (leave the carbon in there). Most projectiles have a "pressure ring" near the back end of the bearing surface.

Alan

[Quick]

Gents,

Well I just bought a 6x47L for FO, it has 176rds on the barrel so just run in should have it withing the next two months I hope. Be interesting to see how long the barrel lasts.

Cheers for the advice guys.

[Brad Y]

[Quick]

Hey all,

Can the gents and ladies who own 6x47 Lapua'a post up there load data for this cartridge? Just so I have somewhere to kinda start and an idea. I could have started a different thread but I thought here would do.

Cheers.