What caliber for the new build

[Bob259]

Ok, we're coming down to decision time on a HP build and it's narrowed down to three calibers. The 260, 6.5x47 or the 6.5x55. In talking to Evelio he felt the 6.5x55 would be a very good choice. The 6.5x47 components are around 2x the other two and the dies are the same.

Would like to hear comments from the folks who have been shooting HP for awhile to help steer this newbie in the right direction.

THANKS IN ADVANCE!!

[Jim Beckley]

Bob, As I have posted here before my barrel leaning against the wall right now is going to be a 6.5x47 Lapua. I have been shooting a .260 and you can't go wrong with it or the 6.5x55, there are a few around here that shoot a 6.5 benchrest and are happy with it. I think the 47 Lapua fills the void between the .260 and the benchrest.

[Fat NDN]

Go with the 6.5X55 Swede

[Jim Beckley]

Bob, Forgot to mention, The actual diamater of the European Swede has a larger case head than the standard .308 case, if you want to use Euro brass (Lapua, Norma, RWS), you will have to open up your bolt face, and when I wanted to go from .257 Roberts to 6.5x55, I was told that was the last thing that I would want to do. Remington makes brass for the Swede that the case head is just slightly larger than the .308 size bolt face, once you chamber the case and close the bolt on them a couple of times they will work just fine, minus the brass shavings!

[Bob259]

Thanks Jim... Also, if I understad correctly, the 6.5x55 needs to be in the long action Vs the short action for the 260 & 6.5x47. I was thinking I wanted a short action, but if I go to the 6.5x55 and have to use a long action are there any things I should be aware of there to consider.

[Evelio Mc Donald]

Jim the head dia. of a 6.5x55 is 0.470" same as a 308 260 6.5x47 243 30.06 etc. the bolt face does not have to be modify at all. I use Rem.6.5x55 swedish brass, and it works great.
Evelio.

[Bob Mc Alice]

Bob, are you thinking of building a hunter gun to compete in both classes or a heavy gun? Either way, my vote goes for 7-08.

[Bob259]

Bob, are you thinking of building a hunter gun to compete in both classes or a heavy gun? Either way, my vote goes for 7-08.

That is the plan, one rifle for both 'to get my feet wet'

I'd have to sell the wife to get two (hmmmm... now that I think about it that might not be a bad trade )

[stsbuyer]

Bob,

I have a 6.5 X 47 and the 6.5 x 55 SM both are great rounds for silhouette. One thing to think about that Evelio has not mentioned is that you would need a long action for the 6.5x55 unless he purchased a special reamer with a shorter throat. I think you will see more of the 6.5 x 47 in the future. With it you can use a short action, the reamer Evelio has cuts the throat were you can get land engagement with 107 and 142 grain bullets and still have the full diameter part of the bullet in the neck of the case. You will also burn less powder for close to the same velocity as the larger case. The difference between my ram loads for the two is close to 10 grains less powder with only a 40 fps reduction in velocity. Less powder behind the bullet equals less recoil.

My 2 cents, Paul Freeman

[Bob Mc Alice]

Hey Jim, you are right about european manufactured brass being larger than domestic of same cartridge (as for 7x57) My 7x57 has the same issues. The domestics keep with basic .308 head dimensions for their conveniance because they will work OK. They also have thinner neck wall thickness compared to say Norma. I get only three loadings before a neck split develops with new w-w, r-p etc. The Ruger chamber is cut to true 7x57 dimensions and allows more case neck expansion than a 7-08 does. A look at cartridge & chamber dimension drawings proves this. Norma brass has the correct neck wall thickness and will last thru a dozen loadings. Using reformed military.30-06 brass gives me the correct wall thickness without paying dearly for the imported stuff.

[Evelio Mc Donald]

OK GUYS, for you mathematicians out there here is the formula for calculating recoil in FT. LBS.
( Bw x Mv + 4700 x Pw ) SQUARE / ( 64.348 x Gw )
where:
Gw= Weight of the gun in pounds
Bw= weight of the bullet in pounds
Pw= powder weight in pounds
Mv= muzzle velocity in feet per second
To convert gr. to lbs. you need to divide the grains by 7000
So here we go:
Gw= 8.5 lbs.
Bw= .015 lbs. ( 107 gr. bullet )
Pw= .005 lbs ( 36.0gr. Varget )
Mv= 2700 fps
All equals to 7.48 ft. lbs. of recoil
Now changing to 142.gr bullet 45.0 grains of (reloader 22) powder and 1500 fps.
will give you 11.18 ft. lbs. of recoil about 1/3 more recoil than the 107gr. bullets.
Practically the loads on the 260 6.5x55 and the 6.5x47 with the 107 bullets are pretty much the same to be able to develop between 2650 and 2700 fps. which is where you achive the best accuracy with the 107gr. bullet. So the way I look at it the recoil is going to be the same in all 3 calibers. In the 7 08 using the 130.gr. bullet and same velocity, the recoil is going to be more severe.
Now once you go to the 142 gr. the recoil could change somewhat depending on how many grains of powder is used, like Paul stated earlier he is using 10 gr. of powder less in the 6.5x47 that I am using on the 6.5x55, now if I went to reloader 15, I would need about 10grains less of powder, since it is a much faster powder.
All in all like Mr Newton said: FOR EVERY ACTION THERE IS AND EQUAL OPPOSITE REACTION so in other words if you are pushing the same weight of bullet at the same velocity from guns that weight the same, the recoil should be about the same regardless of the caliber.
By the way the recoil of a 12 gauge shotgun is about 21 ft. lbs.
Now does anybody knows how many FT. LBS. of energy is required to knock a ram down consistently ???????
Evelio.
Just my .002 cents worth, hope I did not confused anybody.

[Bob259]

..... Yes Evelio not only am I totally confused now, but now my long action is getting short and some how this is going back to the angle of the.....oops sorry that's another topic????

I think we need Kitty's help on this lol

THANKS for the help everyone but like everything there are lots of opinions and I'm just trying to figure out the best way to go and keep Evelio busy over the winter

[Krasmussen]

Geeez...this is starting to sound like physical science to me.

[sobrbiker883]

I got some very interesting responses when I asked about energy needed for rams (see the last few posts especially:

http://www.steelchickens.com/phpBB2/vie ... highlight=

[Evelio Mc Donald]

Soberbyker
MR ramslammer is correct when we first started shooting about 33 years ago there was no standard on the rails or support for the rams, every club just went out there and found anything they could set the targerts on. I shot in places where railroad ties were used for stands, that was the time when some times you needed a 50 cal. to get the stupid rams down.
Now after the years, and better rules about stands and feet on the rams, I think that anything going above 2500fps. and about 140 gr. will get them down about 99% of the time,but every once in a while one will stand there and laught at you no matter what you throw at them.
I really got a kick out of the comment about Jerry Tuerou ringing a pig in Zwolle, well that pig was 4" thick and weighted about 60 lbs. We set him up.
A lot of fun and good times at Zwolle. Will be packing up in the morning to go there again for their once a year match. I have been going there since 1977 ( just look up the date on the trophy ) never missed once, but I really miss the man that started the matches in his property, Mr. Bucky Murdock.
Well I guess I am deviating from the main subject. Now a days, if the targets and the stands are made to NRA regulations it will take 800 ft. lbs. with a center hit to knock the ram down, again 99% of the time.
Evelio