Reloading for 6x47LAP

[Tony Z]

It was interesting to read the mention of Kendrick and the use of the 44 mm version which has been around for a long time but better known to many in the 30x44 version used in VFS score shooting. The actual forming i did with the 308 Lap cases was not limited to just the 47 version as i quickly went to the 44 version when i felt that 2209 was just not the right burn rate for this bore size with this sized case. Then 2208 and Re15 come into their own combined with the enormous strength of the 308 Lap case in the web and head area. This combination shot far better for me that the 47 version in the same barrel, especially when Re15 was used. Velocities of 3100 fps were easily achieved. But the aggregate of any of the subsequent chamberings was not equal to the original 6BR. So the original 6 BR reamer was used again in that barrel where it is still in use today at 28 inches long.
I think that now after doing full circle and revising all the 6 mils i have done in the past, the 6 BR would only be replaced with the 6BR +600, which is simply the 6BR reamer plunged in a further 600 thou and Lap/RWS 6.5x55 brass used. A simple cartridge that achieves an easy 3400 fps with the ideal case volume for 2209, but without the savage barrel erosion associated with the 6/284 and its very short neck. That extra 500 fps can justify the not quite as accurate as a 6BR performance when the wind is up.

[Rinso]

6x47L
AR2209 ... 39.5grns
105 Lapua Scenar
Fed 205
MV 3070fps
ES 9fps

Tested from 34grns to 42grns 2209

2213SC tested fine ES good but never got around to finishing testing.

Now that I have sold the 260AI will likely get back to developing more load data for the 6x47L

[GregT]

Sorry to drag up an old thread but I'm interested in the velocity readings that are mentioned for the 6x47. My 6BR gets just under 3000fps using a 108 Berger and 30.2g of 2208 out of a 22" barrel. 9 grains seems like a lot of extra powder for another 80 or 90fps, is that normal? I'm no reloading expert, just wondering where the energy from that extra powder goes?

[MISSED]

Interesting question Greg and it is something I often think about.Think compare the 221 fireball to the 223,17 Ackley Hornet to the 17 rem.These are a lot smaller capacity cases but tread on the heels of the larger cartridges.But then you may have a quick barrel I think Trevorts 204R barrel is a Krieger and I think he runs with slightly less powder to achieve similar velocities (is this right Trevor)

[Tony Z]

I ran a 6BR chamber in a barrel for a time, then extended the chamber to accept the 6 x 47 case. The velocity at peak pressures of the two cartridges was less than a 100 fps apart but the accuracy was worlds apart and i went back to the 6 BR. This is what i am running in 1 K right now.
If i did it again i would go to 9 twist for the 6 x 47 as opposed to the 8.5 i run in the 6 BR. Even though it is less than 100 fps speed difference, the RPM rate has shifted above the threshold somewhat. Hence the spread in accuracy potential of the two cartridges. I think the 6x 47/44 would be worth a look at with the likes of the 88 grain BIB bullets in a 10 or 11 twist sometime soon. This capacity and weight range seems to be the direction a few of the top 600 IBS guns are settling on. A scaled down version of the highly successful 187 BIB at similar working velocities of around 3200 fps.

[GregT]

Interesting question Greg and it is something I often think about.Think compare the 221 fireball to the 223,17 Ackley Hornet to the 17 rem.These are a lot smaller capacity cases but tread on the heels of the larger cartridges.But then you may have a quick barrel I think Trevorts 204R barrel is a Krieger and I think he runs with slightly less powder to achieve similar velocities (is this right Trevor)

That is interesting, I was thinking of rechambering this barrel one day to a longer cartridge, mainly so it could feed easily from a 10 round mag but in reality this shoots too well to play around with and does shoot pretty flat even with the small amount of powder it's burning. I'm getting spot on 8 mil drop at 900m from a 100m zero, any idea what a 6x47 or 243 AI might do?

[JasonF]

I'm getting spot on 8 mil drop at 900m from a 100m zero, any idea what a 6x47 or 243 AI might do?

With the 105gn Berger Hybrid an extra 100fps should give 20" less drop and 5" less drift (10mph cross wind) at 900m. Hopefully in a few weeks I will know

I certainly wouldn't mess with your 6BR with the velocity and accuracy you are getting out it.

[GregT]

You're probably right Jason, maybe I should just shoot it more, I haven't had it out since December. This having a job gets in the way of fun stuff sometimes and we're not allowed to shoot anything at work so I really need to get to the range

[MISSED]

we're not allowed to shoot anything at work so I really need to get to the range

[GregT]

we're not allowed to shoot anything at work so I really need to get to the range

Apparently a stern talking to is all that's required these days

[trevort]

Andrew, I think the science behind it is pressure produces velocity and since krieger barrels have tight bores, more pressure comes in it than would in a "looser" barrel so .6 of a grain less powder gets the same velocity as my old ruger did. Tight chamber would help too

[Rinso]

Yes trevort that does make a difference although many other things come into play such as the type of action used, some take more pressure than others.
One thing to remember is that you can normally find 2 or 3 accuracy nodes depending on how hard you are prepared to run your loads.
I know of loads that are very hot and others that are much slower but both are in an accuracy node for that gun.
All this being equal you stil have to complete the basics ie loading, bench techique & wind reading to achieve a result.
If speed was the only factor then building Long Range Target rifles would be easy.