Thread: Seriously underrated 6.5x47 Lapua

Originally Posted by Gibo

Up to our necks in tussock

Don't light a match Gibo

Originally Posted by Micky Duck

GENERALLY a hgiher projectile weight requires a lower powder weight somewhere around 2 grns powder for 10 grns projectile..so the 150 grn load will be a way hotter load than the 130..so it has TWO differences,or to flip it around the 150grn load so so and the 130 a piss weak/mild one.

Good point.

I guess we have no choice but to load these and strap an Iphone to the top?

Originally Posted by Wingman

The only real question here is why would anyone use 2209 in a .308?

Because they want to remind Tussock of the 6kg that he ruined by leaving it in the sun of course

Originally Posted by Moa Hunter

Because they want to remind Tussock of the 6kg that he ruined by leaving it in the sun of course

I had forgotten about that. It might be perfect for .308 now.

Originally Posted by Micky Duck

GENERALLY a hgiher projectile weight requires a lower powder weight somewhere around 2 grns powder for 10 grns projectile..so the 150 grn load will be a way hotter load than the 130..so it has TWO differences,or to flip it around the 150grn load so so and the 130 a piss weak/mild one.

So if what you say is correct then recoil would increase at a linear rate with projectile weight if the powder charge stayed the same. However taking what Tussock has said about the different 'reactions', if the pressure/ heat/ vibration also increases then the recoil thrust may not actually increase as much as might be expected because the energy loss also increases ….
Can we have our cake and eat it too - a low recoiling but high performance superlight mountain rifle ??

Im not sure where this convo is going or how it relates but I can shoot .260rem 6.5x47 Lap and 6.5 Creedmoor in this same chassis, if any of you can feel a difference in recoil you are doing better than me. All are light recoiling "kid friendly" cartridges. If you are scared of a little recoil its probably best you forget about hunting and take up cycling

Originally Posted by Wingman

Im not sure where this convo is going or how it relates but I can shoot .260rem 6.5x47 Lap and 6.5 Creedmoor in this same chassis, if any of you can feel a difference in recoil you are doing better than me. All are light recoiling "kid friendly" cartridges. If you are scared of a little recoil its probably best you forget about hunting and take up cycling

Well Wingman, by your own pen hand you have written (typed) that for the same powder charge / projectile in the 305.5 you have greater velocity than the CM … so I couldn't help wondering if this is at the expense of anything, including an increase in recoil ??

is a SIMILAR weight/shape projectile at a SIMILAR speed with somewhere around 15-20 grns LESS powder than another often slighted cartridge that is often said "to boot like a mule".....

Recoil energy formulae typically attribute an average of 4700 ft/sec (or similar) departure speed to the mass of gas escaping behind the bullet treated as a point mass of the same weight as the starting powder charge leaving in the same direction as the bullet. Sum the momentum of the bullet and powder, apply conservation of momentum using the rifle weight, and then calculate the recoil energy from the resulting rearward velocity of the rifle.

For a given weight of rifle and barrel length within a single calibre, bullet energy plotted against rifle recoil energy follows an efficiency curve for different cases and bullet weights. More efficient cases may move their data points somewhat above the average, and the converse is also true. The same applies to the suitability of powder in its ability to transfer energy to the bullet. But where a shooter chooses to operate on this curve depends more on where it is felt the optimal trade-off exists between bullet energy and rifle recoil. Tussock has identified what he considers to be the sweet spot on this curve for 6.5mm (probably also factoring in the ability of this calibre & bullet weight to kill red deer sized critters at normal hunting ranges), and it is a 140gr bullet in a 6.5x47 with a suitable powder - and I'm inclined to agree with him.

Originally Posted by Moa Hunter

Well Wingman, by your own pen hand you have written (typed) that for the same powder charge / projectile in the 305.5 you have greater velocity than the CM … so I couldn't help wondering if this is at the expense of anything, including an increase in recoil ??

Yip all of about 100fps more.. but I bet there is no one that could tell the difference in recoil between those two cartridge loads in the same rifle.

Originally Posted by Wingman

Yip all of about 100fps more.. but I bet there is no one that could tell the difference in recoil between those two cartridge loads in the same rifle.

What I find really interesting with this discussion is that in the past, to gain greater velocity a bigger case and more powder was needed. Now I am seeing that concept change from a bigger case to a more efficient for calibre case.

Originally Posted by Moa Hunter

Can we have our cake and eat it too - a low recoiling but high performance superlight mountain rifle ??

6.5x47L

Originally Posted by Moa Hunter

What I find really interesting with this discussion is that in the past, to gain greater velocity a bigger case and more powder was needed. Now I am seeing that concept change from a bigger case to a more efficient for calibre case.

Thats always been my jive.. high efficiently bench rest style cartridges with heavier bullets and short actions

Originally Posted by Wingman

...and chambered it with one of Dave Mansons match reamers...

Wingman, please tell me a bit about your reamer: your freebore length and neck diameter (clearance) choice and perhaps your thinking that led to these dimensions? I think I would be right in saying that these are likely to be the two variables with everything else staying much the same at standard CIP - unless you also requested the leade angle be tweaked?

Originally Posted by Tussock

6.5x47L

or if you want a little more poke, 6.5 SAUM or PRC