160gr Woodleigh .264 bullets. Anyone ever play with them?

[Dee]

I have noticed a .264" 160gr bullet from Woodleigh of Australia and was wondering if anyone has messed around with it for Rams? They aren't cheap at nearly twice SMK prices but for the occasional match rams not outrageous all things considered if they can perform.

The BC is a little lower than others at around .509 according to Midways catalog. I might give a box a try and see how they perform sometime in the future along with the Nosler Custom Competition 140's and Hornady SST and Match HPBT.

Dee

[DanDeMan]

Dee,

Interesting 6.5mm bullet. I used a "screen caliper" to measure the bullet's dimensions and then ran them though the JBM Bullet Drag and Twist simulator. The bullet's BC is about 0.480. When shot out of an 8-twist barrel the bullets are optimally stable with an SF of 1.5. If the bullet is launched at 2,600 fps, the 500 meter momentum is 1.202 ft-s. I would guess the Woodleigh bullets have tough jackets so with that much momentum on top of a tough bullet they should be "smashing" on rams.

Please let us know how they work out. There's some load data in the link below. I'd imagine they are "lawyer loads;" that is, loads below what might be safe. I have a set of Sierra reloading manuals from 1980. The new manuals' max loads are considerably below the old ones. The Hodgdon's site also has 260 loads for 160-grain bullets.

http://www.woodleighbullets.com.au/info ... eigh%2080A

[Dee]

I am definitely going to have to give them a try. Would make a good game round as well in the event I ever drag my rifle out for some meat and not just steel. That velocity sounds pretty good for that far downrange. Going to go checkout the link. I will post my findings when I get to test them out.

Just now about to get loading again and overclock the ChargeMaster Need to go back and revisit that thread.

Thanks..

Dee

[DanDeMan]

Dee,

If you like, send 3 or 4 bullets, or maybe more, my way and I'll smash them in the bullet-smasher. A few pics of the Woodleighs compared to other top, 6.5mm, ram contenders, would be very interesting, indeed. If so inclined, please PM me for my snailmail address.

Also, like a number of other riflecranks, I've been into "pointing" bullets for a good long time. I think we could boost the Woodleight BC substantially with proper "pointing." I'm thinking the BC could be pumped-up from a nominal 0.480 to maybe 0.550....OK, now I need to pack-up and back-up my claim....be back in a jiffy.....OK, it looks like we could boost the BC to 0.540, how's that for pulling the proverbial rabbit out the hat. Now, if said bullet was launched at 2,600 fps, like in the first discussion, the 500-meter momentum would be increase a bit to 1.265. But, from all the bullets I've PROPERLY pointed, accuracy has increased as well as BC.

[Joaquin B]

Woodleigh bullets are probably the best hunting bullets around, especially in larger calibers, from 9.3 mm on up. I'm still waiting for an opportunity to use my .375 cal. 300 grain Woodleighs on cape buffalo. Fellow silhouette shooter Hector Elias has taken quite a few large critters with them and swears by them. If their 6.5 mm bullets are as solidly constructed as their other bullets are, they would hold up a little better at higher velocity on rams, IMHO.

[Dee]

I came across some data sheets for 155gr SMK's but I can not find any for sale and never noticed them offering anything over 142gr in .264". Might these SMK 155s be discontinued or something? I was thinking they might be a better option with regards to cost anyway.

Dan whenever I get some I will send you a few for the smasher just to see how them compare to the others. Won't be anytime soon but I intend to get a box next time I need to order items from someplace that has them in stock.



Dee

[DanDeMan]

Dee,

I shoot the 155 SMK's out of my Swedish Mauser in 6.5 x 55. The barrel is about a 7.5-twist (original military match barrel.) I tried the 155's in 8-twist barrels. The bullets were not stable enough. Accuracy at 100-yds in warm weather was excellent, but at rams the bullets produced a shotgun pattern. Sierra discontinued them back in the mid-90's I believe. I still have a small stash for the Swede. They are of an old Sierra design so the BC is quite low, lower than the 142 SMK's. But, they work super on rams out of the Swede. As I posted earlier, the 160 Woodleigh's are optimally stable out of an 8-twist barrel, for which they were probably designed. Given their reputation for being accurate, tough bullets you might just have stumbled onto a great ram bullet.

[Taps]

G'day All
I used to shoot a 6.5/.257Roberts Improved using the aforementioned 155 SMKs. Accuracy was excellent in my rifle, 2" groups @ 500. Never stood a ram no matter where it was hit. Changed calibres when that barrel was shot out due to being unable to get the 155's anymore or the powder I used to use. So Dee, if you can get hold of a stash I would highly recommend them.
Taps

[DanDeMan]

Dee,

Given the topic of heavy-for-caliber, 6.5mm bullets has been a focus of discussion; and, I worked on launching the 155 SMK's years ago out of an 8-twist barrel, some ciphering and air density vs. stability discussion seems in order for those interested in this technical stuff.

First some background. Sierra's 155-gr SMK's are excellent on rams when shot from a 6.5 x 55, 7.5-twist Swede. So, back in 99 a wildcat cartridge based on a 1.75" long Win 243 case made by Lapua was designed. The idea was to launch the 155's to about 2,700 fps with VVO N160. The case body is almost the same as the 6.5 x 47 Lapua but with a bit longer neck and 40 degree shoulder angle instead of the Lapua's 30 degree angle. The chamber's front-end (freebore and leade angle) was designed to accommodate the long bullet-shank of the 155's. Load testing was done on a warm day at 100-yds. Accuracy was excellent and MV requirement met. But, when testing before a silhouette match in December of 99, the rifle/load combo produced terrible accuracy at 500-meters even though it was calm.

Here's the reason accuracy was so poor. It was quite cool that morning, in the 40 F degree range. When air cools it becomes denser, which means nose drag increases. It is nose drag that acts to destabilize bullets. When marginally stable bullets are fired in warm air and later fired in considerably cooler air the bullets can become destabilized and yaw (wobble) excessively or even tumble. When air temperature drops from 85 F down to 35 F, air density increases by about 13%, assuming barometric pressure remains constant. That is enough to cause marginally stable bullets to tumble. Humidity has negligible effect on air density. Going from 100% humidity down to zero % only increases air density by 4%, all other barometric variables held constant. And yes, dry air is denser then humid air.

A 155 SMK was measured and dimensions run through a JBM Ballistics program to determine stability. The (Gyroscopic) Stability Factor (SF) is a measure of a spin-stabilized projectile's gyroscopic stability. By definition a bullet with an SF of 1.0 is gyroscopically stable. But, the SF equation does not take into account air density effects on nose drag. That is a serious shortcoming of the SF equation. Most bullet/rifle designers typically design to an SF of 1.5 so that there is plenty of room for air density to vary considerably without the risk of bullets not being sufficiently stable. Out of an 8-twist barrel, the 6.5mm, 155-gr SMK has an SF of only 1.1 at an MV of 2,700 fps. Over the years my experience, and that of others, has shown such a low SF is not sufficient for a wide range of air densities to insure the bullets will not tumble from increased nose drag that results from increased air density. When those bullets are shot out of the 7.5-twist Swede the SF is 1.3; still low, but the load has worked down to about 45 F, to the best of my recollection. I've heard from numerous hunters that their ammo went south in cold weather. Load testing in 80-plus degree weather can show fine accuracy with marginally stable bullets. But, then the same ammo is shot in cold weather, shotgun patterns can emerge.

As was posted earlier, the 160-gr, Woodleigh bullet has an estimated SF of 1.5 when shot at 2,700 fps out of an 8-twist barrel.