TODAY'S GUN TIME

[paulsharvey]

Qstott,
You sound like you have a lot of long range experience. Can you explain to me in layman's terms why rounds like the .260 and 6.5 are considered superior for long range shooting? Is it a diameter vs length vs weight ratio thing? If that's the case, then why can't those same advantages be made by modifying the bullet length/weight with many other rounds?

I've always liked "fast for caliber" bullets and therefore usually go with a lighter weight bullet in any given chambering. With the .25-06 I always hand loaded 100gr bullets; With the .300 WM, 168gr; .260 Rem 120gr etc. I also usually only hunt with mono-metal bullets such as Barnes TTSX or Hornady GMX, just because I've liked their wound channel performance with less blood shot meat. Plus the mono-metal makers usually suggest lighter bullet weights for better performance.

I'm interested in what makes certain loads better ballistically.

Ballistic Coefficient and Muzzle Velocity. What you say about making an existing bullet longer and heavier, that does work But, most "old cartridges" have too slow of a twist to stabalize long, heavy for caliber projectiles. For example, .270 Win traditionally uses a 1:10, and that will work great for 110gr upto 150gr (some people report working with 160gr RN shorter bullets); but to stabalize some of the slick new "boutique" bullets needs a faster twist. In 277 diameter, thats a special order thing, noone that I know of sells ready to buy 270Win in a 1:8 twist. Creedmore, for instance 1:8 is standard.

It's more then twist rate as well, and include velocity and barrel length as well, into stability. The fad or trend of 18" .308 barrels, even at the same twisy as a 24"; in theory won't stabalize something on the ragged edge as well, say 220gr pills.

No expert, just a determined idiot here, so if I misspoke, or am flat out wrong, feel free to set me right.

 

[sea2summit]

Qstott,
You sound like you have a lot of long range experience. Can you explain to me in layman's terms why rounds like the .260 and 6.5 are considered superior for long range shooting? Is it a diameter vs length vs weight ratio thing? If that's the case, then why can't those same advantages be made by modifying the bullet length/weight with many other rounds?

I've always liked "fast for caliber" bullets and therefore usually go with a lighter weight bullet in any given chambering. With the .25-06 I always hand loaded 100gr bullets; With the .300 WM, 168gr; .260 Rem 120gr etc. I also usually only hunt with mono-metal bullets such as Barnes TTSX or Hornady GMX, just because I've liked their wound channel performance with less blood shot meat. Plus the mono-metal makers usually suggest lighter bullet weights for better performance.

I'm interested in what makes certain loads better ballistically.

"Fast for caliber" uses light bullets, which subsequently have low ballistic coefficients. "Heavy for caliber" will maintain velocity better and actually pass up fast for caliber loads fairly quickly.

6.5 (.260) and 6mm (.243) are a pretty sweet spot in terms of manufacturing capabilities and velocity potentials without burning out barrels too badly. By having a high BC even if they start out not a whole lot faster than a .308 at 5-800 yards they are getting there a lot faster by comparison and you have more forgiveness for bad range and wind calls as a result.

 

[sea2summit]

It's more then twist rate as well, and include velocity and barrel length as well, into stability. The fad or trend of 18" .308 barrels, even at the same twisy as a 24"; in theory won't stabalize something on the ragged edge as well, say 220gr pills.

18" .308? Who shoot's muskets anymore?

 

[qstott]

Yep, it’s about the ballistic coefficient. There is a balancing act there. Think long tapered at both ends. (Not exactly but kinda). A 168 grain .30 caliber bullet is shorter and fatter than a 160 grain .260 caliber boat tail bullet. The better the b.c., the less drag on the bullet. The more drag, the more quickly it slows. Light bullets may be faster at the start, but generally experience more drag because of the shape. Most lighter (in relation to bore diameter ) bullets, have flat bases and fat ogives. That makes them short and stumpy, not very well suited to the streamlined profile that gives a higher b.c.

160 grains is quite heavy for a .260 actually. My 600 yd load in the AR was a 90 grain bullet. The bullets were too long to fit in the magazine. At the other end, the load for 200 yds was a 52 grain bullet. It’s amazing how little recoil there is in a 14 pound AR shooting itty bitty 52 grain bullets. It’s perfect for sitting rapid fire. Drag is not nearly as detrimental at 200 yds as it is at 600, 800, or 1000. Another advantage to having a “slippery” bullet is that the wind has slightly less effect. Part of that is since it retains its speed better, the wind has less time to act on the flight path.

Newton’s law says an object in motion tends to stay in motion unless acted on by outside forces. That outside force is drag in the case of a bullet.

paulsharvey has a good example of weight, b.c., and barrel twist. Notice that .270 bullet is 170 grains. The typical hunting bullet for a .270 is usually 130 grains.

I shot high power for at least 25 years and everything always is a trade off. Recoil vs bullet weight vs b.c. vs barrel twist vs powder charge vs barrel life, etc, etc, etc.

For normal hunting distances It doesn’t really matter. It’s much more important to estimate the correct range and know how much your particular bullet will drop than be overly concerned about the b.c. Most hunters won’t have a clean shot on anything past 200 to 300 yards anyway. At least not in eastern North Carolina.

And, just in case anyone cares, if you haven’t replaced your AR barrel after burning an 8 pound can of powder in it, you should. It’s shot out by then.

 

[the old grind]

IMO, as 'old' as it is .270 Win (mid-'20s) is hard to beat compared to so many newer introductions. Also IMO 6.8 Western and 6.5 CM don't offer much more for those of us who think a 200 yd shot is long enough and 300 is pushing it. Any new caliber = a new gun if we buy in.

btw, I have far more 7x57s and 8x57s than any other caliber except maybe .22 RF or .22 pellet. Heck of it is that for putting meat
in the freezer a guy only has 20-25 adequate if old calibers to choose from for hogs, white tails, muleys, antelope, elk, ...

 

[CalG]

18" .308? Who shoot's muskets anymore?

Mostly just crack pots

"The U.S. Marine Corps M40A3 uses a 25 inches (635 mm) Schneider barrel and the U.S. Army M24 used a 24 inches (610 mm) Rock Creek 5R barrel."

 

[sea2summit]

Mostly just crack pots

"The U.S. Marine Corps M40A3 uses a 25 inches (635 mm) Schneider barrel and the U.S. Army M24 used a 24 inches (610 mm) Rock Creek 5R barrel."

It was mostly in jest, my meat stick is a 16” .308 and as soon as this barrel dies (she’s at about 4,500 now) the 14.5” sitting in the tube on the shelf is going in. Couldn’t even guess how many pounds of meat it’s put on my table but it’s in the thousands.

 

[shooterdon]

Never had coyote...how is it?

 

[sea2summit]

Tastes like chicken.

 

[VroomVroom]

Tastes like chicken.

I’d probably eat about anything. But the smell off those things would knock a hyena off a gut cart. Better add some spice, salt it in brine, boil it in broth and smother it in gravy before it tastes any good.