Twist Rate for Long Bullets in the .223 Remington
Date: Aug 10 2010
New .22-caliber, lead-free bullets and long, slender target bullets mean it’s time to reassess the rifling twist in .223 Remington rifles. Standard one-in-12 and one-in-14-inch twists in .223 barrels are keeping .223 shooters from receiving full use – and fun – from their rifles.
My Remington Model 700 SPS .223 has a 12-inch twist. It shoots itsy-bitsy groups with Sierra 40- grain BlitzKings, Nosler 55-grain Ballistic Tips and Sierra 60-grain hollowpoints. But the 60-grain bullet is about as long as the rifle’s twist will stabilize. If I want to shoot the rifle in an area or range that requires lead-free bullets, my options are limited. The rifle shoots fine with lightweight lead-free bullets like the Nosler 35-grain Lead Free Ballistic Tips, but heavier lead-free bullets fail to stabilize in the rifle. Just for the heck of it, I shot Barnes 50-grain Varmint Grenade bullets in the rifle. It was a good thing there was a tall mountain behind the targets, because the bullets flew all over the place.
There has been some concern that bullets with a thin jacket shot at such speeds might tear apart in flight from the stress placed on the bullets by such a quick rifling twist. I’ve shot thin-jacketed bullets like the Hornady Super Explosive and Sierra hollowpoint and Blitz bullets as fast as I could out of my Savage .223 with no problems. However, most of the Hornady 50-grain Super Explosive bullets with 28.0 grains of W-748 did disintegrate in flight when shot through a Smith & Wesson M&P15 PC .223/5.56 NATO with a one-in-8-inch twist. The few bullets that did not tear apart hit a foot or so to one side or the other of the target at 100 yards. Still, this is really no problem because only a few bullets made these days have such thin jackets, while dozens and dozens of bullets readily accept anything a quick rifling twist can dish out.
Sierra’s 69-grain MatchKing bullets with their boat-tails and long tapered noses shot well in the Savage’s one-in-9-inch twist. With 26.5 grains of Vihtavuori N540 the MatchKing bullets had a muzzle velocity of 3,022 fps. Groups were .66 inch at 100 yards, 1.08 inches at 300, 3.30 inches at 400 and 4.00 inches at 500 yards. I can certainly live with that. However, prairie dogs cannot.
Sierra recommends a minimum 8-inch twist for its 77- and 80-grain MatchKings. However, the Hornady Handbook of Cartridge Reloading Sixth Edition states a one-in-9-inch twist was used to shoot its 75-grain A-MAX bullets. So I thought Nosler Custom Competition 77-grain hollowpoint boat-tails might stabilize in the 9-inch twist of the Savage Predator Hunter rifle. Just to see, I shot five of the bullets with 23.0 grains of H-4895. Much to my delight, the bullets grouped in .73 inch. Two other loads with Reloder 15 and Varget also shot well.
I figured, however, there was no way the Nosler Custom Competition 80-grain hollowpoint boat-tails (HPBT) would shoot worth a hoot from the Savage. These bullets have an extra long taper to their noses that makes them much longer than the Nosler 77-grain HPBTs. A couple of months ago, I shot 80-grain bullets in an Anschutz Model 1770 with a 9-inch twist, and the bullets hit the target sideways at 100 yards. So I never even considered loading any of the 80-grain bullets in the Savage.
However, one day I was shooting the 80-grain bullets in a Smith & Wesson M&P15 PC .223/5.56 NATO with an 8-inch twist. At the conclusion of shooting the Smith & Wesson, five cartridges remained loaded with 80-grain bullets and 23.5 grains of Reloder 15. I happened to have the Savage along, so I shot them through it just to see. To my surprise, the bullets grouped in .73 inch at 100 yards.
So back at the loading bench I went to load more of the 80-grain bullets. As the load table shows, five-shot groups with H-4895 and TAC shot accurately.