I read in a nother forum that ""The 222 with 50-52 gr bullets and 1-12 twist is where it earned its reputation as a tack-driver, "" I allways though it was a 1:14 twist that made a 222 a tack driver ?
I read in a nother forum that ""The 222 with 50-52 gr bullets and 1-12 twist is where it earned its reputation as a tack-driver, "" I allways though it was a 1:14 twist that made a 222 a tack driver ?
My 1968 40 XBR 222 has a 14 twist. I’m pretty sure that was most common when the 222 was winning matches in the 1950’s-60’s.
Back in the days before the .223 all .224 center fire cartridges were 14” twist. In fact the .223 started life at 14” then 12” an then 9”. We can thank the military for that. The original 14” barrels in colder weather would not stabilize the military 55 gr. solid jacket bullets very well. They were a little to long.
Back in the days before the .223 all .224 center fire cartridges were 14” twist. In fact the .223 started life at 14” then 12” an then 9”. We can thank the military for that. The original 14” barrels in colder weather would not stabilize the military 55 gr. solid jacket bullets very well. They were a little to long.
Actually, DENSITY of the bullet determines twist rate, not the length. You can get an 80 grain HPBT bullet to stabilize in a .221 Fireball, assuming the twist rate is appropriate. Change bullet composition to say, copper, and you might need more spin to stabilize the projectile. Or, change part of the core from lead to a lighter material, and you might encounter the same situation, hence faster twists for the M16A2, when the US adopted the Belgian designed 62 grain bullet (w/steel insert), and the associated 5.56 mm tracer (lower density material, replacing part of the core).The length determines twist rate not weight
The M-249 was originally built in Belgum and used Belgian designed ammo. The added length of the tracer added burn time, as existing 5.56 mm bullets did not have sufficient capacity for the desired performance. (Provide trace out to 800 yards?) The US adopted the ammo, and redesigned the M-16 rifles to use them, hence the M-16A2 (and follow-ons) and M-4 series of rifles and carbines. Initial barrel twist was 1 7", with later rifles changing to 1-9". (Think carbines have remained 1-7".)when the m249 came along it came with a tracer and it more twist as it was long for its weight.
Is that why a 5.56 tracer will shoot in the same place as the ball round? The tracer is longer but the back end is tracer powder. Doug
Tracer bullets NEVER fly the same as a ball round. Why? The ball round keeps most of its mass in flight, the tracer's is affected by the tracer's burn. For starters, the bullet leaves the barrel with mass, and as it flies dowrange, loses mass as the tracer compound burns. It also flies differently, due to the reduced low pressure at the base, resulting from the tracer burn. Dispersion on a tracer is greater, due to the uneven burn of the "pellet". Ever wonder why some of the best aerial gunners removed the tracers from their ammo loadouts? Now you know why.Is that why a 5.56 tracer will shoot in the same place as the ball round? The tracer is longer but the back end is tracer powder. Doug
last fall with a 6 Beggs, 67 gn bullets and LT32 powder and it doesn't shoot all that great. Bad barrel or wrong twist rate?
Pete
Pete, If I would have been the shooter the problem would probably have been me! Your twist rate was on the quick side but certainly within specs. Maybe the barrel? The bullet was certainly in right weight range. A while back Berger made a 70gr bullet that had a 9 ogive. They recommended a 12” twist rate because of it’s length. A fellow by the name of Skip ,you may have shot with him, used a bunch of them. They were a flat base and were considered a varmint bullet. Skip used them with 28.0 gr. N133. He said they shot best on the low side. If I remember right he did pretty good especially at 200 yds. His barrels were 13.5T.