Hangingrock
Member
In reference to the Sierra 5th Edition has anyone loaded the #9390 .224” 80gr HPBT-MK to the C.O.A.L specified 2.550”? Tell us about it please. Maximum of 2.260” is specified in the cartridge drawing a difference of 0.29”.
Sierra 5th Edition #9390 .224” 80gr HPBT-MK
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wanderinwalker
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Mr. Rock,
Welcome to the realm of VLD-type bullets in the .223! That's a pretty standard "book" OAL for those bullets in a Colt chamber. Magazine loading is definitely NOT an option for those bullets.
I've loaded my fair share of 80gr Noslers in the .223 for Service Rifle shooting. They're very similar to the Sierras. If you push these to a 2.26" OAL the main bearing surface of the bullet is going to be somewhere inside the case. They have 1 use IME, and that's single-loaded into a Service or .223 Match rifle for the 600 yard line. The bullets are quite a bit sleeker and slipperier than the common 68-77gr magazine bullets, and by the numbers will shoot with the standard 168gr .308 loads at 600 yards.
As for OAL, I don't know what the tip-to-tail measurement of my rounds are, I load with a comparator and aim (punny) to be about .020" off the lands. If I had to guess, I'd say the OAL is probably in the 2.4s with my new barrel; the last ones for my old barrel were probably in the 2.55" range. They're not super picky about jumping from my experience, but I like to keep them closer anyway. And I don't consider .020" to be super close to the rifling.
Oh, and fuel them with Varget, RL-15, H4895 or something of similar burn rate.
Welcome to the realm of VLD-type bullets in the .223! That's a pretty standard "book" OAL for those bullets in a Colt chamber. Magazine loading is definitely NOT an option for those bullets.
I've loaded my fair share of 80gr Noslers in the .223 for Service Rifle shooting. They're very similar to the Sierras. If you push these to a 2.26" OAL the main bearing surface of the bullet is going to be somewhere inside the case. They have 1 use IME, and that's single-loaded into a Service or .223 Match rifle for the 600 yard line. The bullets are quite a bit sleeker and slipperier than the common 68-77gr magazine bullets, and by the numbers will shoot with the standard 168gr .308 loads at 600 yards.
As for OAL, I don't know what the tip-to-tail measurement of my rounds are, I load with a comparator and aim (punny) to be about .020" off the lands. If I had to guess, I'd say the OAL is probably in the 2.4s with my new barrel; the last ones for my old barrel were probably in the 2.55" range. They're not super picky about jumping from my experience, but I like to keep them closer anyway. And I don't consider .020" to be super close to the rifling.
Oh, and fuel them with Varget, RL-15, H4895 or something of similar burn rate.
The Sierra 80 bthp MK bullet is designed to be seated very long and they can not be loaded to magazine length which is 2.260" maximum. The Sierra length of 2.550" you mentioned would not work in my WOA National Match rifle. That length would be too long. I seat the Sierra 80 gr. MK's to 2.459-2.460" and that puts the ogive of the bullet approximately .015" from the rifling. The overall length in my rifle is 2.472" for the bullet to touch the rifling. Your rifles chamber will probably be different than my one rifle that I've measured oal to the lands. It's reported that best overall length for the 80 gr Sierra MK bullet is from .005-.015" off the lands for best accuracy. You definitely need to check your rifle and measure YOUR maximum oal to touch the rifling with the ogive of the bullet. The 80 gr. Sierra MK is designed to be single loaded, one at a time into the chamber. They can't be seated to magazine length. Now the 77 gr. MK is designed to be seated to mag length at 2.260" and they will feed and function. The 80 Sie MK is for long range match shooting single shot loading. 2.550" may not be too long for a military sized chamber but you definitely HAVE to check.
Hangingrock
Member
Thank you both for the information. I’ve been using the .223-Rem in a bolt gun for short course shooting 200yd-300yd. For those venues I’ve used The Sierra 77Gr.
I decided to use the .223-Rem in some full course matches thus the Sierra/Nosler – 80Gr experimentation. The barrel twist rate is 8”. Usually I’ll shoot full course matches with my Remington 40X-7.62mm NATO. Since I employ R-15 for both cartridges that’s what I’ll use to push the Sierra/Nosler – 80Gr down range.
I decided to use the .223-Rem in some full course matches thus the Sierra/Nosler – 80Gr experimentation. The barrel twist rate is 8”. Usually I’ll shoot full course matches with my Remington 40X-7.62mm NATO. Since I employ R-15 for both cartridges that’s what I’ll use to push the Sierra/Nosler – 80Gr down range.
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