Benchmark is my go to powder for .223Rem using Sierra #1390 (55gr HPBT). My rifle REALLY likes 24 grains. I THINK (don't feel like walking to the shop to look at my book) out of my 22" barrel I'm in the 2700's. I don't think any extra speed is worth my accuracy, but hey, that's me. If speed is your thing, burn it up..........
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trouble working up benchamrk in .223
- Thread starter Shadow9mm
- Start date
accuracy is what should matter. that's still pretty fast IMO. I tried 2 lbs of h335 and couldn't really get it to shoot good than I shot 23.3gr of benchmark in my bolt gun and put 5 in one ragged hole.
whats the point of it when you go from shooting such precise loads to throwing them all over the paper for a couple fps.
whats the point of it when you go from shooting such precise loads to throwing them all over the paper for a couple fps.
brasscollector
New member
If it's accurate, I'd use it. If it's not, I'd go looking for another load even if that one was 3,150.
whats the point of it when you go from shooting such precise loads to throwing them all over the paper for a couple fps.
Seems like a pattern of advice here. I reload for accuracy. I push my loads as fast as they will go accurately. I won't settle for patterns, gotta have groups. Once I find a good, consistently performing load that groups I will run it over the chrono and see if I'm in the ballpark.
Benchmark not cutting it for ya? Try some CFE223. I didn't get the accuracy I wanted from CFE223 when I tried it but that's irrelevant here.
CAUTION!
243winxb,
IMHO, that Western data is bad. The pressure number they used was for European channel transducers which measure 223 Remington and 5.56 NATO at 4,300 bar or 62,366 psi. The same exact ammo in a U.S. style conformal transducer measures 55,000 psi. What Western did to develop that data was ignore the transducer differences and use a U.S. style conformal transducer to produce 62,366 psi. I got that information from the horse's mouth, speaking with one of their technicians. On the European style gear it should measure about 4,876 bar, or 70,718 psi. That's still below proof range (73,500-81,500 psi), but not by a lot. It's likely to lead to shorten barrel life by eroding the throat fast, and operates some gas systems pretty hard.
I pointed out to their tech that they'd done an apples to oranges pressure comparison, and he said he'd report it up stream, but I haven't seen any change. Maximum European measured pressures should have the exact same powder charges as maximum SAAMI measured pressures. The PSI differences are intrinsic to differences in the measuring instrumentation and not differences in absolute pressures.
If you are curious, take a look at the 223 Remington on CIP's site, at the top of page 6. You will see it is 4300 bar max pressure. Multiply bar by 14.50377 to get psi, or use one of the numerous on line converters. This is the number all European made 223 Remington is loaded to, but the velocities are no higher than U.S. ammo with similar bullet weights, and the pressures are the same when measured on the same equipment.
T. O'Heir,
Whenever an ammo maker fails to list a test barrel length, it means they are using the SAAMI standard test barrel of the ammo type. If you read through the SAAMI centerfire rifle standard you will find the test barrel length listed in the lower half. For 223 Remington it is page 264 on document (or page 276 as Acrobat Reader counts pages, due to it counting the non-numbered title and index pages at the top of the document). You will see the last dimension with arrows at the bottom of the test barrel and chamber drawing is the barrel length, which, for 223 Remington is 24±0.010 inches.
Shadow9mm,
The American Eagle ammo is rated at 3,240 fps from a 24" barrel. You should expect about 2,940 fps from a 16" barrel that has the same chamber and bore dimensions as a SAAMI test barrel. So your gun is measuring a little fast. Usually production guns are slower and not faster, though occasionally the opposite occurs. But I assume you are using an optical chronograph, and 50 fps is about as accurate as many of them are. Plus, you can fool one under some conditions.
It is that last point I think you should double-check. Set the unit out at 20 feet and get readings for both your load and the Federal load and confirm they are still different. This will eliminate any significant possibility of one powder producing more powder debris among its ejecta and causing false triggering. Be sure to fire both rounds alternating between one and the other for both your fouling shots and the measurement shots so bore fouling condition changes don't influence the comparative readings appreciably.
That said, assuming your existing measurements were good and that, even if the absolute velocity isn't tight, the comparative velocity difference percentages are. Then I would expect the commercial load is simply using a slower powder than Benchmark. That will make it possible to get more velocity from the same peak pressure by holding pressure up higher past the peak value. H335 (canister grade WC844) is the old 1960's military type ball powder and is about as slow as I like to go with 55 grain bullets in the 223, and I don't like it for anything lighter than that. H4895 may be a better choice, though. Like Benchmark, it is temperature stable (H335 is not) and it is known to burn well even in reduced loads, which means it is also going to be less sensitive to having lower inertial resistance to build pressure against, as a higher bullet weight provides. Hodgdon's data shows both those powders produce higher maximum velocities than Benchmark does.
Note that if you go to H335, the old WC series sphericals generally ignite better and more consistently with magnum primers. CCI even reformulated their magnum priming mix in 1989 specifically for these powders. That same mix is used in their #41 military sensitivity spec primer for the AR.
243winxb said:Look up the hotter Nato load data for 5.56 here http://www.accuratepowder.com/load-data/
243winxb,
IMHO, that Western data is bad. The pressure number they used was for European channel transducers which measure 223 Remington and 5.56 NATO at 4,300 bar or 62,366 psi. The same exact ammo in a U.S. style conformal transducer measures 55,000 psi. What Western did to develop that data was ignore the transducer differences and use a U.S. style conformal transducer to produce 62,366 psi. I got that information from the horse's mouth, speaking with one of their technicians. On the European style gear it should measure about 4,876 bar, or 70,718 psi. That's still below proof range (73,500-81,500 psi), but not by a lot. It's likely to lead to shorten barrel life by eroding the throat fast, and operates some gas systems pretty hard.
I pointed out to their tech that they'd done an apples to oranges pressure comparison, and he said he'd report it up stream, but I haven't seen any change. Maximum European measured pressures should have the exact same powder charges as maximum SAAMI measured pressures. The PSI differences are intrinsic to differences in the measuring instrumentation and not differences in absolute pressures.
If you are curious, take a look at the 223 Remington on CIP's site, at the top of page 6. You will see it is 4300 bar max pressure. Multiply bar by 14.50377 to get psi, or use one of the numerous on line converters. This is the number all European made 223 Remington is loaded to, but the velocities are no higher than U.S. ammo with similar bullet weights, and the pressures are the same when measured on the same equipment.
T. O'Heir,
Whenever an ammo maker fails to list a test barrel length, it means they are using the SAAMI standard test barrel of the ammo type. If you read through the SAAMI centerfire rifle standard you will find the test barrel length listed in the lower half. For 223 Remington it is page 264 on document (or page 276 as Acrobat Reader counts pages, due to it counting the non-numbered title and index pages at the top of the document). You will see the last dimension with arrows at the bottom of the test barrel and chamber drawing is the barrel length, which, for 223 Remington is 24±0.010 inches.
Shadow9mm,
The American Eagle ammo is rated at 3,240 fps from a 24" barrel. You should expect about 2,940 fps from a 16" barrel that has the same chamber and bore dimensions as a SAAMI test barrel. So your gun is measuring a little fast. Usually production guns are slower and not faster, though occasionally the opposite occurs. But I assume you are using an optical chronograph, and 50 fps is about as accurate as many of them are. Plus, you can fool one under some conditions.
It is that last point I think you should double-check. Set the unit out at 20 feet and get readings for both your load and the Federal load and confirm they are still different. This will eliminate any significant possibility of one powder producing more powder debris among its ejecta and causing false triggering. Be sure to fire both rounds alternating between one and the other for both your fouling shots and the measurement shots so bore fouling condition changes don't influence the comparative readings appreciably.
That said, assuming your existing measurements were good and that, even if the absolute velocity isn't tight, the comparative velocity difference percentages are. Then I would expect the commercial load is simply using a slower powder than Benchmark. That will make it possible to get more velocity from the same peak pressure by holding pressure up higher past the peak value. H335 (canister grade WC844) is the old 1960's military type ball powder and is about as slow as I like to go with 55 grain bullets in the 223, and I don't like it for anything lighter than that. H4895 may be a better choice, though. Like Benchmark, it is temperature stable (H335 is not) and it is known to burn well even in reduced loads, which means it is also going to be less sensitive to having lower inertial resistance to build pressure against, as a higher bullet weight provides. Hodgdon's data shows both those powders produce higher maximum velocities than Benchmark does.
Note that if you go to H335, the old WC series sphericals generally ignite better and more consistently with magnum primers. CCI even reformulated their magnum priming mix in 1989 specifically for these powders. That same mix is used in their #41 military sensitivity spec primer for the AR.
unklenick
I had my chronograp set out about 6-7ft away from the muzzle. I also have a closed end compensator so that should have redirected most of the blast sideways. It was a nice shady day, and the american eagle velocities were within 8ps of a previous trip when i had measured them. thanks for the info I have been looking at w748 since i can get it locally. and I may order some H4895.
I had my chronograp set out about 6-7ft away from the muzzle. I also have a closed end compensator so that should have redirected most of the blast sideways. It was a nice shady day, and the american eagle velocities were within 8ps of a previous trip when i had measured them. thanks for the info I have been looking at w748 since i can get it locally. and I may order some H4895.
748 is good with the 68 and 69 grain match bullets and up, but is too slow for light bullets and has poor ballistic efficiency there (you'll waste a lot of powder). Powders too slow for the bullet weight have been known to cause barrel ringing, too, but usually further down than 16", so you may or may not have an issue there.
IME, 6-7 ft is just too close to be reliable with anything producing more gas volume than a handgun. Even then, at least 10 ft is really preferable. You'd expect the comp to handle a lot of that, but a 16" barrel will leave some powder still burning and thrown out forward, so you can't completely count on that compensator to make the readings reliable without testing the unit further away. With typical rifle bullets near the muzzle, figure to lose around 0.8 ft/s for each foot of travel when comparing results with the Hornady 55 grain FMJ BT. SAAMI uses 15 ft at the midpoint between sensors. The military used 15 ft for small cartridges and 78 feet for rifle for a long time. You just have to determine what your instrumentation is up to.
I threw up my hands recently and spanked my wallet to get a Labradar unit to measure speed by Doppler radar and to let me opt out of the optical problems altogether. As near as I can determine it is accurate within two or three fps at the standard 15 foot and 78 foot ranges (3 and 16 yards).
IME, 6-7 ft is just too close to be reliable with anything producing more gas volume than a handgun. Even then, at least 10 ft is really preferable. You'd expect the comp to handle a lot of that, but a 16" barrel will leave some powder still burning and thrown out forward, so you can't completely count on that compensator to make the readings reliable without testing the unit further away. With typical rifle bullets near the muzzle, figure to lose around 0.8 ft/s for each foot of travel when comparing results with the Hornady 55 grain FMJ BT. SAAMI uses 15 ft at the midpoint between sensors. The military used 15 ft for small cartridges and 78 feet for rifle for a long time. You just have to determine what your instrumentation is up to.
I threw up my hands recently and spanked my wallet to get a Labradar unit to measure speed by Doppler radar and to let me opt out of the optical problems altogether. As near as I can determine it is accurate within two or three fps at the standard 15 foot and 78 foot ranges (3 and 16 yards).
I'm using 24.5 grains of benchmark with a 55 grain vmax out of 18 inch ar and it chronos at 2815 average. I'm super happy with accuracy out to 400 yards. Farthest I've tried it so far. I've room to go higher but groups start opening up. I've got about 5000 rounds of American Eagle fmj that I've never chrono graphed. I just wanted a decent coyote load and it works wonders.