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Posted: 10/19/2012 4:48:39 AM EDT
| I normally don't use 748 powder, but I got a really good deal on 8 lbs so I figured I would give it a try. I am running 55grn hornady SPBT. I am trying to come up with a good plinking load for the 55grn. Again its just for plinking so what should I load it with, I have 2 different books and they both say different loads for this powder. Does anyone load 748 powder what's the good and bad with it what's a good load for plinking. I am fairly new to reloading and have a XL650 on order (I have been using a rock chucker for past year or so) so when that comes in I plan on loading all 8 lbs and having some range fun. |
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I really like 748 for my ARs. It meters well and it shoots great for me out of several different ARs.
I normally load 26.3 grains under a 52gr Sierra MK BTHP, but the same charge shoots well with the Hornady 55gr FMJ. My A4 type rifle w/ACOG will keep these around an inch or so at 100 yards, which I'm plenty happy with out of a gov't profile barrel and a 4x optic. |
| What primer do you use? The Speer manual recommends a magnum with all ball powder(s). I have used them including W748 with standard primers but have also loaded some with the magnum primer. I have gotten good results either way but if you don't already have primers you may want to consider getting either magnum or the mil-spec primer to use with your W748. |
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What primer do you use? The Speer manual recommends a magnum with all ball powder(s). I have used them including W748 with standard primers but have also loaded some with the magnum primer. I have gotten good results either way but if you don't already have primers you may want to consider getting either magnum or the mil-spec primer to use with your W748. I have about 2000 small rifle primers and will need to get more primers. I did shoot 10 rounds with regular small rifle primers and had no problems I ran 25 grains.and a 55grn SPBT. Are the Magnum primers that much better to justify the extra cost, since the regular primers seem to be working just fine. I plan on buying a bunch of w844 and more 55 grn SPBT for plinking and having fun when wiedners gets them in stock. If I like to 748 I may stay with it, not sure yet have only shot 10 with it and cost is a issue to so I gotta look at it and keep my options open. |
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I thought they cost the same. Anyway, it's kind of a toss up. I have only ever had one ignition problem with standard primers and ball powder and that was in a .280 Rem. which uses nearly twice the amount of powder.
I have gotten some nice accuracy with the magnums as has many other reloaders in the AR rifle but there are probably a lot more guys who get just as good loads with the regular primers. Before you load up a few thousand rounds why not try some both ways? |
| With 55 grain bullets and Win 748 I'd limit maximum charges to 26.4 grains. Some data sources list maximums as high as 27 plus grains but I believe it is too much. Pressure signs in my AR's didn't show up but the same 27 plus charge in a bolt action in hot summer temperatures showed scary pressure signs. My most accurate load in a couple AR's was at 26.4 grains using RP and LC brass with RP 7 1/2 primers. It's a good powder for .223 but not as good as H335 for 55 grain bullets. Again, I'd limit charges of 748 to 26.4-26.5 grains maximum and I believe it to be safe for any case brand or appropriate primer for AR's. I've shot a lot of 55 grain loads using 748 but have switched to H335. |
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Back-in-the-day when I worked for Hercules Inc, I ran flame temperature calculations for IMR, 748, and our Reloder propellants. From low to high were: IMR, Reloder, and 748.
Last year, I EMailed about 748 and asked why the container is marked as having a low flame temperature. After getting a couple of political say-nothing answers from the manufacturer, I finally explained to them about my long ago calculations and have they changed their formulation. With that, I got no answers. 748: Good - throws very uniform charge weights, easily found, delivers very good velocities. Bad - high flame temperature, premature throat wear, very temperature sensitive |
| Well, you should actually work up your own load for your rifle, nuff said on that. I've used a lot of 748 for years in the AR. I have used various primers, standard and magnum. I have settled on Rem 7 1/2's. I have used 25.0 grains to start and found this to be too light in all guns tested. It functioned every time but cases are very sooty and accuracy is wanting. For plinking with 55 gr FMJ or SP, I load 25.8 grains. Some of my 55 gr varmint loads are a bit hotter and should be worked up. I have a 20" RRA that really likes an even 26.0 grains with a Sierra 55gr BTHP (#1390 IIRC). Overall I like 748 quite a bit for .223. There are possibly "better" powders but 748 does a darn good job for a lot of folks and I'm one of them. |
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I have 2 different books and they both say different loads for this powder.
And if you had 10 different books they would all "say different loads". You cannot find an accurate or safe load on the internet or in your manuals, without doing some load development. That means do your research , start low and work up. It's the only way. |
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Quoted:
Back-in-the-day when I worked for Hercules Inc, I ran flame temperature calculations for IMR, 748, and our Reloder propellants. From low to high were: IMR, Reloder, and 748. Last year, I EMailed about 748 and asked why the container is marked as having a low flame temperature. After getting a couple of political say-nothing answers from the manufacturer, I finally explained to them about my long ago calculations and have they changed their formulation. With that, I got no answers. 748: Good - throws very uniform charge weights, easily found, delivers very good velocities. Bad - high flame temperature, premature throat wear, very temperature sensitive There is a difference between "calculations" and actual peak flame temperature, 748 was the standard powder used in the 7.62x51 and was the first ball powder loaded in the 5.56x45. The military prefers ball powders and the deterrent coating and chamber pressure control the peak flame temperature. At 43,000 cup the peak flame temperature is just approaching the melting point of modern barrel steels and the 5.56 operates at approximately 52,000 cup and bore erosion is a given. Double base ball powder peak flame temperature is slightly cooler than single base powders. 
"Flame temperature is very close to the same for all smokeless powders and runs about 3300 degrees F. Ball type powders tend to be from 3200 to 3300 degrees F and extruded powders tend to run 3300 to 3400 degrees F but there is wide variation." Internal Ballistics http://www.frfrogspad.com/intballi.htm |
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Quoted:
Back-in-the-day when I worked for Hercules Inc, I ran flame temperature calculations for IMR, 748, and our Reloder propellants. From low to high were: IMR, Reloder, and 748. Last year, I EMailed about 748 and asked why the container is marked as having a low flame temperature. After getting a couple of political say-nothing answers from the manufacturer, I finally explained to them about my long ago calculations and have they changed their formulation. With that, I got no answers. 748: Good - throws very uniform charge weights, easily found, delivers very good velocities. Bad - high flame temperature, premature throat wear, very temperature sensitive I agree with the very temperature sensitive part for sure. I had a friend give be 8# of 748 for loading prairie dog loads. I worked up a load in the spring that shot great out of a RRA varmint barrel with no pressure signs. When I got to South Dakots in late June, I was flattening primers. I have found that much more than 25 grains with 55 V-Max's will flatten primers in hot weather in my rifles. |
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Quoted:
Back-in-the-day when I worked for Hercules Inc, I ran flame temperature calculations for IMR, 748, and our Reloder propellants. From low to high were: IMR, Reloder, and 748. Last year, I EMailed about 748 and asked why the container is marked as having a low flame temperature. After getting a couple of political say-nothing answers from the manufacturer, I finally explained to them about my long ago calculations and have they changed their formulation. With that, I got no answers. 748: Good - throws very uniform charge weights, easily found, delivers very good velocities. Bad - high flame temperature, premature throat wear, very temperature sensitive I would very much believe this. This is one of 2 powders (W748 and BLC2) that I see over pressue in .223 55 grain FMJ loads worked up in fall or spring and used in the summer. Also if your Temps swing your accuracy changes noticeably. I went from a worked up Spring load of 1" with 748 with hornady 55 FMJ's and went to overpressure signs, really flat primers, in summer and groups opened up to 3-4" inches. Really brought home the warnings in the books to real life. |
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Quoted:
Quoted:
Back-in-the-day when I worked for Hercules Inc, I ran flame temperature calculations for IMR, 748, and our Reloder propellants. From low to high were: IMR, Reloder, and 748. Last year, I EMailed about 748 and asked why the container is marked as having a low flame temperature. After getting a couple of political say-nothing answers from the manufacturer, I finally explained to them about my long ago calculations and have they changed their formulation. With that, I got no answers. 748: Good - throws very uniform charge weights, easily found, delivers very good velocities. Bad - high flame temperature, premature throat wear, very temperature sensitive There is a difference between "calculations" and actual peak flame temperature, 748 was the standard powder used in the 7.62x51 and was the first ball powder loaded in the 5.56x45. The military prefers ball powders and the deterrent coating and chamber pressure control the peak flame temperature. At 43,000 cup the peak flame temperature is just approaching the melting point of modern barrel steels and the 5.56 operates at approximately 52,000 cup and bore erosion is a given. Double base ball powder peak flame temperature is slightly cooler than single base powders.
"Flame temperature is very close to the same for all smokeless powders and runs about 3300 degrees F. Ball type powders tend to be from 3200 to 3300 degrees F and extruded powders tend to run 3300 to 3400 degrees F but there is wide variation." Internal Ballistics http://www.frfrogspad.com/intballi.htm You have quite a bit of urban legend in your information, including some that I've never seen before. Flame temperature is calculated because with a burn action time of 2 thousandths of a second, no thermometer could respond and measure the max temperature. The first 7.62X51 propellant was IMR (single base). The flame temp not only has to be above the melting point of steel to have an effect, it also has to have a heat dwell time to start to melt the steel. 2 milliseconds doesn't do it. Double base propellant (nitrocellulose AND nitroglycerin) is hotter than single base (nitrocellulose). NG is hotter and has more power per unit weight. The shape of the granulation (stick/flake/ball/single perforation extruded/multi perforation extruded) will affect the burn rate but NOT its flame temperature. That is strictly controlled by its chemistry, not its geometry. I've done this for a few years (Hercules Inc, Picatinny Arsenal, Redstone Arsenal, and a short tour at the NJ State Police Ballistics Lab). |
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hello;
note input by armyordguy, the bad about ww748. worked up a super accurate 308win load, using 125 grain bullet and ww748. load was near max per my manual using large rifle primers. outside temps were in the 50's. shoot this super accurate loads again but outside temp was in the high 80s. had to beat the action open. no edge what so ever on primer and case. flat primer was an under statement. rifle is a savage 16flss. strongly suggest you work up loads in warm weather first. rp |
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