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Posted: 2/28/2011 5:04:08 PM EDT
| I used to always use 4198 in my mini 14 and never had a problem, but I read some where that it doesn't make enough pressure to cycle the action in an AR, any body experience this? I made up 10 rounds with 2 different bullet types (same weight) to see but wont' get to the range for a while with it. |
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It's not a great powder for .223. It burns very quickly, so you get your peak pressure quickly, and then it falls to a relatively low pressure by the time the bullet makes it to the muzzle. Which means same peak pressure rounds with this powder will be slower than other more popular powders. In a carbine or Mini-14, the gas port is closer to the chamber, so sufficient pressure to cycle is less of an issue.
That said, I've never had a problem with it in my 20" rifle. Maybe because I load a fairly high dose with it, so that I'll have a little bit more pressure down by the gas port. I've stopped using it altogether though, there are plenty of much better powders out there. |
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I can't speak for AR's but I've used IMR 4198 almost exclusively in all my small capacity and low pressure rifle rounds for the past 20 some years and 10's of thousands of rounds of .222 Rem, .223 Rem. 7.62x39, and 30/30 Win. with both jacketed and cast bullets. The results I've gotten are very low standard of deviation, superb accuracy and very high velocity, even in short barreled "14" contender pistols".
If I could pick only one powder for all my small capacity cartridges it would definitely be IMR 4198. 
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Quoted:
I can't speak for AR's but I've used IMR 4198 almost exclusively in all my small capacity and low pressure rifle rounds for the past 20 some years and 10's of thousands of rounds of .222 Rem, .223 Rem. 7.62x39, and 30/30 Win. with both jacketed and cast bullets. The results I've gotten are very low standard of deviation, superb accuracy and very high velocity, even in short barreled "14" contender pistols". If I could pick only one powder for all my small capacity cartridges it would definitely be IMR 4198. Interestingly, I too got good accuracy with it. One thing that really was a thought change for me though was the importance of the shape of the powder to accuracy - or at least what it was back in the days of old. IIRC 4198 is an unusually long/skinny powder by todays standards. It can be difficult to meter in a powder drop. But I just read an interesting chapter in great book that discusses such matters in detail, and noted that long, skinny powders tend to have more uniform primer flame, and thus produce more uniform accuracy. Even when actual charges vary from round to round. They used such a powder one year for the National Matches in Camp Parry, and noted that charge weights were some of the worst consistency ever, yet the accuracy was so good that many records were broken that year. They caught a lot of flack for it though, because someone kept bitching at them about how crappy the ammo was, due to the inconsistent charge weight - never mind that scores were some of the best ever. It makes me wonder what an excellent powder like Varget would do if they made it long and skinny rather than short and fat. I've mentioned it several times recently (probably annoying Aero by now, but the book is Hatcher's Notebook, and is one of the most enjoyable reads I've had in some time. It's a technical notebook that is basically the biography of one of the chief WW1/WW2 ordinance officers in charge of such things. |
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H4198 and IMR-4198 are the fastest powder you should try in .223. I would never consider using it for any bullet over 55 grains. I think it shines with 50, 52 and 53 grain bullets. Very accurate and economical because of the light charge weights.
Actual port pressure on a 20" barrel with a rifle gas system and a full power charge of H4198 (21.0) or IMR-4198 (20.0) is close to ideal reportedly 15,000 psi. That's the design parameter for the rifle. It will operate fine provided it's getting that much pressure. I use 20.6 grains of the H variety with 52 grain SMK's and it's a maximum load in my rifles. Things happen very quickly in the pressure arena when using this powder. The books say I should be able to load 21.5 grains w/52 grain SMK's and achieve 3200 fps. I'm getting that speed (3177 fps) with nearly a whole grain less powder. Try to locate a chronograph and make sure you take your barrel length into consideration when making comparisons. I would not push the envelope at all with these powders. |
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I ran a whole pound of it through my stag. 55g fmj Rem bullets. various grains, but all under max. I didnt have any issues cycling my gun. But on the higher end, I was starting to get pressure signs on the primers. accuracy was very good, but metering was a bear. especially for a first timer.
my next batch i am using h335. |
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Quoted:
Quoted:
I can't speak for AR's but I've used IMR 4198 almost exclusively in all my small capacity and low pressure rifle rounds for the past 20 some years and 10's of thousands of rounds of .222 Rem, .223 Rem. 7.62x39, and 30/30 Win. with both jacketed and cast bullets. The results I've gotten are very low standard of deviation, superb accuracy and very high velocity, even in short barreled "14" contender pistols". If I could pick only one powder for all my small capacity cartridges it would definitely be IMR 4198. Interestingly, I too got good accuracy with it. One thing that really was a thought change for me though was the importance of the shape of the powder to accuracy - or at least what it was back in the days of old. IIRC 4198 is an unusually long/skinny powder by todays standards. It can be difficult to meter in a powder drop. But I just read an interesting chapter in great book that discusses such matters in detail, and noted that long, skinny powders tend to have more uniform primer flame, and thus produce more uniform accuracy. Even when actual charges vary from round to round. They used such a powder one year for the National Matches in Camp Parry, and noted that charge weights were some of the worst consistency ever, yet the accuracy was so good that many records were broken that year. They caught a lot of flack for it though, because someone kept bitching at them about how crappy the ammo was, due to the inconsistent charge weight - never mind that scores were some of the best ever. It makes me wonder what an excellent powder like Varget would do if they made it long and skinny rather than short and fat. I've mentioned it several times recently (probably annoying Aero by now, but the book is Hatcher's Notebook, and is one of the most enjoyable reads I've had in some time. It's a technical notebook that is basically the biography of one of the chief WW1/WW2 ordinance officers in charge of such things. 
You are correct about Hatchers Notebook being a great read. Got my copy at a recent funshow. That was 1932 or 33 with the match ammo "problem" IIRC. I have only used IMR-4198 in 7.62x39 with cast bullet loads. They shot fine. |
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H4198 supposedly does well in 6.8 SPC with the lighter 85 & 90 grain bullets. It's not as good as Reloader 7
for the light bullets, but does well, supposedly. I have a pound of H4198 (should be very close to IMR-4198) and a couple boxes of Speer 90 TNT's to load up for my 6.8. -ZA |
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