AR and H4198

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Anybody else using this powder for their AR? It's the most accurate of all of my powders but it wont cycle. Dont know why, i'm using up to and uncluding 22.5 grains. The cases that do eject are not going very far from me. Talking about accutate though, it is! 26.0 grains of H335, 27 or so of BLC-2 and everything else ejects fine. Any suggestions? More powder?
 
Don't know what bullet weight you are using but H4198 is to fast of burning powder for a gas operated ar-15. Its pressure curve is to fast. Hence it is not cycling correctly.
 
^ yes, could be not enough dwell time, what sized gas system is your AR? there is only so much time after the bullet passes the gas block and before it is out the muzzle for the gas to operate the action
 
^ yes, could be not enough dwell time, what sized gas system is your AR? there is only so much time after the bullet passes the gas block and before it is out the muzzle for the gas to operate the action
I have no idea. Its whatever comes on a Bushmaster. I dont know much about these things.
 
Every time i had to cycle it manualy, the bullet that was suppose to go in next had a discoloration to it. Just the bullet not the case. Like i said, all other powders work fine and none of them are max. By looking at Hodgdons site, it looks like it should be throwing the brass out good.
 
All of the loads except for the 4198 wotk great.
I will defer to the more experienced guys then.

I wonder why Sierra would include this load in the #5 book (for 55gr bullets) if it wouldn't cycle the rifle.

Just rechecked the book....Sierra lists a load for IMR4198 not H4198.

That could be the problem.
 
20"A2? then it is rifle length gas system,

did you start off at 20.5 grains or just go straight to 22.5? lots of times max load in a bolt gun is too much for a gas gun
 
I started at 21.5 and none would work. Went to 22.5 and a few worked but didnt throw the brass very good at all.

Hodgdon lists the H4198 and it has it on the can too. I can see no reason for it not working.
 
I'm not a big fan of H4198, but I use IMR4198 with great success. My AR eats them all day long.


Bass
But have you actually used H4198 in your AR? If so, would it eject? It sure looks to me like the loads should be plenty hot enough. I'd sure like to get this figured out since it was quite accurate. I'll call Hodgdons today and get their view.
 
My Guess is 1. Measure the neck of a fired case. Has the neck expanded to its full normal diameter? If the neck has Not expanded fully, you have a low pressure condition. This is caused by light bullet pull because of bullet design? The full diameter bearing surface of the bullet is to short or the bullet is seated to long?? 2. The gas port , the hole drilled into the barrel, might not be at the best location or be the correct diameter for the lite bullets. I know on M16A1's the carbine compared to the rifle have much different gas port size and location. IMR 4198 runs fine in my 3 different auto with Sierra 50 or 55gr bullets. I do NOT like any of H's copies of the IMR's. There was another poster on here using IMR 4198, same problem, very strange. Just a guess.
 
Thanks 243. All testing yesterday was with 40g bullets. All seated to about 2.250. Like i said, all other powders functioned fine. This was the most accurate so thats why it bothers me as to why it wont work. I'll measure a fired case today.
 
AR. 20'' Bushy national match upper 1-9 twist

The gas port pressure curve is a critical part of internal ballistics for cartridges used in gas operated firearms. Gas operated weapons are generally tailored to a narrow range of powder burning rates and characteristics. If the port pressure is too low the weapon will fail to function and if to high the weapon may function too forcefully or rapidly causing extraction or cycling problems. When using the fast H4198, the pressure peaks very fast and is done producing pressure sooner than your slow powders. With such a wide range of bullet weights from 40gr to 80gr, matching the gas port location and size is critical. If the gas port was moved closer to the chamber and drilled larger, H4198 would work. http://www.6mmbr.com/223Rem.html
 
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22.5 is MAX according to Hodgdon.

I agree.

H or IMR 4198 is too fast burning to provide the correct gas port pressure with light bullets in some guns.

4198 was at it's best in the smaller capacity .222 Rem in bolt-action rifles.

It is not an ideal .223 powder with any bullet weight.

rc
 
Yea you guys are probably right. I was sure hoping for a different answer since this stuff is so accurate. I'm not having the best of luck with h335. I have a good variety so i guess i'll move on.:mad:
 
I use the same load in my super 14" Contender. I fully agree on the accuracy! It will do 3/8" at 100 yds in my TC. Good luck with your AR. Seems as if it should work.
 
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