IMR 4198 for .223 / 5.56 questions.

If nothing else, this has been educational for me. You guys and gals have thrown a lot of information my way. Thank you again

I got to the bench tonight and loaded some test rounds with charges of 21grains, 21.2grains, and 21.3grains.

FrankenMauser, I am using IMR4198.

I probably will switch powders in the end, but my curiosity has been spiked. With all the different load data out there, how is a person supposed to know what the actual "max load" is without doing a load work up personally?
 
There is no single max load, since every action, barrel, case, primer, bullet, and lot of powder is different.

That's why the first rule in reloading is: "Start low and work up."


If you turn to an alternative powder after the 4198...
H335, as mentioned, is a good choice.
Ramshot TAC is also a good performer.
I use a lot of Ramshot Xterminator.
Benchmark is a popular option.
Much of my family absolutely loves Accurate 2230.
Some of the most consistent, "smoothest", cleanest, and best loads I've ever run in .223/5.56 with 50-55 gr bullets used IMR 3031.

A couple things I advise staying away from:
--Reloder 10X. For myself and a few other shooters that have tried it, it was a filthy, nasty, dirty powder. Ran great. Fairly consistent. But filthy, filthy, filthy.
--CFE-223. The burn rate is slow for light bullets, and that combined with the 'de-coppering' agent (tin dioxide) leaves a sooty grey residue on everything. Some people still like it, but I think Hodgdon should have named it CFE-308, instead.
 
Its still a port pressure problem. Not normal. I have loaded 18.5 grs with a 55 gr bullet , still cycled the M16 action.
 
243, although I agree it's a port pressure issue .

When the OP says
My AR is a 16" Bushmaster M4 chambered in 5.56. It cycles perfectly with factory ammo, so I do not feel it is anything with the gun. I take factory rounds out each time to verify it cycles correctly.
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Tells me even if he has a small gas port , it's not to small . That and the fact I've heard many times of guys having cycling issues with 4198 . Says to me 4198 does not have the optimum pressure curve for this application . It's the reason I've never even tried it is any AR's I load for . These include all three gas systems at varying barrel lengths .

I'm sure if he changed to a lighter buffer or buffer spring . Maybe a low mass BCG he could get 4198 to cycle just fine at even less then max charges . How ever as I pointed out earlier . I personally would not manipulate things so much to a point the firearm is custom just to shoot one powder that's really not all that great compared to many others out there .

Put it away for SHTF and then load it in the cartridges you sell or trade for food and water ;)
 
"My barrel is a 1:8 twist though so I switched to a heavier bullet to tighten the groups."
I question that logic based on the results I get with multiple 1-8 twist barrels. Some of the most accurate ammo we've used the last 2-3 years in 1-7,8,9 barrels has been 50 grain bullets.
 
243winxb said:
Sierra lists 21.8 gr maximum of IMR4198, for there 55 gr bullets, fired in a Colt 20" barrel Ar15. http://www.6mmbr.com/223Rem.html
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I checked on Sierra's web site that you linked, and it definitely says for the AR, a 55gr fmjbt has a max load of 21.8 grains. Thank you for the info.

The IMR4198 loads of 21.3 grains cycled in my AR 8 out of 10 shots. I loaded up ten more rounds tonight with 21.5 grains. I am pretty confident they will do fine. I will put an update later how they turn out.

On a side note, I went to Cabela's today looking for the H335. I found someone working there to ask if they had any in the back, because there was none on the shelf. He spent about five or ten minutes and came back. Their system said they have one pound left, but he could not find it. I guess I will check a local guy's business on my way to test out the new loads.
 
OP asked: said:
Is there a powder I should look into specifically for running in the
AR platform?
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If there are any "standard" powders for mid-50 grain
AR-15 loads it's likely Win748 and/or Hodgdon BL-C(2)
(Use Mag primers)
 
Isn't the 55gr XM193 Federal makes using H-335 or the bulk equivalent ?? Would that not be the "standard" for an AR mid 55gr bullet ???

The two most recommended powders for 55gr bullets in the AR platform I've seen are Ramshot tac and H-335 . Many other are recommended including BLC-2 but by far the most I've seen are TAC and H-335 . The main reason I use H-335 is because it meters so well . It's the powder I plink with and I throw all those charges .
 
I have officially retired the IMR4198. I will save it to use if I ever get a .223 bolt action or something different. I tried the 21.5 grain loads and they cycled worse than the 21.3 grains.

I went to the locally owned business today and he had the H335 in stock. I picked up a pound to try out.
 
The two most recommended powders for 55gr bullets in the AR platform I've seen are Ramshot tac and H-335 . Many other are recommended including BLC-2 but by far the most I've seen are TAC and H-335 . The main reason I use H-335 is because it meters so well . It's the powder I plink with and I throw all those charges
Click to expand...

Benchmark is my favorite powder for 55 gr and below in 556 and 150 and below 7.62 x51. It is a very small grain stick powder. It meters like ball powder, burns cleaner than anything I have ever tried, and is an extreme powder so temperature insensitive. The extreme spreads are usually below 25fps thrown.

The drawbacks are it is expensive compared to tac or h335, it won't get the best velocities, and it isn't well suited for heavier bullets
 
Reloading101: This is my best 223/.556 load. 20grs of IMR4198 and a 52gr BTHP Match bullet from Speer, Hornady, or Sierra. They all three work very well for me. I have been using this load since 1975 in all of my Son and my own 223/556 Bolt Guns, and all of our AR`s. We have shot literally 1000`s of rounds loaded with this load. And it functions well in all of our AR`s. Accuracy is superb
in every 223/556 we own or have tried it in. But IMR4198 does not drop from our Powder Drop, as well as we would like. 50gr Hornady V-MAX`s work well, for us too with 20grs of IMR4198.
ken
 
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