223 IMR 4198 Need data help

[raddiver]

So here's the deal.
I was working up a ladder for my AR. 55g with 4198.
According to Hornady the max listed is 20.00. If memory is serving me correctly, lyman states 21.7 as the max. I am unable to get to IMR's site to get data right now.
I cant get it to cycle reliably at anything under 20.5.

Can someone give me some max's from some other sources?
Newest Hornady, speer, etc.

Thanks
-Rad

 

[nix4me]

Max from the Lee book is 20.4

 

[Jesse Heywood]

Hodgdon 2002 manual shows H4198, 55 gr SPR SP 21.0 gr, 3150 fps, 47,600 cup. IMR 2003 manual does not list I4198 for a 55 gr.

 

[kerreckt]

Handloader #85 lists a 55gr Speer FMJ using 23gr IMR4198 going 3393fps.

 

[243winxb]

Maximums -20.4-21.8-22.0 -- 55 gr Bullets

21.5 is my person maximum with old Dupont IMR 4198. This powder may have change some, currently made in Australia. 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 IMR4198, 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, IMR4198 would work better.

 

[raddiver]

I think ill stick with your max of 21.5.
You explanation on burn rate has me pondering if i should switch to I4895(only other powder i have in stock atm) or varget(i dont have).
On the burn rate chart listed on IMR's site
IMR 4198 is #71
IMR 4895 is #89
Varget is #99

Thats kind of a bummer though because i just bought 2 lbs of I4198. Works awesome in my Savage bolt action.

 

[KansasSasquatch]

IMR4198 is listed by Hodgdon as one spot faster than H4198. Knowin that and the fact that I couldn't get H4198 to cycle an AR with any listed loads tells me that its probably not a good choice for any auto loaders. It was accurate enough with max loads but it would only cycle the action maybe 1 out of every 5 rounds. Save it for a small caliber bolt gun or .300blk., or maybe an AR pistol. Hodgdon alone has at least 7 other powders that will work much better for .223. It may be tough to find one of those better powders right now but it'll be easier than trying to make 4198 work.

 

[243winxb]

I have used IMR 4198 (Dupont) in M16, AR180 & Mini 14 autos with no problems. There are so many different brands out now, that an adjustable gas block should be standard on the AR 15 firearms.

 

[rcmodel]

IMO:

4198 of either Hodgdon or IMR persuasion was one of the best powders ever invented for the .222 Remington in a bolt gun.

But also IMO, it is too fast to provide proper gas port pressure in an AR-15 in .223 unless you load hotter then I like to do it.

It saves a little money in that it doesn't take as much powder as the ones I use.
But that's the last thing I worry about when I want a load that Feeds, Fires, & Functions Freely in an AR-15.

rc

 

[ArchAngelCD]

With a 55gr bullet using IMR4198 the following sources list this data as a max charge weight:
Speer #9 doesn't list 4198 with any bullet over 50gr in the .223.
Speer #10 lists 22.0gr max.
Speer #12 lists H4198, not IMR4198. The H4198 data is 21.0gr max.
Hornady #9 lists 20.6gr max.
Lyman #49 lists 21.7gr max.
Hodgdon lists 20.4gr max.

It seems the current Lyman data supports the 21.5gr charge weight you want to use. The Speer #10 data is probably a little outdated.

 

[raddiver]

So on the advice of carbine85 from a different thread i worked up a load with IMR 4895.

Much better. Each set in the ladder cycled perfectly.
So for my gun somewhere between 24 and 24.5 is the sweet spot.
Now i just need to work up another ladder in that range.

Ill admit this threw me though. This is on the lighter end of the scale, most of my handguns and the bolt action like it hotter. This AR seems to like it cooler.

 

[243winxb]

You have to go with what works/cycles. Glad you found a fix.