I bought this powder before knowing anything about powders based on the recommendation from a guy at Bass Pro.  I've since learned it's a very fast powder and may not work well with 62gr. bullets and trying to achieve nato ammo power, my rifle (20" Colt 1:7) needs very high 223 or 556 power levels to cycle.  Can it be achieved with this powder and what would be considered the load limit?  I'm not totally opposed to buying some 55gr bullets if I have to, but rather use my 62gr if I can.

It's not "power levels" or chamber pressure that cycles the action of an AR or other Semi-Autos.  It's port pressure.

Port pressure is the amount of gas that is produced by the burning of the powder that enters the Gas Port.

Slower powders produce more "gas" and will have higher port pressure.

Faster powders like IMR 4198 produce less gas resulting in less port pressure.  To little port pressure and the action suffers.

Port pressure is adjusted by changing the powder itself.  Chamber pressure is adjusted by increasing or decreasing the powder charge.  They are not the same and trying to increase Port pressure by exceeding recommended chamber pressure is not a good idea.

If your action will not cycle with standard 223 loads, then switch to a slower powder or have the rifle itself check out.

Steve4102 nailed it.

I would suggest you try lighter bullets rather then struggle with the IMR 4198 and 62gr bullets.

Which can be frustrating enough for a veteran reloader.

I suggest you buy some VMax ( or ZMax ) 55gr or 50gr and give those a try, I have found most ballistic tips to be very tolerant of reloading quirks... ( the IMR 4198 )

http://www.cabelas.com/product/Shooting/Reloading/Reloading-Bullets%7C/pc/104792580/c/104761080/sc/112555080/Hornadyreg-Z-MAX-Zombie-Rifle-Bullets/1330008.uts?destination=%2Fcatalog%2Fbrowse%2Freloading-bullets%2F_%2FN-1109589%2F&WT.mc_id=ir92929&WT.tsrc=AFF&rid=10#productChart

Forget this - with IMR4198. But Hodgdon load data goes up to the 68gr Sierra match bullet.  Hodgdon link  Accuracy has been very good for  me in many firearms, including an M16A1 carbine. Do try IMR4198 as there are many different types/brands of ARs.   Another good read. Sierra AR data link  Colt AR-15A2 HBAR used.

Port pressure is what I was concerned about, I didn't state it properly at all, and what you state is what I was thinking might happen with the fast powder--I'm a newbie still on the learn.

As far as I can tell, and I had another guy check it over, the rifle is in good condition with no mods other than a spike's lower.

It shoots XM193 flawlessly, anything less and it short strokes.

I made some test loads with Tac that I bought after I'd bought the 4198 and at 25gr. (first time loading and the hottest load I made that day) it was just starting to be reliable.

I'm going to return the 4198 if they'll let me (still sealed) if not I'll offer it to one of my friends that has a more suited use for it and make a couple testers for myself just to see what it does.


Thanks to everyone for their input.

I tried some IMR4198 in my AR but did not like it. I loaded 10 rounds with a each from min to max with a .5gr spread. The min rounds would not cycle the bolt at all. Only until I got up to about mid load did the action fully cycle.

Vince

Is yours picky about ammo?  At what load did it cycle well?

Ive used IMR 4198 for a couple hundred rounds over Hornady 55gr Vmax's and 55gr Softpoints.  Got the powder free from my Uncle, so I found a load that worked, and shot it up.  If memory serves it was like 21.7gr.  Please verify this before you try it, as Im think this is the max load in the Lyman manual.

Do I recommend it?  Nope.  My rifle will fire just about anything, including these, but it was such a powder puff load that is just barely functioned the rifle.  That an earlier poster said about port pressure is very true.  You rifle may be a nightmare to get these running.

Not to mention, unless your weighing charges, this stuff doesnt meter worth a crap.

Find a different powder.

My AR has a full auto WMD BCG, a Dave Tubbs CS flat wire flat wire buffer spring with a standard AR buffer. I have run H335, LT32, TAC and IMR4895 with zero problems. Bullets from 52gr HPBT Hornady Match, 55gr Hornady V-Max, and 75gr BTHP Match.

Vince

I use IMR-4198 with 50gr V-Max in the rifle that is my avatar photo. I've had zero problems. Try it.

Motor1