Powder for heavy(200+gr) supers in AR

[MinimalistNutter]

So i am working up some scooper loads with the Lee 230 5r but the first powder I tried, Lil Gun wound up overgassing my pistol at any supersonic velocity. That was kind of shocking to me because how well it cycles 168gr supers. Unique is next on my list to try but I haven't heard anyone saying it has enough giddy up to cycle a gas gun(unlike lil gun)

Anybody found powders that work well in gas guns with heavy supers? I know most blackout shooters don't like heavy supers in general but I am sure someone else has played with them?

I am working with a 10.5" standard buffer(IIRC), bcg. Pistol gas system with an .091 port roughly, I don't have pin gauges just an approx-meter and drill bit shanks... I am sure a heavier buffer and/or adjustable gas block could bandaid this issue but a load that works is the better solution in my mind.

Thanks for any help you can offer.

[MinimalistNutter]

Oops I stand corrected, 9.1gr did cycle and lock back in the 3 round test with acceptable grouping(tested at 12 yards so I'd hope so...) but because that's not even a lukewarm load being just this side of the supersonic threshold so my question still remains.
9.4gr and up were overgassed and 8.8 and under were undergassed. That's seems like a pretty small functioning window compared to what I was seeing with lighter supers.

Being on a very limited income throwing lead down range to work up loads is not as fun as when I had the icome of a full time job LOL.

[Freedom1973]

Nutter,
I would refer you to the sticky posts at the top of this section. "Powders for the 300BLK" and the "PET Load" section. I would also highly recommend you talk with the guys in the cast bullet section. Please take care as what works in one gun might not work for another. Just make sure to describe your rifle completely and your problem load. Good luck and welcome to the group.
Freedom

[dellet]

Unique is a no go.

Heavy supers and cast can be a challenge with the faster powders. It has do do with lead hardness. I have been able to load similar weight jacketed bullets to higher velocities than some cast, because the cast show pressure signs earlier. Most commercial cast is just not hard enough to withstand the pressure.

Shooters World Blackout, 1680 and CFE BLK are probably the best choices.

This is one combination that I would expect CFE BLK to be the best choice. It will be the lowest pressure load of the three powders. The powder likes compression, but watch out for damaging the bullet when seating.

I have not used the exact bullet in question so I can not give you a COL, but load as long as the chamber and magazine will allow. Load to mag length or .020" off the lands, whichever is shorter. Then find 100% fill of CFE at that length. Use that as your max load. Do the same for 15 Grains, use that or 2 grains off max as your starting load, change length about every .3-.5 grains as you work up.

I got to just over 15 grains and 1450 fps with a 265 grain cast with that method using CFE. I ran out of powder capacity before pressure signs with better accuracy than 1680. Again peak pressure matching bullet hardness better.

With 1680 or Shooters World start around 14 grains.

As for your buffer, pistol gas really should have an H2 buffer and a Full auto carrier.

[MinimalistNutter]

Awesome, thanks guys. Yeah it's a C buffer and PSA F/A BCG. It gets nice 4:00 ejection with factory supers and other super handloads. Bolt speed didn't seem excessive but I also have no way to measure it. I'll have to look into an H or H2 buffer.

So CFE BLK goes on the shopping list and hopefully soon I will have a good functioning load. A bulky or compressed charge is a big plus for my intentions with this load(to load without a scale once developed) making it foolproof or fool-resistant

[dellet]

Awesome, thanks guys. Yeah it's a C buffer and PSA F/A BCG. It gets nice 4:00 ejection with factory supers and other super handloads. Bolt speed didn't seem excessive but I also have no way to measure it. I'll have to look into an H or H2 buffer.

So CFE BLK goes on the shopping list and hopefully soon I will have a good functioning load. A bulky or compressed charge is a big plus for my intentions with this load(to load without a scale once developed) making it foolproof or fool-resistant not to mention foolhardy.

Fixed that for you.

If you were loading Lilgun without a scale, that explains your problem.

[MinimalistNutter]

Make no mistake I am using a scale in the development, the goal however is a volume based load by a dipper. I have learned over the years scales are a major liabilty once you step outside the shelter of stick built reloading room. Should be no more foolhardy than to use a powder measure except there's no adjustment that can creep out of spec on a dipper.

[dellet]

Make no mistake I am using a scale in the development, the goal however is a volume based load by a dipper. I have learned over the years scales are a major liabilty once you step outside the shelter of stick built reloading room. Should be no more foolhardy than to use a powder measure except there's no adjustment that can creep out of spec on a dipper.

Something like CFE or 1680, you can get away with it. The magnum powders not so much.

One thing has helped me keep load development to minimum time and materials, is to use percentages for ladder loads. The small case capacity really drove this point home. Example your 8.8-9.1 jump was 3.5%. I’ve gone from just starting to flatten a primer to blowing a pocket in less than .5 grain at the top end with heavy bullets and magnum powders. 2% is a very noticeable change.

[MinimalistNutter]

Thanks again for the help dellet, After doing a few function test loads with CFE BLK it looks like I am stuck with lighter weight supers until I do some modifications to my configuration to slow down the bolt speed. Might as well load up some subs while I am here so I have something other than carry ammo until I can get funds or barter for such changes.

I will definitely revisit this in the future... Back to lurking and learning.

[dellet]

Thanks again for the help dellet, After doing a few function test loads with CFE BLK it looks like I am stuck with lighter weight supers until I do some modifications to my configuration to slow down the bolt speed. Might as well load up some subs while I am here so I have something other than carry ammo until I can get funds or barter for such changes.

I will definitely revisit this in the future... Back to lurking and learning.

You said you have a C buffer an H2, 4.6 oz. would be correct by spec. There are ways to cheaply add weight to a buffer. I know of people who have replaced the weights with shot.

Is the bolt moving too fast to feed, or is there another problem?

I’m a bit surprised at being over gassed with the CFE, there may be something else going on.