Sorry. I forgot to mention that I shoot 7.62x39 which has slightly more case capacity. Also, the 220gr bullets are the round nose flat base design which has a shorter OAL.

I put together a mock up round to get a feel for OAL and case capacity, then followed up with a QL mock up as well. Here are the details:

1.575" COL (nets a seating depth of 7.63mm)

I had to get ahold of a Redding seating stem #6 to reach this short of an OAL. Their customer service (Redding) has once again proven to be top notch for both customer service as well as technical expertise.

19gn of H110 shows 99.5% case capacity and a potential velocity of just under 2400 fps. I'm not sure if this round will hold up to these velocities in a fast twist barrel but someone did post earlier of speeds ~1900 fps.

Also showing a powder burnt % of 91% indicating that this should cycle an AR but feeding will mostly likely not be reliable given the HP design and short OAL.

Trailboss
 

I tried TB in my AR15 762x39 /220gr RN, 458 Socom / 500gr RN, 300W / 220RN, and 308 Win / 180RN & 220RN. It is the powder I use in the 308 Win and found better powders for the other cal. for cycling and the 458 Socom needs a short barrel to reduce bullet drag. I use mostly RN for hog hunting.

Don't flip them backward just Dremal and Drill. 210 grain HP from 220 grain OTM the ones under it are 216 grains from 220 OTM Remington 300 Blackouts. Very easy to do.
http://i10.photobucket.com/albums/a1...hpblackout.jpg

I shoot mostly 220gr pro hunters and 240 Outlaw in a 7in bbl ar. I use VVN110 and 1680 and they work well but not that quiet. Would trailboss be quieter AND cycle the action?

Trailboss will not work for heavy bullets. I only used it for the 90 grain bullets because they don't take up much case capacity like the longer bullets do. You do not want to compress Trailboss. I wouldn't try it for anything heavier than 125 grain subsonic. I've only tested it with the 90 XTP's, so go forth at your own risk.

Ok, thanks for the info

Snipercatcher, I flattened a foked horn Blacktail buck with the 90 gr XTP at about 35 yds the Bullet worked great. DRT kill one round in the bioler room. the load was 9.8 gr Trailboss and a cci 300 ....from my Boltgun it is way quite through my can its sounds like an airgun...:smile:

FYI, since you said you didn't have a chrony 4.8 gr trailboss, 90 gr xtp run 945 – 1040 fps out of my 16 inch bolt gun at 90 degrees & 900 ft above sea level.