I finally has a decent day to shoot this new bullet.  It took some cleaning, several hundred bullets and finally a good candle 'smoke' to get the bullets to fill out completely in the 4 cavity aluminum version that I received.  I have to cast using the rearmost 3 cavities only if I want to cut the sprue without whacking it with a mallet.  Besides, it gets heavy when filling all 4.  I skipped out of work late morning and had favorable conditions most of the time.  I did fight some twitchy head/tail winds which is not unusual at my home range. I believe the slight vertical dispersion of this group was due to wind. I was trying different charges about .5 gr apart and finally settled on this load.

Winchester Low Wall 25-20 Win 10 twist McGowan barrel. 
NOE 260-117
20-1 - home brew lube
7.6 gr IMR 4227

6 shots measuring approx 1.25 inches at 200 yds.

Jack

Nice shooting Jack.

I was breach seating with a plugged case.  I am going to try some fixed ammo just for fun.  It would be more convenient for the offhand relays. 

Jack

bpjack,
any chance you can provide a diagram of your chamber, particularly any freebore and leade? and groove and bore dia of barrel.
Tx
beltfed/arnie

Thanks,bpjack'
I am just getting started with my recently acquired Hoch
25-20, 11 twist.  Bought the NOE 260-117 to try. 
I have shot a few rounds so far with  8 and 8.5 gr IMR4227.
decent at 100yds, but not nearly your result.
I have trouble with the offhand stock wanting to slide back and down, to cause elevation trouble. So now contemplating
somehow attaching something to the hooked buttplate to end up with a bottom support on the rear bag that is nearly parallel to the barrel.
Will try your 7.8 gr, also.
reason for asking about your leade, is that I use a hard bullet and the 260-117, when seating tight in the leade, still is in the mouth of the case by about 0.150". So not really breech seating, YET.
Thanks again
beltfed/arnie